Pysimplegui python руководство на русском

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PySimpleGUI User’s Manual

Python GUI For Humans — Transforms tkinter, Qt, Remi, WxPython into portable people-friendly Pythonic interfaces

The Call Reference Section Moved to here

This manual is crammed full of answers so start your search for answers here. Read/Search this prior to opening an Issue on GitHub. Press Control F and type.

Jump-Start

Install

pip install pysimplegui
or
pip3 install pysimplegui

This Code

import PySimpleGUI as sg

sg.theme('DarkAmber')	# Add a touch of color
# All the stuff inside your window.
layout = [  [sg.Text('Some text on Row 1')],
            [sg.Text('Enter something on Row 2'), sg.InputText()],
            [sg.Button('Ok'), sg.Button('Cancel')] ]

# Create the Window
window = sg.Window('Window Title', layout)
# Event Loop to process "events" and get the "values" of the inputs
while True:
    event, values = window.read()
    if event == sg.WIN_CLOSED or event == 'Cancel':	# if user closes window or clicks cancel
        break
    print('You entered ', values[0])

window.close()

Makes This Window

and returns the value input as well as the button clicked.

Any Questions? It’s that simple.

2021 Updates….

This documentation was originally written in 2018. So much has changed since, but the early stuff still runs just fine so there’s not been a huge rush to update.

Some sections have been updated and added so it’s not like this is a stale document.

What’s newer?

New APIs to save you time — not just for beginners

• Exec APIs (execution of subprocesses)
• User Settings APIs (management of settings in form of a dictionary)
• Threading API call — write_event_value
• True multiple windows support — read_all_windows
• System-wide global settings — theme, interpreter to use, Mac settings, …
• Advanced error handling including launching your editor to line of code with error
• More advanced layouts — still trivial,maybe more trivial, to make windows
• Go wild — have a complicated (i.e. not simple) application… no problem here supporting your App. «It’s on you». PSG solved the GUI problem, but you still have to make an application
• Docstrings — Tight integration with docstrings provides type checking and in-IDE documentation
• sg.main utilities — upgrade to the GitHub version in 1 click. Lots of good stuff built-into PySimpleGUI
• Demo Browser — Navigate the 315+ Demo Programs easily. Search, execute, edit all from one application
• Cookbook — There have been a number of updates in 2021
• This document has some sections new such as the User Settings APIs

Dynamic Windows

• Making parts of windows expand/contract with the window.
• Swap out or collapse sections
• More parms in Elements to help with justification
• New Push & VPush Elements trivialize justification

Threading

One simple call, write_event_value, solves threading issues.

Not ready for the threading module but need to run a thread? Use window.perform_long_operation to use threads. One call and done.

What’s Old?

The old parts of this documentation are the images. The good news is that things look better than you see here. Themes have made Windows colorful in 1 line of code.

Looking for a GUI package? Are you…

• looking to take your Python code from the world of command lines and into the convenience of a GUI?
• sitting on a Raspberry Pi with a touchscreen that’s going to waste because you don’t have the time to learn a GUI SDK?
• into Machine Learning and are sick of the command line?
• an IT guy/gal that has written some cool tools but due to corporate policies are unable to share unless it is an EXE file?
• wanting to share your program with your friends or families (that aren’t so freakish that they have Python running)
• wanting to run a program in your system tray?
• a teacher wanting to teach your students how to program using a GUI?
• a student that wants to put a GUI onto your project that will blow away your teacher?
• looking for a GUI package that is «supported» and is being constantly developed to improve it?
• longing for documentation and scores of examples?

Look no further, you’ve found your GUI package.

The basics

• Create windows that look and operate identically to those created directly with tkinter, Qt, WxPython, and Remi.
• Requires 1/2 to 1/10th the amount of code as underlying frameworks.
• One afternoon is all that is required to learn the PySimpleGUI package and write your first custom GUI.
• Students can begin using within their first week of Python education.
• No callback functions. You do not need to write the word class anywhere in your code.
• Access to nearly every underlying GUI Framework’s Widgets.
• Supports both Python 2.7 & 3 when using tkinter.
• Supports both PySide2 and PyQt5 (limited support).
• Effortlessly move across tkinter, Qt, WxPython, and the Web (Remi) by changing only the import statement.
• The only way to write both desktop and web-based GUIs at the same time in Python.
• Developed from nothing as a pure Python implementation with Python friendly interfaces.
• Run your program in the System Tray using WxPython. Or, change the import and run it on Qt with no other changes.
• Works with Qt Designer.
• Built in Debugger.
• Actively maintained and enhanced — 4 ports are underway, all being used by users.
• Corporate as well as home users.
• Appealing to both newcomers to Python and experienced Pythonistas.
• The focus is entirely on the developer (you) and making their life easier, simplified, and in control.
• 170+ Demo Programs teach you how to integrate with many popular packages like OpenCV, Matplotlib, PyGame, etc.
• 200 pages of documentation, a Cookbook, and built-in help using docstrings. In short it’s heavily documented.

GUI Development does not have to be difficult nor painful. It can be (and is) FUN

What users are saying about PySimpleGUI

(None of these comments were solicited & were not paid endorsements — other than a huge thank-you they received!)

«I’ve been working to learn PyQT for the past week in my off time as an intro to GUI design and how to apply it to my existing scripts… Took me ~30 minutes to figure out PySimpleGUI and get my scripts working with a GUI.»

«Python has been an absolute nightmare for me and I’ve avoided it like the plague. Until I saw PySimpleGUI.»

«I’ve been pretty amazed at how much more intuitive it is than raw tk/qt. The dude developing it is super active on the project too, so if you come across situations that you just can’t get the code to do what you want you can make bug/enhancement issues that are almost assured to get a meaningful response.»

«This library is the easiest way of GUI programming in python! I’m totally in love with it»

«Wow that readme is extensive and great.» (hear the love for docs often)

«Coming from R, Python is absolutely slick for GUIs. PySimpleGUI is a dream.»

«I have been writing Python programs for about 4 or 5 months now. Up until this week, I never had luck with any UI libraries like Tkinter, Qt and Kivy. I went from not even being able to load a window in Tkinter reliably to making a loading screen, and full program in one night with PySimpleGUI.»

«I love PySimpleGUI! I’ve been teaching it in my Python classes instead of Tkinter.»

«I wish PySimpleGUI was available for every friggin programming language»

START HERE — User Manual with Table of Contents

ReadTheDocs <—— THE best place to read the docs due to TOC, all docs in 1 place, and better formatting. START here in your education. Easy to remember PySimpleGUI.org.

The Call Reference documentation is located on the same ReadTheDocs page as the main documentation, but it’s on another tab that you’ll find across the top of the page.

The quick way to remember the documentation addresses is to use these addresses:

http://docs.PySimpleGUI.org
http://calls.PySimpleGUI.org

Quick Links To Help and The Latest News and Releases

Homepage — Lastest Readme and Code — GitHub Easy to remember: PySimpleGUI.com

Announcements of Latest Developments, Release news, Misc

COOKBOOK!

Trinket an online Cookbook

Brief Tutorial

Latest Demos and Master Branch on GitHub

Repl.it Home for PySimpleGUI

Lots of screenshots

How to submit an Issue

The YouTube videos — If you like instructional videos, there are over 15 videos made by PySimpleGUI project over the first 18 months.
In 2020 a new series was begun. As of May 2020 there are 12 videos completed so far with many more to go….

• PySimpleGUI 2020 — The most up to date information about PySimpleGUI
• 5 part series of basics
• 10 part series of more detail
• The Naked Truth (An update on the technology)
• There are numerous short videos also on that channel that demonstrate PySimpleGUI being used

YouTube Videos made by others. These have much higher production values than the above videos.

• A fantastic tutorial PySimpleGUI Concepts — Video 1
• Build a calculator Python Calculator with GUI | PySimpleGUI | Texas Instruments DataMath II
• Notepad Notepad in Python — PySimpleGUI
• File Search Engine File Search Engine | Project for Python Portfolio with GUI | PySimpleGUI

About The PySimpleGUI Documentation System

This User’s Manual (also the project’s readme) is one vital part of the PySimpleGUI programming environment. The best place to read it is at http://www.PySimpleGUI.org

If you are a professional or skilled in how to develop software, then you understand the role of documentation in the world of technology development. Use it, please.

It WILL be required, at times, for you to read or search this document in order to be successful.

Using Stack Overflow and other sites to post your questions has resulted in advice given by a lot of users that have never looked at the package and are sometimes just flat bad advice. When possible, post an Issue on this GitHub. Definitely go through the Issue checklist. Take a look through the docs again.

There are 5 resources that work together to provide you with the fastest path to success. They are:

1. This User’s Manual
2. The Cookbook
3. The 170+ Demo Programs
4. Docstrings enable you to access help directly from Python or your IDE
5. Searching the GitHub Issues as a last resort (search both open and closed issues)

Pace yourself. The initial progress is exciting and FAST PACED. However, GUIs take time and thought to build. Take a deep breath and use the provided materials and you’ll do fine. Don’t skip the design phase of your GUI after you run some demos and get the hang of things. If you’ve tried other GUI frameworks before, successful or not, then you know you’re already way ahead of the game using PySimpleGUI versus the underlying GUI frameworks. It may feel like the 3 days you’ve been working on your code has been forever, but by comparison of 3 days learning Qt, PySimpleGUI will look trivial to learn.

It is not by accident that this section, about documentation, is at the TOP of this document.

This documentation is not HUGE in length for a package this size. In fact it’s still one document and it’s the readme for the GitHub. It’s not written in complex English. It is understandable by complete beginners. And pressing Control+F is all you need to do to search this document. USUALLY you’ll find less than 6 matches.

Documentation and Demos Get Out of Date

Sometimes the documentation doesn’t match exactly the version of the code you’re running. Sometimes demo programs haven’t been updated to match a change made to the SDK. Things don’t happen simultaneously generally speaking. So, it may very well be that you find an error or inconsistency or something no longer works with the latest version of an external library.

If you’ve found one of these problems, and you’ve searched to make sure it’s not a simple mistake on your part, then by ALL means log an Issue on the GitHub. Don’t be afraid to report problems if you’ve taken the simple steps of checking out the docs first.

Platforms

Hardware and OS Support

PySimpleGUI runs on Windows, Linux and Mac, just like tkinter, Qt, WxPython and Remi do. If you can get the underlying GUI Framework installed / running on your machine then PySimpleGUI will also run there.

Hardware

• PC’s, Desktop, Laptops
• Macs of all types
• Raspberry Pi
• Android devices like phones and tablets
• Virtual machine online (no hardware) — repl.it

OS

• Windows 7, 8, 10
• Linux on PC — Tested on several distributions
• Linux on Raspberry Pi
• Linux on Android — Can use either Termux or PyDroid3
• Mac OS

Python versions

As of 9/25/2018 both Python 3 and Python 2.7 are supported when using tkinter version of PySimpleGUI! The Python 3 version is named PySimpleGUI. The Python 2.7 version is PySimpleGUI27. They are installed separately and the imports are different. See instructions in Installation section for more info. None of the other ports can use Python 2.

Python 2.7 Code was be deleted from this GitHub on Dec 31, 2019

At the suggestion of the Python community at large, the experts, and security folks, the support for 2.7 was pulled from this Repo.

Warning — tkinter + Python 3.7.3 and later, including 3.8 has problems

The version of tkinter that is being supplied with the 3.7.3 and later versions of Python is known to have a problem with table colors. Basically, they don’t work. As a result, if you want to use the plain PySimpleGUI running on tkinter, you should be using 3.7.2 or less. 3.6 is the version PySimpleGUI has chosen as the recommended version for most users.

Output Devices

In addition to running as a desktop GUI, you can also run your GUI in a web browser by running PySimpleGUIWeb.

This is ideal for «headless» setups like a Raspberry Pi that is at the core of a robot or other design that does not have a normal display screen. For these devices, run a PySimpleGUIWeb program that never exits.

Then connect to your application by going to the Pi’s IP address (and port #) using a browser and you’ll be in communication with your application. You can use it to make configuration changes or even control a robot or other piece of hardware using buttons in your GUI.

A Complete PySimpleGUI Program (Getting The Gist)

Before diving into details, here’s a description of what PySimpleGUI is/does and why that is so powerful.

You keep hearing «custom window» in this document because that’s what you’re making and using… your own custom windows.

ELEMENTS is a word you’ll see everywhere… in the code, documentation, … Elements == PySimpleGUI’s Widgets. As to not confuse a tkinter Button Widget with a PySimpleGUI Button Element, it was decided that PySimpleGUI’s Widgets will be called Elements to avoid confusion.

Wouldn’t it be nice if a GUI with 3 «rows» of Elements were defined in 3 lines of code? That’s exactly how it’s done. Each row of Elements is a list. Put all those lists together and you’ve got a window.

What about handling button clicks and stuff. That’s 4 lines of the code below beginning with the while loop.

Now look at the layout variable and then look at the window graphic below. Defining a window is taking a design you can see visually and then visually creating it in code. One row of Elements = 1 line of code (can span more if your window is crowded). The window is exactly what we see in the code. A line of text, a line of text and an input area, and finally ok and cancel buttons.

This makes the coding process extremely quick and the amount of code very small

import PySimpleGUI as sg
sg.theme('DarkAmber')   # Add a little color to your windows
# All the stuff inside your window. This is the PSG magic code compactor...
layout = [  [sg.Text('Some text on Row 1')],
            [sg.Text('Enter something on Row 2'), sg.InputText()],
            [sg.OK(), sg.Cancel()]]

# Create the Window
window = sg.Window('Window Title', layout)
# Event Loop to process "events"
while True:             
    event, values = window.read()
    if event in (sg.WIN_CLOSED, 'Cancel'):
        break

window.close()

You got to admit that the code above is a lot more «fun» looking that tkinter code you’ve studied before. Adding stuff to your GUI is trivial. You can clearly see the «mapping» of those 3 lines of code to specific Elements laid out in a Window. It’s not a trick. It’s how easy it is to code in PySimpleGUI. With this simple concept comes the ability to create any window layout you wish. There are parameters to move elements around inside the window should you need more control.

It’s a thrill to complete your GUI project way ahead of what you estimated. Some people take that extra time to polish their GUI to make it even nicer, adding more bells and whistles because it’s so easy and it’s a lot of fun to see success after success as you write your program.

Some are more advanced users and push the boundaries out and extend PySimpleGUI using their own extensions.

Others, like IT people and hackers, are busily cranking out GUI program after GUI program, and creating tools that others can use. Finally, there’s an easy way to throw a GUI onto your program and give it to someone. It’s a pretty big leap in capability for some people. It’s GREAT to hear these successes. It’s motivating for everyone in the end. Your success can easily motivate the next person to give it a try and also potentially be successful.

Usually, there’s a one to one mapping of a PySimpleGUI Element to a GUI Widget. A «Text Element» in PySimpleGUI == «Label Widget» in tkinter. What remains constant for you across all PySimpleGUI platforms is that no matter what the underlying GUI framework calls the thing that places text in your window, you’ll always use the PySimpleGUI Text Element to access it.

The final bit of magic is in how Elements are created and changed.

So far you’ve seen simple layouts with no customization of the Elements. Customizing and configuring Elements is another place PySimpleGUI utilizes the Python language to make your life easier.

What about Elements that have settings other than the standard system settings? What if I want my Text to be blue, with a Courier font on a green background. It’s written quite simply:

Text('This is some text', font='Courier 12', text_color='blue', background_color='green')

The Python named parameters are extensively in PySimpleGUI. They are key in making the code compact, readable, and trivial to write.

As you’ll learn in later sections that discuss the parameters to the Elements, there are a LOT of options available to you should you choose to use them. The Text Element has 15 parameters that you can change. This is one reason why PyCharm is suggested as your IDE… it does a fantastic job of displaying documentation as you type in your code.

That’s The Basics

What do you think? Easier so far than your previous run-ins with GUIs in Python? Some programs, many in fact, are as simple as this example has been.

But PySimpleGUI certainly does not end here. This is the beginning. The scaffolding you’ll build upon.

The Underlying GUI Frameworks & Status of Each

At the moment there are 4 actively developed and maintained «ports» of PySimpleGUI. These include:

1. tkinter — Fully complete
2. Qt using Pyside2 — Alpha stage. Not all features for all Elements are done
3. WxPython — Development stage, pre-releaser. Not all Elements are done. Some known problems with multiple windows
4. Remi (Web browser support) — Development stage, pre-release.

While PySimpleGUI, the tkinter port, is the only 100% completed version of PySimpleGUI, the other 3 ports have a LOT of functionality in them and are in active use by a large portion of the installations. You can see the number of Pip installs at the very top of this document to get a comparison as to the size of the install base for each port. The «badges» are right after the logo.

The Chain Link Fence

Maybe you’ve heard the «Walled Garden» term before. It’s a boxing in effect.

While PySimpleGUI has a well-established parameter so you know where the edges are, there is no wall between you and the rest of the GUI framework. There’s a chain link fence that’s easy to reach through and get full access to the underlying frameworks.

The net result — it’s easy to expand features that are not yet available in PySimpleGUI and easy to remove them too. Maybe the Listbox Element doesn’t have a mode exposed that you want to enable. No problem, you can access the underlying Listbox Widget and make what is likely 1 or 2 calls and be done.

The PySimpleGUI «Family»

What’s The Big Deal? What is it?

PySimpleGUI wraps tkinter, Qt, WxPython, and Remi so that you get all the same widgets, but you interact with them in a more friendly way that’s common across the ports.

What does a wrapper do (Yo! PSG in the house!)? It does the layout, boilerplate code, creates and manages the GUI Widgets for you and presents you with a simple, efficient interface. Most importantly, it maps the Widgets in tkinter/Qt/Wx/Remi into PySimpleGUI Elements. Finally, it replaces the GUIs’ event loop with one of our own.

You’ve seen examples of the code already. The big deal of all this is that anyone can create a GUI simply and quickly that matches GUIs written in the native GUI framework. You can create complex layouts with complex element interactions. And, that code you wrote to run on tkinter will also run on Qt by changing your import statement.

If you want a deeper explanation about the architecture of PySimpleGUI, you’ll find it on ReadTheDocs in the same document as the Readme & Cookbook. There is a tab at the top with labels for each document.

The «Ports»

There are distinct ports happening as mentioned above. Each has its own location on GitHub under the main project. Heac has its own Readme which is an augmentation of this document… they are meant to be used together.

PySimpleGUI is released on PyPI as 5 distinct packages.

1. PySimpleGUI — tkinter version
2. PySimpleGUI27 — tkinter version that runs on 2.7
3. PySimpleGUIWx — WxPython version
4. PySimpleGUIQt — PySided2 version
5. PySimpleGUIWeb — The web (Remi) version

You will need to install them separately

There is also an accompanying debugger known as imwatchingyou. If you are running the tkinter version of PySimpleGUI, you will not need to install the debugger as there is a version embedded directly into PySimpleGUI.

Qt Version

Qt was the second port after tkinter. It is the 2nd most complete with the original PySimpleGUI (tkinter) being the most complete and is likely to continue to be the front-runner. All of the Elements are available on PySimpleGUIQt.

As mentioned previously each port has an area. For Qt, you can learn more on the PySimpleGUIQt GitHub site. There is a separate Readme file for the Qt version that you’ll find there. This is true for all of the PySimpleGUI ports.

Give it a shot if you’re looking for something a bit more «modern». PySimpleGUIQt is currently in Alpha. All of the widgets are operational but some may not yet be full-featured. If one is missing and your project needs it, log an Issue. It’s how new features are born.

Here is a summary of the Qt Elements with no real effort spent on design clearly. It’s an example of the «test harness» that is a part of each port. If you run the PySimpleGUI.py file itself then you’ll see one of these tests.

As you can see, you’ve got a full array of GUI Elements to work with. All the standard ones are there in a single window. So don’t be fooled into thinking PySimpleGUIQt is barely working or doesn’t have many widgets to choose from. You even get TWO «Bonus Elements» — Dial and Stretch

WxPython Version

PySimpleGUIWx GitHub site. There is a separate Readme file for the WxPython version.

Started in late December 2018 PySimpleGUIWx started with the SystemTray Icon feature. This enabled the package to have one fully functioning feature that can be used along with tkinter to provide a complete program. The System Tray feature is complete and working very well. It was used not long ago in a corporate setting and has been performing with few problems reported.

The Windowing code was coming together with Reads operational. The elements were getting completed on a regular basis. But I ran into multiwindow problems. And it was at about this time that Remi was suggested as a port.

Remi (the «web port») overnight leapt the WxPython effort and Web became a #1 priority and continues to be. The thought is that the desktop was well represented with PySimpleGUI, PySimpleGUIQt, and PySimpleGUIWx. Between those ports is a solid windowing system and 2 system tray implementations and a nearly feature complete Qt effort. So, the team was switched over to PySimpleGUIWeb.

Web Version (Remi)

PySimpleGUIWeb GitHub site. There is a separate Readme file for the Web version.

New for 2019, PySimpleGUIWeb. This is an exciting development! PySimpleGUI in your Web Browser!

The underlying framework supplying the web capability is the Python package Remi. https://github.com/dddomodossola/remi Remi provides the widgets as well as a web server for you to connect to. It’s an exiting new platform to be running on and has temporarily bumped the WxPython port from the highest priority. PySimpleGUIWeb is the current high priority project.

Use this solution for your Pi projects that don’t have anything connected in terms of input devices or display. Run your Pi in «headless» mode and then access it via the Web interface. This allows you to easily access and make changes to your Pi without having to hook up anything to it.

It’s not meant to «serve up web pages»

PySimpleGUIWeb is first and foremost a GUI, a program’s front-end. It is designed to have a single user connect and interact with the GUI.

If more than 1 person connects at a time, then both users will see the exact same stuff and will be interacting with the program as if a single user was using it.

Android Version

PySimpleGUI runs on Android devices with the help of either the PyDroid3 app or the Termux app. Both are capable of running tkinter programs which means both are capable of running PySimpleGUI.

To use with PyDroid3 you will need to add this import to the top of all of your PySimpleGUI program files:

This evidently triggers PyDroid3 that the application is going to need to use the GUI.

You will also want to create your windows with the location parameter set to (0,0).

Here’s a quick demo that uses OpenCV2 to display your webcam in a window that runs on PyDroid3:

import tkinter
import cv2, PySimpleGUI as sg
USE_CAMERA = 0      # change to 1 for front facing camera
window, cap = sg.Window('Demo Application - OpenCV Integration', [[sg.Image(filename='', key='image')], ], location=(0, 0), grab_anywhere=True), cv2.VideoCapture(USE_CAMERA)
while window(timeout=20)[0] != sg.WIN_CLOSED:
    window['image'](data=cv2.imencode('.png', cap.read()[1])[1].tobytes())

You will need to pip install opencv-python as well as PySimpleGUI to run this program.

Also, you must be using the Premium, yes paid, version of PyDroid3 in order to run OpenCV. The cost is CHEAP when compared to the rest of things in life. A movie ticket will cost you more. Which is more fun, seeing your Python program running on your phone and using your phone’s camera, or some random movie currently playing? From experience, the Python choice is a winner. If you’re cheap, well, then you won’t get to use OpenCV. No, there is no secret commercial pact between the PySimpleGUI project and the PyDroid3 app team.

Source code compatibility

In theory, your source code is completely portable from one platform to another by simply changing the import statement. That’s the GOAL and surprisingly many times this 1-line change works. Seeing your code run on tkinter, then change the import to import PySimpleGUIWeb as sg and instead of a tkinter window, up pops your default browser with your window running on it is an incredible feeling.

But, caution is advised. As you’ve read already, some ports are further along than others. That means when you move from one port to another, some features may not work. There also may be some alignment tweaks if you have an application that precisely aligns Elements.

What does this mean, assuming it works? It means it takes a trivial amount of effort to move across GUI Frameworks. Don’t like the way your GUI looks on tkinter? No problem, change over to try PySimpleGUIQt. Made a nice desktop app but want to bring it to the web too? Again, no problem, use PySimpleGUIWeb.

repl.it Version

Want to really get your mind blown? Check out this PySimpleGUI program running in your web browser.

Thanks to the magic of repl.it and Remi it’s possible to run PySimpleGUI code in a browser window without having Python running on your computer. This should be viewed as a teaching and demonstration aid. It is not meant to be a way of serving up web pages. It wouldn’t work any way as each user forks and gets their own, completely different, workspace.

There are 2 ports of PySimpleGUI that run on repl.it — PySimpleGUI and PySimpleGUIWeb.

PySimpleGUI (tkinter based)

The primary PySimpleGUI port works very well on repl.it due to the fact they’ve done an outstanding job getting tkinter to run on these virtual machines. Creating a program from scratch, you will want to choose the «Python with tkinter» project type.

The virtual screen size for the rendered windows isn’t very large, so be mindful of your window’s size or else you may end up with buttons you can’t get to.

You may have to «install» the PySimpleGUI package for your project. If it doesn’t automatically install it for you, then click on the cube along the left edge of the browser window and then type in PySimpleGUI or PySimpleGUIWeb depending on which you’re using.

PySimpleGUIWeb (Remi based)

For PySimpleGUIWeb programs you run using repl.it will automatically download and install the latest PySimpleGUIWeb from PyPI onto a virtual Python environment. All that is required is to type import PySimpleGUIWeb you’ll have a Python environment up and running with the latest PyPI release of PySimpleGUIWeb.

Creating a repl.it project from scratch / troubleshooting

To create your own repl.it PySimpleGUI project from scratch, first choose the type of Python virtual machine you want. For PySimpleGUI programs, choose the «Python with tkinter» project type. For PySimpleGUIWeb, choose the normal Python project.

There have been times where repl.it didn’t do the auto import thing. If that doesn’t work for some reason, you can install packages by clicking on the package button on the left side of the interface, typing in the package name (PySimpleGUI or PySimpleGUIWeb) and install it.

Why this is so cool (listen up Teachers, tutorial writers)

Educators in particular should be interested. Students can not only post their homework easily for their teacher to access, but teachers can also run the students programs online. No downloading needed. Run it and check the results.

For people wanting to share their code, especially when helping someone with a problem, it’s a great place to do it. Those wishing to see your work do not have to be running Python nor have PySimpleGUI installed.

The way I use it is to first write my PySimpleGUI code on Windows, then copy and paste it into Repl.it.

Finally, you can embed these Repl.it windows into web pages, forum posts, etc. The «Share» button is capable of giving you the block of code for an «iframe» that will render into a working repl.it program in your page. It’s amazing to see, but it can be slow to load.

Repl.it is NOT a web server for you to «deploy» applications!

Repl.it is not meant to serve up applications and web pages. Trying to use it that way will not result in satisfactory results. It’s simply too slow and too technical of an interface for trying to «deploy» using it. PySimpleGUIWeb isn’t a great choice in serving web pages. It’s purpose is more to build a GUI that runs in a browser.

Macs

It’s surprising that Python GUI code is completely cross platform from Windows to Mac to Linux. No source code changes. This is true for both PySimpleGUI and PySimpleGUIQt.

Historically, PySimpleGUI using tkinter have struggled on Macs. This was because of a problem setting button colors on the Mac. However, two events has turned this problem around entirely.

1. Use of ttk Buttons for Macs
2. Ability for Mac users to install Python from python.org rather than the Homebrew version with button problems

It’s been a long road for Mac users with many deciding to use PySimpleGUIQt so that multi-colored windows could be made. It’s completely understandable to want to make attractive windows that utilize colors.

PySimpleGUI now supports Macs, Linux, and Windows equally well. They all are able to use the «Themes» that automatically add color to your windows.

Be aware that Macs default to using ttk buttons. You can override this setting at the Window and Button levels. If you installed Python from python.org, then it’s likely you can use the non-ttk buttons should you wish.

Support

Don’t Suffer Silently

The GitHub Issues are checked often. Very often. Please post your questions and problems there and there only. Please don’t post on Reddit, StackOverflow, on forums, until you’ve tried posting on the GitHub.

Why? It will get you the best support possible. Second, you’ll be helping the project as what you’re experiencing might very well be a bug, or even a known bug. Why spend hours thrashing, fighting against a known bug?

It’s not a super-buggy package, but users do experience problems just the same. Maybe something’s not explained well enough in the docs. Maybe you’re making a common mistake. Maybe that feature isn’t complete yet.

You won’t look stupid posting an Issue on GitHub. It’s just the opposite.

How to log issues

PySimpleGUI is an active project. Bugs are fixed, features are added, often. Should you run into trouble, open an issue on the GitHub site and you’ll receive help. Posting questions on StackOverflow, Forums, Mailing lists, Reddit, etc, is not the fastest path to support and taking it may very well lead you astray as folks not familiar with the package struggle to help you. You may also run into the common response of «I don’t know PySimpleGUI (and perhaps dislike it as a result), but I know you can do that with Qt».

Why only 1 location? It’s simple…. it’s where the bugs, enhancements, etc are tracked. It’s THE spot on the Internet for this project. There’s not driven by a freakish being in control, telling people how to do things, reasoning. It’s so that YOU get the best and quickest support possible.

So, open an Issue, choose «custom form» and fill it out completely. There are very good reasons behind all of the questions. Cutting corners only cuts your chances of getting help and getting quality help as it’s difficult enough to debug remotely. Don’t handicap people that want to help by not providing enough information.

Be sure and run your program outside of your IDE first. Start your program from the shell using python or python3 command. On numerous occasions much time was spent chasing problems caused by the IDE. By running from a command line, you take that whole question out of the problem, an important step.

Don’t sit and stew, trying the same thing over and over, until you hate life… stop, and post an Issue on the GitHub. Someone WILL answer you. Support is included in the purchase price for this package (the quality level matches the price as well I’m afraid). Just don’t be too upset when your free support turns out to be a little bit crappy, but it’s free and typically good advice.

Target Audience

PySimpleGUI is trying to serve the 80% of GUI problems. The other 20% go straight to tkinter, Qt, WxPython, Remi, or whatever fills that need. That 80% is a huge problem space.

The «Simple» of PySimpleGUI describes how easy it is to use, not the nature of the problem space it solves. Note that people are not part of that description. It’s not trying to solve GUI problems for 80% of the people trying it. PySimpleGUI tries to solve 80% of GUI problems, regardless of the programmer’s experience level.

Is file I/O in Python limited to only certain people? Is starting a thread, building a multi-threaded Python program incredibly difficult such that it takes a year to learn? No. It’s quite easy. Like most things Python, you import the object from package and you use it. It is 2 lines of Python code to create and start a thread.

Why can’t it be 2 lines of code to show a GUI window? What’s SO special about the Python GUI libraries that they require you to follow a specific Object Oriented model of development? Other parts and packages of Python don’t tend to do that.

The reason is because they didn’t originate in Python. They are strangers in a strange land and they had to be «adapted». They started as C++ programs / SDKs, and remain that way too. There’s a veneer of Python slapped onto the top of them, but that sure didn’t make them fit the language as well as they could have.

PySimpleGUI is designed with both the beginner and the experienced developer in mind. Why? Because both tend to like compact code. Most like people, we just want to get sh*t done, right? And, why not do it in a way that’s like how most of Python works?

The beginners can begin working with GUIs in their first week of Python education. The professionals can jump right into the deep end of the pool to use the entire array of Elements and their capabilities to build stuff like a database application.

Here’s a good example of how PySimpleGUI serves these 2 groups…. the InputText Element has 16 potential parameters, yet you’ll find 0 or 1 parameters set by beginners. Look at the examples throughout this document and you’ll see the code fragments utilize a tiny fraction of the potential parameters / settings. Simple… keep it simple for the default case. This is part of the PySimpleGUI mission.

Some developers are heavily wedded to the existing GUI Framework Architectures (Qt, WxPython, tkinter). They like the existing GUI architectures (they’re all roughly the same, except this one). If you’re in that crowd, join the «20% Club» just down the street. There’s plenty of room there with plenty of possible solutions.

But how about a quick stop-in for some open mindedness exercises. Maybe you will come up with an interesting suggestion even if you don’t use it. Or maybe PySimpleGUI does something that inspires you to write something similar directly in Qt. And please, at least be civil about it. There is room for multiple architectures. Remember, you will not be harmed by writing some PySimpleGUI code just like you won’t by writing some tkinter or Qt code. Your chances of feeling harmed is more likely from one of those 2.

Beginners & Easier Programs

There are a couple of reasons beginners stop in for a look. The first is to simply throw a simple GUI onto the front of an existing command line application. Or maybe you need to popup a box to get a filename. These can often be simple 1-line popup calls. Of course, you don’t have to be a beginner to add a GUI onto one of your existing command line programs. Don’t feel like because you’re an advanced programmer, you need to have an advanced solution.

If you have a more intricate, complete, perhaps multi-window design in mind, then PySimpleGUI still could be your best choice.

This package is not only great to use as your first GUI package, but it also teaches how to design and utilize a GUI. It does it better than the existing GUIs by removing the syntax, and lengthy code that can take an otherwise very simple appearing program into something that’s completely unrecognizable. With PySimpleGUI your ‘layout’ is all you need to examine to see the different GUI Elements that are being used.

Why does PySimpleGUI make it any easier to learn about GUIs? Because it removes the classes, callback functions, object oriented design to better get out of your way and let you focus entirely on your GUI and not how to represent it in code.

The result is 1/2 to 1/10th the amount of code that implements the exact same layout and widgets as you would get from coding yourself directly in Qt5. It’s been tested many times… again and again, PySimpleGUI produces significantly less code than Qt and the frameworks it runs on.

Forget syntax completely and just look on the overall activities of a PySimpleGUI programmer. You have to design your window…. determine your inputs and your outputs, place buttons in strategic places, create menus, …. You’ll be busy just doing all those things to design and define your GUI completely independent upon the underlying framework.

After you get all those design things done and are ready to build your GUI, it’s then that you face the task of learning a GUI SDK. Why not start with the easy one that gives you many successes? You’re JUST getting started, so cut yourself a break and use PySimpleGUI so that you can quickly get the job done and move on to the next GUI challenge.

Advanced Programmers, Sharp Old-Timers, Code Slingers and Code Jockeys

It’s not perfect, but PySimpleGUI is an amazing bit of technology. It’s the programmer, the computer scientist, that has experience working with GUIs in the past that will recognize the power of this simple architecture.

What I hear from seasoned professionals is that PySimpleGUI saves them a ton of time. They’ve written GUI code before. They know how to lay out a window. These folks just want to get their window working and quick.

With the help of IDE’s like PyCharm, Visual Studio and Wing (the officially supported IDE list) you get instant documentation on the calls you are making. On PyCharm you instantly see both the call signature but also the explanations about each parameter.

If the screenshots, demo programs and documentation don’t convince you to at least give it a try, once, then you’re way too busy, or ….. I dunno, I stopped guessing «why?» some time ago.

Some of the most reluctant of people to try PySimpleGUI have turned out to be some of the biggest supporters.

A Moment of Thanks To The PySimpleGUI Users

I want to thank the early users of PySimpleGUI that started in 2018. Your suggestions helped shape the package and have kept it moving forward at a fast pace.

For all the users, while I can’t tell you the count of the number of times someone has said «thank you for PySimpleGUI» as part of logging and Issue, or a private message or email, but I can tell you that it’s been significant.

EVERY one of those «thank you» phrases, no matter how small you may think it is, helps tremendously.

Sometimes it’s what gets me past a problem or gets me to write yet more documentation to try and help people understand quicker and better. Let’s just say the effect is always positive and often significant.

PySimpleGUI users have been super-nice. I doubt all Open Source Projects are this way, but I could be wrong and every GitHub repository has awesome users. If so, that’s even more awesome!

THANK YOU PySimpleGUI USERS!

Learning Resources

This document…. you must be willing to read this document if you expect to learn and use PySimpleGUI.

If you’re unwilling to even try to figure out how to do something or find a solution to a problem and have determined it’s «easier to post a question first than to look at the docs», then this is not the GUI package for you. If you’re unwilling to help yourself, then don’t expect someone else to try first. You need to hold up your end of the bargain by at least doing some searches of this document.

While PySimpleGUI enables you to write code easily, it doesn’t mean that it magically fills your head with knowledge on how to use it. The built-in docstrings help, but they can only go so far.

Searching this document is as easy as pressing Control + F.

This document is on the GitHub homepage, as the readme. http://www.PySimpleGUI.com will get you there. If you prefer a version with a Table of Contents on the left edge then you want to go to http://www.PySimpleGUI.org .

The PySimpleGUI, Developer-Centric Model

You may think that you’re being fed a line about all these claims that PySimpleGUI is built specifically to make your life easier and a lot more fun than the alternatives…. especially after reading the bit above about reading this manual.

Psychological Warfare

Brainwashed. Know that there is an active campaign to get you to be successful using PySimpleGUI. The «Hook» to draw you in and keep you working on your program until you’re satisfied is to work on the dopamine in your brain. Yes, your a PySimpleGUI rat, pressing on that bar that drops a food pellet reward in the form of a working program.

The way this works is to give you success after success, with very short intervals between. For this to work, what you’re doing must work. The code you run must work. Make small changes to your program and run it over and over and over instead of trying to do one big massive set of changes. Turn one knob at a time and you’ll be fine.

Find the keyboard shortcut for your IDE to run the currently shown program so that running the code requires 1 keystroke. On PyCharm, the key to run what you see is Control + Shift + F10. That’s a lot to hold down at once. I programmed a hotkey on my keyboard so that it emits that combination of keys when I press it. Result is a single button to run.

Tools

These tools were created to help you achieve a steady stream of these little successes.

• This readme and its example pieces of code
• The Cookbook & eCoobook — Copy, paste, run, success
• Demo Programs — Copy these small programs to give yourself an instant head-start
• Documentation shown in your IDE (docstrings) means you do not need to open any document to get the full assortment of options available to you for each Element & function call

The initial «get up and running» portion of PySimpleGUI should take you less than 5 minutes (the 5 minute challenge). The goal is 5 minutes from your decision «I’ll give it a try» to having your first window up on the screen. «Oh wow, it was that easy?!»

The primary learning paths for PySimpleGUI are:

• The Documentation
  • Resist the urge to «Google It»
  • The old-school way, «Read the Documenation», for this project, will be the most efficient path.
  • PySimpleGUI Documentation — http://www.PySimpleGUI.org
  • Here you will find the main doc, the Cookbook, the Call Reference, the Readme… all in 1 location.
• This readme document on GitHub and in the main documentation
  • PySimpleGUI GitHub: http://www.PySimpleGUI.com
• The Cookbook — Recipes to get you going and quick
  • http://Cookbook.PySimpleGUI.org
  • The online Interactive eCookbook is also available — http://eCookbook.PySimpleGUI.org
• The Demo Programs — Start hacking on one of these running solutions
  • http://Demos.PySimpleGUI.org
  • The easiest way to obtain and use them is by pip installing psgdemos
• The Udemy Course! «The Official PySimpleGUI Course»
  • The is ONE and only 1 video course on the Internet that helps the PySimpleGUI financially.
  • http://udemy.pysimplegui.org/
  • There are 61 lessons that will teach you all aspects of PySimpleGUI
  • It was a year in the making and covers features up through end of 2021
  • It’s the best course I’ve ever written and recorded (says Mike). Each lesson is compact, consise, focused, easy to understand
• The YouTube videos — If you like instructional videos, there are 15+ videos.
  • Caution is advised… these videos are from 2020. Much has changed since they were made. They are still quite valid as what you’re taught will work. But, you’re missing 2 years of intense development that are not represented in these lessons. The Udemy course is a more complete and current course.
  • 2020 to 2022 update — https://youtu.be/lRuvKfilJnA-Lists a few of the many changes to PySimpleGUI since the 2020 lessons were recorded.
  • 5 part series of basics
  • 10 part series of more detail

Everything is geared towards giving you a «quick start» whether that be a Recipe or a Demo Program. The idea is to give you something running and let you hack away at it. As a developer this saves tremendous amounts of time.

You start with a working program, a GUI on the screen. Then have at it. If you break something ("a happy little accident" as Bob Ross put it), then you can always backtrack a little to a known working point.

A high percentage of users report both learning PySimpleGUI and completing their project in a single day.

This isn’t a rare event and it’s not bragging. GUI programming doesn’t HAVE to be difficult by definition and PySimpleGUI has certainly made it much much more approachable and easier (not to mention simpler).

But there will be times that you need to read documentation, look at examples, when pushing into new, unknown territory. Don’t guess… or more specifically, don’t guess and then give up when it doesn’t work.

This Documentation, Call Reference and Cookbook

The quickest way to the docs is to visit:
http://www.PySimpleGUI.org

You will be auto-forwarded to the right destination. There are multiple tabs on ReadTheDocs.

The call reference is an important document as it explains every call and every parameter. Note that this same information is available to you via docstrings so that as you are writing your code, you can read the documentation without ever leaving your IDE (e.g. PyCharm)

Demo Programs

The GitHub repo has the Demo Programs. There are ones built for plain PySimpleGUI that are usually portable to other versions of PySimpleGUI. And there are some that are associated with one of the other ports.

As of the start of 2022 there are over 300 Demo Programs.

These programs demonstrate to you how to use the Elements and how to integrate PySimpleGUI with some of the popular open source technologies such as OpenCV, PyGame, PyPlot, and Matplotlib to name a few.

Many Demo Programs that are in the main folder will run on multiple ports of PySimpleGUI. There are also port-specific Demo Programs. You’ll find those in the folder with the port. So, Qt specific Demo Programs are in the PySimpleGUIQt folder.

Jump Start! Get the Demo Programs & Demo Browser Quickly!

The over 300 Demo Programs will give you a jump-start and provide many design patterns for you to learn how to use PySimpleGUI and how to integrate PySimpleGUI with other packages. By far the best way to experience these demos is using the Demo Browser. This tool enables you to search, edit and run the Demo Programs.

The psgdemos PyPI Package

In Jan 2022 a new package was added so that you can get both the Demo Programs and the Demo Browser by entering 1 install command.

To get them installed quickly along with the Demo Browser, use pip to install psgdemos:

python -m pip install psgdemos

or if you’re in Linux, Mac, etc, that uses python3 instead of python to launch Python:

python3 -m pip install psgdemos

Once installed, launch the demo browser by typing psgdemos from the command line»

psgdemos

The Quick Tour

Let’s take a super-brief tour around PySimpleGUI before digging into the details. There are 2 levels of windowing support in PySimpleGUI — High Level and Customized.

The high-level calls are those that perform a lot of work for you. These are not custom made windows (those are the other way of interacting with PySimpleGUI).

Let’s use one of these high level calls, the popup and use it to create our first window, the obligatory «Hello World». It’s a single line of code. You can use these calls like print statements, adding as many parameters and types as you desire.

import PySimpleGUI as sg

sg.popup('Hello From PySimpleGUI!', 'This is the shortest GUI program ever!')

Or how about a custom GUI in 1 line of code? No kidding this is a valid program and it uses Elements and produce the same Widgets like you normally would in a tkinter program. It’s just been compacted together is all, strictly for demonstration purposes as there’s no need to go that extreme in compactness, unless you have a reason to and then you can be thankful it’s possible to do.

import PySimpleGUI as sg

event, values = sg.Window('Get filename example', [[sg.Text('Filename')], [sg.Input(), sg.FileBrowse()], [sg.OK(), sg.Cancel()] ]).read(close=True)

The Beauty of Simplicity

One day I will find the right words, and they will be simple.
― Jack Kerouac

That’s nice that you can crunch things into 1 line, like in the above example, but it’s not readable. Let’s add some whitespace so you can see the beauty of the PySimpleGUI code. And while we’re at it, we’ll change the color theme to something darker that’s perhaps more attractive to some of you.

Take a moment and look at the code below. Can you «see» the window looking at the layout variable, knowing that each line of code represents a single row of Elements? There are 3 «rows» of Elements shown in the window and there are 3 lines of code that define it.

Creating and reading the user’s inputs for the window occupy the last 2 lines of code, one to create the window, the last line shows the window to the user and gets the input values (what button they clicked, what was input in the Input Element)

import PySimpleGUI as sg

sg.theme('Dark Grey 13')

layout = [[sg.Text('Filename')],
          [sg.Input(), sg.FileBrowse()],
          [sg.OK(), sg.Cancel()]]

window = sg.Window('Get filename example', layout)

event, values = window.read()
window.close()

Unlike other GUI SDKs, you can likely understand every line of code you just read, even though you have not yet read a single instructional line from this document about how you write Elements in a layout.

There are no pesky classes you are required to write, no callback functions to worry about. None of that is required to show a window with some text, an input area and 2 buttons using PySimpleGUI.

The same code, in tkinter, is 5 times longer and I’m guessing you won’t be able to just read it and understand it. While you were reading through the code, did you notice there are no comments, yet you still were able to understand, using intuition alone.

You will find this theme of Simple everywhere in and around PySimpleGUI. It’s a way of thinking as well as an architecture direction. Remember, you, Mr./Ms. Developer, are at the center of the package. So, from your vantage point, of course everything should look and feel simple.

Not only that, it’s the Pythonic thing to do. Have a look at line 3 of the «Zen of Python».

The Zen of Python, by Tim Peters

Beautiful is better than ugly .
Explicit is better than implicit .
Simple is better than complex.
Complex is better than complicated.
Flat is better than nested.
Sparse is better than dense.
Readability counts.
Special cases aren’t special enough to break the rules.
Although practicality beats purity.
Errors should never pass silently.
Unless explicitly silenced.
In the face of ambiguity, refuse the temptation to guess.
There should be one— and preferably only one —obvious way to do it.
Although that way may not be obvious at first unless you’re Dutch.
Now is better than never.
Although never is often better than right now.
If the implementation is hard to explain, it’s a bad idea.
If the implementation is easy to explain, it may be a good idea.
Namespaces are one honking great idea — let’s do more of those!

I just hope reading all these pages of documentation is going to make you believe that we’re breaking suggestion:

If the implementation is hard to explain, it’s a bad idea.
If the implementation is easy to explain, it may be a good idea.

I don’t think PySimpleGUI is difficult to explain, but I am striving to fully explain it so that you don’t do this:

In the face of ambiguity, refuse the temptation to guess.

Sometimes you can guess and be fine. Other times, things may work, but the side effects are potentially significant. Are be a much better way to solve a problem:

• Look in the documentation
• Log an Issue on GitHub!

Some Examples

Polishing Your Windows = Building «Beautiful Windows»

And STILL the Zen of Python fits:

Beautiful is better than ugly.

but this fits too:

Although practicality beats purity.

Find a balance that works for you.

«But tkinter sucks»
«It looks like the 1990s» (this one is often said by people that were not alive in the 1990s)
«What Python GUI SDK will make my window look beautiful?» (posted to Reddit at least every 2 weeks)

These windows below were ALL made using PySimpleGUI, the tkinter version and they look good enough to not be simply scoffed at and dismissed. Remember, developer, you have a rather significant hand in how your application looks and operates. You certainly cannot pin it all on the GUIs you’re using.

So many posts on Reddit asking which GUI is going to result in a «beautiful window», as if there’s a magic GUI library that pretties things up for you. There are some calls in PySimpleGUI that will help you. For example, you can make a single call to «Change the Theme» which loads predefined color pallets so your windows will instantly have colors that match.

Beautiful windows are created, not simply given to you. There are people that design and create artwork for user interfaces, you know that… right? Artists draw buttons, artwork that you include in the window to make it nicer. They understand color theory and how to design an attractive user interface.

Custom Titlebars — A Trivial Start at Beautification

You can replace the titlebar that your operating system provides with one that is custom to your user interface by using the Titlebar element.

Normally, the Operating System provides the titlebar. This means they are unlikely to match your color scheme. Here is a Window with a dark color theme and the default titlebar provided by Windows.

It’s an OK window. By adding a Titlebar element to your layout, then your window completely matches your color theme. Here is the same window with a PySimpleGUI Titlebar element

Regardless of the «Theme» you choose for your window, the Titlebar will match it.

Some Examples Of More «Polished» Windows

A** note from the «2022 Mike»**… these windows were created 2 years ago. A lot more work has been completed to enable even better windows using packages like Pillow. In other words, these are not the current «best» examples.

The User Screenshots Gallery is currently housed in Issue #10 on GitHub. GitHub does very strange pagination. The MIDDLE portion of the text and images on the page is hidden and you have to repeatedly press a «Load More» link.

Some of these have been «polished», others like the Matplotlib example is more a functional example to show you it works.

This chess program is capable of running multiple AI chess engines and was written by another user using PySimpleGUI.

This downloader can download files as well as YouTube videos and metadata. If you’re worried about multiple windows working, don’t. Worried your project is «too much» or «too complex» for PySimpleGUI? Do an initial assessment if you want. Check out what others have done.

Your program have 2 or 3 windows and you’re concerned? Below you’ll see 11 windows open, each running independently with multiple tabs per window and progress meters that are all being updated concurrently.

Just because you can’t match a pair of socks doesn’t mean your windows have to all look the same gray color. Choose from over 100 different «Themes». Add 1 line call to theme to instantly transform your window from gray to something more visually pleasing to interact with. If you misspell the theme name badly or specify a theme name is is missing from the table of allowed names, then a theme will be randomly assigned for you. Who knows, maybe the theme chosen you’ll like and want to use instead of your original plan.

In PySimpleGUI release 4.6 the number of themes was dramatically increased from a couple dozen to over 100. To use the color schemes shown in the window below, add a call to theme('Theme Name) to your code, passing in the name of the desired color theme. To see this window and the list of available themes on your release of software, call the function theme_previewer(). This will create a window with the frames like those below. It will shows you exactly what’s available in your version of PySimpleGUI.

In release 4.9 another 32 Color Themes were added… here are the current choices

Make beautiful looking, alpha-blended (partially transparent) Rainmeter-style Desktop Widgets that run in the background.

Want to build a Crossword Puzzle? No problem, the drawing primitives are there for you.

There are built-in drawing primitives

Frame from integration with a YOLO Machine Learning program that does object identification in realtime while allowing the user to adjust the algorithms settings using the sliders under the image. This level of interactivity with an AI algorithm is still unusual to find due to difficulty of merging the technologies of AI and GUI. It’s no longer difficult. This program is under 200 lines of code.

Pi Windows

Perhaps you’re looking for a way to interact with your Raspberry Pi in a more friendly way. Your PySimpleGUI code will run on a Pi with no problem. Tkinter is alive and well on the Pi platform. Here is a selection of some of the Elements shown on the Pi. You get the same Elements on the Pi as you do Windows and Linux.

You can add custom artwork to make it look nice, like the Demo Program — Weather Forecast shown in this image:

One thing to be aware of with Pi Windows, you cannot make them semi-transparent. This means that the Window.Disappear method will not work. Your window will not disappear. Setting the Alpha Channel will have no effect.

Don’t forget that you can use custom artwork anywhere, including on the Pi. The weather application looks beautiful on the Pi. Notice there are no buttons or any of the normal looking Elements visible. It’s possible to build nice looking applications, even on the lower-end platforms.

Games

It’s possible to create some cool games by simply using the built-in PySimpleGUI graphic primitives’ like those used in this game of pong. PyGame can also be embedded into a PySimpleGUI window and code is provided to you demonstrating how. There is also a demonstration of using the pymunk physics package that can also be used for games.

Games haven’t not been explored much, yet, using PySimpleGUI.

Windows Programs That Look Like Windows Programs

Do you have the desire to share your code with other people in your department, or with friends and family? Many of them may not have Python on their computer. And in the corporate environment, it may not be possible for you to install Python on their computer.

PySimpleGUI + PyInstaller to the rescue!!

Combining PySimpleGUI with PyInstaller creates something truly remarkable and special, a Python program that looks like a Windows WinForms application.

The application you see below with a working menu was created in 20 lines of Python code. It is a single .EXE file that launches straight into the screen you see. And more good news, the only icon you see on the taskbar is the window itself… there is no pesky shell window. Nice, huh?

With a simple GUI, it becomes practical to «associate» .py files with the python interpreter on Windows. Double click a py file and up pops a GUI window, a more pleasant experience than opening a dos Window and typing a command line.

There is even a PySimpleGUI program that will take your PySimpleGUI program and turn it into an EXE. It’s nice because you can use a GUI to select your file and all of the output is shown in the program’s window, in realtime.

Background — Why PySimpleGUI Came to Be

Feel free to skip all this if you don’t care to know the backstory and reasons behind decisions.

There was a project looming and a GUI was needed. It wasn’t a very complex GUI so thus began a search for a simplified GUI package that would enable me to work with tkinter easier. I found a few, and they were pretty popular too, but they lacked the full-compliment of Widgets and it was impossible to define my own window using those widgets.

A whacky idea came to mind… what if I wrote a simplified GUI and then used THAT to write my application. It would be a lot less code and it would be «easy» to write my application then. And that is exactly what was done.

First an early version of PySimpleGUI was written that had a subset of the Elements available today. It had just enough for my application. Then I wrote my application in PySimpleGUI.

Thus PySimpleGUI was born out of necessity and it’s been the necessity of others that have helped evolve it into the package it is today. It would not be 1/2 as good without the help of the community.

Once PySimpleGUI was done, it was time to start working on «the ports». And, of course, also this documentation.

The Non-OO and Non-Event-Driven Model

The two «advanced concepts» that beginning Python students have with GUIs are the use of classes and callbacks with their associated communication and coordination mechanisms (semaphores, queues, etc)

How do you make a GUI interface easy enough for first WEEK Python students?

This meant classes could be used to build and use it, but classes can not be part of the code the user writes. Of course, an OO design is quite possible to use with PySimpleGUI, but it’s not a requirement. The sample code and docs stay away from writing new classes in the user space for the most part.

What about those pesky callbacks? They’re difficult for beginners to grasp and they’re a bit of a pain in the ass to deal with. The way PySimpleGUI got around events was to utilize a «message passing» architecture instead.

Instead of a user function being called when there’s some event, instead the information is «passed» to the user when they call the function Window.read()

Everything is returned through this Window.read call. Of course the underlying GUI frameworks still perform callbacks, but they all happen inside of PySimpleGUI where they are turned into messages to pass to you.

All of the boilerplate code, the event handling, widget creation, frames containing widgets, etc, are exactly the same objects and calls that you would be writing if you wrote directly in tkinter, Qt, etc. With all of this code out of the way and done for you, that leaves you with the task of doing something useful with the information the user entered. THAT, after all, is the goal here…. getting user information and acting on it.

The full complement of Widgets are available to you via PySimpleGUI Elements. And those widgets are presented to you in a unique and fun way.

If you wish to learn more about the Architecture of PySimpleGUI, take a look at the Architecture document located on ReadTheDocs.

The Result

A GUI that’s appealing to a broad audience that is highly customizable, easy to program, and is solid with few bugs and rarely crashes (99% of the time it’s some other error that causes a crash).

PySimpleGUI is becoming more and more popular. The number of installs and the number of successes grows daily. Pip installs have exceeded 350,000 in the first year of existence. Over 300 people a day visit the GitHub and the project has 1,800 stars (thank you awesome users!)

The number of ports is up to 4. The number of integrations with other technologies is constantly being expanded. It’s a great time to try PySimpleGUI! You’ve got no more than 5 or 10 minutes to lose.

Caution is needed, however, when working with the unfinished ports. PySimpleGUI, the tkinter version, is the only fully complete port. Qt is next. All of its Elements are completed, but not all of the options of each element are done. PySimpleGUIWeb is next in order of completeness and then finally PySimpleGUIWx.

Features

While simple to use, PySimpleGUI has significant depth to be explored by more advanced programmers. The feature set goes way beyond the requirements of a beginner programmer, and into the required features needed for complex multi-windowed GUIs.

The SIMPLE part of PySimpleGUI is how much effort you expend to write a GUI, not the complexity of the program you are able to create. It’s literally «simple» to do… and it is not limited to simple problems.

Features of PySimpleGUI include:

• Support for Python versions 2.7 and 3
• Text
• Single Line Input
• Buttons including these types:
  • File Browse
  • Files Browse
  • Folder Browse
  • SaveAs
  • Normal button that returns event
  • Close window
  • Realtime
  • Calendar chooser
  • Color chooser
  • Button Menu
• TTK Buttons or «normal» TK Buttons
• Checkboxes
• Radio Buttons
• Listbox
• Option Menu
• Menubar
• Button Menu
• Slider
• Spinner
• Dial
• Graph
• Frame with title
• Icons
• Multi-line Text Input
• Scroll-able Output
• Images
• Tables
• Trees
• Progress Bar Async/Non-Blocking Windows
• Tabbed windows
• Paned windows
• Persistent Windows
• Multiple Windows — Unlimited number of windows can be open at the same time
• Redirect Python Output/Errors to scrolling window
• ‘Higher level’ APIs (e.g. MessageBox, YesNobox, …)
• Single-Line-Of-Code Progress Bar & Debug Print
• Complete control of colors, look and feel
• Selection of pre-defined palettes
• Button images
• Horizontal and Vertical Separators
• Return values as dictionary
• Set focus
• Bind return key to buttons
• Group widgets into a column and place into window anywhere
• Scrollable columns
• Keyboard low-level key capture
• Mouse scroll-wheel support
• Get Listbox values as they are selected
• Get slider, spinner, combo as they are changed
• Update elements in a live window
• Bulk window-fill operation
• Save / Load window to/from disk
• Borderless (no titlebar) windows (very classy looking)
• Always on top windows
• Menus with ALT-hotkey
• Right click pop-up menu
• Tooltips
• Clickable text
• Transparent windows
• Movable windows
• Animated GIFs
• No async programming required (no callbacks to worry about)
• Built-in debugger and REPL
• User expandable by accessing underlying GUI Framework widgets directly
• Exec APIs — wrapper for subprocessing and threading
• UserSettings APIs — wrapper for JSON and INI files

Design Goals

With the developer being the focus, the center of it all, it was important to keep this mindset at all times, including now, today. Why is this such a big deal? Because this package was written so that the universe of Python applications can grow and can include EVERYONE into the GUI tent.

Up in 5 minutes

Success #1 has to happen immediately. Installing and then running your first GUI program. FIVE minutes is the target. The Pip install is under 1 minute. Depending on your IDE and development environment, running your first piece of code could be a copy, paste, and run. This isn’t a joke target; it’s for real serious.

Beginners and Advanced Together

Design an interface that both the complete beginner can understand and use that has enough depth that an advanced programmer can make some very nice looking GUIs amd not feel like they’re playing with a «toy».

Success After Success

Success after success…. this is the model that will win developer’s hearts. This is what users love about PySimpleGUI. Make your development progress in a way you can run and test your code often. Add a little bit, run it, see it on your screen, smile, move on.

Copy, Paste, Run.

The Cookbook and Demo Programs are there to fulfill this goal. First get the user seeing on their screen a working GUI that’s similar in some way to what they want to create.

If you’re wanting to play with OpenCV download the OpenCV Demo Programs and give them a try. Seeing your webcam running in the middle of a GUI window is quite a thrill if you’re trying to integrate with the OpenCV package.

«Poof» instant running OpenCV based application == Happy Developer

Make Simpler Than Expected Interfaces

The Single Line Progress Meter is a good example. It requires one and only 1 line of code. Printing to a debug window is as easy as replacing print with sg.Print which will route your console output to a scrolling debug window.

Be Pythonic

Be Pythonic…

This one is difficult for me to define. The code implementing PySimpleGUI isn’t PEP8 compliant, but it is consistent. The important thing was what the user saw and experienced while coding, NOT the choices for naming conventions in the implementation code. The user interface to PySimpleGUI now has a PEP8 compliant interface. The methods are snake_case now (in addition to retaining the older CamelCase names)

I ended up defining it as — attempt to use language constructs in a natural way and to exploit some of Python’s interesting features. It’s Python’s lists and optional parameters make PySimpleGUI work smoothly.

Here are some Python-friendly aspects to PySimpleGUI:

• Windows are represented as Python lists of Elements
• Return values are an «event» such a button push and a list/dictionary of input values
• The SDK calls collapse down into a single line of Python code that presents a custom GUI and returns values should you want that extreme of a single-line solution
• Elements are all classes. Users interact with elements using class methods but are not required to write their own classes
• Allow keys and other identifiers be any format you want. Don’t limit user to particular types needlessly.
• While some disagree with the single source file, I find the benefits greatly outweigh the negatives

Lofty Goals

Teach GUI Programming to Beginners

By and large PySimpleGUI is a «pattern based» SDK. Complete beginners can copy these standard design patterns or demo programs and modify them without necessarily understanding all of the nuts and bolts of what’s happening. For example, they can modify a layout by adding elements even though they may not yet grasp the list of lists concept of layouts.

Beginners certainly can add more if event == 'my button': statements to the event loop that they copied from the same design pattern. They will not have to write classes to use this package.

Capture Budding Graphic Designers & Non-Programmers

The hope is that beginners that are interested in graphic design, and are taking a Python course, will have an easy way to express themselves, right from the start of their Python experience. Even if they’re not the best programmers they will be able express themselves to show custom GUI layouts, colors and artwork with ease.

Fill the GUI Gap (Democratize GUIs)

There is a noticeable gap in the Python GUI solution. Fill that gap and who knows what will happen. At the moment, to make a traditional GUI window using tkinter, Qt, WxPython and Remi, it takes much more than a week, or a month of Python education to use these GUI packages.

They are out of reach of the beginners. Often WAY out of reach. And yet, time and time again, beginners that say they JUST STARTED with Python will ask on a Forum or Reddit for a GUI package recommendation. 9 times out of 10 Qt is recommended. (smacking head with hand). What a waste of characters. You might as well have just told them, «give up».

Is There a There?

Maybe there’s no «there there». Or maybe a simple GUI API will enable Python to dominate yet another computing discipline like it has so many others. This is one attempt to find out. So far, it sure looks like there’s PLENTY of demand in this area.

Getting Started with PySimpleGUI

There is a «Troubleshooting» section towards the end of this document should you run into real trouble. It goes into more detail about what you can do to help yourself.

Installing PySimpleGUI

Of course if you’re installing for Qt, WxPython, Web, you’ll use PySimpleGUIQt, PySimpleGUIWx, and PySimpleGUIWeb instead of straight PySimpleGUI in the instructions below. You should already have the underlying GUI Framework installed and perhaps tested. This includes tkinter, PySide2, WxPython, Remi

Installing on Python 3

pip install --upgrade PySimpleGUI

On some systems you need to run pip3. (Linux and Mac)

pip3 install --upgrade PySimpleGUI

On a Raspberry Pi, this is should work:

sudo pip3 install --upgrade pysimplegui

Some users have found that upgrading required using an extra flag on the pip --no-cache-dir.

pip install --upgrade --no-cache-dir PySimpleGUI

On some versions of Linux you will need to first install pip. Need the Chicken before you can get the Egg (get it… Egg?)

sudo apt install python3-pip

tkinter is a requirement for PySimpleGUI (the only requirement). Some OS variants, such as Ubuntu, do not some with tkinter already installed. If you get an error similar to:

ImportError: No module named tkinter

then you need to install tkinter.

For python 2.7

sudo apt-get install python-tk

For python 3
sudo apt-get install python3-tk

More information about installing tkinter can be found here: https://www.techinfected.net/2015/09/how-to-install-and-use-tkinter-in-ubuntu-debian-linux-mint.html

Installing typing module for Python 3.4 (Raspberry Pi)

In order for the docstrings to work correctly the typing module is used. In Python version 3.4 the typing module is not part of Python and must be installed separately. You’ll see a warning printed on the console if this module isn’t installed.

You can pip install typing just like PySimpleGUI. However it’s not a requirement as PySimpleGUI will run fine without typing installed as it’s only used by the docstrings.

Installing for Python 2.7

IMPORTANT PySimpleGUI27 will disappear from the GitHub on Dec 31, 2019. PLEASE migrate to 3.6 at least. It’s not painful for most people.

pip install --upgrade PySimpleGUI27
or
pip2 install --upgrade PySimpleGUI27

You may need to also install «future» for version 2.7

pip install future
or
pip2 install future

Like above, you may have to install either pip or tkinter. To do this on Python 2.7:

sudo apt install python-pip

sudo apt install python-tkinter

Upgrading from GitHub Using PySimpleGUI

There is code in the PySimpleGUI package that upgrades your previously pip installed package to the latest version checked into GitHub.

It overwrites your PySimpleGUI.py file that you installed using pip with the currently posted version on GitHub. Using this method when you’re ready to install the next version from PyPI or you want to maybe roll back to a PyPI release, you only need to run pip.

The PySimpleGUI «Test Harness»

If you call sg.main() then you’ll get the test harness and can use the upgrade feature.

After you’ve pip installed, you can use the commands psgmain to run the test harness or psgupgrade to invoke the GitHub upgrade code.

There have been problems on some machines when psgmain and psgupgrade are used to upgrade PySimpleGUI. The upgrade is in-place so there can be file locking problems. If you have trouble using these commands, then you can also upgrade using this command:

python -m PySimpleGUI.PySimpleGUI upgrade

The «Safest» approach is to call sg.main() from your code and then click the red upgrade button.

Recovering From a Bad GitHub Release

If you run into a problem upgrading after upgrading from GitHub, you can likely use pip to uninstall, then re-install from PyPI to see if you can upgrade again from GitHub.

pip uninstall PySimpleGUI
pip install PySimpleGUI

Testing your installation and Troubleshooting

Once you have installed, or copied the .py file to your app folder, you can test the installation using python.

The Quick Test

The PySimpleGUI Test Harness pictured in the previous section on GUI upgrades is the short program that’s built into PySimpleGUI that serves multiple purposes. It exercises many/most of the available Elements, displays version and location data and works as a quick self-test.

psgmain is a command you can enter to the run PySimpleGUI test harness if you pip installed. You can also use:

From your command line type:
python -m PySimpleGUI.PySimpleGUI

If you’re on Linux/Mac and need to run using the command python3 then of course type that.

This will display the test harness window.

You can also test by using the REPL….

Instructions for Testing Python 2.7:

>>> import PySimpleGUI27
>>> PySimpleGUI27.main()

Instructions for Testing Python 3:

>>> import PySimpleGUI
>>> PySimpleGUI.main()

You will see a «test harness» that exercises the SDK, tells you the version number, allows you to try a number of features as well as access the built-in GitHub upgrade utility.

Finding Out Where Your PySimpleGUI Is Coming From

It’s critical for you to be certain where your code is coming from and which version you’re running.

Sometimes when debugging, questions arise as to exactly which PySimpleGUI you are running. The quick way to find this out is to again, run Python from the command line. This time you’ll type:

>>> import PySimpleGUI as sg
>>> sg

When you type sg, Python will tell you the full patch to your PySimpleGUI file / package. This is critical information to know when debugging because it’s really easy to forget you’ve got an old copy of PySimpleGUI laying around somewhere.

Finding Out Where Your PySimpleGUI Is Coming From (from within your code)

If you continue to have troubles with getting the right version of PySimpleGUI loaded, THE definitive way to determine where your program is getting PySimpleGUI from is to add a print to your program. It’s that simple! You can also get the version you are running by also printing

import PySimpleGUI as sg

print(sg)
print(sg.version)

Just like when using the REPL >>> to determine the location, this print in your code will display the same path information.

Manual installation

If you’re not connected to the net on your target machine, or pip isn’t working, or you want to run the latest code from GitHub, then all you have to do is place the single PySimpleGUI source file PySimpleGUI.py (for tkinter port) in your application’s folder (the folder where the py file is that imports PySimpleGUI). Your application will load that local copy of PySimpleGUI as if it were a package.

Be sure that you delete this PySimpleGUI.py file if you install a newer pip version. Often the sequence of events is that a bug you’ve reported was fixed and checked into GitHub. You download the PySimpleGUI.py file (or the appropriately named one for your port) and put with your app. Then later your fix is posted with a new release on PyPI. You’ll want to delete the GitHub one before you install from pip.

Prerequisites

Python 2.7 or Python 3
tkinter

PySimpleGUI Runs on all Python3 platforms that have tkinter running on them. It has been tested on Windows, Mac, Linux, Raspberry Pi. Even runs on pypy3.

EXE file creation

If you wish to create an EXE from your PySimpleGUI application, you will need to install PyInstaller or cx_freeze. There are instructions on how to create an EXE at the bottom of this document.

The PySimpleGUI EXE Maker can be found in a repo in the PySimpleGUI GitHub account. It’s a simple front-end to pyinstaller.

IDEs

A lot of people ask about IDEs, and many outright fear PyCharm. Compared to your journey of learning Python, learning to use PyCharm as your IDE is nothing. It’s a DAY typically (from 1 to 8 hours). Or, if you’re really really new, perhaps as much as a week to get used to. So, we’re not talking about you needing to learn to flap your arms and fly.

If you found this package, then you’re a bright person Have some confidence in yourself for Christ sake…. I do. Not going to lead you off some cliff, promise!

Some IDEs provide virtual environments, but it’s optional. PyCharm is one example. For these, you will either use their GUI interface to add packages or use their built-in terminal to do pip installs. It’s not recommended for beginners to be working with Virtual Environments. They can be quite confusing. However, if you are a seasoned professional developer and know what you’re doing, there is nothing about PySimpleGUI that will prevent you from working this way.

Officially Supported IDEs

A number of IDEs have known problems with PySimpleGUI. IDLE, Spyder, and Thonny all have known, demonstrable, problems with intermittent or inconsistent results, especially when a program exits and you want to continue to work with it. *** Any IDE that is based on tkinter is going to have issues with the straight PySimpleGUI port.*** This is NOT a PySimpleGUI problem.

The official list of supported IDEs is:

1. PyCharm (or course this is THE IDE to use for use with PySimpleGUI)
2. Wing
3. Visual Studio

If you’re on a Raspberry Pi or some other limited environment, then you’ll may have to use IDLE or Thonny. Just be aware there could be problems using the debugger to debug due to both using tkinter.

Using The Docstrings (Don’t skip this section)

Beginning with the 4.0 release of PySimpleGUI, the tkinter port, a whole new world opened up for PySimpleGUI programmers, one where referencing the readme and ReadTheDocs documentation is no longer needed. PyCharm and Wing both support these docstrings REALLY well and I’m sure Visual Studio does too. Why is this important? Because it will teach you the PySimpleGUI SDK as you use the package.

Don’t know the parameters and various options for the InputText Element? It’s a piece of cake with PyCharm. You can set PyCharm to automatically display documentation about the class, function, method, etc, that your cursor is currently sitting on. You can also manually bring up the documentation by pressing CONTROL+Q. When you do, you’ll be treated to a window similar to this:

Note that my cursor is on InputText. On the left side of the screen, the InputText element’s parameters are not just shown to you, but they are each individually described to you, and, the type is shown as well. I mean, honestly, how much more could you ask for?

OK, I suppose you could ask for a smaller window that just shows the parameters are you’re typing them in. Well, OK, in PyCharm, when your cursor is between the ( ) press CONTROL+P. When you do, you’ll be treated to a little window like this one:

See…. written with the «Developer» in mind, at all times. It’s about YOU, Mr/Ms Developer! So enjoy your package.

The other ports of PySimpleGUI (Qt, WxPython, Web) have not yet had their docstrings updated. They’re NEXT in line to be better documented. Work on a tool has already begun to make that happen sooner than later.

Type Checking With Docstrings

In version 4.17.0 a new format started being used for docstrings. This new format more clearly specified the types for each parameter. It will take some time to get all of the parameter types correctly identified and documented.

Pay attention when you’re working with PyCharm and you’ll see where you may have a mismatch… or where there’s a bad docstring, take your pick. It will shade your code in a way that makes mismatched types very clear to see.

Using — Python 3

To use in your code, simply import….
import PySimpleGUI as sg

Then use either «high level» API calls or build your own windows.

sg.popup('This is my first popup')

Yes, it’s just that easy to have a window appear on the screen using Python. With PySimpleGUI, making a custom window appear isn’t much more difficult. The goal is to get you running on your GUI within minutes, not hours nor days.

Python 3.7

If you must run 3.7, try 3.7.2. It does work with PySimpleGUI with no known issues.

PySimpleGUI with Python 3.7.3 and 3.7.4+. tkinter is having issues with all the newer releases. Things like Table colors stopped working entirely.

March 2020 — Still not quite sure if all issues have been ironed out with tkinter in the 3.7 and 3.8 releases.

Python 2.7

On December 31, 2019 the Python 2.7 version of PySimpleGUI will be deleted from the GitHub. Sorry but Legacy Python has no permanent home here. The security experts claim that supporting 2.7 is doing a disservice to the Python community. I understand why. There are some very narrow cases where 2.7 is required. If you have one, make a copy of PySimpleGUI27.py quickly before it disappears for good.

PEP8 Bindings For Methods and Functions

Beginning with release 4.3 of PySimpleGUI, all methods and function calls have PEP8 equivalents. This capability is only available, for the moment, on the PySimpleGUI tkinter port. It is being added, as quickly as possible, to all of the ports.

As long as you know you’re sticking with tkinter for the short term, it’s safe to use the new bindings.

The Non-PEP8 Methods and Functions

Why the need for these bindings? Simply put, the PySimpleGUI SDK has a PEP8 violation in the method and function names. PySimpleGUI uses CamelCase names for methods and functions. PEP8 suggests using snake_case_variables instead.

This has not caused any problems and few complaints, but it’s important the the interfaces into PySimpleGUI be compliant. Perhaps one of the reasons for lack of complaints is that the Qt library also uses SnakeCase for its methods. This practice has the effect of labelling a package as being «not Pythonic» and also suggests that this package was originally used in another language and then ported to Python. This is exactly the situation with Qt. It was written for C++ and the interfaces continue to use C++ conventions.

PySimpleGUI was written in Python, for Python. The reason for the name problem was one of ignorance. The PEP8 convention wasn’t understood by the developers when PySimpleGUI was designed and implemented.

You can, and will be able to for some time, use both names. However, at some point in the future, the CamelCase names will disappear. A utility is planned to do the conversion for the developer when the old names are remove from PySimpleGUI.

The help system will work with both names as will your IDE’s docstring viewing. However, the result found will show the CamelCase names. For example help(sg.Window.read) will show the CamelCase name of the method/function. This is what will be returned:

Read(self, timeout=None, timeout_key='__TIMEOUT__', close=False)

The Renaming Convention

To convert a CamelCase method/function name to snake_case, you simply place an _ where the Upper Case letter is located. If there are none, then only the first letter is changed.

Window.FindElement becomes Window.find_element

Class Variables

For the time being, class variables will remain the way they are currently. It is unusual, in PySimpleGUI, for class variables to be modified or read by the user code so the impact of leaving them is rarely seen in your code.

High Level API Calls — Popup’s

«High level calls» are those that start with «popup». They are the most basic form of communications with the user. They are named after the type of window they create, a pop-up window. These windows are meant to be short lived while, either delivering information or collecting it, and then quickly disappearing.

Think of Popups as your first windows, sorta like your first bicycle. It worked well, but was limited. It probably wasn’t long before you wanted more features and it seemed too limiting for your newly found sense of adventure.

When you’ve reached the point with Popups that you are thinking of filing a GitHub «Enhancement Issue» to get the Popup call extended to include a new feature that you think would be helpful…. not just to you but others is what you had in mind, right? For the good of others.

Well, don’t file that enhancement request. Instead, it’s at THIS time that you should immediately turn to the section entitled «Custom Window API Calls — Your First Window». Congratulations, you just graduated and are now an official «GUI Designer». Oh, never mind that you only started learning Python 2 weeks ago, you’re a real GUI Designer now so buck up and start acting like one. Write a popup function of your own. And then, compact that function down to a single line of code. Yes, these popups can be written in 1 line of code. The secret is to use the close parameter on your call to window.read()

But, for now, let’s stick with these 1-line window calls, the Popups. This is the list of popup calls available to you:

popup_animated
popup_annoying
popup_auto_close
popup_cancel
popup_error
popup_get_file
popup_get_folder
popup_get_text
popup_no_border
popup_no_buttons
popup_no_frame
popup_no_titlebar
popup_no_wait
popup_notify
popup_non_blocking
popup_ok
popup_ok_cancel
popup_quick
popup_quick_message
popup_scrolled
popup_timed
popup_yes_no

Popup Output

Think of the popup call as the GUI equivalent of a print statement. It’s your way of displaying results to a user in the windowed world. Each call to Popup will create a new Popup window.

popup calls are normally blocking. your program will stop executing until the user has closed the Popup window. A non-blocking window of Popup discussed in the async section.

Just like a print statement, you can pass any number of arguments you wish. They will all be turned into strings and displayed in the popup window.

There are a number of Popup output calls, each with a slightly different look or functionality (e.g. different button labels, window options).

The list of Popup output functions are:

• popup
• popup_ok
• popup_yes_no
• popup_cancel
• popup_ok_cancel
• popup_error
• popup_timed, popup_auto_close, popup_quick, popup_quick_message
• popup_no_waitWait, popup_non_blocking
• popup_notify

The trailing portion of the function name after Popup indicates what buttons are shown. PopupYesNo shows a pair of button with Yes and No on them. PopupCancel has a Cancel button, etc..

While these are «output» windows, they do collect input in the form of buttons. The Popup functions return the button that was clicked. If the Ok button was clicked, then Popup returns the string ‘Ok’. If the user clicked the X button to close the window, then the button value returned is None or WIN_CLOSED is more explicit way of writing it.

The function popup_timed or popup_auto_close are popup windows that will automatically close after come period of time.

Here is a quick-reference showing how the Popup calls look.

sg.popup('popup')  # Shows OK button
sg.popup_ok('popup_ok')  # Shows OK button
sg.popup_yes_no('popup_yes_no')  # Shows Yes and No buttons
sg.popup_cancel('popup_cancel')  # Shows Cancelled button
sg.popup_ok_cancel('popup_ok_cancel')  # Shows OK and Cancel buttons
sg.popup_error('popup_error')  # Shows red error button
sg.popup_timed('popup_timed')  # Automatically closes
sg.popup_auto_close('popup_auto_close')  # Same as PopupTimed

Preview of popups:

Popup — Display a popup Window with as many parms as you wish to include. This is the GUI equivalent of the
«print» statement. It’s also great for «pausing» your program’s flow until the user can read some error messages.

If this popup doesn’t have the features you want, then you can easily make your own. Popups can be accomplished in 1 line of code:
choice, _ = sg.Window(‘Continue?’, [[sg.T(‘Do you want to continue?’)], [sg.Yes(s=10), sg.No(s=10)]], disable_close=True).read(close=True)

popup(args=*<1 or N object>,
    title = None,
    button_color = None,
    background_color = None,
    text_color = None,
    button_type = 0,
    auto_close = False,
    auto_close_duration = None,
    custom_text = (None, None),
    non_blocking = False,
    icon = None,
    line_width = None,
    font = None,
    no_titlebar = False,
    grab_anywhere = False,
    keep_on_top = None,
    location = (None, None),
    relative_location = (None, None),
    any_key_closes = False,
    image = None,
    modal = True,
    button_justification = None,
    drop_whitespace = True)

Parameter Descriptions:

The other output Popups are variations on parameters. Usually the button_type parameter is the primary one changed.

The choices for button_type are (you should not specify these yourself however):

POPUP_BUTTONS_YES_NO
POPUP_BUTTONS_CANCELLED
POPUP_BUTTONS_ERROR
POPUP_BUTTONS_OK_CANCEL
POPUP_BUTTONS_OK
POPUP_BUTTONS_NO_BUTTONS

Note that you should not call Popup yourself with different button_types. Rely on the Popup function named that sets that value for you. For example popup_yes_no will set the button type to POPUP_BUTTONS_YES_NO for you.

Scrolled Output

There is a scrolled version of Popups should you have a lot of information to display.

Show a scrolled Popup window containing the user’s text that was supplied. Use with as many items to print as you
want, just like a print statement.

popup_scrolled(args=*<1 or N object>,
    title = None,
    button_color = None,
    background_color = None,
    text_color = None,
    yes_no = False,
    no_buttons = False,
    button_justification = "l",
    auto_close = False,
    auto_close_duration = None,
    size = (None, None),
    location = (None, None),
    relative_location = (None, None),
    non_blocking = False,
    no_titlebar = False,
    grab_anywhere = False,
    keep_on_top = None,
    font = None,
    image = None,
    icon = None,
    modal = True,
    no_sizegrip = False)

Parameter Descriptions:

Typical usage:

sg.popup_scrolled(my_text)

The popup_scrolled will auto-fit the window size to the size of the text. Specify None in the height field of a size parameter to get auto-sized height.

This call will create a scrolled box 80 characters wide and a height dependent upon the number of lines of text.

sg.popup_scrolled(my_text, size=(80, None))

Note that the default max number of lines before scrolling happens is set to 50. At 50 lines the scrolling will begin.

If non_blocking parameter is set, then the call will not blocking waiting for the user to close the window. Execution will immediately return to the user. Handy when you want to dump out debug info without disrupting the program flow.

Non-Blocking Popups — popup_no_wait and the non_blocking parameter

Show Popup window and immediately return (does not block)

popup_no_wait(args=*<1 or N object>,
    title = None,
    button_type = 0,
    button_color = None,
    background_color = None,
    text_color = None,
    auto_close = False,
    auto_close_duration = None,
    non_blocking = True,
    icon = None,
    line_width = None,
    font = None,
    no_titlebar = False,
    grab_anywhere = False,
    keep_on_top = None,
    location = (None, None),
    relative_location = (None, None),
    image = None,
    modal = False)

Parameter Descriptions:

The popup call popup_no_wait or popup_non_blocking will create a popup window and then immediately return control back to you. You can turn other popup calls into non-blocking popups if they have a non_blocking parameter. Setting non_blocking to True will cause the function to return immediately rather than waiting for the window to be closed.

This function is very handy for when you’re debugging and want to display something as output but don’t want to change the programs’s overall timing by blocking. Think of it like a print statement. There are no return values on one of these Popups.

Popup Parameter Combinations

So that you don’t have to specify a potentially long list common parameters there are a number of popup functions that set combinations of parameters. For example popup_quick_message will show a non-blocking popup that autocloses and does not have a titlebar. You could achieve this same end result using the plain popup call.

Popup Input

There are Popup calls for single-item inputs. These follow the pattern of popup_get followed by the type of item to get. There are 3 of these input Popups to choose from, each with settings enabling customization.

• popup_get_text — get a single line of text
• popup_get_file — get a filename
• popup_get_folder — get a folder name

Use these Popups instead of making a custom window to get one data value, call the Popup input function to get the item from the user. If you find the parameters are unable to create the kind of window you are looking for, then it’s time for you to create your own window.

popup_get_text

Use this Popup to get a line of text from the user.

Display Popup with text entry field. Returns the text entered or None if closed / cancelled

popup_get_text(message,
    title = None,
    default_text = "",
    password_char = "",
    size = (None, None),
    button_color = None,
    background_color = None,
    text_color = None,
    icon = None,
    font = None,
    no_titlebar = False,
    grab_anywhere = False,
    keep_on_top = None,
    location = (None, None),
    relative_location = (None, None),
    image = None,
    history = False,
    history_setting_filename = None,
    modal = True)

Parameter Descriptions:

import PySimpleGUI as sg
text = sg.popup_get_text('Title', 'Please input something')
sg.popup('Results', 'The value returned from PopupGetText', text)

popup_get_file

Gets one or more filenames from the user. There are options to configure the type of dialog box to show. Normally an «Open File» dialog box is shown.

Display popup window with text entry field and browse button so that a file can be chosen by user.

popup_get_file(message,
    title = None,
    default_path = "",
    default_extension = "",
    save_as = False,
    multiple_files = False,
    file_types = (('ALL Files', '*.* *'),),
    no_window = False,
    size = (None, None),
    button_color = None,
    background_color = None,
    text_color = None,
    icon = None,
    font = None,
    no_titlebar = False,
    grab_anywhere = False,
    keep_on_top = None,
    location = (None, None),
    relative_location = (None, None),
    initial_folder = None,
    image = None,
    files_delimiter = ";",
    modal = True,
    history = False,
    show_hidden = True,
    history_setting_filename = None)

Parameter Descriptions:

If configured as an Open File Popup then (save_as is not True) the dialog box will look like this.

If you set the parameter save_As to True, then the dialog box looks like this:

If you choose a filename that already exists, you’ll get a warning popup box asking if it’s OK. You can also specify a file that doesn’t exist. With an «Open» dialog box you cannot choose a non-existing file.

A typical call produces this window.

text = sg.popup_get_file('Please enter a file name')
sg.popup('Results', 'The value returned from popup_get_file', text)

popup_get_folder

The window created to get a folder name looks the same as the get a file name. The difference is in what the browse button does. popup_get_file shows an Open File dialog box while popup_get_folder shows an Open Folder dialog box.

Display popup with text entry field and browse button so that a folder can be chosen.

popup_get_folder(message,
    title = None,
    default_path = "",
    no_window = False,
    size = (None, None),
    button_color = None,
    background_color = None,
    text_color = None,
    icon = None,
    font = None,
    no_titlebar = False,
    grab_anywhere = False,
    keep_on_top = None,
    location = (None, None),
    relative_location = (None, None),
    initial_folder = None,
    image = None,
    modal = True,
    history = False,
    history_setting_filename = None)

Parameter Descriptions:

This is a typical call

	text = sg.popup_get_folder('Please enter a folder name')
	sg.popup('Results', 'The value returned from popup_get_folder', text)

popup_animated

The animated Popup enables you to easily display a «loading» style animation specified through a GIF file that is either stored in a file or a base64 variable.

Show animation one frame at a time. This function has its own internal clocking meaning you can call it at any frequency
and the rate the frames of video is shown remains constant. Maybe your frames update every 30 ms but your
event loop is running every 10 ms. You don’t have to worry about delaying, just call it every time through the
loop.

popup_animated(image_source,
    message = None,
    background_color = None,
    text_color = None,
    font = None,
    no_titlebar = True,
    grab_anywhere = True,
    keep_on_top = True,
    location = (None, None),
    relative_location = (None, None),
    alpha_channel = None,
    time_between_frames = 0,
    transparent_color = None,
    title = "",
    icon = None)

Parameter Descriptions:

To close animated popups, call PopupAnimated with image_source=None. This will close all of the currently open PopupAnimated windows.

Progress Meters!

We all have loops in our code. ‘Isn’t it joyful waiting, watching a counter scrolling past in a text window? How about one line of code to get a progress meter, that contains statistics about your code?

one_line_progress_meter(title,
    current_value,
    max_value,
    args=*<1 or N object>,
    key = "OK for 1 meter",
    orientation = "v",
    bar_color = (None, None),
    button_color = None,
    size = (20, 20),
    border_width = None,
    grab_anywhere = False,
    no_titlebar = False,
    keep_on_top = None,
    no_button = False)

Parameter Descriptions:

Here’s the one-line Progress Meter in action!

for i in range(1,10000):
	sg.one_line_progress_meter('My Meter', i+1, 10000, 'key','Optional message')

That line of code resulted in this window popping up and updating.

A meter AND fun statistics to watch while your machine grinds away, all for the price of 1 line of code.
With a little trickery you can provide a way to break out of your loop using the Progress Meter window. The cancel button results in a False return value from one_line_progress_meter. It normally returns True.

Be sure and add one to your loop counter so that your counter goes from 1 to the max value. If you do not add one, your counter will never hit the max value. Instead it will go from 0 to max-1.

Debug Output (easy_print = Print = eprint)

Another call in the ‘Easy’ families of APIs is EasyPrint. As is with other commonly used PySimpleGUI calls, there are other names for the same call. You can use Print or eprint in addition to EasyPrint. They all do the same thing, output to a debug window. If the debug window isn’t open, then the first call will open it. No need to do anything but stick an ‘sg.Print’ call in your code. You can even replace your ‘print’ calls with calls to EasyPrint by simply sticking the statement

at the top of your code.

Print is one of the better ones to use as it’s easy to remember. It is simply print with a capital P. sg.Print('this will go to the debug window')

import PySimpleGUI as sg

for i in range(100):
	sg.Print(i)

Or if you didn’t want to change your code:

import PySimpleGUI as sg

print=sg.Print
for i in range(100):
    print(i)

Just like the standard print call, easy_print supports the sep and end keyword arguments. Other names that can be used to call easy_print include Print, eprint, If you want to close the window, call the function easy_print_close.

You can change the size of the debug window using the set_options call with the debug_win_size parameter.

There is an option to tell PySimpleGUI to reroute all of your stdout and stderr output to this window. To do so call easy_print with the parameter do_not_reroute_stdout set to False. After calling it once with this parameter set to True, all future calls to a normal print will go to the debug window.

If you close the debug window it will re-open the next time you Print to it. If you wish to close the window using your code, then you can call either easy_print_close() or PrintClose()

Printing To Multiline Elements

Another technique for outputting information that you would normally print is to use the function Multiline.print. You’ll find it discussed further into this document. The basic idea is that you can easily modify your normal print calls to route your printed information to your window.

Custom window API Calls (Your First window)

This is the FUN part of the programming of this GUI. In order to really get the most out of the API, you should be using an IDE that supports auto complete or will show you the definition of the function. This will make customizing go smoother.

This first section on custom windows is for your typical, blocking, non-persistent window. By this I mean, when you «show» the window, the function will not return until the user has clicked a button or closed the window with an X.

Two other types of windows exist.

1. Persistent window — the Window.read() method returns and the window continues to be visible. This is good for applications like a chat window or a timer or anything that stays active on the screen for a while.
2. Asynchronous window — the trickiest of the lot. Great care must be exercised. Examples are an MP3 player or status dashboard. Async windows are updated (refreshed) on a periodic basis. You can spot them easily as they will have a timeout parameter on the call to read. event, values = window.read(timeout=100)

It’s both not enjoyable nor helpful to immediately jump into tweaking each and every little thing available to you. Make some simple windows. Use the Cookbook and the Demo Programs as a way to learn and as a «starting point».

The window Designer

The good news to newcomers to GUI programming is that PySimpleGUI has a window designer. Better yet, the window designer requires no training, no downloads, and everyone knows how to use it.

It’s a manual process, but if you follow the instructions, it will take only a minute to do and the result will be a nice looking GUI. The steps you’ll take are:

1. Sketch your GUI on paper
2. Divide your GUI up into rows
3. Label each Element with the Element name
4. Write your Python code using the labels as pseudo-code

Let’s take a couple of examples.

Enter a number…. Popular beginner programs are often based on a game or logic puzzle that requires the user to enter something, like a number. The «high-low» answer game comes to mind where you try to guess the number based on high or low tips.

Step 1- Sketch the GUI

Step 2 — Divide into rows

Step 3 — Label elements

Step 4 — Write the code
The code we’re writing is the layout of the GUI itself. This tutorial only focuses on getting the window code written, not the stuff to display it, get results.

We have only 1 element on the first row, some text. Rows are written as a «list of elements», so we’ll need [ ] to make a list. Here’s the code for row 1

[ sg.Text('Enter a number') ]

Row 2 has 1 elements, an input field.

Row 3 has an OK button

Now that we’ve got the 3 rows defined, they are put into a list that represents the entire window.

layout = [ [sg.Text('Enter a Number')],
           [sg.Input()],
           [sg.OK()] ]

Finally we can put it all together into a program that will display our window.

import PySimpleGUI as sg

layout = [[sg.Text('Enter a Number')],
          [sg.Input()],
          [sg.OK()] ]

window = sg.Window('Enter a number example', layout)

event, values = window.read()

window.close()

sg.Popup(event, values[0])

Your call to read will normally return a dictionary, but will «look like a list» in how you access it. The first input field will be entry 0, the next one is 1, etc.. Later you’ll learn about the key parameter which allows you to use your own values to identify elements instead of them being numbered for you.

Example 2 — Get a filename

Let’s say you’ve got a utility you’ve written that operates on some input file and you’re ready to use a GUI to enter than filename rather than the command line. Follow the same steps as the previous example — draw your window on paper, break it up into rows, label the elements.

Writing the code for this one is just as straightforward. There is one tricky thing, that browse for a file button. Thankfully PySimpleGUI takes care of associating it with the input field next to it. As a result, the code looks almost exactly like the window on the paper.

import PySimpleGUI as sg

sg.theme('Dark Blue 3')  # please make your windows colorful

layout = [[sg.Text('Filename')],
			[sg.Input(), sg.FileBrowse()],
			[sg.OK(), sg.Cancel()] ]

window = sg.Window('Get filename example', layout)
event, values = window.read()
window.close()

sg.Popup(event, values[0])

Read on for detailed instructions on the calls that show the window and return your results.

Copy these design patterns!

All of your PySimpleGUI programs will utilize one of these 2 design patterns depending on the type of window you’re implementing.

Beginning in release 4.19.0 the constant WIN_CLOSED replaced using None as the event signaling that a window was closed.

Pattern 1 A — «One-shot Window» — Read a window one time then close it

This will be the most common pattern you’ll follow if you are not using an «event loop» (not reading the window multiple times). The window is read and closed.

The input fields in your window will be returned to you as a dictionary (syntactically it looks just like a list lookup)

import PySimpleGUI as sg

sg.theme('Dark Blue 3')  # please make your windows colorful

layout = [[sg.Text('SHA-1 and SHA-256 Hashes for the file')],
				 [sg.InputText(), sg.FileBrowse()],
				 [sg.Submit(), sg.Cancel()]]

window = sg.Window('SHA-1 & 256 Hash', layout)

event, values = window.read()
window.close()

source_filename = values[0]     # the first input element is values[0]

Pattern 1 B — «One-shot Window» — Read a window one time then close it (compact format)

Same as Pattern 1, but done in a highly compact way. This example uses the close parameter in window.read to automatically close the window as part of the read operation (new in version 4.16.0). This enables you to write a single line of code that will create, display, gather input and close a window. It’s really powerful stuff!

import PySimpleGUI as sg

sg.theme('Dark Blue 3')  # please make your windows colorful

event, values  = sg.Window('SHA-1 & 256 Hash', [[sg.Text('SHA-1 and SHA-256 Hashes for the file')],
				        [sg.InputText(), sg.FileBrowse()],
				        [sg.Submit(), sg.Cancel()]]).read(close=True)

source_filename = values[0]     # the first input element is values[0]

Pattern 2 A — Persistent window (multiple reads using an event loop)

Some of the more advanced programs operate with the window remaining visible on the screen. Input values are collected, but rather than closing the window, it is kept visible acting as a way to both output information to the user and gather input data.

This code will present a window and will print values until the user clicks the exit button or closes window using an X.

import PySimpleGUI as sg

sg.theme('Dark Blue 3')  # please make your windows colorful

layout = [[sg.Text('Persistent window')],
		  [sg.Input()],
		  [sg.Button('Read'), sg.Exit()]]

window = sg.Window('Window that stays open', layout)

while True:
	event, values = window.read()
	if event == sg.WIN_CLOSED or event == 'Exit':
		break
	print(event, values)

window.close()

Pattern 2 B — Persistent window (multiple reads using an event loop + updates data in window)

This is a slightly more complex, but maybe more realistic version that reads input from the user and displays that input as text in the window. Your program is likely to be doing both of those activities (input and output) so this will give you a big jump-start.

Do not worry yet what all of these statements mean. Just copy it so you can begin to play with it, make some changes. Experiment to see how thing work.

This example introduces the concept of «keys». Keys are super important in PySimpleGUI as they enable you to identify and work with Elements using names you want to use. Keys can be (almost) ANYTHING, except None or a List (a tuple is fine). To access an input element’s data that is read in the example below, you will use values['-IN-'] instead of values[0] like before.

import PySimpleGUI as sg

sg.theme('Dark Blue 3')  # please make your windows colorful

layout = [[sg.Text('Your typed chars appear here:'), sg.Text(size=(12,1), key='-OUTPUT-')],
          [sg.Input(key='-IN-')],
          [sg.Button('Show'), sg.Button('Exit')]]

window = sg.Window('Window Title', layout)

while True:  # Event Loop
    event, values = window.read()
    print(event, values)
    if event == sg.WIN_CLOSED or event == 'Exit':
        break
    if event == 'Show':
        # change the "output" element to be the value of "input" element
        window['-OUTPUT-'].update(values['-IN-'])

window.close()

Qt Designer

There actually is a PySimpleGUI Window Designer that uses Qt’s window designer. It’s outside the scope of this document however. You’ll find the project here: https://github.com/nngogol/PySimpleGUIDesigner

I hope to start using it more soon.

How GUI Programming in Python Should Look? At least for beginners ?

While one goal was making it simple to create a GUI another just as important goal was to do it in a Pythonic manner. Whether it achieved these goals is debatable, but it was an attempt just the same.

The key to custom windows in PySimpleGUI is to view windows as ROWS of GUI Elements. Each row is specified as a list of these Elements. Put the rows together and you’ve got a window. This means the GUI is defined as a series of Lists, a Pythonic way of looking at things.

Let’s dissect this little program

import PySimpleGUI as sg

sg.theme('Dark Blue 3')  # please make your windows colorful

layout = [[sg.Text('Rename files or folders')],
	  [sg.Text('Source for Folders', size=(15, 1)), sg.InputText(), sg.FolderBrowse()],
	  [sg.Text('Source for Files ', size=(15, 1)), sg.InputText(), sg.FileBrowse()],
	  [sg.Submit(), sg.Cancel()]]

window = sg.Window('Rename Files or Folders', layout)

event, values = window.read()
window.close()
folder_path, file_path = values[0], values[1]       # get the data from the values dictionary
print(folder_path, file_path)

Themes

The first line of code after the import is a call to theme.

Until Dec 2019 the way a «theme» was specific in PySimpleGUI was to call change_look_and_feel. That call has been replaced by the more simple function theme.

Window contents (The Layout)

Let’s agree the window has 4 rows.

The first row only has text that reads Rename files or folders

The second row has 3 elements in it. First the text Source for Folders, then an input field, then a browse button.

Now let’s look at how those 2 rows and the other two row from Python code:

layout = [[sg.Text('Rename files or folders')],
          [sg.Text('Source for Folders', size=(15, 1)), sg.InputText(), sg.FolderBrowse()],
          [sg.Text('Source for Files ', size=(15, 1)), sg.InputText(), sg.FileBrowse()],
          [sg.Submit(), sg.Cancel()]]

See how the source code mirrors the layout? You simply make lists for each row, then submit that table to PySimpleGUI to show and get values from.

And what about those return values? Most people simply want to show a window, get the input values and do something with them. So why break up the code into button callbacks, etc., when I simply want my window’s input values to be given to me.

For return values the window is scanned from top to bottom, left to right. Each field that’s an input field will occupy a spot in the return values.

In our example window, there are 2 fields, so the return values from this window will be a dictionary with 2 values in it. Remember, if you do not specify a key when creating an element, one will be created for you. They are ints starting with 0. In this example, we have 2 input elements. They will be addressable as values[0] and values[1]

«Reading» the window’s values (also displays the window)

event, values = window.read()
folder_path, file_path = values[0], values[1]

In one statement we both show the window and read the user’s inputs. In the next line of code the dictionary of return values is split into individual variables folder_path and file_path.

Isn’t this what a Python programmer looking for a GUI wants? Something easy to work with to get the values and move on to the rest of the program, where the real action is taking place. Why write pages of GUI code when the same layout can be achieved with PySimpleGUI in 3 or 4 lines of code. 4 lines or 40? Most would choose 4.

Return values

There are 2 return values from a call to Window.read(), an event that caused the Read to return and values a list or dictionary of values. If there are no elements with keys in the layout, then it will be a list. However, some elements, like some buttons, have a key automatically added to them. It’s best to use keys on all of your input type elements.

Two Return Values

All Window Read calls return 2 values. By convention a read statement is written:

event, values = window.read()

You don’t HAVE to write your reads in this way. You can name your variables however you want. But if you want to code them in a way that other programmers using PySimpleGUI are used to, then use this statement.

Events

The first parameter event describes why the read completed. Events are one of these:

For all Windows:

• Button click
• Window closed using X

For Windows that have specifically enabled these. Please see the appropriate section in this document to learn about how to enable these and what the event return values are.

• Keyboard key press
• Mouse wheel up/down
• Menu item selected
• An Element Changed (slider, spinner, etc.)
• A list item was clicked
• Return key was pressed in input element
• Timeout waiting for event
• Text was clicked
• Combobox item chosen
• Table row selected
• etc.

Most of the time the event will be a button click or the window was closed. The other Element-specific kinds of events happen when you set enable_events=True when you create the Element.

Button Click Events

By default buttons will always return a click event, or in the case of realtime buttons, a button down event. You don’t have to do anything to enable button clicks. To disable the events, disable the button using its Update method.

You can enable an additional «Button Modified» event by setting enable_events=True in the Button call. These events are triggered when something ‘writes’ to a button, usually it’s because the button is listed as a «target» in another button.

The button value from a Read call will be one of 2 values:

1. The Button’s text — Default
2. The Button’s key — If a key is specified

If a button has a key set when it was created, then that key will be returned, regardless of what text is shown on the button. If no key is set, then the button text is returned. If no button was clicked, but the window returned anyway, the event value is the key that caused the event to be generated. For example, if enable_events is set on an Input Element and someone types a character into that Input box, then the event will be the key of the input box.

Element Events

Some elements are capable of generating events when something happens to them. For example, when a slider is moved, or list item clicked on or table row clicked on. These events are not enabled by default. To enable events for an Element, set the parameter enable_events=True. This is the same as the older click_submits parameter. You will find the click_submits parameter still in the function definition. You can continue to use it. They are the same setting. An ‘or’ of the two values is used. In the future, click_submits will be removed so please migrate your code to using enable_events.

Other Events

Menubar menu item chosen for MenuBar menus and ButtonMenu menus

You will receive the key for the MenuBar and ButtonMenu. Use that key to read the value in the return values dictionary. The value shown will be the full text plus key for the menu item chosen. Remember that you can put keys onto menu items. You will get the text and the key together as you defined it in the menu
definition.

Right Click menu item chosen

Unlike menu bar and button menus, you will directly receive the menu item text and its key value. You will not do a dictionary lookup to get the value. It is the event code returned from WindowRead().

Windows — keyboard, mouse scroll wheel

Windows are capable of returning keyboard events. These are returned as either a single character or a string if it’s a special key. Experiment is all I can say. The mouse scroll wheel events are also strings. Put a print in your code to see what’s returned.

Timeouts

If you set a timeout parameter in your read, then the system TIMEOUT_KEY will be returned. If you specified your own timeout key in the Read call then that value will be what’s returned instead.

Window Closed Events

Detecting and correctly handling Windows being closed is an important part of your PySimpleGUI application. You will find in every event loop in every Demo Program an if statement that checks for the events that signal that a window has closed.

The most obvious way to close a window is to click the «X» in the upper right corner of the window (on Windows, Linux…. Mac doesn’t use an «X» but still has a close button). On Windows systems, the keyboard keys ALT+F4 will force a Window to close. This is one way to close a window without using a mouse. Some programs can also send a «close» command to the window.

Regardless of how the close is performed on the window, PySimpleGUI returns an event for this closure.

WIN_CLOSED Event

The constant WIN_CLOSED (None) is returned when the user clicks the X to close a window.

Typically, the check for a closed window happens right after the window.read() call returns. The reason for this is that operating on a closed window can result in errors. The check for closure is an «if» statement.

ALWAYS include a check for a closed window in your event loop.

The Window Closed If Statement

There are 2 forms you’ll find for this if statement in the documentation and the Demo Programs. One is «Pythonic» the other is more understandable by beginners. This is the format you’ll see most often in the PySimpleGUI materials if the window has both a button that is used to signal the user wishes to exit. In this example, I’m using a «Quit» button:

if event == sg.WIN_CLOSED or event == 'Exit':
    break

The more «Pythonic» version of this same statement is:

if event in (sg.WIN_CLOSED, 'Exit'):
    break

In case you’re yelling at your screen right now that the second form should always be used, remember that many of the PySimpleGUI users are new to Python. If the very first example of a PySimpleGUI program they see has that if statement in it, they will instantly be lost before they can even begin their journey. So, the decision was made to, you guessed it, go SIMPLE. The statement with the «or» is simpler to understand.

This notion of binary choices in programming that’s crept in over the past couple decades… that there’s a «BEST» or «only 1 right way»… loses the sophisticated thinking that a software engineer needs to be successful in a wide variety of situations. Every situation, every person, every problem… is unique. There is no idealized best that always fits.

A Complete Example — Traditional Window Closed Check

Let’s put this if statement into context so you can see where it goes and how it works with the event loop

import PySimpleGUI as sg

layout = [[sg.Text('Very basic Window')],
          [sg.Text('Click X in titlebar or the Exit button')],
          [sg.Button('Go'), sg.Button('Exit')]]

window = sg.Window('Window Title', layout)

while True:
    event, values = window.read()
    print(event, values)
    if event == sg.WIN_CLOSED or event == 'Exit':
        break

window.close()

Notice that the line after the while loop is a call to window.close(). The reason for this is that exiting the loop can be in 2 ways.

• The «X» is clicked
• The Exit button is clicked

If the Exit button is clicked, the window will still be open. Get in the habit of closing your windows explicitly like this.

If the user clicked «X» and closed the window, then it will have been destroyed by the underlying framework. You should STILL call window.close() because come cleanup work may be needed and there is no harm in closing an already closed window.

tkinter can generate an error/warning sometimes if you don’t close the window. For other ports, such as PySimpleGUIWeb, not closing the Window will potentially cause your program to continue to run in the background. This can cause your program to not be visible and yet consuming 100% of the CPU time. Not fun for your users.

Window Close Confirmation

In 4.33.0 a new parameter, enable_close_attempted_event, was added to the Window object. This boolean parameter indicates if you would like to receive an event that a user wants to close the window rather than an event that the user has closed the window.

To enable this feature, the Window is created with something like this:

window = sg.Window('Window Title', layout, enable_close_attempted_event=True)

When the close attempted feature is enabled, when the user clicks the «X» or types ALT+F4, you will not get a WIN_CLOSED event like previously, you will instead get an event WINDOW_CLOSE_ATTEMPTED_EVENT and the window will remain open.

Usually this feature is used to add a «close confirmation» popup. The flow goes something like this:

• Window is shown
• User clicks X
• A popup window is shown with message «Do you really want to close the window?»
• If confirmed a close is desired, the window is closed. It not, the event loop continues on, basically ignoring the event occurred.

A Complete Example — Window Closed Confirmation (enable_close_attempted_event=True)

Returning to the example used above, there has been only 2 modifications.

1. Added the parameter enable_close_attempted_event=True to the call to Window
2. The if statement in the event loop has changed to add a confirmation

import PySimpleGUI as sg

layout = [[sg.Text('Very basic Window')],
          [sg.Text('Click X in titlebar or the Exit button')],
          [sg.Button('Go'), sg.Button('Exit')]]

window = sg.Window('Window Title', layout, enable_close_attempted_event=True)

while True:
    event, values = window.read()
    print(event, values)
    if (event == sg.WINDOW_CLOSE_ATTEMPTED_EVENT or event == 'Exit') and sg.popup_yes_no('Do you really want to exit?') == 'Yes':
        break

window.close()

The event loop changed from a check like this:

    if event == sg.WIN_CLOSED or event == 'Exit':
        break

To one like this:

    if (event == sg.WINDOW_CLOSE_ATTEMPTED_EVENT or event == 'Exit') and sg.popup_yes_no('Do you really want to exit?') == 'Yes':
        break

Let’s run this last program so you can see what all this looks like to users.

In both cases that a user previously exited the window, there is now an additional confirmation step.

Demo Programs…. A PySimpleGUI Program’s Best Friend

Like all features of PySimpleGUI, one of the best resources available to you to learn about parameters, like this close attempted parameter, are the Demo Programs. When you run into a parameter or a feature you’ve not used before, one way to find some examples of its use is to use the Demo Browser to search through the demo programs. You’ll find the Demo Browser described in the Cookbook.

As of this writing, the name of the Demo Program Browser is:

Browser_START_HERE_Demo_Programs_Browser.py

If you enter the parameter described in this section — enable_close_attempted_event you’ll find a Demo Program that uses this parameter.

This demo shows you code similar to the code used in this section of the documentation. Use this Browser program! It will make finding examples much easier!

See the section up above on the pip-installable version of the demos (search for — psgdemos) to get the super-quick method of getting the demo programs and the Demo Browser.

The values Variable — Return values as a list

The second parameter from a Read call is either a list or a dictionary of the input fields on the Window.

By default return values are a list of values, one entry for each input field, but for all but the simplest of windows the return values will be a dictionary. This is because you are likely to use a ‘key’ in your layout. When you do, it forces the return values to be a dictionary.

Each of the Elements that are Input Elements will have a value in the list of return values. If you know for sure that the values will be returned as a list, then you could get clever and unpack directly into variables.

event, (filename, folder1, folder2, should_overwrite) = sg.Window(‘My title’, window_rows).read()

Or, more commonly, you can unpack the return results separately. This is the preferred method because it works for both list and dictionary return values.

event, values = sg.Window('My title', window_rows).read()
event, value_list = window.read()
value1 = value_list[0]
value2 = value_list[1]
	 ...

However, this method isn’t good when you have a lot of input fields. If you insert a new element into your window then you will have to shuffle your unpacks down, modifying each of the statements to reference value_list[x].

The more common method is to request your values be returned as a dictionary by placing keys on the «important» elements (those that you wish to get values from and want to interact with)

values Variable — Return values as a dictionary

For those of you that have not encountered a Python dictionary, don’t freak out! Just copy and paste the sample code and modify it. Follow this design pattern and you’ll be fine. And you might learn something along the way.

For windows longer than 3 or 4 fields you will want to use a dictionary to help you organize your return values. In almost all (if not all) of the demo programs you’ll find the return values being passed as a dictionary. It is not a difficult concept to grasp, the syntax is easy to understand, and it makes for very readable code.

The most common window read statement you’ll encounter looks something like this:

window = sg.Window("My title", layout).read()

To use a dictionary, you will need to:

• Mark each input element you wish to be in the dictionary with the keyword key.

If any element in the window has a key, then all of the return values are returned via a dictionary. If some elements do not have a key, then they are numbered starting at zero.

Let’s take a look at your first dictionary-based window.

import PySimpleGUI as sg

sg.theme('Dark Blue 3')  # please make your windows colorful

layout = [
			[sg.Text('Please enter your Name, Address, Phone')],
			[sg.Text('Name', size=(15, 1)), sg.InputText('1', key='-NAME-')],
			[sg.Text('Address', size=(15, 1)), sg.InputText('2', key='-ADDRESS-')],
			[sg.Text('Phone', size=(15, 1)), sg.InputText('3', key='-PHONE-')],
			[sg.Submit(), sg.Cancel()]
			]

window = sg.Window('Simple data entry window', layout)
event, values = window.read()
window.close()

sg.Popup(event, values, values['-NAME-'], values['-ADDRESS-'], values['-PHONE-'])

To get the value of an input field, you use whatever value used as the key value as the index value. Thus to get the value of the name field, it is written as

Think of the variable values in the same way as you would a list, however, instead of using 0,1,2, to reference each item in the list, use the values of the key. The Name field in the window above is referenced by values['-NAME-'].

You will find the key field used quite heavily in most PySimpleGUI windows unless the window is very simple.

One convention you’ll see in many of the demo programs is keys being named in all caps with an underscores at the beginning and the end. You don’t HAVE to do this… your key value may look like this:
key = '-NAME-'

The reason for this naming convention is that when you are scanning the code, these key values jump out at you. You instantly know it’s a key. Try scanning the code above and see if those keys pop out.
key = '-NAME-'

The Event Loop / Callback Functions

All GUIs have one thing in common, an «event loop». Usually the GUI framework runs the event loop for you, but sometimes you want greater control and will run your own event loop. You often hear the term event loop when discussing embedded systems or on a Raspberry Pi.

With PySimpleGUI if your window will remain open following button clicks, then your code will have an event loop. If your program shows a single «one-shot» window, collects the data and then has no other GUI interaction, then you don’t need an event loop.

There’s nothing mysterious about event loops… they are loops where you take care of…. wait for it….. events. Events are things like button clicks, key strokes, mouse scroll-wheel up/down.

This little program has a typical PySimpleGUI Event Loop.

The anatomy of a PySimpleGUI event loop is as follows, generally speaking.

• The actual «loop» part is a while True loop
• «Read» the event and any input values the window has
• Check to see if window was closed or user wishes to exit
• A series of if event .... statements

All Elements

Here is a complete, short, program that contains all of the PySimpleGUI Elements.

import PySimpleGUI as sg

"""
    Demo - Element List

    All 34 elements shown in 1 window as simply as possible.

    Copyright 2022 PySimpleGUI
"""

use_custom_titlebar = False

def make_window(theme=None):
    NAME_SIZE = 23

    def name(name):
        dots = NAME_SIZE-len(name)-2
        return sg.Text(name + ' ' + '•'*dots, size=(NAME_SIZE,1), justification='r',pad=(0,0), font='Courier 10')

    sg.theme(theme)

    treedata = sg.TreeData()

    treedata.Insert("", '_A_', 'Tree Item 1', [1234], )
    treedata.Insert("", '_B_', 'B', [])
    treedata.Insert("_A_", '_A1_', 'Sub Item 1', ['can', 'be', 'anything'], )

    layout_l = [[name('Text'), sg.Text('Text')],
                [name('Input'), sg.Input(s=15)],
                [name('Multiline'), sg.Multiline(s=(15,2))],
                [name('Output'), sg.Output(s=(15,2))],
                [name('Combo'), sg.Combo(sg.theme_list(), default_value=sg.theme(), s=(15,22), enable_events=True, readonly=True, k='-COMBO-')],
                [name('OptionMenu'), sg.OptionMenu(['OptionMenu',],s=(15,2))],
                [name('Checkbox'), sg.Checkbox('Checkbox')],
                [name('Radio'), sg.Radio('Radio', 1)],
                [name('Spin'), sg.Spin(['Spin',], s=(15,2))],
                [name('Button'), sg.Button('Button')],
                [name('ButtonMenu'), sg.ButtonMenu('ButtonMenu', sg.MENU_RIGHT_CLICK_EDITME_EXIT)],
                [name('Slider'), sg.Slider((0,10), orientation='h', s=(10,15))],
                [name('Listbox'), sg.Listbox(['Listbox', 'Listbox 2'], no_scrollbar=True,  s=(15,2))],
                [name('Image'), sg.Image(sg.EMOJI_BASE64_HAPPY_THUMBS_UP)],
                [name('Graph'), sg.Graph((125, 50), (0,0), (125,50), k='-GRAPH-')]  ]

    layout_r  = [[name('Canvas'), sg.Canvas(background_color=sg.theme_button_color()[1], size=(125,50))],
                [name('ProgressBar'), sg.ProgressBar(100, orientation='h', s=(10,20), k='-PBAR-')],
                [name('Table'), sg.Table([[1,2,3], [4,5,6]], ['Col 1','Col 2','Col 3'], num_rows=2)],
                [name('Tree'), sg.Tree(treedata, ['Heading',], num_rows=3)],
                [name('Horizontal Separator'), sg.HSep()],
                [name('Vertical Separator'), sg.VSep()],
                [name('Frame'), sg.Frame('Frame', [[sg.T(s=15)]])],
                [name('Column'), sg.Column([[sg.T(s=15)]])],
                [name('Tab, TabGroup'), sg.TabGroup([[sg.Tab('Tab1',[[sg.T(s=(15,2))]]), sg.Tab('Tab2', [[]])]])],
                [name('Pane'), sg.Pane([sg.Col([[sg.T('Pane 1')]]), sg.Col([[sg.T('Pane 2')]])])],
                [name('Push'), sg.Push(), sg.T('Pushed over')],
                [name('VPush'), sg.VPush()],
                [name('Sizer'), sg.Sizer(1,1)],
                [name('StatusBar'), sg.StatusBar('StatusBar')],
                [name('Sizegrip'), sg.Sizegrip()]  ]

    layout = [[sg.MenubarCustom([['File', ['Exit']], ['Edit', ['Edit Me', ]]],  k='-CUST MENUBAR-',p=0)] if use_custom_titlebar else [sg.Menu([['File', ['Exit']], ['Edit', ['Edit Me', ]]],  k='-CUST MENUBAR-',p=0)],
              [sg.Checkbox('Use Custom Titlebar & Menubar', use_custom_titlebar, enable_events=True, k='-USE CUSTOM TITLEBAR-')],
              [sg.T('PySimpleGUI Elements - Use Combo to Change Themes', font='_ 18', justification='c', expand_x=True)],
              [sg.Col(layout_l), sg.Col(layout_r)]]

    window = sg.Window('The PySimpleGUI Element List', layout, finalize=True, right_click_menu=sg.MENU_RIGHT_CLICK_EDITME_VER_EXIT, keep_on_top=True, use_custom_titlebar=use_custom_titlebar)

    window['-PBAR-'].update(30)                                                     # Show 30% complete on ProgressBar
    window['-GRAPH-'].draw_image(data=sg.EMOJI_BASE64_HAPPY_JOY, location=(0,50))   # Draw something in the Graph Element

    return window

# Start of the program...
window = make_window()

while True:
    event, values = window.read()
    sg.popup(event, values)                     # show the results of the read in a popup Window
    if event == sg.WIN_CLOSED or event == 'Exit':
        break
    if values['-COMBO-'] != sg.theme():
        sg.theme(values['-COMBO-'])
        window.close()
        window = make_window()
    if event == '-USE CUSTOM TITLEBAR-':
        use_custom_titlebar = values['-USE CUSTOM TITLEBAR-']
        window.close()
        window = make_window()
window.close()

When you run it, assuming you’ve not set a default theme in the system settings, you’ll see a window that looks like this (when on Windows):

The checkbox at the top that reads «Use Custom Titlebar & Menubar» will enable you to see the what the window looks like using the PySimpleGUI Custom Titlebar and Custom Menubar.

Using this one test program, you can easily browse the PySimpleGUI Themes by choosing a new color Theme using the Combo Element.

But it’s so UGLY!

On Windows, using straight Python, this is the non-GUI alternative.

The 1970s and 1980s were a great era for computing, but I wouldn’t call the user interfaces «attractive». Borland made some great tools in the 90’s for doing TUIs. There are some excellent Python packages available for you if you’re after a TUI! If that’s the look you’re after, give them a try. You may like the results. But, it’s not what PySimpleGUI is about.

We’re making GUIs for the masses, something you can give to anyone and they’ll understand how to use it. If you asked a Windows user (i.e. a normal person, not a programmer) to open a command window in the past decade then you likely got a worried look back. Normal people aren’t going to use your Python program that’s command line based and be thrilled about it. Your programming pals will love your TUI, Mary, who works in accounting, will not.

The example window may look «ugly» or dated to you. It’s fair to say that it looks dated. While PySimpleGUI Themes instantly give you a color scheme that matches, it doesn’t go much further in making tkinter more attractive/»modern».

However, you are far from being out of options to improve the look of your GUI. This bare-bones program is your starting point. This is where you begin the process of making an attractive user interface. You’ve not yet started to make your interface look better.

No effort has been made to make it look nice. It’s purely functional. There are 34 Elements in the window. 34 Elements. Considering what it does, it’s miraculous or in the least incredibly impressive. Why? Because in 65 lines of Python code that window was created, shown, and collected the results.

Let’s be clear here… this window will take a massive amount of code using the conventional Python GUI packages. If you manage to write a tkinter, Qt or WxPython program that shows all of these Widgets in under 65 lines of Python code, then by all means send the code over.

Fair, side by side tests, recreating the exact same application, have shown numerous times that PySimpleGUI code is at least 1/2 to 1/10th the amount of code than tkinter requires.

There is no magic behind why it’s so much shorter. PySimpleGUI is writing all the boilerplate code on your behalf. The same tkinter code is being executed that you would write by hand. The difference is that the code is contained in the PySimpleGUI source code instead of in your application code. That’s all that’s going on with «wrappers» like PySimpleGUI. Code is being generated and executed for you in order to simplify your code.

A large amount of time nor code is required to create custom Buttons and other elements, including entirely new and more complex elements such a Dials or Gauges. Transforming a button from plain to an image is a parameter to the Button element. It’s… not… THAT… HARD. You’re a programmer, write some code, or add a parameter if you want more attractive interfaces. The hooks are there waiting for you to be creative.

Window Closed Events

Note, event values can be None. The value for event will be the text that is displayed on the button element when it was created or the key for the button. If the user closed the window using the «X» in the upper right corner of the window, then event will be sg.WIN_CLOSED which is equal to None. It is vitally important that your code contain the proper checks for sg.WIN_CLOSED.

For «persistent windows», always give your users a way out of the window. Otherwise you’ll end up with windows that never properly close. It’s literally 2 lines of code that you’ll find in every Demo Program. While you’re at it, make sure a window.close() call is after your event loop so that your window closes for sure.

The values Dictionary

You can see in the results Popup window that the values returned are a dictionary. Each input field in the window generates one item in the return values list. Input fields often return a string. Check Boxes and Radio Buttons return bool. Sliders return float or perhaps int depending on how you configured it or which port you’re using.

If your window has no keys and it has no buttons that are «browse» type of buttons, then it will return values to you as a list instead of a dictionary. If possible PySimpleGUI tries to return the values as a list to keep things simple.

Note in the list of return values in this example, many of the keys are numbers. That’s because no keys were specified on any of the elements (although one was automatically made for you). If you don’t specify a key for your element, then a number will be sequentially assigned. For elements that you don’t plan on modifying or reading values from, like a Text Element, you can skip adding keys. For other elements, you’ll likely want to add keys so that you can easily access the values and perform operations on them.

Operations That Take a «Long Time»

If you’re a Windows user you’ve seen windows show in their title bar «Not Responding» which is soon followed by a Windows popup stating that «Your program has stopped responding». Well, you too can make that message and popup appear if you so wish! All you need to do is execute an operation that takes «too long» (i.e. a few seconds) inside your event loop.

You have a couple of options for dealing this with. If your operation can be broken up into smaller parts, then you can call Window.refresh() occasionally to avoid this message. If you’re running a loop for example, drop that call in with your other work. This will keep the GUI happy and Window’s won’t complain.

If, on the other hand, your operation is not under your control or you are unable to add refresh calls, then the next option available to you is to move your long operations into a thread.

Threading Made Simple

You’ve been at Python for a couple weeks, bravely ventured into GUI world, and the function you called when a button click is detected takes 20 seconds to complete. Your window displays the «Not Responding» message. If you ask what to do on StackOverflow, you’ll be told that «all you have to do is use threads».

Two weeks into programming, and you’ve just been told you need to learn Threading?

This exact scenario is why the window method perform_long_operation was created. It’s a way for you to «ease into» threading without learning about threading. Forget that thread was even mentioned. Let’s just talk about «long operations» instead.

There are 2 ways you can use this call. If your function does not take any parameters, then you can enter the name of the function (without the parentheses!) as the first parameter to perform_long_operation.

window.perform_long_operation(my_function, '-FUNCTION COMPLETED-')

If your function has parameters, then you’ll need to use a lambda. Don’t freak out at hearing «lambda» (yet). Just add it as in this example code…

window.perform_long_operation(lambda: my_function_with_parms(10), '-FUNCTION COMPLETED-')

Write the first parameter was if you were calling your function, and then put lambda: in front of that.

The second parameter to perform_long_operation is the event (a key) that you want to get back from window.read() when your function returns.

Finally, if your function has a return value, then that value will show up in the values dictionary with the key that you provided. In this example, values['-FUNCTION COMPLETED-'] will contain the return value from your function.

import PySimpleGUI as sg
import time

def my_function():
    time.sleep(30)

def my_function_with_parms(duration):
    time.sleep(duration)
    return 'My Return Value'

layout = [  [sg.Text('Call a lengthy function')],
            [sg.Button('Start'), sg.Button('Start 2'), sg.Button('Exit')]  ]

window = sg.Window('Long Operation Example', layout)

while True:
    event, values = window.read()
    print(event, values)
    if event == sg.WIN_CLOSED or event == 'Exit':
        break
    if event == 'Start':
        window.perform_long_operation(my_function, '-FUNCTION COMPLETED-')
    elif event == 'Start 2':
        window.perform_long_operation(lambda: my_function_with_parms(10), '-FUNCTION COMPLETED-')
    elif event == '-FUNCTION COMPLETED-':
        sg.popup('Your function completed!')
window.close()

So, in summary, window.perform_long_operation starts and manages the thread on your behalf. You are returned an event when your «long operation» completes. If your function returns a value, then that value will show up in the values variable from your window.read() call. Threading made simple.

window.perform_long_operationHas An Alias window.start_thread

If you’re a threading pro, then maybe you would prefer the alias for window.perform_long_operation. In addition to this name for the method, you’ll get the exact same results by calling window.start_thread. Since threading is becoming more popular due to the write_event_value capability, it makes sense to enable you to call a thread a thread if that’s what you prefer… so enjoy the start_thread alias if that’s how you roll.

Threading the «New Way» — Window.write_event_value

This new function that is available currently only in the tkinter port as of July 2020 is exciting and represents the future way multi-threading is handled in PySimpleGUI.

Previously, a queue was used where your event loop would poll for incoming messages from a thread.

Now, threads can directly inject events into a Window so that it will show up in the window.read() calls. This allows a your event loop to «pend», waiting for normal window events as well as events being generated by threads. It is much more efficient than polling.

You can see this new capability in action in this demo: Demo_Multithreaded_Write_Event_Value.py

Just use the Demo Browser to search for write_event_value to get more examples.

Here is that program for your inspection and education. It’s SO nice to no longer poll for threaded events.

import threading
import time
import PySimpleGUI as sg

"""
    Threaded Demo - Uses Window.write_event_value communications

    Requires PySimpleGUI.py version 4.25.0 and later

    This is a really important demo  to understand if you're going to be using multithreading in PySimpleGUI.

    Older mechanisms for multi-threading in PySimpleGUI relied on polling of a queue. The management of a communications
    queue is now performed internally to PySimpleGUI.

    The importance of using the new window.write_event_value call cannot be emphasized enough.  It will hav a HUGE impact, in
    a positive way, on your code to move to this mechanism as your code will simply "pend" waiting for an event rather than polling.

    Copyright 2020 PySimpleGUI.org
"""

THREAD_EVENT = '-THREAD-'

cp = sg.cprint

def the_thread(window):
    """
    The thread that communicates with the application through the window's events.

    Once a second wakes and sends a new event and associated value to the window
    """
    i = 0
    while True:
        time.sleep(1)
        window.write_event_value('-THREAD-', (threading.current_thread().name, i))      # Data sent is a tuple of thread name and counter
        cp('This is cheating from the thread', c='white on green')
        i += 1

def main():
    """
    The demo will display in the multiline info about the event and values dictionary as it is being
    returned from window.read()
    Every time "Start" is clicked a new thread is started
    Try clicking "Dummy" to see that the window is active while the thread stuff is happening in the background
    """

    layout = [  [sg.Text('Output Area - cprint's route to here', font='Any 15')],
                [sg.Multiline(size=(65,20), key='-ML-', autoscroll=True, reroute_stdout=True, write_only=True, reroute_cprint=True)],
                [sg.T('Input so you can see data in your dictionary')],
                [sg.Input(key='-IN-', size=(30,1))],
                [sg.B('Start A Thread'), sg.B('Dummy'), sg.Button('Exit')]  ]

    window = sg.Window('Window Title', layout, finalize=True)

    while True:             # Event Loop
        event, values = window.read()
        cp(event, values)
        if event == sg.WIN_CLOSED or event == 'Exit':
            break
        if event.startswith('Start'):
            threading.Thread(target=the_thread, args=(window,), daemon=True).start()
        if event == THREAD_EVENT:
            cp(f'Data from the thread ', colors='white on purple', end='')
            cp(f'{values[THREAD_EVENT]}', colors='white on red')
    window.close()

if __name__ == '__main__':
    main()

You’ll find plenty of examples to help you with these concepts if you look in the Demo Programs. So, pip install the Demo Programs and the Demo Browser so that you can easily search and find examples of what you’re trying to accomplish.

Building Custom Windows

You will find it much easier to write code using PySimpleGUI if you use an IDE such as PyCharm. The features that show you documentation about the API call you are making will help you determine which settings you want to change, if any. In PyCharm, two commands are particularly helpful.

Control-Q (when cursor is on function name) brings up a box with the function definition
Control-P (when cursor inside function call "()") shows a list of parameters and their default values

Synchronous / Asynchronous Windows

The most common use of PySimpleGUI is to display and collect information from the user. The most straightforward way to do this is using a «blocking» GUI call. Execution is «blocked» while waiting for the user to close the GUI window/dialog box.

You’ve already seen a number of examples above that use blocking windows. You’ll know it blocks if the Read call has no timeout parameter.

A blocking Read (one that waits until an event happens) look like this:

event, values = window.read()

A non-blocking / Async Read call looks like this:

event, values = window.read(timeout=100)

You can learn more about these async / non-blocking windows toward the end of this document.

Themes — Automatic Coloring of Your Windows

In Dec 2019 the function change_look_and_feel was replaced by theme. The concept remains the same, but a new group of function calls makes it a lot easier to manage colors and other settings.

By default the PySimpleGUI color theme is now Dark Blue 3. Gone are the «system default» gray colors. If you want your window to be devoid of all colors so that the system chooses the colors (gray) for you, then set the theme to ‘gray gray gray’. This tells PySimpleGUI that you’re a boring person…. no no no… I’m just kidding!…. it just means you want PySimpleGUI to not set any colors so that the default colors provided by the OS/tkinter will be used. It’s a memorable theme name. There are several with «default» in the name and it got confusing which was the full-on-add-no-color name, so ‘gray gray gray’ was added to make it easy to recall.

There are 154 themes available. You can preview these themes by calling theme_previewer() which will create a LARGE window displaying all of the color themes available.

You can see the current available themes by calling sg.theme_previewer(). It creates a window that looked like this in June 2022:

Default is Dark Blue 3

In Dec 2019 the default for all PySimpleGUI windows changed from the system gray with blue buttons to a more complete theme using a grayish blue with white text. Previously users were nagged into choosing color theme other than gray. Now it’s done for you instead of nagging you.

If you’re struggling with this color theme, then add a call to theme to change it.

Theme Name Formula

Themes names that you specify can be «fuzzy». The text does not have to match exactly what you see printed. For example «Dark Blue 3» and «DarkBlue3» and «dark blue 3» all work.

One way to quickly determine the best setting for your window is to simply display your window using a lot of different themes. Add the line of code to set the theme — theme('Dark Green 1'), run your code, see if you like it, if not, change the theme string to 'Dark Green 2' and try again. Repeat until you find something you like.

The «Formula» for the string is:

Dark Color #

or

Light Color #

Color can be Blue, Green, Black, Gray, Purple, Brown, Teal, Red. The # is optional or can be from 1 to XX. Some colors have a lot of choices. There are 13 «Light Brown» choices for example.

«System» Default — No Colors (e.g. "Gray Gray Gray")

If you’re bent on having no colors at all in your window, then choose Default 1 or System Default 1. Use the "Gray Gray Gray" theme if you really want to ensure system defaults only.

If you want the original PySimpleGUI color scheme of a blue button and everything else gray then you can get that with the theme Default or System Default.

Theme Functions

The basic theme function call is theme(theme_name). This sets the theme. Calling without a parameter, theme() will return the name of the current theme.

If you want to get or modify any of the theme settings, you can do it with these functions that you will find detailed information about in the function definitions section at the bottom of the document. Each will return the current value if no parameter is used.

You’ll find a detailed list of the theme calls in the SDK Call Reference in this section:

https://pysimplegui.readthedocs.io/en/latest/call%20reference/#themes

theme
theme_add_new
theme_background_color
theme_border_width
theme_button_color
theme_button_color_background
theme_button_color_text
theme_element_background_color
theme_element_text_color
theme_global
theme_input_background_color
theme_input_text_color
theme_list
theme_previewer
theme_previewer_swatches
theme_progress_bar_border_width
theme_progress_bar_color
theme_slider_border_width
theme_slider_color
theme_text_color
theme_text_element_background_color
theme_use_custom_titlebar

These will help you get a list of available choices.

theme_list
theme_previewer

Window Object — Beginning a window

The first step is to create the window object using the desired window customizations.

Modal Windows (only applied to tkinter port currently

)
NOTE — as of PySimpleGUI 4.25.0 Modal Windows are supported! By default the popup windows that block will be marked Modal by default. This is a somewhat risky change because your existing applications will behave differently. However, in theory, you shouldn’t have been interacting with other windows while the popup is active. All of those actions are at best queued. It’s implementation dependent.

«Modal» in this case means that you must close this «modal» window before you will be able to interact with windows created before this window. Think about an «about» box. You normally have to close this little popup in most programs. So, that’s what PySimpleGUI is doing now.

Making your window modal

To make a Modal Window you have 2 options.

1. Set the moodel=True parameter in your Window calls.

2. Call the method Window.make_modal() to chance a window from non-modal to modal. There is no modal to non-modal. Don’t see the need for one. If one comes up, sure!

Disabling modal windows

Popups that block are the only windows that have modal on by default. There is a modal parameter than you can set to False to turn it off.

For the earlier than 4.25.0 and other ports of PySimpleGUI There is no direct support for «modal windows» in PySimpleGUI. All windows are accessible at all times unless you manually change the windows’ settings.

IMPORTANT — Many of the Window methods require you to either call Window.read or Window.Finalize (or set finalize=True in your Window call) before you call the method. This is because these 2 calls are what actually creates the window using the underlying GUI Framework. Prior to one of those calls, the methods are likely to crash as they will not yet have their underlying widgets created.

Window Location

PySimpleGUI computes the exact center of your window and centers the window on the screen. If you want to locate your window elsewhere, such as the system default of (0,0), if you have 2 ways of doing this. The first is when the window is created. Use the location parameter to set where the window. The second way of doing this is to use the SetOptions call which will set the default window location for all windows in the future.

Multiple Monitors and Linux

The auto-centering (default) location for your PySimpleGUI window may not be correct if you have multiple monitors on a Linux system. On Windows multiple monitors appear to work ok as the primary monitor the tkinter utilizes and reports on.

Linux users with multiple monitors that have a problem when running with the default location will need to specify the location the window should be placed when creating the window by setting the location parameter.

Window Size

You can get your window’s size by access the Size property. The window has to be Read once or Finalized in order for the value to be correct. Note that it’s a property, not a call.

my_windows_size = window.Size

To finalize your window:

window = Window('My Title', layout, finalize=True)

Element Sizes

There are multiple ways to set the size of Elements. They are:

1. The global default size — change using SetOptions function
2. At the Window level — change using the parameter default_element_size in your call to Window
3. At the Element level — each element has a size parameter

Element sizes are measured in characters (there are exceptions). A Text Element with size = (20,1) has a size of 20 characters wide by 1 character tall.

The default Element size for PySimpleGUI is (45,1).

There are a couple of widgets where one of the size values is in pixels rather than characters. This is true for Progress Meters and Sliders. The second parameter is the ‘height’ in pixels.

No Titlebar

Should you wish to create cool looking windows that are clean with no windows titlebar, use the no_titlebar option when creating the window.

Be sure an provide your user an «exit» button or they will not be able to close the window! When no titlebar is enabled, there will be no icon on your taskbar for the window. Without an exit button you will need to kill via taskmanager… not fun.

Windows with no titlebar rely on the grab anywhere option to be enabled or else you will be unable to move the window.

Windows without a titlebar can be used to easily create a floating launcher.

Linux users! Note that this setting has side effects for some of the other Elements. Multi-line input doesn’t work at all, for example So, use with caution.

Grab Anywhere

This is a feature unique to PySimpleGUI.

Note — there is a warning message printed out if the user closes a non-blocking window using a button with grab_anywhere enabled. There is no harm in these messages, but it may be distressing to the user. Should you wish to enable for a non-blocking window, simply get grab_anywhere = True when you create the window.

Always on top

To keep a window on top of all other windows on the screen, set keep_on_top = True when the window is created. This feature makes for floating toolbars that are very helpful and always visible on your desktop.

Focus

PySimpleGUI will set a default focus location for you. This generally means the first input field. You can set the focus to a particular element. If you are going to set the focus yourself, then you should turn off the automatic focus by setting use_default_focus=False in your Window call.

TTK Buttons

Beginning in release 4.7.0 PySimpleGUI supports both «normal» tk Buttons and ttk Buttons. This change was needed so that Mac users can use colors on their buttons. There is a bug that causes tk Buttons to not show text when you attempt to change the button color. Note that this problem goes away if you install Python from the official Python.org site rather than using Homebrew. A number of users have switched and are quite happy since even tk Buttons work on the Mac after the switch.

By default Mac users will get ttk Buttons when a Button Element is used. All other platforms will get a normal tk Button. There are ways to override this behavior. One is by using the parameter use_ttk_buttons when you create your window. If set to True, all buttons will be ttk Buttons in the window. If set to False, all buttons will be normal tk Buttons. If not set then the platform or the Button Element determines which is used.

If a system-wide setting is desired, then the default can be set using set_options. This will affect all windows such as popups and the debug window.

TTK Themes

tkinter has a number of «Themes» that can be used with ttk widgets. In PySimpleGUI these widgets include — Table, Tree, Combobox, Button, ProgressBar, Tabs & TabGroups. Some elements have a ‘theme’ parameter but these are no longer used and should be ignored. The initial release of PySimpleGUI attempted to mix themes in a single window but since have learned this is not possible so instead it is set at the Window or the system level.

If a system-wide setting is desired, then the default can be set using set_options. This will affect all windows such as popups and the debug window.

The ttk theme choices depend on the platform. Linux has a shorter number of selections than Windows.

The minimum list of TTK themes is:

• default
• alt
• clam
• classic

Most Windows systems have some additional themes that come standard with tkinter:

• default
• alt
• clam
• classic
• winnative
• vista
• xpnative

The list of available themes is populated automatically when you open the Global PySimpleGUI Settings window. Previously the list of themes was hard-coded by the PySimpleGUI code. Now the list is retrieved from tkinter.

There are constants defined to help you with code completion to determine what your choices are. Theme constants start with THEME_. For example, the «clam» theme is THEME_CLAM

If you try to manually set a TTK theme while making a Window or calling set_options and it is not a valid theme, you will be shown the list of valid themes in the error popup. The popup may resemble one like this:

Closing Windows

When you are completely done with a window, you should close it and then delete it so that the resources, in particular the tkinter resources, are properly cleaned up.

If you wish to do this in 1 line of code, here’s your line:

window.close(); del window

The delete helps with a problem multi-threaded application encounter where tkinter complains that it is being called from the wrong thread (not the program’s main thread)

Window Methods That Complete Formation of Window

After you have completed making your layout, stored in a variable called layout in these examples, you will create your window.

The creation part of a window involves 3 steps.

1. Create a Window object
2. Adding your Layout to the window
3. Optional — Finalize if want to make changes prior to read call

Over time the PySimpleGUI code has continued to compact, compress, so that as little code as possible will need to be written by the programmer.

The Individual Calls

This is the «long form» as each method is called individually.

window = sg.Window('My Title')
window.layout(layout)
window.finalize()

Chaining The Calls (the old method)

The next level of compression that was done was to chain the calls together into a single line of code.

window = sg.Window('My Title').Layout(layout).finalize()

Using Parameters Instead of Calls (New Preferred Method)

Here’s a novel concept, instead of using chaining, something that’s foreign to beginners, use parameters to the Window call. And that is exactly what’s happened as of 4.2 of the PySimpleGUI port.

window = sg.Window('My Title', layout, finalize=True)

Rather than pushing the work onto the user of doing the layout and finalization calls, let the Window initialization code do it for you. Yea, it sounds totally obvious now, but it didn’t a few months ago.

This capability has been added to all 4 PySimpleGUI ports but none are on PyPI just yet as there is some runtime required first to make sure nothing truly bad is going to happen.

Call to set the window layout. Must be called prior to Read. Most likely «chained» in line with the Window creation.

window = sg.Window('My window title', layout)

finalize() or Window parameter finalize=True

Call to force a window to go through the final stages of initialization. This will cause the tkinter resources to be allocated so that they can then be modified. This also causes your window to appear. If you do not want your window to appear when Finalize is called, then set the Alpha to 0 in your window’s creation parameters.

If you want to call an element’s Update method or call a Graph element’s drawing primitives, you must either call Read or Finalize prior to making those calls.

read(timeout=None, timeout_key=TIMEOUT_KEY, close=False)

Read the Window’s input values and button clicks in a blocking-fashion

Returns event, values. Adding a timeout can be achieved by setting timeout=number of milliseconds before the Read times out after which a «timeout event» is returned. The value of timeout_key will be returned as the event. If you do not specify a timeout key, then the value TIMEOUT_KEY will be returned.

If you set the timeout = 0, then the Read will immediately return rather than waiting for input or for a timeout. It’s a truly non-blocking «read» of the window.

Layouts

While at this point in the documentation you’ve not been shown very much about each Element available, you should read this section carefully as you can use the techniques you learn in here to build better, shorter, and easier to understand PySimpleGUI code.

If it feels like this layout section is too much too soon, then come back to this section after you’re learned about each Element. Whatever order you find the least confusing is the best.

While you’ve not learned about Elements yet, it makes sense for this section to be up front so that you’ll have learned how to use the elements prior to learning how each element works. At this point in your PySimpleGUI education, it is better for you to grasp time efficient ways of working with Elements than what each Element does. By learning now how to assemble Elements now, you’ll have a good model to put the elements you learn into.

There are several aspects of PySimpleGUI that make it more «Pythonic» than other Python GUI SDKs. One of the areas that is unique to PySimpleGUI is how a window’s «layout» is defined, specified or built. A window’s «layout» is simply a list of lists of elements. As you’ve already learned, these lists combine to form a complete window. This method of defining a window is super-powerful because lists are core to the Python language as a whole and thus are very easy to create and manipulate.

Think about that for a moment and compare/contrast with Qt, tkinter, etc.. With PySimpleGUI the location of your element in a matrix determines where that Element is shown in the window. It’s so simple and that makes it incredibly powerful. Want to switch a row in your GUI that has text with the one below it that has an input element? No problem, swap the lines of code and you’re done.

Layouts were designed to be visual. The idea is for you to be able to envision how a window will look by simply looking at the layout in the code. The CODE itself matches what is drawn on the screen. PySimpleGUI is a cross between straight Python code and a visual GUI designer.

In the process of creating your window, you can manipulate these lists of elements without having an impact on the elements or on your window. Until you perform a «layout» of the list, they are nothing more than lists containing objects (they just happen to be your window’s elements).

Many times your window definition / layout will be a static, straightforward to create.

However, window layouts are not limited to being one of these statically defined list of Elements.

Generated Layouts (For sure want to read if you have > 5 repeating elements/rows)

There are 5 specific techniques of generating layouts discussed in this section. They can be used alone or in combination with each other.

1. Layout + Layout concatenation [[A]] + [[B]] = [[A], [B]]
2. Element Addition on Same Row [[A] + [B]] = [[A, B]]
3. List Comprehension to generate a row [A for x in range(10)] = [A,A,A,A,A...]
4. List Comprehension to generate multiple rows [[A] for x in range(10)] = [[A],[A],...]
5. User Defined Elements / Compound Elements

Example — List Comprehension To Concatenate Multiple Rows — «To Do» List Example

Let’s create a little layout that will be used to make a to-do list using PySimpleGUI.

Brute Force

import PySimpleGUI as sg

layout = [
            [sg.Text('1. '), sg.In(key=1)],
            [sg.Text('2. '), sg.In(key=2)],
            [sg.Text('3. '), sg.In(key=3)],
            [sg.Text('4. '), sg.In(key=4)],
            [sg.Text('5. '), sg.In(key=5)],
            [sg.Button('Save'), sg.Button('Exit')]
         ]

window = sg.Window('To Do List Example', layout)
event, values = window.read()

The output from this script was this window:

Take a moment and look at the code and the window that’s generated. Are you able to look at the layout and envision the Window on the screen?

Build By Concatenating Rows

The brute force method works great on a list that’s 5 items long, but what if your todo list had 40 items on it. THEN what? Well, that’s when we turn to a «generated» layout, a layout that is generated by your code. Replace the layout= stuff from the previous example with this definition of the layout.

import PySimpleGUI as sg

layout = []
for i in range(1,6):
    layout += [sg.Text(f'{i}. '), sg.In(key=i)],
layout += [[sg.Button('Save'), sg.Button('Exit')]]

window = sg.Window('To Do List Example', layout)
event, values = window.read()

It produces the exact same window of course. That’s progress…. went from writing out every row of the GUI to generating every row. If we want 48 items as suggested, change the range(1,6) to range(1,48). Each time through the list another row is added onto the layout.

Create Several Rows Using List Comprehension

BUT, we’re not done yet!

This is Python, we’re using lists to build something up, so we should be looking at list comprehensions. Let’s change the for loop into a list comprehension. Recall that our for loop was used to concatenate 6 rows into a layout.

layout =  [[sg.Text(f'{i}. '), sg.In(key=i)] for i in range(1,6)]

Here we’ve moved the for loop to inside of the list definition (a list comprehension)

Concatenating Multiple Rows

We have our rows built using the list comprehension, now we just need the buttons. They can be easily «tacked onto the end» by simple addition.

layout =  [[sg.Text(f'{i}. '), sg.In(key=i)] for i in range(1,6)]
layout += [[sg.Button('Save'), sg.Button('Exit')]]

Anytime you have 2 layouts, you can concatenate them by simple addition. Make sure your layout is a «list of lists» layout. In the above example, we know the first line is a generated layout of the input rows. The last line adds onto the layout another layout… note the format being [ [ ] ].

This button definition is an entire layout, making it possible to add to our list comprehension

[[sg.Button('Save'), sg.Button('Exit')]]

It’s quite readable code. The 2 layouts line up visually quite well.

But let’s not stop there with compressing the code. How about removing that += and instead change the layout into a single line with just a + between the two sets of row.

Doing this concatenation on one line, we end up with this single statement that creates the entire layout for the GUI:

layout =  [[sg.Text(f'{i}. '), sg.In(key=i)] for i in range(1,6)] + [[sg.Button('Save'), sg.Button('Exit')]]

Final «To Do List» Program

And here we have our final program… all 4 lines.

import PySimpleGUI as sg

layout  = [[sg.Text(f'{i}. '), sg.In(key=i)] for i in range(1,6)] + [[sg.Button('Save'), sg.Button('Exit')]]

window = sg.Window('To Do List Example', layout)

event, values = window.read()

If you really wanted to crunch things down, you can make it a 2 line program (an import and 1 line of code) by moving the layout into the call to Window

import PySimpleGUI as sg

event, values = sg.Window('To Do List Example', layout=[[sg.Text(f'{i}. '), sg.In(key=i)] for i in range(1,6)] + [[sg.Button('Save'), sg.Button('Exit')]]).read()

Example — List Comprehension to Build Rows — Table Simulation — Grid of Inputs

In this example we’re building a «table» that is 4 wide by 10 high using Input elements

The end results we’re seeking is something like this:

HEADER 1    HEADER 2    HEADER 3    HEADER 4
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT
INPUT       INPUT       INPUT       INPUT

Once the code is completed, here is how the result will appear:

We’re going to be building each row using a list comprehension and we’ll build the table by concatenating rows using another list comprehension. That’s a list comprehension that goes across and another list comprehension that goes down the layout, adding one row after another.

Building the Header

First let’s build the header. There are 2 concepts to notice here:

import PySimpleGUI as sg

headings = ['HEADER 1', 'HEADER 2', 'HEADER 3','HEADER 4']  # the text of the headings
header =  [[sg.Text('  ')] + [sg.Text(h, size=(14,1)) for h in headings]]  # build header layout

There are 2 things in this code to note

1. The list comprehension that makes the heading elements
2. The spaces added onto the front

Let’s start with the headers themselves.

This is the code that makes a row of Text Elements containing the text for the headers. The result is a list of Text Elements, a row.

[sg.Text(h, size=(14,1)) for h in headings]

Then we add on a few spaces to shift the headers over so they are centered over their columns. We do this by simply adding a Text Element onto the front of that list of headings.

header =  [[sg.Text('  ')] + [sg.Text(h, size=(14,1)) for h in headings]]

This header variable is a layout with 1 row that has a bunch of Text elements with the headings.

Building the Input Elements

The Input elements are arranged in a grid. To do this we will be using a double list comprehension. One will build the row the other will add the rows together to make the grid. Here’s the line of code that does that:

input_rows = [[sg.Input(size=(15,1), pad=(0,0)) for col in range(4)] for row in range(10)]

This portion of the statement makes a single row of 4 Input Elements

[sg.Input(size=(15,1), pad=(0,0)) for col in range(4)]

Next we take that list of Input Elements and make as many of them as there are rows, 10 in this case. We’re again using Python’s awesome list comprehensions to add these rows together.

input_rows = [[sg.Input(size=(15,1), pad=(0,0)) for col in range(4)] for row in range(10)]

The first part should look familiar since it was just discussed as being what builds a single row. To make the matrix, we simply take that single row and create 10 of them, each being a list.

Putting it all together

Here is our final program that uses simple addition to add the headers onto the top of the input matrix. To make it more attractive, the color theme is set to ‘Dark Brown 1’.

import PySimpleGUI as sg

sg.theme('Dark Brown 1')

headings = ['HEADER 1', 'HEADER 2', 'HEADER 3','HEADER 4']
header =  [[sg.Text('  ')] + [sg.Text(h, size=(14,1)) for h in headings]]

input_rows = [[sg.Input(size=(15,1), pad=(0,0)) for col in range(4)] for row in range(10)]

layout = header + input_rows

window = sg.Window('Table Simulation', layout, font='Courier 12')
event, values = window.read()

User Defined Elements / Compound Elements

«User Defined Elements» and «Compound Elements» are one or more PySimpleGUI Elements that are wrapped in a function definition. In a layout, they have the appearance of being a custom elements of some type.

User Defined Elements are particularly useful when you set a lot of parameters on an element that you use over and over in your layout.

Example — A Grid of Buttons for Calculator App

Let’s say you’re making a calculator application with buttons that have these settings:

• font = Helvetica 20
• size = 5,1
• button color = white on blue

The code for one of these buttons is:

sg.Button('1', button_color=('white', 'blue'), size=(5, 1), font=("Helvetica", 20))

If you have 6 buttons across and 5 down, your layout will have 30 of these lines of text.

One row of these buttons could be written:

    [sg.Button('1', button_color=('white', 'blue'), size=(5, 1), font=("Helvetica", 20)),
     sg.Button('2', button_color=('white', 'blue'), size=(5, 1), font=("Helvetica", 20)),
     sg.Button('3', button_color=('white', 'blue'), size=(5, 1), font=("Helvetica", 20)),
     sg.Button('log', button_color=('white', 'blue'), size=(5, 1), font=("Helvetica", 20)),
     sg.Button('ln', button_color=('white', 'blue'), size=(5, 1), font=("Helvetica", 20)),
     sg.Button('-', button_color=('white', 'blue'), size=(5, 1), font=("Helvetica", 20))],

By using User Defined Elements, you can significantly shorten your layouts. Let’s call our element CBtn. It would be written like this:

def CBtn(button_text):
    return sg.Button(button_text, button_color=('white', 'blue'), size=(5, 1), font=("Helvetica", 20))

Using your new CBtn Element, you could rewrite the row of buttons above as:

[CBtn('1'), CBtn('2'), CBtn('3'), CBtn('log'), CBtn('ln'), CBtn('-')],

See the tremendous amount of code you do not have to write! USE this construct any time you find yourself copying an element many times.

But let’s not stop there.

Since we’ve been discussing list comprehensions, let’s use them to create this row. The way to do that is to make a list of the symbols that go across the row make a loop that steps through that list. The result is a list that looks like this:

[CBtn(t) for t in ('1','2','3', 'log', 'ln', '-')],

That code produces the same list as this one we created by hand:

[CBtn('1'), CBtn('2'), CBtn('3'), CBtn('log'), CBtn('ln'), CBtn('-')],

Compound Elements

Just like a Button can be returned from a User Defined Element, so can multiple Elements.

Going back to the To-Do List example we did earlier, we could have defined a User Defined Element that represented a To-Do Item and this time we’re adding a checkbox. A single line from this list will be:

• The item # (a Text Element)
• A Checkbox Element to indicate completed
• An Input Element to type in what to do

The definition of our User Element is this ToDoItem function. It is a single User Element that is a combination of 3 PySimpleGUI Elements.

def ToDoItem(num):
    return [sg.Text(f'{num}. '), sg.CBox(''), sg.In()]

This makes creating a list of 5 to-do items downright trivial when combined with the list comprehension techniques we learned earlier. Here is the code required to create 5 entries in our to-do list.

layout = [ToDoItem(x) for x in range(1,6)]

We can then literally add on the buttons

layout = [ToDoItem(x) for x in range(1,6)] + [[sg.Button('Save'), sg.Button('Exit')]]

And here is our final program

import PySimpleGUI as sg

def ToDoItem(num):
    return [sg.Text(f'{num}. '), sg.CBox(''), sg.In()]

layout = [ToDoItem(x) for x in range(1,6)] + [[sg.Button('Save'), sg.Button('Exit')]]

window = sg.Window('To Do List Example', layout)
event, values = window.read()

And the window it creates looks like this:

Elements

You will find information on Elements and all other classes and functions are located in the Call Reference Tab of the documentation.

«Elements» are the building blocks used to create windows. Some GUI APIs use the term «Widget» to describe these graphic elements. So that it’s clear when a PySimpleGUI Element is being referenced versus an underlying GUI Framework’s Widget. PySimpleGUI Elements map to a GUI Framework Widget, usually in a 1-to-1 manner. For example, a Text Element is implemented in tkinter using a Label Widget.

Table of Elements in Tkinter Port

Each port of PySimpleGUI has a core set of Elements as well as port-specific elements. Some port-specific elements include the Dial element in the Qt port, and the Pane element in the tkinter port.

Layout Helper Functions

Your Window’s layout is composed of lists of Elements. In addition to elements, these Layout Help Functions may also be present in a layout definition

Keys

Keys are a super important concept to understand in PySimpleGUI.

If you are going to do anything beyond the basic stuff with your GUI, then you need to understand keys.

You can think of a «key» as a «name» for an element. Or an «identifier». It’s a way for you to identify and talk about an element with the PySimpleGUI library. It’s the exact same kind of key as a dictionary key. They must be unique to a window.

Keys are specified when the Element is created using the key parameter.

Keys are used in these ways:

• Specified when creating the element
• Returned as events. If an element causes an event, its key will be used
• In the values dictionary that is returned from window.read()
• To make updates (changes), to an element that’s in the window

After you put a key in an element’s definition, the values returned from window.read will use that key to tell you the value. For example, if you have an input element in your layout:

Input(key='mykey')

And your read looks like this: event, values = Read()

Then to get the input value from the read it would be: values['mykey']

You also use the same key if you want to call Update on an element. Please see the section Updating Elements to understand that usage. To get find an element object given the element’s key, you can call the window method find_element (also written FindElement, element), or you can use the more common lookup mechanism:

While you’ll often see keys written as strings in examples in this document, know that keys can be ANYTHING.

Let’s say you have a window with a grid of input elements. You could use their row and column location as a key (a tuple)

key=(row, col)

Then when you read the values variable that’s returned to you from calling Window.read(), the key in the values variable will be whatever you used to create the element. In this case you would read the values as:
values[(row, col)]

Most of the time they are simple text strings. In the Demo Programs, keys are written with this convention:
_KEY_NAME_ (underscore at beginning and end with all caps letters) or the most recent convention is to use a dash at the beginning and end (e.g. '-KEY_NAME-'). You don’t have to follow the convention, but it’s not a bad one to follow as other users are used to seeing this format and it’s easy to spot when element keys are being used.

If you have an element object, to find its key, access the member variable .Key for the element. This assumes you’ve got the element in a variable already.

text_elem = sg.Text('', key='-TEXT-')

the_key = text_elem.Key

Default Keys

If you fail to place a key on an Element, then one will be created for you automatically.

For Buttons, the text on the button is that button’s key. Text elements will default to the text’s string (for when events are enabled and the text is clicked)

If the element is one of the input elements (one that will cause an generate an entry in the return values dictionary) and you fail to specify one, then a number will be assigned to it beginning with the number 0. The effect will be as if the values are represented as a list even if a dictionary is used.

Menu Keys

Menu items can have keys associated with them as well. See the section on Menus for more information about these special keys. They aren’t the same as Element keys. Like all elements, Menu Element have one of these Element keys. The individual menu item keys are different.

WRITE_ONLY_KEY Modifier

Sometimes you have input elements (e.g. Multiline) that you are using as an output. The contents of these elements may get very long. You don’t need to «read» these elements and doing so will potentially needlessly return a lot of data.

To tell PySimpleGUI that you do not want an element to return a value when Window.read is called, add the string WRITE_ONLY_KEY to your key name.

If your Multiline element was defined like this originally:

sg.Multiline(size=(40,8), key='-MLINE-')

Then to turn off return values for that element, the Multiline element would be written like this:

sg.Multiline(size=(40,8), key='-MLINE-' + sg.WRITE_ONLY_KEY)

Key Errors — Key error recovery algorithm

In the primary (tkinter) port of PySimpleGUI, starting in version 4.27.0 (not yet on PyPI… but available on GitHub as 4.26.0.14+)

There are now 3 controls over key error handling and a whole new era of key reporting.

SUPPRESS_ERROR_POPUPS = False
SUPPRESS_RAISE_KEY_ERRORS = False
SUPPRESS_KEY_GUESSING = False

You can modify these values by calling set_options.

    sg.set_options(suppress_raise_key_errors=False, suppress_error_popups=False, suppress_key_guessing=False)

A basic definition of them are:
suppress_error_popups — Disables error popups that are generated within PySimpleGUI itself to not be shown
suppress_raise_key_errors — Disables raising a key error if a key or a close match are not found
suppress_key_guessing — Disables the key guessing algorithm should you have a key error

With the defaults left as defined (all False), here is how key errors work.

This is the program being used in this example:

import PySimpleGUI as sg

def main():
    sg.set_options(suppress_raise_key_errors=False, suppress_error_popups=False, suppress_key_guessing=False)

    layout = [  [sg.Text('My Window')],
                [sg.Input(k='-IN-'), sg.Text(size=(12,1), key='-OUT-')],
                [sg.Button('Go'), sg.Button('Exit')]  ]

    window = sg.Window('Window Title', layout, finalize=True)

    while True:             # Event Loop
        event, values = window.read()
        print(event, values)
        if event == sg.WIN_CLOSED or event == 'Exit':
            break
        window['-O U T'].update(values['-IN-'])
    window.close()

def func():

    main()

func()

A few things to note about it:

• There are multiple levels of functions being called, not just a flat program
• There are 2 keys explicitly defined, both are text at this point (we’ll change them later)
• There are 2 lookups happening, one with window the other with values

This key error recovery algorithm only applies to element keys being used to lookup keys inside of windows. The values key lookup is a plain dictionary and so nothing fancy is done for that lookup.

Example 1 — Simple text string misspelling

In our example, this line of code has an error:

window['-O U T'].update(values['-IN-'])

There are multiple problems with the key '-OUT-'. It is missing a dash and it has a bunch of extra spaces.

When the program runs, you’ll first see the layout with no apparent problems:

Clicking the OK button will cause the program to return from window.read() and thus hit our bad key. The result will be a popup window that resembles this:

Note a few things about this error popup. Your shown your bad key and you’re also shown what you likely meant. Additionally, you’re shown the filename, the line number and the line of code itself that has the error.

Because this error was recoverable, the program continues to run after you close the error popup. The result is what you expect from this program… the output field is the same as your information input.

Example 2 — Tuple error

Keys can be a variety of types, including tuples. In this particular program we have a tuple specified in the layout and have used an incorrect tuple in the lookup. Once again the recovery process worked and the program continued.

Example 3 — No close match found

In this example, as you can see in the error popup, there was such a mismatch that no substitution could be performed.

This is an unrecoverable error, so a key error exception is raised.

Traceback (most recent call last):
  File "C:/Users/mike/.PyCharmCE2019.1/config/scratches/scratch_978 - key error example.py", line 25, in <module>
    func()
  File "C:/Users/mike/.PyCharmCE2019.1/config/scratches/scratch_978 - key error example.py", line 23, in func
    main()
  File "C:/Users/mike/.PyCharmCE2019.1/config/scratches/scratch_978 - key error example.py", line 17, in main
    window[(1,2,3)].update(values['-IN-'])
  File "C:PythonPycharmProjectsPSGPySimpleGUI.py", line 8591, in __getitem__
    return self.FindElement(key)
  File "C:PythonPycharmProjectsPSGPySimpleGUI.py", line 7709, in FindElement
    raise KeyError(key)
KeyError: (1, 2, 3)

If you’re running an IDE such as PyCharm, you can use the information from the assert to jump to the line of code in your IDE based on the crash data provided.

Choose Your Desired Combination

There are enough controls on this error handling that you can control how you want your program to fail. If you don’t want any popups, and no guessing and would instead like to simply get an exception when the key error happens, then call set_options with this combination:

    sg.set_options(suppress_raise_key_errors=False, suppress_error_popups=True, suppress_key_guessing=True)

This will cause Example #1 above to immediately get an exception when hitting the statement with the error. Even though the guessing is turned off, you’re still provided with the closest match to help with your debugging….

** Error looking up your element using the key:  -O U T The closest matching key:  -OUT-
Traceback (most recent call last):
  File "C:/Users/mike/.PyCharmCE2019.1/config/scratches/scratch_978 - key error example.py", line 25, in <module>
    func()
  File "C:/Users/mike/.PyCharmCE2019.1/config/scratches/scratch_978 - key error example.py", line 23, in func
    main()
  File "C:/Users/mike/.PyCharmCE2019.1/config/scratches/scratch_978 - key error example.py", line 17, in main
    window['-O U T'].update(values['-IN-'])
  File "C:PythonPycharmProjectsPSGPySimpleGUI.py", line 8591, in __getitem__
    return self.FindElement(key)
  File "C:PythonPycharmProjectsPSGPySimpleGUI.py", line 7709, in FindElement
    raise KeyError(key)
KeyError: '-O U T'

Common Element Parameters

Some parameters that you will see on almost all Element creation calls include:

• key — Used with window[key], events, and in return value dictionary
• tooltip — Hover your mouse over the element and you’ll get a popup with this text
• size — (width, height) — usually measured in characters-wide, rows-high. Sometimes they mean pixels
• font — specifies the font family, size, etc.
• colors — Color name or #RRGGBB string
• pad — Amount of padding to put around element
• enable_events — Turns on the element specific events
• visible — Make elements appear and disappear

Tooltip

Tooltips are text boxes that popup next to an element if you hold your mouse over the top of it. If you want to be extra kind to your window’s user, then you can create tooltips for them by setting the parameter tooltip to some text string. You will need to supply your own line breaks / text wrapping. If you don’t want to manually add them, then take a look at the standard library package textwrap.

Tooltips are one of those «polish» items that really dress-up a GUI and show’s a level of sophistication. Go ahead, impress people, throw some tooltips into your GUI. You can change the color of the background of the tooltip on the tkinter version of PySimpleGUI by setting TOOLTIP_BACKGROUND_COLOR to the color string of your choice. The default value for the color is:

TOOLTIP_BACKGROUND_COLOR = "#ffffe0"

Size

Info on setting default element sizes is discussed in the Window section above.

Specifies the amount of room reserved for the Element. For elements that are character based, such a Text, it is (# characters, # rows). Sometimes it is a pixel measurement such as the Image element. And sometimes a mix like on the Slider element (characters long by pixels wide).

Some elements, Text and Button, have an auto-size setting that is on by default. It will size the element based on the contents. The result is that buttons and text fields will be the size of the string creating them. You can turn it off. For example, for Buttons, the effect will be that all buttons will be the same size in that window.

Beginning in release 4.47.0 sizes can also be an int in addition to a tuple. If an int is specified, then that value is taken as the width and the height is set to 1. If given size=12 then it’s the same as size=(12,1)

Element Sizes — Non-tkinter Ports (Qt, WxPython, Web)

In non-tkinter ports you can set the specific element sizes in 2 ways. One is to use the normal size parameter like you’re used to using. This will be in characters and rows.

The other way is to use a new parameter, size_px. This parameter allows you to specify the size directly in pixels. A setting of size_px=(300,200) will create an Element that is 300 x 200 pixels.

Additionally, you can also indicate pixels using the size parameter, if the size exceeds the threshold for conversion. What does that mean? It means if your width is > 20 (DEFAULT_PIXEL_TO_CHARS_CUTOFF), then it is assumed you’re talking pixels, not characters. However, some of the «normally large» Elements have a cutoff value of 100. These include, for example, the Multline and Output elements.

If you’re curious about the math used to do the character to pixels conversion, it’s quite crude, but functional. The conversion is completed with the help of this variable:

DEFAULT_PIXELS_TO_CHARS_SCALING = (10,26)

The conversion simply takes your size[0] and multiplies by 10 and your size[1] and multiplies it by 26.

Specifying Size as an INT

Beginning in version 4.47.0 you can specify a single int as the size. This will set the size to be a single row in height (1). Writing size=10 is now the same as writing size=(10,1). A tuple is created on your behalf when you specify a size and an int. This will save a considerable amount of typing, especially for the elements where you typically have only 1 row or can only have 1 row.

Colors

A string representing color. Anytime colors are involved, you can specify the tkinter color name such as ‘lightblue’ or an RGB hex value ‘#RRGGBB’. For buttons, the color parameter is a tuple (text color, background color)

Anytime colors are written as a tuple in PySimpleGUI, the way to figure out which color is the background is to replace the «,» with the word «on». (‘white’, ‘red’) specifies a button that is «white on red». Works anywhere there’s a color tuple.

Pad

The amount of room around the element in pixels. The default value is (5,3) which means leave 5 pixels on each side of the x-axis and 3 pixels on each side of the y-axis. You can change this on a global basis using a call to SetOptions, or on an element basis.

If you want more pixels on one side than the other, then you can split the number into 2 number. If you want 200 pixels on the left side, and 3 pixels on the right, the pad would be ((200,3), 3). In this example, only the x-axis is split.

Specifying pad as an INT

Starting in version 4.47.0, it’s possible to set pad to be an int rather than a tuple. If an int is specified, then the pad is set to a tuple with each position being the same as the int. This reduces the code in your layout significantly if you use values such as (0,0) for your pad. This is not an uncommon value. Now you can write pad=0 and you will get the same result as if you typed pad=(0,0)

Font

Specifies the font family, size, and style. Font families on Windows include:

• Arial
• Courier
• Comic,
• Fixedsys
• Times
• Verdana
• Helvetica (the default I think)

The fonts will vary from system to system, however, Tk 8.0 automatically maps Courier, Helvetica and Times to their corresponding native family names on all platforms. Also, font families cannot cause a font specification to fail on Tk 8.0 and greater.

If you wish to leave the font family set to the default, you can put anything not a font name as the family. The PySimpleGUI Demo programs and documentation use the family ‘Any’ to demonstrate this fact.. You could use «default» if that’s more clear to you.

There are 2 formats that can be used to specify a font… a string, and a tuple
Tuple — (family, size, styles)
String — «Family Size Styles»

To specify an underlined, Helvetica font with a size of 15 the values:
(‘Helvetica’, 15, ‘underline italics’)
‘Helvetica 15 underline italics’

Font Style — Valid font styles include:

• italic
• roman
• bold
• normal
• underline
• overstrike

An example with many styles is:

font='Courier 12 italic bold underline overstrike'

The same styles can be used with the tuple format for fonts.

Key

See the section above that has full information about keys.

Visible

Beginning in version 3.17 you can create Elements that are initially invisible that you can later make visible.

To create an invisible Element, place the element in the layout like you normally would and add the parameter

visible=False.

Later when you want to make that Element visible you simply call the Element’s Update method and pass in the parameter visible=True

This feature works best on Qt, but does work on the tkinter version as well. The visible parameter can also be used with the Column and Frame «container» Elements.

Note — Tkinter elements behave differently than Qt elements in how they arrange themselves when going from invisible to visible.

tkinter elements tend to STACK themselves.

One workaround is to place the element in a Column with other elements on its row. This will hold the place of the row it is to be placed on. It will move the element to the end of the row however.

If you want to not only make the element invisible, on tkinter you can call `Element.

Qt elements tend to hold their place really well and the window resizes itself nicely. It is more precise and less clunky.

Shortcut Functions / Multiple Function Names

Perhaps not the best idea, but one that’s done none the less is the naming of methods and functions. Some of the more «Heavily Travelled Elements» (and methods/functions) have «shortcuts».

In other words, I am lazy and don’t like to type. The result is multiple ways to do exactly the same thing. Typically, the Demo Programs and other examples use the full name, or at least a longer name. Thankfully PyCharm will show you the same documentation regardless which you use.

This enables you to code much quicker once you are used to using the SDK. The Text Element, for example, has 3 different names Text, Txt orT. InputText can also be written Input or In .

The shortcuts aren’t limited to Elements. The Window method Window.FindElement can be written as Window.Element because it’s such a commonly used function. BUT, even that has now been shortened to window[key]

It’s an ongoing thing. If you don’t stay up to date and one of the newer shortcuts is used, you’ll need to simply rename that shortcut in the code. For examples Replace sg.T with sg.Text if your version doesn’t have sg.T in it.

Text Element | T == Txt == Text

Basic Element. It displays text.

layout = [
            [sg.Text('This is what a Text Element looks like')],
         ]

When creating a Text Element that you will later update, make sure you reserve enough characters for the new text. When a Text Element is created without a size parameter, it is created to exactly fit the characters provided.

With proportional spaced fonts (normally the default) the pixel size of one set of characters will differ from the pixel size of a different set of characters even though the set is of the same number of characters. In other words, not all letters use the same number of pixels. Look at the text you’re reading right now and you will see this. An «i» takes up a less space then an «A».

Window.FindElement(key) shortened to Window[key]

There’s been a fantastic leap forward in making PySimpleGUI code more compact.

Instead of writing:

window.FindElement(key).update(new_value)

You can now write it as:

window[key].update(new_value)

This change has been released to PyPI for PySimpleGUI

MANY Thanks is owed to the nngogol that suggested and showed me how to do this. It’s an incredible find as have been many of his suggestions.

Element.update() -> Element() shortcut

This has to be one of the strangest syntactical constructs I’ve ever written.

It is best used in combination with FindElement (see prior section on how to shortcut FindElement).

Normally to change an element, you «find» it, then call its update method. The code usually looks like this, as you saw in the previous section:

window[key].update(new_value)

The code can be further compressed by removing the .update characters, resulting in this very compact looking call:

Yes, that’s a valid statement in Python.

What’s happening is that the element itself is being called. You can also writing it like this:

elem = sg.Text('Some text', key='-TEXT-')
elem('new text value')

Side note — you can also call your window variable directly. If you «call» it it will actually call Window.read.

window = sg.Window(....)
event, values = window()

# is the same as
window = sg.Window(....)
event, values = window.read()

It is confusing looking however so when used, it might be a good idea to write a comment at the end of the statement to help out the poor beginner programmer coming along behind you.

Because it’s such a foreign construct that someone with 1 week of Python classes will not recognize, the demos will continue to use the .update method.

It does not have to be used in conjuction with FindElement. The call works on any previously made Element. Sometimes elements are created, stored into a variable and then that variable is used in the layout. For example.

graph_element = sg.Graph(...... lots of parms ......)

layout = [[graph_element]]
.
.
.
graph_element(background_color='blue')      # this calls Graph.update for the previously defined element

Hopefully this isn’t too confusing. Note that the methods these shortcuts replace will not be removed. You can continue to use the old constructs without changes.

Fonts

Already discussed in the common parameters section. Either string or a tuple.

Color in PySimpleGUI are in one of two formats — color name or RGB value.

Individual colors are specified using either the color names as defined in tkinter or an RGB string of this format:

auto_size_text

A True value for auto_size_text, when placed on Text Elements, indicates that the width of the Element should be shrunk do the width of the text. The default setting is True. You need to remember this when you create Text elements that you are using for output.

Text(key='-TXTOUT-) will create a Text Element that has 0 length. Notice that for Text elements with an empty string, no string value needs to be indicated. The default value for strings is '' for Text Elements. Prior to release 4.45.0 you needed to reserve enough room for your longest string. If you tried to output a string that’s 5 characters, it wasn’t shown in the window because there wasn’t enough room. The remedy was to manually set the size to what you expect to output

Text(size=(15,1), key='-TXTOUT-) creates a Text Element that can hold 15 characters.

With the newer versions, after 4.45.0, if you set no size at all, that is size=(None, None), then both the Text element will grow and shrink to fit the text and so will the Window. Additionally, if you indicate that the height is None then the element will grow and shrink in their to match the string.

The way the Text element now works is truly auto-sized.

Chortcut functions

The shorthand functions for Text are Txt and T

Events enable_events

If you set the parameter enable_events then you will get an event if the user clicks on the Text.

Multiline Element

This Element doubles as both an input and output Element.

layout = [[sg.Multiline('This is what a Multi-line Text Element looks like', size=(45,5))]]

This element has been expanded upon quite a bit over time. Two of the more exciting additions have been

• Ability to output unique text and background colors on a per-character basis
• The print method that allows you to easily reroute your normally printed output to a multiline element instead

The Multiline.print() call is made using the same element-lookup technique you’re used to using to call update. One of these lookups generally appear:

window['-MULTILINE KEY-']

To change one of your normal prints to output to your multiline element, you simply add the above lookup expression to the front of your print statement.

print('My variables are', a, b, c)       # a normal print statement

window['-MULTILINE KEY-'].print('My variables are', a, b, c)     # Routed to your multiline element

It gets even better though…. you can add color to your prints

# Outputs red text on a yellow background
window['-MULTILINE KEY-'].print('My variables are', a, b, c, text_color='red', background_color='yellow')

Redefine print

Another way to use this print capability is to redefine the print statement itself. This will allow you to leave your code entirely as is. By adding this line of code your entire program will output all printed information to a multiline element.

print = lambda *args, **kwargs: window['-MULTILINE KEY-'].print(*args, **kwargs)

Text Input Element | InputText == Input == In

layout = [[sg.InputText('Default text')]]

Note about the do_not_clear parameter

This used to really trip people up, but don’t think so anymore. The do_not_clear parameter is initialized when creating the InputText Element. If set to False, then the input field’s contents will be erased after every Window.read() call. Use this setting for when your window is an «Input Form» type of window where you want all of the fields to be erased and start over again every time.

Combo Element | Combo == InputCombo == DropDown == Drop

Also known as a drop-down list. Only required parameter is the list of choices. The return value is a string matching what’s visible on the GUI.

layout = [[sg.Combo(['choice 1', 'choice 2'])]]

Listbox Element

The standard listbox like you’ll find in most GUIs. Note that the return values from this element will be a list of results, not a single result. This is because the user can select more than 1 item from the list (if you set the right mode).

layout = [[sg.Listbox(values=['Listbox 1', 'Listbox 2', 'Listbox 3'], size=(30, 6))]]

ListBoxes can cause a window to return from a Read call. If the flag enable_events is set, then when a user makes a selection, the Read immediately returns.

Another way ListBoxes can cause Reads to return is if the flag bind_return_key is set. If True, then if the user presses the return key while an entry is selected, then the Read returns. Also, if this flag is set, if the user double-clicks an entry it will return from the Read.

Slider Element

Sliders have a couple of slider-specific settings as well as appearance settings. Examples include the orientation and range settings.

layout = [[sg.Slider(range=(1,500),
         default_value=222,
         size=(20,15),
         orientation='horizontal',
         font=('Helvetica', 12))]]

Qt Sliders

There is an important difference between Qt and tkinter sliders. On Qt, the slider values must be integer, not float. If you want your slider to go from 0.1 to 1.0, then make your slider go from 1 to 10 and divide by 10. It’s an easy math thing to do and not a big deal. Just deal with it…. you’re writing software after all. Presumably you know how to do these things.

Radio Button Element

Creates one radio button that is assigned to a group of radio buttons. Only 1 of the buttons in the group can be selected at any one time.

layout =  [
	[sg.Radio('My first Radio!', "RADIO1", default=True),
	sg.Radio('My second radio!', "RADIO1")]
]

Checkbox Element | CBox == CB == Check

Checkbox elements are like Radio Button elements. They return a bool indicating whether or not they are checked.

layout =  [[sg.Checkbox('My first Checkbox!', default=True), sg.Checkbox('My second Checkbox!')]]

Spin Element

An up/down spinner control. The valid values are passed in as a list.

layout =  [[sg.Spin([i for i in range(1,11)], initial_value=1), sg.Text('Volume level')]]

Image Element

Images can be placed in your window provide they are in PNG, GIF, PPM/PGM format. JPGs cannot be shown because tkinter does not naively support JPGs. You can use the Python Imaging Library (PIL) package to convert your image to PNG prior to calling PySimpleGUI if your images are in JPG format.

layout = [
            [sg.Image(r'C:PySimpleGUILogosPySimpleGUI_Logo_320.png')],
         ]

You can specify an animated GIF as an image and can animate the GIF by calling UpdateAnimation. Exciting stuff!

You can call the method without setting the time_between_frames value and it will show a frame and immediately move on to the next frame. This enables you to do the inter-frame timing.

Button Element

Buttons are the most important element of all! They cause the majority of the action to happen. After all, it’s a button press that will get you out of a window, whether it be Submit or Cancel, one way or another a button is involved in all windows. The only exception is to this is when the user closes the window using the «X» in the upper corner which means no button was involved.

The Types of buttons include:

• Folder Browse
• File Browse
• Files Browse
• File SaveAs
• File Save
• Close window (normal button)
• Read window
• Realtime
• Calendar Chooser
• Color Chooser

Close window — Normal buttons like Submit, Cancel, Yes, No, do NOT close the window… they used to. Now to close a window you need to use a CloseButton / CButton.

Folder Browse — When clicked a folder browse dialog box is opened. The results of the Folder Browse dialog box are written into one of the input fields of the window.

File Browse — Same as the Folder Browse except rather than choosing a folder, a single file is chosen.

Calendar Chooser — Opens a graphical calendar to select a date.

Color Chooser — Opens a color chooser dialog

Read window — This is a window button that will read a snapshot of all of the input fields, but does not close the window after it’s clicked.

Realtime — This is another async window button. Normal button clicks occur after a button’s click is released. Realtime buttons report a click the entire time the button is held down.

Most programs will use a combination of shortcut button calls (Submit, Cancel, etc.), normal Buttons which leave the windows open and CloseButtons that close the window when clicked.

Sometimes there are multiple names for the same function. This is simply to make the job of the programmer quicker and easier. Or they are old names that are no longer used but kept around so that existing programs don’t break.

The 4 primary windows of PySimpleGUI buttons and their names are:

1. Button= ReadButton = RButton = ReadFormButton (Use Button, others are old methods)
2. CloseButton = CButton
3. RealtimeButton
4. DummyButton

You will find the long-form names in the older programs. ReadButton for example.

In Oct 2018, the definition of Button changed. Previously Button would CLOSE the window when clicked. It has been changed so the Button calls will leave the window open in exactly the same way as a ReadButton. They are the same calls now. To enables windows to be closed using buttons, a new button was added… CloseButton or CButton.

Your PySimpleGUI program is most likely going to contain only Button calls. The others are generally not found in user code.

The most basic Button element call to use is Button

layout =  [[sg.Button('Ok'), sg.Button('Cancel')]]

You will rarely see these 2 buttons in particular written this way. Recall that PySimpleGUI is focused on YOU (which generally directly means…. less typing). As a result, the code for the above window is normally written using shortcuts found in the next section.

You will typically see this instead of calls to Button:

layout =  [[sg.Ok(), sg.Cancel()]]

In reality Button is in fact being called on your behalf. Behind the scenes, sg.Ok and sg.Cancel call Button with the text set to Ok and Cancel and returning the results that then go into the layout. If you were to print the layout it will look identical to the first layout shown that has Button shown specifically in the layout.

TTK Buttons & Macs

In 2019 support for ttk Buttons was added. This gets around the problem of not being able to change button colors on a Mac. There are a number of places you can control whether or not ttk buttons are used, be it on MAc or other platform.

TTK Buttons and TK Buttons operate slightly differently. Button highlighting is one different. How images and text are displayed at the same time is another. You’ve got options now that weren’t there previously. It’s nice to see that Mac users can finally use the color themes.

Button Element Shortcuts

These Pre-made buttons are some of the most important elements of all because they are used so much. They all basically do the same thing, set the button text to match the function name and set the parameters to commonly used values. If you find yourself needing to create a custom button often because it’s not on this list, please post a request on GitHub. . They include:

• OK
• Ok
• Submit
• Cancel
• Yes
• No
• Exit
• Quit
• Help
• Save
• SaveAs
• Open

«Chooser» Buttons

These buttons are used to show dialog boxes that choose something like a filename, date, color, etc.. that are filled into an InputText Element (or some other «target»…. see below regarding targets)

• CalendarButton
• ColorChooserButton
• FileBrowse
• FilesBrowse
• FileSaveAs
• FolderBrowse

IMPORT NOTE ABOUT SHORTCUT BUTTONS
Prior to release 3.11.0, these buttons closed the window. Starting with 3.11 they will not close the window. They act like RButtons (return the button text and do not close the window)

If you are having trouble with these buttons closing your window, please check your installed version of PySimpleGUI by typing pip list at a command prompt. Prior to 3.11 these buttons close your window.

Using older versions, if you want a Submit() button that does not close the window, then you would instead use RButton(‘Submit’). Using the new version, if you want a Submit button that closes the window like the sold Submit() call did, you would write that as CloseButton('Submit') or CButton('Submit')

Button targets

The FileBrowse, FolderBrowse, FileSaveAs , FilesSaveAs, CalendarButton, ColorChooserButton buttons all fill-in values into another element located on the window. The target can be a Text Element or an InputText Element or the button itself. The location of the element is specified by the target variable in the function call.

The Target comes in two forms.

1. Key
2. (row, column)

Targets that are specified using a key will find its target element by using the target’s key value. This is the «preferred» method.

If the Target is specified using (row, column) then it utilizes a grid system. The rows in your GUI are numbered starting with 0. The target can be specified as a hard coded grid item or it can be relative to the button.

The (row, col) targeting can only target elements that are in the same «container». Containers are the Window, Column and Frame Elements. A File Browse button located inside of a Column is unable to target elements outside of that Column.

The default value for target is (ThisRow, -1). ThisRow is a special value that tells the GUI to use the same row as the button. The Y-value of -1 means the field one value to the left of the button. For a File or Folder Browse button, the field that it fills are generally to the left of the button is most cases. (ThisRow, -1) means the Element to the left of the button, on the same row.

If a value of (None, None) is chosen for the target, then the button itself will hold the information. Later the button can be queried for the value by using the button’s key.

Let’s examine this window as an example:

The InputText element is located at (1,0)… row 1, column 0. The Browse button is located at position (2,0). The Target for the button could be any of these values:

Target = (1,0)
Target = (-1,0)

The code for the entire window could be:

layout = [[sg.T('Source Folder')],
              [sg.In()],
              [sg.FolderBrowse(target=(-1, 0)), sg.OK()]]

or if using keys, then the code would be:

layout = [[sg.T('Source Folder')],
              [sg.In(key='input')],
              [sg.FolderBrowse(target='input'), sg.OK()]]

See how much easier the key method is?

Invisible Targets

One very handy trick is to make your target invisible. This will remove the ability to edit the chosen value like you normally would be able to with an Input Element. It’s a way of making things look cleaner, less cluttered too perhaps.

Save & Open Buttons

There are 4 different types of File/Folder open dialog box available. If you are looking for a file to open, the FileBrowse is what you want. If you want to save a file, SaveAs is the button. If you want to get a folder name, then FolderBrowse is the button to use. To open several files at once, use the FilesBrowse button. It will create a list of files that are separated by ‘;’

Calendar Buttons

These buttons pop up a calendar chooser window. The chosen date is returned as a string.

Color Chooser Buttons

These buttons pop up a standard color chooser window. The result is returned as a tuple. One of the returned values is an RGB hex representation.

Custom Buttons

Not all buttons are created equal. A button that closes a window is different that a button that returns from the window without closing it. If you want to define your own button, you will generally do this with the Button Element Button, which closes the window when clicked.

layout =  [[sg.Button('My Button')]]

All buttons can have their text changed by changing the button_text parameter in the button call. It is this text that is returned when a window is read. This text will be what tells you which button was clicked. However, you can also use keys on your buttons so that they will be unique. If only the text were used, you would never be able to have 2 buttons in the same window with the same text.

layout =  [[sg.Button('My Button', key='_BUTTON_KEY_')]]

With this layout, the event that is returned from a Window.read() call when the button is clicked will be «_BUTTON_KEY_«

Button Images

Now this is an exciting feature not found in many simplified packages…. images on buttons! You can make a pretty spiffy user interface with the help of a few button images.

This is one of the quickest and easiest ways to transform tkinter from a «1990s looking GUI» into a «modern GUI». If you don’t like the default buttons, then simply bring your own button images and use those instead.

Your button images need to be in PNG or GIF format. When you make a button with an image, set the button background to the same color as the background. You can get the theme’s background color by calling theme_background_color()

TRANSPARENT_BUTTON — Important — This is a legacy value that is misleading. It is currently defined as this constant value:

TRANSPARENT_BUTTON = ('#F0F0F0', '#F0F0F0')

As you can see it is simply a tuple of 2 gray colors. The effect is that the button text and the button background color to a specific shade of gray. Way back in time, before you could change the background colors and all windows were gray, this value worked. But now that your button can be on any background color, you’ll want to set the buttons color to match the background so that your button blends with the background color.

sg.Button('Restart Song', button_color=(sg.theme_background_color(), sg.theme_background_color()),
               image_filename=image_restart, image_size=(50, 50), image_subsample=2, border_width=0)

There are several parameters in Button elements that are used for button images.

image_filename - Filename of image. Can be a relative path
image_data - A Base64 image
image_size - Size of image in pixels
image_subsample - Amount to divide the size by.  2 means your image will be 1/2 the size.  3 means 1/3

Here’s an example window made with button images.

You’ll find the source code in the file Demo Media Player. Here is what the button calls look like to create media player window

sg.Button('Pause', button_color=(sg.theme_background_color(), sg.theme_background_color()),
             image_filename=image_pause,
             image_size=(50, 50),
             image_subsample=2,
             border_width=0)

Experimentation is sometimes required for these concepts to really sink in and they can vary depending on the underlying GUI framework.

Button Images do work so play with them. You can use PIL to change the size of your images before passing to PySimpleGUI.

Realtime Buttons

Normally buttons are considered «clicked» when the mouse button is let UP after a downward click on the button. What about times when you need to read the raw up/down button values. A classic example for this is a robotic remote control. Building a remote control using a GUI is easy enough. One button for each of the directions is a start. Perhaps something like this:

This window has 2 button types. There’s the normal «Read Button» (Quit) and 4 «Realtime Buttons».

Here is the code to make, show and get results from this window:

import PySimpleGUI as sg

gui_rows = [[sg.Text('Robotics Remote Control')],
            [sg.T(' '  * 10), sg.RealtimeButton('Forward')],
            [sg.RealtimeButton('Left'), sg.T(' '  * 15), sg.RealtimeButton('Right')],
            [sg.T(' '  * 10), sg.RealtimeButton('Reverse')],
            [sg.T('')],
            [sg.Quit(button_color=('black', 'orange'))]
            ]

window = sg.Window('Robotics Remote Control', gui_rows)

#
# Some place later in your code...
# You need to perform a Read or Refresh call on your window every now and then or
# else it will apprear as if the program has locked up.
#
# your program's main loop
while (True):
    # This is the code that reads and updates your window
    event, values = window.read(timeout=50)
    print(event)
    if event in ('Quit', sg.WIN_CLOSED):
        break

window.close()  # Don't forget to close your window!

This loop will read button values and print them. When one of the Realtime buttons is clicked, the call to window.read will return a button name matching the name on the button that was depressed or the key if there was a key assigned to the button. It will continue to return values as long as the button remains depressed. Once released, the Read will return timeout events until a button is again clicked.

File Types
The FileBrowse & SaveAs buttons have an additional setting named file_types. This variable is used to filter the files shown in the file dialog box. The default value for this setting is

FileTypes=(("ALL Files", "*.*"),)

This code produces a window where the Browse button only shows files of type .TXT

layout =  [[sg.In() ,sg.FileBrowse(file_types=(("Text Files", "*.txt"),))]]

NOTE — Mac users will not be able to use the file_types parameter. tkinter has a bug on Macs that will crash the program is a file_type is attempted so that feature had to be removed. Sorry about that!

The ENTER key
The ENTER key is an important part of data entry for windows. There’s a long tradition of the enter key being used to quickly submit windows. PySimpleGUI implements this by tying the ENTER key to the first button that closes or reads a window.

The Enter Key can be «bound» to a particular button so that when the key is pressed, it causes the window to return as if the button was clicked. This is done using the bind_return_key parameter in the button calls.
If there are more than 1 button on a window, the FIRST button that is of type Close window or Read window is used. First is determined by scanning the window, top to bottom and left to right.

ButtonMenu Element

The ButtonMenu element produces a unique kind of effect. It’s a button, that when clicked, shows you a menu. It’s like clicking one of the top-level menu items on a MenuBar. As a result, the menu definition take the format of a single menu entry from a normal menu definition. A normal menu definition is a list of lists. This definition is one of those lists.

 ['Menu', ['&Pause Graph', 'Menu item::optional_key']]

The very first string normally specifies what is shown on the menu bar. In this case, the value is not used. You set the text for the button using a different parameter, the button_text parm.

One use of this element is to make a «fake menu bar» that has a colored background. Normal menu bars cannot have their background color changed. Not so with ButtonMenus.

Return values for ButtonMenus are sent via the return values dictionary. If a selection is made, then an event is generated that will equal the ButtonMenu’s key value. Use that key value to look up the value selected by the user. This is the same mechanism as the Menu Bar Element, but differs from the pop-up (right click) menu.

VerticalSeparator Element

This element has limited usefulness and is being included more for completeness than anything else. It will draw a line between elements.

It works best when placed between columns or elements that span multiple rows. If on a «normal» row with elements that are only 1 row high, then it will only span that one row.

VerticalSeparator(pad=None)

HorizontalSeparator Element

In PySimpleGUI, the tkinter port, there is no HorizontalSeparator Element. One will be added as a «stub» so that code is portable. It will likely do nothing just like the Stretch Element.

An easy way to get a horizontal line in PySimpleGUI is to use a Text Element that contains a line of underscores

sg.Text('_'*30)             # make a horizontal line stretching 30 characters

ProgressBar Element

The ProgressBar element is used to build custom Progress Bar windows. It is HIGHLY recommended that you use OneLineProgressMeter that provides a complete progress meter solution for you. Progress Meters are not easy to work with because the windows have to be non-blocking and they are tricky to debug.

The easiest way to get progress meters into your code is to use the OneLineProgressMeter API. This consists of a pair of functions, OneLineProgressMeter and OneLineProgressMeterCancel. You can easily cancel any progress meter by calling it with the current value = max value. This will mark the meter as expired and close the window.
You’ve already seen OneLineProgressMeter calls presented earlier in this readme.

sg.OneLineProgressMeter('My Meter', i+1, 1000,  'key', 'Optional message')

The return value for OneLineProgressMeter is:
True if meter updated correctly
False if user clicked the Cancel button, closed the window, or vale reached the max value.

Progress Meter in Your window

Another way of using a Progress Meter with PySimpleGUI is to build a custom window with a ProgressBar Element in the window. You will need to run your window as a non-blocking window. When you are ready to update your progress bar, you call the UpdateBar method for the ProgressBar element itself.

import PySimpleGUI as sg

# layout the window
layout = [[sg.Text('A custom progress meter')],
          [sg.ProgressBar(1000, orientation='h', size=(20, 20), key='progressbar')],
          [sg.Cancel()]]

# create the window`
window = sg.Window('Custom Progress Meter', layout)
progress_bar = window['progressbar']
# loop that would normally do something useful
for i in range(1000):
    # check to see if the cancel button was clicked and exit loop if clicked
    event, values = window.read(timeout=10)
    if event == 'Cancel'  or event == sg.WIN_CLOSED:
        break
  # update bar with loop value +1 so that bar eventually reaches the maximum
    progress_bar.UpdateBar(i + 1)
# done with loop... need to destroy the window as it's still open
window.close()

Output Element

The Output Element is a re-direction of Stdout.

If you are looking for a way to quickly add the ability to show scrolling text within your window, then adding an Output Element is about as quick and easy as it gets.

Anything «printed» will be displayed in this element. This is the «trivial» way to show scrolling text in your window. It’s as easy as dropping an Output Element into your window and then calling print as much as you want. The user will see a scrolling area of text inside their window.

IMPORTANT You will NOT see what you print until you call either window.read or window.Refresh. If you want to immediately see what was printed, call window.Refresh() immediately after your print statement.

Here’s a complete solution for a chat-window using an Output Element. To display data that’s received, you would to simply «print» it and it will show up in the output area. You’ll find this technique used in several Demo Programs including the HowDoI application.

import PySimpleGUI as sg

def ChatBot():
    layout = [[(sg.Text('This is where standard out is being routed', size=[40, 1]))],
              [sg.Output(size=(80, 20))],
              [sg.Multiline(size=(70, 5), enter_submits=True),
               sg.Button('SEND', button_color=(sg.YELLOWS[0], sg.BLUES[0])),
               sg.Button('EXIT', button_color=(sg.YELLOWS[0], sg.GREENS[0]))]]

    window = sg.Window('Chat Window', layout, default_element_size=(30, 2))

    # ---===--- Loop taking in user input and using it to query HowDoI web oracle --- #
    while True:
        event, value = window.read()
        if event == 'SEND':
            print(value)
        else:
            break
    window.close()
ChatBot()

Column Element & Frame, Tab «Container» Elements

Columns and Frames and Tabs are all «Container Elements» and behave similarly. This section focuses on Columns but can be applied elsewhere.

Starting in version 2.9 you’ll be able to do more complex layouts by using the Column Element. Think of a Column as a window within a window. And, yes, you can have a Column within a Column if you want.

Columns are specified, like all «container elements», in exactly the same way as a window, as a list of lists.

Columns are needed when you want to specify more than 1 element in a single row.

For example, this layout has a single slider element that spans several rows followed by 7 Text and Input elements on the same row.

Without a Column Element you can’t create a layout like this. But with it, you should be able to closely match any layout created using tkinter only.

import PySimpleGUI as sg

# Demo of how columns work
# window has on row 1 a vertical slider followed by a COLUMN with 7 rows
# Prior to the Column element, this layout was not possible
# Columns layouts look identical to window layouts, they are a list of lists of elements.

window = sg.Window('Columns')                                   # blank window

# Column layout
col = [[sg.Text('col Row 1')],
       [sg.Text('col Row 2'), sg.Input('col input 1')],
       [sg.Text('col Row 3'), sg.Input('col input 2')],
       [sg.Text('col Row 4'), sg.Input('col input 3')],
       [sg.Text('col Row 5'), sg.Input('col input 4')],
       [sg.Text('col Row 6'), sg.Input('col input 5')],
       [sg.Text('col Row 7'), sg.Input('col input 6')]]

layout = [[sg.Slider(range=(1,100), default_value=10, orientation='v', size=(8,20)), sg.Column(col)],
          [sg.In('Last input')],
          [sg.OK()]]

# Display the window and get values

window = sg.Window('Compact 1-line window with column', layout)
event, values = window.read()
window.close()

sg.Popup(event, values, line_width=200)

Columns As a Way to Modify Elements

Sometimes Columns are used to contain a single elemnet, but to give that elemously it was difficult to do these kinds of layouts, if not impossible.

justify the Column element’s row by setting the Column‘s justification parameter.

You can also justify the entire contents within a Column by using the Column’s element_justification parameter.

With these parameter’s it is possible to create windows that have their contents centered. Previously this was very difficult to do.

This is currently only available in the primary PySimpleGUI port.

They can also be used to justify a group of elements in a particular way.

Placing Column elements inside Columns elements make it possible to create a multitude of

Sizer Element

New in 4.3 is the Sizer Element. This element is used to help create a container of a particular size. It can be placed inside of these PySimpleGUI items:

• Column
• Frame
• Tab
• Window

The implementation of a Sizer is quite simple. It returns an empty Column element that has a pad value set to the values passed into the Sizer. Thus isn’t not a class but rather a «Shortcut function» similar to the pre-defined Buttons.

This feature is only available in the tkinter port of PySimpleGUI at the moment. A cross port is needed.

Frame Element (Labelled Frames, Frames with a title)

Frames work exactly the same way as Columns. You create layout that is then used to initialize the Frame. Like a Column element, it’s a «Container Element» that holds one or more elements inside.

Notice how the Frame layout looks identical to a window layout. A window works exactly the same way as a Column and a Frame. They all are «container elements» — elements that contain other elements.

These container Elements can be nested as deep as you want. That’s a pretty spiffy feature, right? Took a lot of work so be appreciative. Recursive code isn’t trivial.

This code creates a window with a Frame and 2 buttons.

frame_layout = [
                  [sg.T('Text inside of a frame')],
                  [sg.CB('Check 1'), sg.CB('Check 2')],
               ]
layout = [
          [sg.Frame('My Frame Title', frame_layout, font='Any 12', title_color='blue')],
          [sg.Submit(), sg.Cancel()]
         ]

window = sg.Window('Frame with buttons', layout, font=("Helvetica", 12))

Canvas Element

In my opinion, the tkinter Canvas Widget is the most powerful of the tkinter widget. While I try my best to completely isolate the user from anything that is tkinter related, the Canvas Element is the one exception. It enables integration with a number of other packages, often with spectacular results.

However, there’s another way to get that power and that’s through the Graph Element, an even MORE powerful Element as it uses a Canvas that you can directly access if needed. The Graph Element has a large number of drawing methods that the Canvas Element does not have. Plus, if you need to, you can access the Graph Element’s «Canvas» through a member variable.

Matplotlib, Pyplot Integration

**NOTE — The newest version of Matplotlib (3.1.0) no longer works with this technique. ** You must install 3.0.3 in order to use the Demo Matplotlib programs provided in the Demo Programs section.

One such integration is with Matplotlib and Pyplot. There is a Demo program written that you can use as a design pattern to get an understanding of how to use the Canvas Widget once you get it.

def Canvas(canvas - a tkinter canvasf if you created one. Normally not set
         background_color - canvas color
         size - size in pixels
         pad - element padding for packing
         key - key used to lookup element
         tooltip - tooltip text)

The order of operations to obtain a tkinter Canvas Widget is:

    figure_x, figure_y, figure_w, figure_h = fig.bbox.bounds
    # define the window layout
    layout = [[sg.Text('Plot test')],
              [sg.Canvas(size=(figure_w, figure_h), key='canvas')],
              [sg.OK(pad=((figure_w / 2, 0), 3), size=(4, 2))]]

    # create the window and show it without the plot
    window = sg.Window('Demo Application - Embedding Matplotlib In PySimpleGUI', layout).Finalize()

    # add the plot to the window
    fig_photo = draw_figure(window['canvas'].TKCanvas, fig)

    # show it all again and get buttons
    event, values = window.read()

To get a tkinter Canvas Widget from PySimpleGUI, follow these steps:

• Add Canvas Element to your window
• Layout your window
• Call window.Finalize() — this is a critical step you must not forget
• Find the Canvas Element by looking up using key
• Your Canvas Widget Object will be the found_element.TKCanvas
• Draw on your canvas to your heart’s content
• Call window.read() — Nothing will appear on your canvas until you call Read

See Demo_Matplotlib.py for a Recipe you can copy.

Methods & Properties

TKCanvas — not a method but a property. Returns the tkinter Canvas Widget

Graph Element

All you math fans will enjoy this Element… and all you non-math fans will enjoy it even more.

I’ve found nothing to be less fun than dealing with a graphic’s coordinate system from a GUI Framework. It’s always upside down from what I want. (0,0) is in the upper left hand corner…. sometimes… or was it in the lower left? In short, it’s a pain in the ass.

How about the ability to get your own location of (0,0) and then using those coordinates instead of what tkinter provides? This results in a very powerful capability — working in your own units, and then displaying them in an area defined in pixels.

If you’ve ever been frustrated with where (0,0) is located on some surface you draw on, then fear not, your frustration ends right here. You get to draw using whatever coordinate system you want. Place (0,0) anywhere you want, including not anywhere on your Graph. You could define a Graph that’s all negative numbers between -2.1 and -3.5 in the X axis and -3 to -8.2 in the Y axis

There are 3 values you’ll need to supply the Graph Element. They are:

• Size of the canvas in pixels
• The lower left (x,y) coordinate of your coordinate system
• The upper right (x,y) coordinate of your coordinate system