It's been a little while getting back around to the Cookbook. As a result, some of the information was using older design patterns and some better examples need to be included. There have been about 1/3 of the changes made so far that need to get made, so be patient.
Welcome to the PySimpleGUI Cookbook! It's provided as but one component of a larger documentation effort for the PySimpleGUI package. Its purpose is to give you a jump start.
You'll find that starting with a Recipe will give you a big jump-start on creating your custom GUI. Copy and paste one of these Recipes and modify it to match your requirements. Study them to get an idea of some design patterns to follow.
This document is not a replacement for the main documentation at http://www.PySimpleGUI.org. If you're looking for answers, they're most likely there in the detailed explanations and call definitions. That document is updated much more frequently than this one.
If you like this Cookbook, then you'll LOVE the 200 sample programs that are just like these. You'll find them in the GitHub at http://Demos.PySimpleGUI.com. They are located in the folder `DemoPrograms` and there is also a `Demo Programs` folder for each of the PySimpleGUI ports.
These programs are updated frequently, much more so than this Cookbook document. It's there that you'll find the largest potential for a big jump-start on your project.
So, for example, if you're trying to use the Graph Element to create a line graph, check out the demo programs... there are 8 different demos for the Graph Element alone.
More and more the recipes are moving online, away from this document and onto Trinket. http://Trinket.PySimpleGUI.org
You'll find a number of "recipes" running on Trinket. The PySimpleGUI [Trinket Demo Programs](https://pysimplegui.trinket.io/demo-programs) are often accompanied by explanatory text. Because it's an actively used educational capability, you'll find newer PySimpleGUI features demonstrated there.
The advantage to "live", online PySimpleGUI demos is that you can examine the source code, run it, and see the GUI in your browser window, without installing *anything* on your local machine. No Python, no PySimpleGUI, only your browser is needed to get going.
# [Repl.it](https://repl.it/@PySimpleGUI)... another online resource
The [PySimpleGUI repl.it repository](https://repl.it/@PySimpleGUI) is also used, but it doesn't provide the same kind of capability to provide some explanatory text and screenshots with the examples. It does, however, automatically install the latest version of PySimpleGUI for many of the examples. It also enables the demo programs to access any package that can be pip installed. Trinket does not have this more expansive capability. Some older demos are located there. You can run PySimpleGUIWeb demos using Repl.it.
A quick explanation about this document. The PySimpleGUI Cookbook is meant to get you started quickly. But that's only part of the purpose. The other, probably most important one, is *coding conventions*. The more of these examples and the programs you see in the [Demo Programs](http://Demos.PySimpleGUI.org) section on the GitHub, the more familiar certain patterns will emerge.
It's through the Cookbook and the Demo Programs that new PySimpleGUI constructs and naming conventions are "rolled out" to the user community. If you are brand new to PySimpleGUI, then you're getting your foundation here. That foundation changes over time as the package improves. The old code still runs, but as more features are developed and better practices are discovered, you'll want to be using newer examples and coding conventions.
PEP8 names are a really good example. Previously many of the method names for the Elements were done with CamelCase which is not a PEP8 compliant way of naming those functions. They should have been snake_case. Now that a complete set of PEP8 bindings is available, the method names are being changed here, in the primary documentation and in the demo programs. `window.Read()` became `window.read()`. It's better that you see examples using the newer `windows.read()` names.
In short, it's brainwashing you to program PySimpleGUI a certain way. The effect is that one person has no problem picking up the code from another PySimpleGUI programmer and recognizing it. If you stick with variable names shown here, like many other PySimpleGUI users have, then you'll understand other people's code (and the demos too) quicker. So far, the coding conventions have been used by most all users. It's improved efficiency for everyone.
Keys are an extremely important concept for you to understand. They are the labels/tags/names/identifiers you give Elements. They are a way for you to communicate about a specific element with the PySimpleGUI API calls.
**Important** - while they are shown as strings in many examples, they can be ANYTHING (ints, tuples, objects). Anything **EXCEPT Lists**. Lists are not valid Keys because in Python lists are not hashable and thus cannot be used as keys in dictionaries. Tuples, however, can.
Keys are specified when you create an element using the `key` keyword parameter. They are used to "find elements" so that you can perform actions on them.
All of your PySimpleGUI programs will utilize one of these 2 design patterns depending on the type of window you're implementing. The two types of windows are:
The **One-shot window** is one that pops up, collects some data, and then disappears. It is more or less a 'form' meant to quickly grab some information and then be closed.
The **Persistent window** is one that sticks around. With these programs, you loop, reading and processing "events" such as button clicks. It's more like a typical Windows/Mac/Linux program.
If you are writing a "typical Windows program" where the window stays open while you collect multiple button clicks and input values, then you'll want Recipe Pattern 2B.
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 then closed.
The `event` is what caused the read to return. It could be a button press, some text clicked, a list item chosen, etc, or `WIN_CLOSED` if the user closes the window using the X.
The `values` is a dictionary of values of all the input-style elements. Dictionaries use keys to define entries. If your elements do not specificy a key, one is provided for you. These auto-numbered keys are ints starting at zero.
This design pattern does not specify a `key` for the `InputText` element, so its key will be auto-numbered and is zero in this case. Thus the design pattern can get the value of whatever was input by referencing `values[0]`
The important part of this bit of code is `close=True`. This is the parameter that instructs PySimpleGUI to close the window just before the read returns.
This is a single line of code, broken up to make reading the window layout easier. It will display a window, let the user enter a value, click a button and then the window will close and execution will be returned to you with the variables `event` and `values` being returned.
Notice use of Element name "Shortcuts" (uses `B` rather than `Button`, `T` instead of `Text`, `In` rather than `InputText`, etc.). These shortcuts are fantastic to use when you have complex layouts. Being able to "see" your entire window's definition on a single screen of code has huge benefits. It's another tool to help you achieve simple code.
The more advanced/typical GUI 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 input and output information. In other words, a typical Window, Mac or Linux window.
*Let this sink in for a moment....* in 10 lines of Python code, you can display and interact with your own custom GUI window. You are writing "*real GUI code*" (as one user put it) that will look and act like other windows you're used to using daily.
Exit {'-IN-': 'clicking the exit button this time'}
```
The first thing printed is the "event" which in this program is the buttons. The next thing printed is the `values` variable that holds the dictionary of return values from the read. This dictionary has only 1 entry. The "key" for the entry is `'-IN-'` and matches the key passed into the `Input` element creation on this line of code:
```python
[sg.Input(key='-IN-')],
```
If the window was close using the X, then the output of the code will be:
The `event` returned from the read is set to `None` (the variable `WIN_CLOSED`) and so are the input fields in the window. This `None` event is super-important to check for. It must be detected in your windows or else you'll be trying to work with a window that's been destroyed and your code will crash. This is why you will find this check after ***every*** `window.read()` call you'll find in sample PySimpleGUI code.
In some cirsumstances when a window is closed with an X, both of the return values from `window.read()` will be `None`. This is why it's important to check for `event is None` before attempting to access anything in the `values` variable.
This is a slightly more complex, but 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 so this pattern will likely be your starting point.
To modify an Element in a window, you call its `update` method. This is done in 2 steps. First you lookup the element, then you call that element's `update` method.
The way we're achieving output here is by changing a Text Element with this statement:
`window['-OUTPUT-']` returns the element that has the key `'-OUTPUT-'`. Then the `update` method for that element is called so that the value of the Text Element is modified. Be sure you have supplied a `size` that is large enough to display your output. If the size is too small, the output will be truncated.
If you need to interact with elements prior to calling `window.read()` you will need to "finalize" your window first using the `finalize` parameter when you create your `Window`. "Interacting" means calling that element's methods such as `update`, `draw_line`, etc.
For persistent windows, after creating the window, you have an event loop that runs until you exit the window. Inside this loop you will read values that are returned from reading the window and you'll operate on elements in your window. To operate on elements, you look them up and call their method functions such as `update`.
The original / old-style way of looking up elements using their key was to call `window.FindElement` or the shortened `window.Element`, passing in the element's key.
These 3 lines of code do the same thing. The first line is the currently accepted way of performing this lookup operation and what you'll find in all of the current demos.
Once you lookup an element, the most often performed operation is `update`. There are other element methods you can call such as `set_tooltip()`. You'll find the list of operations available for each element in the [call summary](https://pysimplegui.readthedocs.io/en/latest/#element-and-function-call-reference) at the end of the main documentation.
For persistent windows, you will find this if statement immediately following every `window.read` call you'll find in this document and likely all of the demo programs:
This is your user's "way out". **Always** give a way out to your user or else they will be using task manager or something else, all the while cursing you.
Beginners to Python may not understand this statement and it's important to understand it so that you don't simply ignore it because you don't understand the syntax.
The if statment is identical to this if statement:
The `event in (sg.WIN_CLOSED, 'Quit')` simply means is the value of the `event` variable in the list of choices shown, in this case `WIN_CLOSED` or `Quit`. If so, then break out of the Event Loop and likely exit the program when that happens for simple programs.
You may find 'Exit' instead of 'Quit' in some programs. Or may find only `WIN_CLOSED` is checked. Exit & Quit in this case refer to a Quit/Exit button being clicked. If your program doesn't have one, then you don't need to include it.
The reason is that for some ports, like PySimpleGUIWeb, you cannot exit the program unless the window is closed. It's nice to clean up after yourself too.
By following some simple coding conventions you'll be able to copy / paste demo program code into your code with minimal or no modifications. Your code will be understandable by other PySimpleGUI programmers as well.
Of course you don't have to follow *any* of these. They're suggestions, but if you do follow them, your code is a lot easier to understand by someone else.
A few tips that have worked well for others. In the same spirit as the coding conventions, these a few observations that may speed up your development or make it easier for others to understand your code. They're guidelines / tips / suggestions / ideas... meant to help you.
Most of these are self-explanatory or will be understood as you learn more about PySimpleGUI. You won't now what a timeout value is at this point, but if/when you do use reads with timeouts, then you'll understand the tip.
A little more detail on a few of them that aren't obvious.
### Write compact layouts
Try to keep your layout definitions to a single screen of code. Don't put every parameter on a new line. Don't add tons of whitespace.
If you've got a lot of elements, use the shortcut names (e.g. using `sg.B` rather than `sg.Button` saves 5 characters per button in your layout).
The idea here to be able to see your entire window in your code without having to scroll.
### Use PySimpleGUI constructs
PySimpleGUI programs were not designed using the same OOP design as the other Python GUI frameworks. Trying to force fit them into an OOP design doesn't buy anything other then lots of `self.` scattered in your code, more complexity, and possibly more confusion
The point is that there is no concept of an "App" or a never-ending event loop or callback functions. PySimpleGUI is different than tkinter and Qt. Trying to code in that style is likely to not result in success. If you're writing a subclass for `Window` as a starting point, it's highly likely you're doing something wrong.
"Beautiful windows" don't just happen, but coloring your window can be accomplished with 1 line of code.
One complaint about tkinter that is often heard is how "ugly" it looks. You can do something about that by using PySimpleGUI themes.
```python
sg.theme('Dark Green 5')
```
A call to `theme` will set the colors to be used when creating windows. It sets text color, background color, input field colors, button color,.... 13 different settings are changed.
Even windows that are created for you, such as popups, will use the color settings you specify. And, you can change them at any point, even mid-way through defining a window layout.
The # is optional and is used when there is more than 1 choice for a color. For example, for "Dark Blue" there are 12 different themes (Dark Blue, and Dark Blue 1-11). These colors specify the rough color of the background. These can vary wildly so you'll have to try them out to see what you like the best.
In addition to getting all of these new themes, the format of the string used to specify them got "fuzzy". You no longer have to specify the ***exact*** string shown in the preview. Now you can add spaces, change the case, even move words around and you'll still get the correct theme.
If you guess incorrectly, then you'll be treated to a random theme instead of some hard coded default. You were calling theme to get more color, in theory, so instead of giving you a gray window, you'll get a randomly chosen theme (and you'll get the name of this theme printed on the console). It's a great way to discover new color combinations via a mistake.
This is an odd recipe, but it's an important one and has nothing to do with your coding PySimpleGUI code. Instead is has to do with modifying youre readme.md file on your GitHub so you can share with the world your creation. Doon't be shy. We all stated with "hello world" and your first GUI is likely to be primitive, but it's very important you post it any way.
In case you've not noticed, you, the now fancy Python GUI programmer that you are, are a rare person in the Python world. The VAST majority of Python projects posted on GitHub do not contain a GUI. This GUI thing is kinda new and novel for Python pbeginning rogrammers.
## People / visitors **love pictures**
They don't have to be what you consider to be "pretty pictures" or of a "compex GUI". GUIs from beginners should be shown as proudly developed creations you've completed or are in the process of completion.
Your GitHub visitors may never have made a GUI and need to see a beginner GUI just as much as they need to see more complex GUIs. It gives them a target. It shows them someone they may be able to achieve.
## The GitHub Issue Technique
This is one of the easiest / laziest / quickest ways of adding a screenshot to your Readme.md and this post on your project's main page.
Here'show you do it:
1. Open a "Screenshots" Issue somehwere in GitHub. It sdoesn't matter which project you open it under.
2. Copy and paste your image into the Issue's comment section. OR Drag and drop your image info the comment section. OR click the upload diaload box by clickin at the bottom on the words "Attach files by dragging & dropping, selecting or pasting them.
3. A line of code will be inserted when you add a the image to your GitHub Issue's comment. The line of code will resemble this:
4. Copy the line of code that is created in the comment. You can see this line when in the "Write" mode for the Issue.. If you want to see how it'll look, switch to the preview tab.
5. Paste the line of code from the Issue Comment into your readme.md file located in your mtop-level FirHub folder
That's it.
Note, if you simply copy the link to the image that's created, in your readme.md file you will see only the link. The image will not be embedded into the page, only the link will be shown The thing you paste into your readme needs to have this format, theat starts with `![filename]`.
Pasting the above line directly into this Cookbook resulted in this Weahter Widget posted::
Let's say you like the `LightGreeen3` Theme, except you would like for the buttons to have black text instead of white. You can change this by modifying the theme at runtime.
Normal use of `theme` calls is to retrieve a theme's setting such as the background color. The functions used to retrieve a theme setting can also be used to modify the setting by passing in the new setting as a parameter.
Calling `theme_background_color()` returns the background color currently in use. Passing in the color `'blue'` as the parameter, `theme_background_color('blue')`, will change the background color for future windows you create to blue.
The great thing about these themes is that you set it onces and all future Elements will use the new settings. If you're adding the same colors in your element definitions over and over then perhaps making your own theme is in order.
Let's say that you need to match a logo's green color and you've come up with matching other colors to go with it. To add the new theme to the standard themes this code will do it:
You can use a combination of these 3 settings to create windows that look like Rainmeter style desktop-widgets.
This window demonstrates these settings. As you can see, there is text showing through the background of the window. This is because the "Alpha Channel" was set to a semi-transparent setting. There is no titlebar going across the window and there is a little red X in the upper corner, resumably to close the window.
When creating a window without a titlebar you create a problem where the user is unable to move your window as they have no titlebar to grab and drag. Another parameter to the window creation will fix this problem - `grab_anywhere`. When `True`, this parameter allows the user to move the window by clicking anywhere within the window and dragging it, just as if they clicked the titlebar. Some PySimpleGUI ports allow you to click on input fields and drag, others require you to grab a spot on the background of the window. Note - you do not have to remove the titlebar in order to use `grab_anywhere`
To make your window semi-transpaerent (change the opacity) use ghe `alhpa_channel` parameter when you create the window. The setting is a float with valid values from 0 to 1.
In PySimpleGUI you can use PNG and GIF image files as buttons. You can also encode those files into Base64 strings and put them directly into your code.
It's a 4 step process to make a button using a graphic
1. Find your PNG or GIF graphic
2. Convert your graphic into a Base64 byte string
3. Add Base64 string to your code as a variable
4. Specify the Base64 string as the image to use when creating your button
#### Step 1 - Find your graphic
There are a LOT of places for you to find your graphics. [This page](https://savedelete.com/design/best-free-icon-search-engines/9644/#.UINbScWWvh4) lists a number of ways to search for what you need. Bing also has a great image search tool that you can filter your results on to get a list of PNG files (choose "Transparent" using their "filter" on the page.)
Here's the [search results](https://www.bing.com/images/search?sp=-1&pq=red+x+i&sc=8-7&sk=&cvid=CAF7086A80704229B299A829D60F330E&q=red+x+icon&qft=+filterui:photo-transparent&FORM=IRFLTR) for "red x icon" using Bing with a filter.
You can download your image or get a copy of the link to it.
#### Step 2 - Convert to Base64
One of the demo programs provided on the PySimpleGUI GitHub is called "Demo_Base64_Image_Encoder.py". This program will convert all of the images in a folder and write the encoded data to a file named `output.py`.
Another demo program, "Demo_Base64_Single_Image_Encoder.py" will convert the input file to a base64 string and place the string onto the clipboard. Paste the result into your code and assign it to a variable.
You can also use an online conversion tool such as https://base64.guru/converter/encode/image
On that page I chose to use the "Remote URL" (see above), pasted it into the input box and clicked "Encode image to Base64". Under the encode button is an area labeled "Base64". If your conversion was successful, you'll see it filled with data like shown here:
You can also copy and paste the byte string from the `output.py` file if you used the demo program or paste the string created using the single file encoder demo program.
You need to set the background color for your button to be the same as the background the button is being placed on if you want it to appear invisible.
When working with PNG/GIF files as button images the background you choose for the button matters. It should match the background of whatever it is being placed upon. If you are using the standard "themes" interfaces to build your windows, then the color of the background can be found by calling `theme_background_color()`. Buttons have 2 colors so be sure and pass in TWO color values when specifying buttons (text color, background color).
Remember how keys are **key** to understanding PySimpleGUI elements? Well, they are, so now you know.
If you do not specify a key and the element is an input element, a key will be provided for you in the form of an integer, starting numbering with zero. If you don't specify any keys, it will appear as if the values returned to you are being returned as a list because the keys are sequential ints.
This example has no keys specified. The 3 input fields will have keys 0, 1, 2. Your first input element will be accessed as `values[0]`, just like a list would look.
Quickly add a GUI allowing the user to browse for a filename if a filename is not supplied on the command line using this simple GUI. It's the best of both worlds. If you want command line, you can use it. If you don't specify, then the GUI will fire up.
If you really want to compress your 1-line of GUI code, you can directly access just the entered data by using this single-line-of-code solution. Dunno if it's the safest way to go, but it's certainly the most compact. Single line GUIs are fun when you can get away with them.
That was simple enough. But maybe you're impatient and don't want to have to cick "Ok". Maybe you don't want an OK button at all. If that's you, then you'll like the `enable_events` parameter that is available for nearly all elements. Setting `enable_events` means that like button presses, when that element is interacted with (e.g. clicked on, a character entered into) then an event is immediately generated causing your `window.read()` call to return.
If the previous example were changed such that the OK button is removed and the `enable_events` parameter is added, then the code and window appear like this:
You won't need to click the OK button anymore because as soon as you make the selection in the listbox the `read()` call returns and the popup will be displayed as before.
This second example code could be used with the OK button. It doesn't matter what event caused the `window.read()` to return. The important thing is whether or not a valid selection was made. The check for `event == 'Ok'` is actually not needed.
Sometimes you want to restrict what a use can input into a field. Maybe you have a zipcode field and want to make sure only numbers are entered and it's no longer than 5 digits.
Perhaps you need a floating point number and only want to allow `0`-`9`, `.`, and `-`. One way restrict the user's input to only those characters is to get an event any time the user inputs a character and if the character isn't a valid one, remove it.
You've already seen (above) that to get an event immediate when an element is interacted with in some way you set the `enable_events` parameter.
```python
import PySimpleGUI as sg
"""
Restrict the characters allowed in an input element to digits and . or -
Accomplished by removing last character input if not a valid character
"""
layout = [ [sg.Text('Input only floating point numbers')],
[sg.Input(key='-IN-', enable_events=True)],
[sg.Button('Exit')] ]
window = sg.Window('Floating point input validation', layout)
# if last character in input element is invalid, remove it
if event == '-IN-' and values['-IN-'] and values['-IN-'][-1] not in ('0123456789.-'):
window['-IN-'].update(values['-IN-'][:-1])
window.close()
```
This code only allows entry of the correct characters.
Note that this example does not fully validate that the entry is a valid floating point number, but rather that it has the correct characters.
If you wanted to take it a step further and verify that the entry is actually a valid floating point number, then you can change the "if" statement to test for valid floating point number.
```python
import PySimpleGUI as sg
"""
Restrict the characters allowed in an input element to digits and . or -
Accomplished by removing last character input if not a valid character
"""
layout = [ [sg.Text('Input only floating point numbers')],
[sg.Input(key='-IN-', enable_events=True)],
[sg.Button('Exit')] ]
window = sg.Window('Floating point input validation', layout)
Outputting text is a very common operation in programming. Your first Python program may have been
```python
print('Hello World')
```
But in the world of GUIs where do "prints" fit in? Well, lots of places! Of course you can still use the normal `print` statement. It will output to StdOut (standard out) which is normally the shell where the program was launched from.
Prining to the console becomes a problem however when you launch using `pythonw` on Windows or if you launch your program in some other way that doesn't have a console. With PySimpleGUI you have many options available to you so fear not.
These Recipes explore how to retain *prints already in your code*. Let's say your code was written for a console and you want to migrate over to a GUI. Maybe there are so many print statements that you don't want to modify every one of them individually.
There are at least 3 ways to transform your `print` statements that we'll explore here
1. The Debug window
2. The Output Element
3. The Multiline Element
The various forms of "print" you'll be introduced to all support the `sep` and `end` parameters that you find on normal print statements.
## Recipe - #1/3 Printing to Debug Window
The debug window acts like a virtual console. There are 2 operating modes for the debug window. One re-routes stdout to the window, the other does not.
### `Print` - Print to the Debug Window
The functions `Print`, `eprint`, `EasyPrint` all refer to the same funtion. There is no difference whic hyou use as they point to identical code. The one you'll see used in Demo Programs is `Print`.
One method for routing your print statements to the debuyg window is to reassign the `print` keyword to be the PySimpleGUI function `Print`. This can be done through simple assignment.
`print = sg.Print`
You can also remap stdout to the debug window by calling `Print` with the parameter `do_not_reroute_stdout = False`. This will reroute all of your print statements out to the debug window.
```python
import PySimpleGUI as sg
sg.Print('Re-routing the stdout', do_not_reroute_stdout=False)
print('This is a normal print that has been re-routed.')
While both `print` and `sg.Print` will output text to your Debug Window.
***Printing in color is only operational if you do not reroute stdout to the debug window.***
If color printing is important, then don't reroute your stdout to the debug window. Only use calls to `Print` without any change to the stdout settings and you'll be able to print in color.
```python
import PySimpleGUI as sg
sg.Print('This text is white on a green background', text_color='white', background_color='green', font='Courier 10')
sg.Print('The first call sets some window settings like font that cannot be changed')
sg.Print('This is plain text just like a print would display')
sg.Print('White on Red', background_color='red', text_color='white')
sg.Print('The other print', 'parms work', 'such as sep', sep=',')
sg.Print('To not extend a colored line use the "end" parm', background_color='blue', text_color='white', end='')
If you want to re-route your standard out to your window, then placing an `Output` Element in your layout will do just that. When you call "print", your text will be routed to that `Output` Element. Note you can only have 1 of these in your layout because there's only 1 stdout.
Of all of the "print" techniques, this is the best to use if you cannot change your print statements. The `Output` element is the best choice if your prints are in another module that you don't have control over such that "redefining / reassigning" what `print` does isn't a possibility.
This layout with an `Output` element shows the results of a few clicks of the Go Button.
```python
import PySimpleGUI as sg
layout = [ [sg.Text('What you print will display below:')],
Beginning in 4.18.0 you can "print" to any `Multiline` Element in your layouts. The `Multiline.print` method acts similar to the `Print` function described earlier. It has the normal print parameters `sep`&`end` and also has color options. It's like a super-charged `print` statement.
"Converting" expring print statements to output to a `Multiline` Element can be done by either
* Adding the `Multiline` element to the `print` statment so that it's calling the `Multiline.print` method
* Redefining `print`
### 3A Appending Element to `print` Statement to print to Multiline
Let's try the first option, adding the element onto the front of an existing `print` statement as well as using the color parameters.
The most basic form of converting your exiting `print` into a `Multline` based `print` is to add the same element-lookup code that you would use when calling an element's `update` method. Generically, that conversion looks like this:
```python
print('Testing 1 2 3')
```
If our Multiline's key is '-ML-' then the expression to look the element up is:
```python
window['-ML-']
```
Combing the two transforms the original print to a `Multline` element print:
```python
window['-ML-'].print('Testing 1 2 3')
```
Because we're using these `Multilne` elements as output only elements, we don't want to have their contents returned in the values dictionary when we call `window.read()`. To make any element not be included in the values dictionary, add the constant `WRITE_ONLY_KEY` onto the end of your key. This would change our previous example to:
There are a number of tricks and techniques burried in this Recpie so study it closely as there are a lot of options being used.
### 3B Redefining `print` to Print to `Multiline`
If you want to use the `Multline` element as the destination for your print, but you don't want to go through your code and modify every print statement by adding an element lookup, then you can simply redefine your call to `print` to either be a function that adds that multline element onto the print for you or a lambda expression if you want to make it a single line of code. Yes, it's not suggested to use a lambda expression by assignment to a vairable, but sometimes it may be easier to understand. Find the right balanace for you and ryour projct.
If you were to use a funciton, then your code my look like this:
Some programs, in particular Desktop Widget like Rainmeter-style prorams, need to retain "state" or some series of settings.
This program is a tad large for a Cookbook, but it's a commmon enough feature to go ahead and include. Besides, it may give you some ideas.
The idea here is that your program's settings are stored in a dictionary. This dictionary is then written to disk and loaded from disk.
One type of program where this kind of feature is a requirement is when yuou make "rainmeter" tyle Desktop Widgets. These little programs almost always need to store some kind of state.... everything from the transprency of the widget to the zip code your program uses to look up the weather.
The architecture is quite simple. You keep your settings ina dictionary. Your GUI settings window modifies the dictionary and eventually it's written to disk so that the next time you run the probgram you don't have to set up everyihng that's been saved previously.
The package used to save / load that data is the JSON package. It makes writing and reading Python dictionaries downright trivial. I use it as a simplified database. You can also hand edit these files easily.
The portions of this Recipe you'll need to modify to integrate into your code will be:
* the default settings at the top
* the mapping table to/from settings keys to element keys
* the settings filename
* the settings window
* replace the "main" program with yours
The simple main program is there to trigger the change settings event:
You'll be converting back and forth between the settings file contents and the values that come out of reading the settings GUI window.
Notice how creation of the window is done is a separate function in this Recipe so that you get a "fresh" layout every time the window is created. It's critical that you do not try to re-use elements.
If you're considering allowing the user to change your program's theme, then this is an excellent way to do that. All that has to be done is to close your window when a new theme is chosen.
```python
import PySimpleGUI as sg
from json import (load as jsonload, dump as jsondump)
from os import path
"""
A simple "settings" implementation. Load/Edit/Save settings for your programs
Uses json file format which makes it trivial to integrate into a Python program. If you can
put your data into a dictionary, you can save it as a settings file.
Note that it attempts to use a lookup dictionary to convert from the settings file to keys used in
your settings window. Some element's "update" methods may not work correctly for some elements.
sg.popup_quick_message(f'exception {e}', 'No settings file found... will create one for you', keep_on_top=True, background_color='red', text_color='white')
Sometimes you just need to get a couple of filenames. Browse to get 2 file names that can be then compared. By using `Input` elements the user can either use the Browse button to browse to select a file or they can paste the filename into the input element directly.
This pattern is really good any time you've got a file or folder to get from the user. By pairing an `Input` element with a browse button, you give the user the ability to do a quick paste if they've already got the path on the clipboard or they can click "Browse" and browse to get the filename/foldername.
-------
## Recipe - Get Filename With No Input Display. Returns when file selected
There are times when you don't want to display the file that's chosen and you want the program to start when the user chooses a file. One way of doing this is to hide the input field that's filled in by the "Browse Button". By enabling events for the input field, you'll get an event when that field is filled in.
## Nearly All Elements with Color Theme, Menus, (The Everything Bagel)
Example of nearly all of the Elements in a single window. Uses a customized color scheme, lots of Elements, default values, Columns, Frames with colored text, tooltips, file browsing. There are at least 13 different Elements used.
Before scrolling down to the code, guess how many lines of Python code were required to create this custom layout window.
[sg.Text('All graphic widgets in one window!', size=(30, 1), justification='center', font=("Helvetica", 25), relief=sg.RELIEF_RIDGE)],
[sg.Text('Here is some text.... and a place to enter text')],
[sg.InputText('This is my text')],
[sg.Frame(layout=[
[sg.Checkbox('Checkbox', size=(10,1)), sg.Checkbox('My second checkbox!', default=True)],
[sg.Radio('My first Radio! ', "RADIO1", default=True, size=(10,1)), sg.Radio('My second Radio!', "RADIO1")]], title='Options',title_color='red', relief=sg.RELIEF_SUNKEN, tooltip='Use these to set flags')],
[sg.Multiline(default_text='This is the default Text should you decide not to type anything', size=(35, 3)),
sg.Multiline(default_text='A second multi-line', size=(35, 3))],
That's what the window definition, creation, display and get values ultimately ended up being when you remove the blank lines above. Try displaying 13 seperate "GUI Widgets" in any of the GUI frameworks. There's $20 waiting for the person that can code up the same window in under 35 lines of Python code using tkinter, WxPython, or Qt. For compactness, it's difficult to beat PySimpleGUI simply because the PySimpleGUI code is running a ton of "boilerplate" code on your behalf.
There are 2 modes sync and async. When running normally (synchronous), calls are made into the GUI ***stay*** in the GUI until something happens. You call `window.read()` and wait for a button or some event that causes the `read` to return.
With async calls, you wait for an event for a certain amount of time and then you return after that amount of time if there's no event. You don't wait forever for a new event.
When running asynchronously, you are giving the illusion that multiple things are happening at the same time when in fact they are interwoven.
It means your program doesn't "block" or stop running while the user is interacting with the window. Your program continues to run and does things while the user is fiddling around.
The critical part of these async windows is to ensure that you are calling either `read` or `refresh` often enough. Just because your code is running doesn't mean you can ignore the GUI. We've all experienced what happens when a GUI program "locks up". We're shown this lovely window.
This happens when the GUI subsystem isn't given an opportunity to run for a long time. Adding a sleep to your event loop will cause one of these to pop up pretty quickly.
We can "cheat" a little though. Rather than being stuck inside the GUI code, we get control back, do a little bit of work, and then jump back into the GUI code. If this is done quickly enough, you don't get the ugly little "not responding" window.
### Async Uses - Polling
Use this design pattern for projects that need to poll or output something on a regular basis. In this case, we're indicating we want a `timeout=10` on our `window.read` call. This will cause the `Read` call to return a "timeout key" as the event every 10 milliseconds has passed without some GUI thing happening first (like the user clicking a button). The timeout key is `PySimpleGUI.TIMEOUT_KEY` usually written as `sg.TIMEOUT_KEY` in normal PySimpleGUI code.
Use caution when using windows with a timeout. You should **rarely** need to use a `timeout=0`. A zero value is a truly non-blocking call, so try not to abuse this design pattern. You shouldn't use a timeout of zero unless you're a realtime application and you know what you're doing. A zero value will consume 100% of the CPU core your code is running on. Abuse it an bad things ***will*** happen.
A note about timers... this is not a good design for a stopwatch as it can very easily drift. This would never pass for a good solution in a bit of commercial code. For better accuracy always get the actual time from a reputable source, like the operating system. Use that as what you use to measure and display the time.
The `focus` parameter for the Button causes the window to start with that button having focus. This will allow you to press the return key or spacebar to control the button.
The architecture of some programs works better with button callbacks instead of handling in-line. While button callbacks are part of the PySimpleGUI implementation, they are not directly exposed to the caller. The way to get the same result as callbacks is to simulate them with a recipe like this one.
Unlike other progress meter Python packages, PySimpleGUI's one-line-progress-meter is 1 line of code, not 2. Historicly you would setup the meter outside your work loop and then update that meter inside of your loop. With PySimpleGUI you do not need to setup the meter outside the loop. You only need to add the line of code to update the meter insdie of your loop.
There are a number of applications built using a GUI that involve a grid of buttons. The games Minesweeper and Battleship can both be thought of as a grid of buttons.
The **most important** thing for you to learn from this recipe is that keys and events can be **any type**, not just strings.
Thinking about this grid of buttons, doesn't it make the most sense for you to get row, column information when a button is pressed. Well, that's exactly what setting your keys for these buttons to be tuples does for you. It gives you the abilty to read events and finding the button row and column, and it makes updating text or color of buttons using a row, column designation.
This program also runs on PySimpleGUIWeb really well. Change the import to PySimpleGUIWeb and you'll see this in your web browser (assuming you've installed PySimpleGUIWeb)
Buttons can have PNG of GIF images on them. This Media Player recipe requires 4 images in order to function correctly. The background is set to the same color as the button background so that they blend together.
This Window doesn't close after button clicks. To achieve this the buttons are specified as `sg.Button` instead of `sg.Button`. The exception to this is the EXIT button. Clicking it will close the window. This program will run commands and display the output in the scrollable window.
Perhaps you don't want all the statistics that the EasyProgressMeter provides and want to create your own progress bar. Use this recipe to do just that.
A Column is required when you have a tall element to the left of smaller elements.
In this example, there is a Listbox on the left that is 3 rows high. To the right of it are 3 single rows of text and input. These 3 rows are in a Column Element.
To make it easier to see the Column in the window, the Column background has been shaded blue. The code is wordier than normal due to the blue shading. Each element in the column needs to have the color set to match blue background.
This recipe is a design pattern for multiple windows where the first window is not active while the second window is showing. The first window is hidden to discourage continued interaction.
```Python
"""
PySimpleGUI The Complete Course Lesson 7 - Multiple Windows"""
import PySimpleGUI as sg
# Design pattern 1 - First window does not remain active
The Canvas Element is one of the few tkinter objects that are directly accessible. The tkinter Canvas widget itself can be retrieved from a Canvas Element like this:
While it's fun to scribble on a Canvas Widget, try Graph Element makes it a downright pleasant experience. You do not have to worry about the tkinter coordinate system and can instead work in your own coordinate system.
## Graph Element - drawing circle, rectangle, etc, objects
Just like you can draw on a tkinter widget, you can also draw on a Graph Element. Graph Elements are easier on the programmer as you get to work in your own coordinate system.
## Keypad Touchscreen Entry - Input Element Update
This Recipe implements a Raspberry Pi touchscreen based keypad entry. As the digits are entered using the buttons, the Input Element above it is updated with the input digits.
There are a number of features used in this Recipe including:
Use the Canvas Element to create an animated graph. The code is a bit tricky to follow, but if you know Matplotlib then this recipe shouldn't be too difficult to copy and modify.
In other GUI frameworks this program would be most likely "event driven" with callback functions being used to communicate button events. The "event loop" would be handled by the GUI engine. If code already existed that used a call-back mechanism, the loop in the example code below could simply call these callback functions directly based on the button text it receives in the window.read call.
Use the upper half to generate your hash code. Then paste it into the code in the lower half. Copy and paste lower 1/2 into your code to get password protection for your script without putting the password into your source code.
Create a secure login for your scripts without having to include your password in the program. Create an SHA1 hash code for your password using the GUI. Paste into variable in final program
1. Choose a password
2. Generate a hash code for your chosen password by running program and entering 'gui' as the password
3. Type password into the GUI
4. Copy and paste hash code Window GUI into variable named login_password_hash
For this and the Time & CPU Widgets you may wish to consider using a tool or technique that will hide your Windows Command Prompt window. I recommend the techniques found on this site:
At the moment I'm using the technique that involves wscript and a script named RunNHide.vbs. They are working beautifully. I'm using a hotkey program and launch by using this script with the command "python.exe insert_program_here.py". I guess the next widget should be one that shows all the programs launched this way so you can kill any bad ones. If you don't properly catch the exit button on your window then your while loop is going to keep on working while your window is no longer there so be careful in your code to always have exit explicitly handled.
### Floating toolbar
This is a cool one! (Sorry about the code pastes... I'm working in it)
Impress your friends at what a tool-wizard you are by popping a custom toolbar that you keep in the corner of your screen. It stays on top of all your other windows.
Demo_Toolbar - A floating toolbar with quick launcher One cool PySimpleGUI demo. Shows borderless windows, grab_anywhere, tight button layout
You can setup a specific program to launch when a button is clicked, or use the Combobox to select a .py file found in the root folder, and run that file. """
This is a little widget you can leave running on your desktop. Will hopefully see more of these for things like checking email, checking server pings, displaying system information, dashboards, etc
.
Much of the code is handling the button states in a fancy way. It could be much simpler if you don't change the button text based on state.
Timer Desktop Widget Creates a floating timer that is always on top of other windows You move it by grabbing anywhere on the window Good example of how to do a non-blocking, polling program using SimpleGUI Can be used to poll hardware when running on a Pi
While the timer ticks are being generated by PySimpleGUI's "timeout" mechanism, the actual value
of the timer that is displayed comes from the system timer, time.time(). This guarantees an
accurate time value is displayed regardless of the accuracy of the PySimpleGUI timer tick. If
this design were not used, then the time value displayed would slowly drift by the amount of time
it takes to execute the PySimpleGUI read and update calls (not good!)
NOTE - you will get a warning message printed when you exit using exit button.
It will look something like: invalid command name \"1616802625480StopMove\"
The spinner changes the number of seconds between reads. Note that you will get an error message printed when exiting because the window does not have have a titlebar. It's a known problem.
Menus are nothing more than buttons that live in a menu-bar. When you click on a menu item, you get back a "button" with that menu item's text, just as you would had that text been on a button.
Menu's are defined separately from the GUI window. To add one to your window, simply insert sg.Menu(menu_layout). The menu definition is a list of menu choices and submenus. They are a list of lists. Copy the Recipe and play with it. You'll eventually get when you're looking for.
If you double click the dashed line at the top of the list of choices, that menu will tear off and become a floating toolbar. How cool! To enable this feature, set the parameter `tearoff=True` in your call to `sg.Menu()`
Use the Graph Element to draw points, lines, circles, rectangles using ***your*** coordinate systems rather than the underlying graphics coordinates.
In this example we're defining our graph to be from -100, -100 to +100,+100. That means that zero is in the middle of the drawing. You define this graph description in your call to Graph.
Tabs bring not only an extra level of sophistication to your window layout, they give you extra room to add more elements. Tabs are one of the 3 container Elements, Elements that hold or contain other Elements. The other two are the Column and Frame Elements.
It's possible to create a single .EXE file that can be distributed to Windows users. There is no requirement to install the Python interpreter on the PC you wish to run it on. Everything it needs is in the one EXE file, assuming you're running a somewhat up to date version of Windows.
Installation of the packages, you'll need to install PySimpleGUI and PyInstaller (you need to install only once)
pip install PySimpleGUI
pip install PyInstaller
To create your EXE file from your program that uses PySimpleGUI, `my_program.py`, enter this command in your Windows command prompt:
pyinstaller -wF my_program.py
You will be left with a single file, `my_program.exe`, located in a folder named `dist` under the folder where you executed the `pyinstaller` command.
That's all... Run your `my_program.exe` file on the Windows machine of your choosing.
> "It's just that easy."
>
(famous last words that screw up just about anything being referenced)
