Toga

Features

* A `justify_content` style attribute has been added, which aligns children along a box's main axis. (1194)
* Toga apps can now detect and set their window states including maximized, minimized, normal, full screen and presentation states. (1857)
* A `gap` style attribute has been added, which adds space between adjacent children of a box. (1943)
* Windows can now respond to changes in focus and visibility. (2009)
* The line height of multi-line text on a Canvas can now be configured. (2144)
* Apps can now interrogate whether they are in dark mode on some platforms. (2841)
* Toga GTK now supports location services via integration with GeoClue and the XDG Location Portal. (2990)
* Android cameras now describe themselves in terms of the direction they are facing (if known). (2996)
* `toga.Row` and `toga.Column` can now be used as a shorthand for `toga.Box(style=Pack(direction=...))`. (3010)
* Style properties can now be passed directly to a widget's constructor, or accessed as attributes, without explicitly using a `style` object. (3011)
* The `Pack.margin` property (and its deprecated alias, `padding`) can now be accessed via bracket notation, as in `style["margin"]`. (Previously this worked for the "sub-properties" of `margin_top` etc., but not for `margin`/`padding` itself.) (3044)
* The `WebView` widget now supports the retrieval of cookies. (3068)
* The Travertino library, providing the base classes for Toga's style and box model, is now managed as part of the Toga release process. (3086)
* Initial experimental support for GTK4 has been added to Toga's GTK backend. This support can be enabled by setting `TOGA_GTK=4` in your environment. (3087)
* The `align_items` and `justify_content` properties now have the aliases `horizontal_align_items`, `vertical_align_items`, `horizontal_align_content` and `vertical_align_content` that explicitly describe layout behavior in the named direction. (3111)
* A Briefcase bootstrap for generating Positron apps (i.e., apps that are a web view in a native wrapper - Electron, but more positive, because it's Python) was added. (3114)
* The Travertino library now has 100% test coverage. (3129)
* The Travertino library now includes APIs to perform alpha blending operations and conversion of RGBA to HSLA color representations. (3140)
* Travertino now has an `aliased_property` descriptor to support declaration of property name aliases in styles. (3213)
* The Pack style representation is now a dataclass. This should allow most IDEs to infer the names and types of properties and suggest them in creating a Pack instance. (3215)

Bugfixes

* On WinForms, Box, Canvas, Label and ImageView widgets now have transparent backgrounds by default. (767)
* On iOS, Box, Canvas, ImageView, Label, ProgressBar, ScrollContainer and Slider widgets now have transparent backgrounds by default. (767)
* DPI scaling on Windows has been improved, fixing a number of resolution and scaling issues. (2155)
* On WinForms, the background color of a widget now correctly honors the alpha channel of the selected color. (2425)
* If a WebView widget completes navigation to a new URL while it is being destroyed, an error is no longer raised on macOS or iOS. (2512)
* Widgets on the iOS backend no longer leak memory when destroyed. (2849)
* On macOS, when a dialog is in focus, `App.current_window` now returns the host window, instead of raising an `AttributeError`. (2926)
* An issue with creating dialogs on the Textual backend was resolved. (2949)
* A newly added, visible widget will be hidden when added to a widget hierarchy where an ancestor is hidden. (2950)
* Multi-letter keyboard navigation in Tables and DetailedLists with the WinForms backend is now functional. (2956)
* The web backend now uses the Shoelace default font in all browsers. (3035)
* The `hardware` example app now correctly demonstrates usage of the location services method `current_location`. (3045)
* On GTK, when a window is hidden, the `window.state` getter now correctly reports the state when the window was last visible. (3105)
* On Android, setting a custom background color on widgets now preserves the native look and feel. (3118)
* On Android, setting widget background color to `TRANSPARENT` now correctly sets it to transparent. (3118)
* The binary dependencies for the GTK backend have been updated to reflect changes in requirements of PyGObject. (3143)
* On Android, `DetailedList` and `Table` widgets now correctly unset the highlight color when a row is deselected. (3156)
* (3163)

Backward Incompatible Changes

* "Full screen mode" on an app has been renamed "Presentation mode" to avoid the ambiguity with "full screen mode" on a window. The `toga.App.enter_full_screen` and `toga.App.exit_full_screen` APIs have been renamed `toga.App.enter_presentation_mode` and `toga.App.exit_presentation_mode`, respectively. (1857)
* The use of generators as event handlers has been deprecated. Any generator-based event handler can be converted into an asynchronous co-routine by converting the handler to `async def`, and using `await asyncio.sleep(t)` in place of `yield t` (for some sleep interval `t`). (2721)
* Widgets now create and return their implementations via a `_create()` method. A user-created custom widget that inherits from an existing Toga widget and uses the same implementation will require no changes. Any user-created widgets that need to specify their own implementation should do so in `_create()` and return that implementation. Existing user code inheriting from `Widget` that assigns its implementation before calling `super().__init__()` will continue to function, but give a `RuntimeWarning`; unfortunately, this change breaks any existing code that doesn't create its implementation until afterward. Such usage will now raise an exception. (2942)
* Pack's `padding` and `alignment` properties have been renamed to `margin` and `align_items`, to match their CSS analogues. `align_items` also now takes CSS-compatible values of `START`, `CENTER`, and `END`, instead of `alignment`'s `TOP`/`RIGHT`/`BOTTOM`/`LEFT`/`CENTER`. The old names are still present — and `alignment` still takes its existing values — but these constants are deprecated. (3033)
* APIs marked as deprecated in Toga 0.4.0 and earlier have been removed. (3059)
* The `show()` and `hide()` APIs can no longer be used on a window while it is in a `MINIMIZED`, `FULLSCREEN` or `PRESENTATION` state. (3109)
* If window size is unchanged as a result of a resize request, a layout of window content is no longer triggered. (3131)
* If you're running on Ubuntu 22.04, Debian 11 or Debian 12, you'll need to manually add a pin for `PyGObject==3.50.0` to your project. This is because recent PyGObject releases specify a requirement on `girepository-2.0`, which is not available on older Debian-based distributions. A manual pin is required because there's no way to express a dependency on a system package as part of Python's requirements specifications. (3143)
* The signature of the `apply` method of `BaseStyle` (and thus `Pack`) has changed. Rather than taking a property name and value, it now takes only the name, and the style object checks its own current value for that property to know what to apply. This method is normally used internally, but any user code calling it manually will get a `DeprecationWarning` if it supplies two arguments. (3159)
* Travertino's `BaseStyle.reapply()` (and thus Toga's `Pack.reapply()`) has been deprecated; the correct usage is now to call `.apply()` with no arguments. User code is unlikely to ever call this method, but Toga releases before (and including) 0.4.8 calls it extensively, so users who update Travertino but not Toga will receive a `DeprecationWarning`. (3160)
* Travertino's `declaration` module has been split into two smaller modules, `properties` and `style`. Toga's imports have been updated to the new locations, but users with Toga <= 0.4.8 that update Travertino to 0.5.0 (and anyone who may be accessing these classes in user code) will get a `DeprecationWarning` explaining the situation. (3195)

Documentation

* Tutorial 3 was extended to explain limitations of the browser example, and suggest some extension activities. (2998)
* A summary of Toga's API design principles has been added. (3170)
* Widget screenshots have been added for the Web backend. (3259)

Misc

* 2547, 2893, 2920, 2921, 2922, 2923, 2925, 2931, 2932, 2933, 2934, 2935, 2936, 2939, 2941, 2942, 2951, 2954, 2965, 2967, 2968, 2970, 2975, 2976, 2978, 2980, 2981, 2982, 2983, 2984, 2985, 2986, 2987, 2988, 2989, 2991, 2997, 3006, 3007, 3008, 3016, 3020, 3029, 3030, 3031, 3039, 3040, 3041, 3042, 3044, 3047, 3048, 3051, 3053, 3055, 3057, 3058, 3060, 3061, 3061, 3062, 3064, 3065, 3071, 3072, 3073, 3074, 3075, 3076, 3077, 3078, 3079, 3080, 3081, 3082, 3089, 3091, 3092, 3093, 3094, 3095, 3096, 3097, 3098, 3099, 3100, 3101, 3102, 3103, 3104, 3115, 3117, 3120, 3121, 3122, 3123, 3124, 3125, 3132, 3133, 3141, 3144, 3145, 3146, 3147, 3148, 3149, 3150, 3151, 3154, 3165, 3166, 3169, 3173, 3174, 3175, 3176, 3178, 3183, 3184, 3186, 3189, 3190, 3191, 3196, 3197, 3198, 3199, 3200, 3201, 3202, 3203, 3204, 3205, 3206, 3207, 3208, 3209, 3210, 3212, 3213, 3216, 3219, 3220, 3221, 3222, 3223, 3224, 3225, 3226, 3227, 3228, 3229, 3230, 3231, 3232, 3233, 3243, 3244, 3245, 3246, 3247, 3248, 3249, 3250, 3251, 3252, 3253, 3254, 3255, 3257, 3258

This release contains no new features. The primary purpose of this release is to add an upper version pin to Toga's Travertino requirement, protecting against the upcoming Toga 0.5.0 release that will include backwards incompatible changes in Travertino. (3167)

Bugfixes

* The testbed app can now be run on *any* supported Python version. (2883)
* App.app is now set to an initial value of `None`, before an app instance is created. This avoids a potential `AttributeError` when the test suite finishes. (2918)

Misc

* 2476, 2913

This is a minor bugfix release, correcting an issue with Toga's support for Python 3.13 on Android.

Bugfixes

* On macOS, apps that specify both `document_types` and a `main_window` no longer display the document selection dialog on startup. (2860)
* The integration with Android's event loop has been updated to support Python 3.13. (2907)


Backward Incompatible Changes

* Toga no longer supports Python 3.8. (2888)
* Android applications should update their Gradle requirements to use version 1.12.0 of the Material library (``com.google.android.material:material:1.12.0``). (2890)
* Android applications should update their Gradle requirements to use version 6.1.20 of the OSMDroid library (``org.osmdroid:osmdroid-android:6.1.20``). (2890)


Misc

* 2868, 2869, 2870, 2876, 2877, 2884, 2885, 2886, 2887, 2893, 2897, 2898, 2899, 2900, 2901, 2902, 2903, 2904, 2905, 2906, 2912

Features

* The GTK backend was modified to use PyGObject's native asyncio handling, instead of GBulb. (2550)
* The ActivityIndicator widget is now supported on iOS. (2829)

Bugfixes

* Windows retain their original size after being unminimized on Windows. (2729)
* DOM storage is now enabled for WebView on Android. (2767)
* A macOS app in full-screen mode now correctly displays the contents of windows that use a `toga.Box()` as the top-level content. (2796)
* Asynchronous tasks are now protected from garbage collection while they are running. This could lead to asynchronous tasks terminating unexpectedly with an error under some conditions. (2809)
* When a handler is a generator, control will now always be released to the event loop between iterations, even if no sleep interval or a sleep interval of 0 is yielded. (2811)
* When the X button is clicked for the About dialog on GTK, it is now properly destroyed. (2812)
* The Textual backend is now compatible with versions of Textual after v0.63.3. (2822)
* The event loop is now guaranteed to be running when your app's `startup()` method is invoked. This wasn't previously the case on macOS and Windows. (2834)
* iOS apps now correctly account for the size of the navigation bar when laying out app content. (2836)
* A memory leak when using Divider or Switch widgets on iOS was resolved. (2849)
* Apps bundled as standalone frozen binaries (e.g., POSIX builds made with PyInstaller) no longer crash on startup when trying to resolve the app icon. (2852)

Misc

* 2088, 2708, 2715, 2792, 2799, 2802, 2803, 2804, 2807, 2823, 2824, 2825, 2826, 2846, 2847, 2848

Features
--------

* Toga can now define apps that persist in the background without having any open windows. (97)
* Apps can now add items to the system tray. (97)
* It is now possible to use an instance of Window as the main window of an app. This allows the creation of windows that don't have a menu bar or toolbar decoration. (1870)
* The initial position of each newly created window is now different, cascading down the screen as windows are created. (2023)
* The API for Documents and document types has been finalized. Document handling behavior is now controlled by declaring document types as part of your `toga.App` definition. (2209)
* Toga can now define an app whose life cycle isn't tied to a single main window. (2209)
* The Divider widget was implemented on iOS. (2478)
* Commands can now be retrieved by ID. System-installed commands (such as "About" and "Visit Homepage") are installed using a known ID that can be used at runtime to manipulate those commands. (2636)
* A `MainWindow` can now have an `on_close` handler. If a request is made to close the main window, the `on_close` handler will be evaluated; app exit handling will only be processed if the close handler allows the close to continue. (2643)
* Dialogs can now be displayed relative to an app, in addition to be being modal to a window. (2669)
* An `on_running` event handler was added to `toga.App`. This event will be triggered when the app's main loop starts. (2678)
* The `on_exit` handler for an app can now be defined by overriding the method on the `toga.App` subclass. (2678)
* CommandSet now exposes a full set and dictionary interface. Commands can be added to a CommandSet using `[]` notation and a command ID; they can be removed using set-like `remove()` or `discard()` calls with a Command instance, or using dictionary-like `pop()` or `del` calls with the command ID. (2701)
* WebView2 on Winforms now uses the v1.0.2592.51 WebView2 runtime DLLs. (2764)

Bugfixes
--------

* The order of creation of system-level commands is now consistent between platforms. Menu creation is guaranteed to be deferred until the user's startup method has been invoked. (2619)
* The type of SplitContainer's content was modified to be a list, rather than a tuple. (2638)
* Programmatically invoking `close()` on the main window will now trigger `on_exit` handling. Previously `on_exit` handling would only be triggered if the close was initiated by a user action. (2643)
* GTK apps no longer have extra padding between the menu bar and the window content when the app does not have a toolbar. (2646)
* On Winforms, the window of an application that is set as the main window is no longer shown as a result of assigning the window as `App.main_window`. (2653)
* Menu items on macOS are now able to correctly bind to the arrow and home/end/delete keys. (2661)
* On GTK, the currently selected tab index on an `OptionContainer` can now be retrieved inside an `on_select` handler. (2703)
* The WebView can now be loaded when using Python from the Windows Store. (2752)
* The WebView and MapView widgets now log an error if initialization fails. (2779)


Backward Incompatible Changes
-----------------------------

* The `add_background_task()` API on `toga.App` has been deprecated. Background tasks can be implemented using the new `on_running` event handler, or by using :any:`asyncio.create_task`. (2099)
* The API for Documents and Document-based apps has been significantly modified. Unfortunately, these changes are not backwards compatible; any existing Document-based app will require modification.

The `DocumentApp` base class is no longer required. Apps can subclass `App` directly, passing the document types as a `list` of `Document` classes, rather than a mapping of extension to document type.

The API for `Document` subclasses has also changed:

* A path is no longer provided as an argument to the Document constructor;

* The `document_type` is now specified as a class property called `description`; and

* Extensions are now defined as a class property of the `Document`; and

* The `can_close()` handler is no longer honored. Documents now track if they are modified, and have a default `on_close` handler that uses the modification status of a document to control whether a document can close. Invoking `touch()` on document will mark a document as modified. This modification flag is cleared by saving the document. (2209)
* It is no longer possible to create a toolbar on a `Window` instance. Toolbars can only be added to `MainWindow` (or subclass). (2646)
* The default title of a `toga.Window` is now the name of the app, rather than `"Toga"`. (2646)
* The APIs on `Window` for displaying dialogs (`info_dialog()`, `question_dialog()`, etc) have been deprecated. They can be replaced with creating an instance of a `Dialog` class (e.g., `InfoDialog`), and passing that instance to `window.dialog()`. (2669)

Documentation
-------------

* Building Toga's documentation now requires the use of Python 3.12. (2745)

Misc
----

* 2382, 2635, 2640, 2647, 2648, 2654, 2657, 2660, 2665, 2668, 2675, 2676, 2677, 2682, 2683, 2684, 2689, 2693, 2694, 2695, 2696, 2697, 2698, 2699, 2709, 2710, 2711, 2712, 2722, 2723, 2724, 2726, 2727, 2728, 2733, 2734, 2735, 2736, 2739, 2740, 2742, 2743, 2755, 2756, 2757, 2758, 2760, 2771, 2775, 2776, 2777, 2783, 2788, 2789, 2790

Features

* The typing for Toga's API surface was updated to be more precise. (2252)
* APIs were added for replacing a widget in an existing layout, and for obtaining the index of a widget in a list of children. (2301)
* The content of a window can now be set when the window is constructed. (2307)
* Size and position properties now return values as a `Size` and `Position` `namedtuple`, respectively. `namedtuple` objects support addition and subtraction operations. Basic tuples can still be used to *set* these properties. (2388)
* Android deployments no longer require the SwipeRefreshLayout component unless the app uses the Toga DetailedList widget. (2454)

Bugfixes

* Invocation order of TextInput on_change and validation is now correct. (2325)
* Dialog windows are now properly modal when using the GTK backend. (2446)
* The Button testbed tests can accommodate minor rendering differences on Fedora 40. (2583)
* On macOS, apps will now raise a warning if camera permissions have been requested, but those permissions have not been declared as part of the application metadata. (2589)

Documentation

* The instructions for adding a change note to a pull request have been clarified. (2565)
* The minimum supported Linux release requirements were updated to Ubuntu 20.04 or Fedora 32. (2566)
* The first-time contributor README link has been updated. (2588)
* Typos in the usage examples of `toga.MapPin` were corrected. (2617)

Misc

* 2567, 2568, 2569, 2570, 2571, 2576, 2577, 2578, 2579, 2580, 2593, 2600, 2601, 2602, 2604, 2605, 2606, 2614, 2621, 2625, 2626, 2627, 2629, 2631, 2632