Use the application binary icon when available

android/src/toga_android/app.py

@@ -231,6 +231,10 @@ def main_loop(self):
         # of the Android Activity system.
         self.create()
 
+    def set_icon(self, icon):
+        # Android apps don't have runtime icons, so this can't be invoked
+        pass  # pragma: no cover
+
     def set_main_window(self, window):
         pass
 

android/src/toga_android/icons.py

@@ -9,6 +9,10 @@ class Icon:
     def __init__(self, interface, path):
         self.interface = interface
         self.interface._impl = self
+
+        if path is None:
+            raise FileNotFoundError("No runtime app icon")
+
         self.path = path
 
         self.native = BitmapFactory.decodeFile(str(path))

android/tests_backend/app.py

@@ -38,6 +38,9 @@ def cache_path(self):
     def logs_path(self):
         return Path(self.get_app_context().getFilesDir().getPath()) / "log"
 
+    def assert_app_icon(self, icon):
+        xfail("Android apps don't have app icons at runtime")
+
     def _menu_item(self, path):
         menu = self.main_window_probe._native_menu()
         for i_path, label in enumerate(path):

android/tests_backend/icons.py

@@ -37,3 +37,6 @@ def assert_default_icon_content(self):
 
     def assert_platform_icon_content(self):
         assert self.icon._impl.path == self.app.paths.app / "resources/logo-android.png"
+
+    def assert_app_icon_content(self):
+        pytest.xfail("Android apps don't have app icons at runtime")

changes/2527.feature.rst

@@ -0,0 +1 @@
+When a Toga apps is packaged as a redistributable binary, and no icon is explicitly configured, Toga will now use the binary's icon as the app icon. This means it is no longer necessary to include the app icon as data in a ``resources`` folder if you are packaging your app for distribution.

cocoa/src/toga_cocoa/app.py

@@ -135,7 +135,11 @@ def create(self):
         self.native = NSApplication.sharedApplication
         self.native.setActivationPolicy(NSApplicationActivationPolicyRegular)
 
-        self.native.setApplicationIconImage_(self.interface.icon._impl.native)
+        # The app icon been set *before* the app instance is created. However, we only
+        # need to set the icon on the app if it has been explicitly defined; the default
+        # icon is... the default. We can't test this branch in the testbed.
+        if self.interface.icon._impl.path:
+            self.set_icon(self.interface.icon)  # pragma: no cover
 
         self.resource_path = os.path.dirname(
             os.path.dirname(NSBundle.mainBundle.bundlePath)
@@ -421,6 +425,13 @@ def exit(self):  # pragma: no cover
     def main_loop(self):
         self.loop.run_forever(lifecycle=CocoaLifecycle(self.native))
 
+    def set_icon(self, icon):
+        # If the icon is a path, it's an explicit icon; otherwise its the default icon
+        if icon._impl.path:
+            self.native.setApplicationIconImage(icon._impl.native)
+        else:
+            self.native.setApplicationIconImage(None)
+
     def set_main_window(self, window):
         pass
 

cocoa/src/toga_cocoa/icons.py

@@ -1,6 +1,8 @@
+from pathlib import Path
+
 from rubicon.objc import NSSize
 
-from toga_cocoa.libs import NSImage
+from toga_cocoa.libs import NSBundle, NSImage
 
 
 class Icon:
@@ -10,17 +12,31 @@ class Icon:
     def __init__(self, interface, path):
         self.interface = interface
         self.interface._impl = self
-        self.path = path
+
+        if path is None:
+            # Look to the app bundle, and get the icon. Set self.path as None
+            # as an indicator that this is the app's default icon.
+            bundle_icon = Path(
+                NSBundle.mainBundle.objectForInfoDictionaryKey("CFBundleIconFile")
+            )
+            path = NSBundle.mainBundle.pathForResource(
+                bundle_icon.stem,
+                ofType=bundle_icon.suffix,
+            )
+            self.path = None
+        else:
+            self.path = path
+
         try:
             # We *should* be able to do a direct NSImage.alloc.init...(), but if the
             # image file is invalid, the init fails, returns NULL, and releases the
-            # Objective-C object. Since we've created an ObjC instance, when the object
-            # passes out of scope, Rubicon tries to free it, which segfaults.
+            # Objective-C object. Since we've created an ObjC instance, when the
+            # object passes out of scope, Rubicon tries to free it, which segfaults.
             # To avoid this, we retain result of the alloc() (overriding the default
-            # Rubicon behavior of alloc), then release that reference once we're done.
-            # If the image was created successfully, we temporarily have a reference
-            # count that is 1 higher than it needs to be; if it fails, we don't end up
-            # with a stray release.
+            # Rubicon behavior of alloc), then release that reference once we're
+            # done. If the image was created successfully, we temporarily have a
+            # reference count that is 1 higher than it needs to be; if it fails, we
+            # don't end up with a stray release.
             image = NSImage.alloc().retain()
             self.native = image.initWithContentsOfFile(str(path))
             if self.native is None:

cocoa/tests_backend/app.py

@@ -1,7 +1,9 @@
 from pathlib import Path
 
+import PIL.Image
 from rubicon.objc import NSPoint, ObjCClass, objc_id, send_message
 
+import toga
 from toga_cocoa.keys import cocoa_key, toga_key
 from toga_cocoa.libs import (
     NSApplication,
@@ -58,6 +60,41 @@ def content_size(self, window):
             window.content._impl.native.frame.size.height,
         )
 
+    def assert_app_icon(self, icon):
+        # We have no real way to check we've got the right icon; use pixel peeping as a
+        # guess. Construct a PIL image from the current icon.
+        img = toga.Image(
+            NSApplication.sharedApplication.applicationIconImage
+        ).as_format(PIL.Image.Image)
+
+        # Due to icon resizing and colorspace issues, the exact pixel colors are
+        # inconsistent, so multiple values must be provided for test purposes.
+        if icon:
+            # The explicit alt icon has blue background, with green at a point 1/3 into
+            # the image
+            assert img.getpixel((5, 5)) in {
+                (205, 226, 243, 255),
+                (211, 226, 243, 255),
+                (211, 230, 245, 255),
+            }
+            mid_color = img.getpixel((img.size[0] // 3, img.size[1] // 3))
+            assert mid_color in {
+                (0, 204, 9, 255),
+                (6, 204, 8, 255),
+                (14, 197, 8, 255),
+                (105, 192, 32, 255),
+            }
+        else:
+            # The default icon is transparent background, and brown in the center.
+            assert img.getpixel((5, 5))[3] == 0
+            mid_color = img.getpixel((img.size[0] // 2, img.size[1] // 2))
+            assert mid_color in {
+                (130, 100, 57, 255),
+                (130, 109, 66, 255),
+                (138, 108, 64, 255),
+                (149, 119, 73, 255),
+            }
+
     def _menu_item(self, path):
         main_menu = self.app._impl.native.mainMenu
 

cocoa/tests_backend/icons.py

@@ -1,7 +1,9 @@
 from pathlib import Path
 
+import PIL.Image
 import pytest
 
+import toga
 import toga_cocoa
 from toga_cocoa.libs import NSImage
 
@@ -38,3 +40,15 @@ def assert_default_icon_content(self):
 
     def assert_platform_icon_content(self):
         assert self.icon._impl.path == self.app.paths.app / "resources/logo-macOS.icns"
+
+    def assert_app_icon_content(self):
+        # We have no real way to check we've got the right icon; use pixel peeping as a
+        # guess. Construct a PIL image from the current icon.
+        img = toga.Image(self.icon._impl.native).as_format(PIL.Image.Image)
+
+        # The default icon is transparent background, and brown in the center.
+        # Due to icon resizing, the exact pixel color is inconsistent, depending
+        # on whether it's the default or the value after a reset.
+        assert img.getpixel((5, 5))[3] == 0
+        mid_color = img.getpixel((img.size[0] // 2, img.size[1] // 2))
+        assert mid_color in {(130, 100, 57, 255), (130, 109, 66, 255)}

core/src/toga/app.py

@@ -16,6 +16,7 @@
     ValuesView,
 )
 from email.message import Message
+from pathlib import Path
 from typing import TYPE_CHECKING, Any, Protocol
 from warnings import warn
 from weakref import WeakValueDictionary
@@ -350,9 +351,12 @@ def __init__(
                distribution name of ``my-app``.
             #. As a last resort, the name ``toga``.
         :param icon: The :any:`icon <IconContent>` for the app. If not provided, Toga
-            will attempt to load an icon from ``resources/app_name``, where ``app_name``
-            is defined above. If no resource matching this name can be found, a warning
-            will be printed, and the app will fall back to a default icon.
+            will attempt to load an icon from the following sources, in order:
+
+            * ``resources/<app_name>``, where ``app_name`` is as defined above
+            * If the Python interpreter is embedded in an app, the icon of the
+              application binary
+            * Otherwise, the Toga logo.
         :param author: The person or organization to be credited as the author of the
             app. If not provided, the metadata key ``Author`` will be used.
         :param version: The version number of the app.  If not provided, the metadata
@@ -472,12 +476,7 @@ def __init__(
         # Instantiate the paths instance for this app.
         self._paths = Paths()
 
-        # If an icon (or icon name) has been explicitly provided, use it;
-        # otherwise, the icon will be based on the distribution name.
-        if icon:
-            self.icon = icon
-        else:
-            self.icon = f"resources/{app_name}"
+        self.icon = icon
 
         self.on_exit = on_exit
 
@@ -543,20 +542,49 @@ def home_page(self) -> str | None:
     def icon(self) -> Icon:
         """The Icon for the app.
 
-        Can be specified as any valid :any:`icon content <IconContent>`.
+        Can be specified as any valid :any:`icon content <IconContent>`, or :any:`None`
+        to use a default icon. See the definition of :class:`~toga.Icon` for how
+        misconfigured and default icons are handled.
+
+        If :any:`None`, Toga will attempt to load an icon from the following sources, in
+        order:
 
-        When setting the icon, you can provide either an :any:`Icon` instance, or a
-        path that will be passed to the ``Icon`` constructor.
+        * ``resources/<app_name>``, where ``app_name`` is as defined above
+        * If the Python interpreter is embedded in an app, the icon of the application
+          binary
+        * Otherwise, the Toga logo.
         """
         return self._icon
 
     @icon.setter
     def icon(self, icon_or_name: IconContent | None) -> None:
         if isinstance(icon_or_name, Icon):
             self._icon = icon_or_name
+        elif icon_or_name is None:
+            if Path(sys.executable).stem in {
+                "python",
+                f"python{sys.version_info.major}",
+                f"python{sys.version_info.major}.{sys.version_info.minor}",
+            }:
+                # We're running as a script, so we can't use the application binary as
+                # an icon source. Fall back directly to the Toga default icon
+                default = Icon.DEFAULT_ICON
+            else:
+                # Use the application binary's icon as an initial default; if that can't
+                # be loaded, fall back to Toga icon as a final default.
+                default = Icon(None, default=Icon.DEFAULT_ICON)
+
+            self._icon = Icon(f"resources/{self.app_name}", default=default)
         else:
             self._icon = Icon(icon_or_name)
 
+        try:
+            self._impl.set_icon(self._icon)
+        except AttributeError:
+            # The first time the icon is set, it is *before* the impl has been created,
+            # so that the app instance can be instantiated with the correct icon.
+            pass
+
     @property
     def id(self) -> str:
         """**DEPRECATED** – Use :any:`app_id`."""