fix(wayland): render layer-shell window opacity

src/axidev_osk/windows/builder.py

@@ -4,9 +4,10 @@
 
 from PySide6.QtCore import QSize
 from PySide6.QtGui import QCloseEvent, QShowEvent
-from PySide6.QtWidgets import QMainWindow, QVBoxLayout, QWidget
+from PySide6.QtWidgets import QGraphicsOpacityEffect, QMainWindow, QVBoxLayout, QWidget
 
 from ..config.models import WindowConfig
+from ..platform.overlay import OverlayBackend
 from ..runtime.context import Context
 from ..runtime.events import WindowCloseRequested
 from .chrome import install_overlay_chrome
@@ -42,10 +43,10 @@ def __init__(self, config: WindowConfig, context: Context, parent: QWidget | Non
         self._config = config
         self._context = context
         self._quit_controller_managed = False
+        self._layer_shell_opacity_effect: QGraphicsOpacityEffect | None = None
         self.setProperty("componentType", "window")
         self.setProperty("componentId", config.id)
         self.setWindowTitle(config.title)
-        self.setWindowOpacity(config.opacity)
         if config.overlay.always_on_top:
             self._overlay = configure_always_on_top_window(self, config=config.overlay.config)
         else:
@@ -63,8 +64,21 @@ def __init__(self, config: WindowConfig, context: Context, parent: QWidget | Non
                     on_resize=self._overlay.resize_by,
                 )
         self.setCentralWidget(central)
+        if self._overlay.backend == OverlayBackend.WAYLAND_LAYER_SHELL:
+            self._layer_shell_opacity_effect = QGraphicsOpacityEffect(central)
+            central.setGraphicsEffect(self._layer_shell_opacity_effect)
+        self.setWindowOpacity(config.opacity)
         self.apply_startup_size(minimum_size=config.surface.minimum_size)
 
+    def setWindowOpacity(self, opacity: float) -> None:  # noqa: N802
+        """Apply opacity through rendered pixels when layer-shell cannot do it."""
+
+        if self._layer_shell_opacity_effect is None:
+            super().setWindowOpacity(opacity)
+            return
+        super().setWindowOpacity(1.0)
+        self._layer_shell_opacity_effect.setOpacity(opacity)
+
     @property
     def window_id(self) -> str:
         """Return this window's deterministic runtime ID."""

tests/test_window_builder.py

@@ -4,17 +4,18 @@
 from unittest.mock import patch
 
 from PySide6.QtCore import Qt
-from PySide6.QtWidgets import QApplication, QLabel, QPushButton
+from PySide6.QtWidgets import QApplication, QGraphicsOpacityEffect, QLabel, QPushButton
 
 from axidev_osk.components import register_components
 from axidev_osk.components.grid.keyboard import KeyboardWidget
 from axidev_osk.config.defaults import build_default_app_config
+from axidev_osk.platform.overlay import OverlayBackend
 from axidev_osk.runtime.registries import ComponentRegistry, SurfaceRegistry
 from axidev_osk.runtime.testing import make_test_context
 from axidev_osk.windows.builder import build_window
 from axidev_osk.windows.chrome import OverlayResizeHandle, OverlayTitleBar
-from axidev_osk.windows.surface import register_surfaces
 from axidev_osk.windows.overlay.always_on_top import OverlayPlacement
+from axidev_osk.windows.surface import register_surfaces
 
 
 class FakeKeyboardBackend:
@@ -49,7 +50,13 @@ def sync_latched_key(self, spec, latched: bool, press_handle=None):
 
 
 class FakeOverlayController:
-    def __init__(self, *, uses_custom_chrome: bool = True) -> None:
+    def __init__(
+        self,
+        *,
+        backend: OverlayBackend = OverlayBackend.WINDOWS_NATIVE,
+        uses_custom_chrome: bool = True,
+    ) -> None:
+        self.backend = backend
         self.uses_custom_chrome = uses_custom_chrome
 
     def prepare_show(self) -> bool:
@@ -207,6 +214,27 @@ def test_keyboard_window_uses_configured_normal_opacity(self) -> None:
         self.addCleanup(window.close)
         self.assertAlmostEqual(window.windowOpacity(), 0.85, delta=0.005)
 
+    def test_layer_shell_window_renders_configured_opacity_in_content(self) -> None:
+        _app()
+        overlay = FakeOverlayController(backend=OverlayBackend.WAYLAND_LAYER_SHELL)
+
+        with patch(
+            "axidev_osk.windows.builder.configure_always_on_top_window",
+            return_value=overlay,
+        ):
+            window = _build_keyboard_window(FakeKeyboardBackend(ready=True))
+
+        self.addCleanup(window.close)
+        effect = window.centralWidget().graphicsEffect()
+        self.assertIsInstance(effect, QGraphicsOpacityEffect)
+        self.assertAlmostEqual(window.windowOpacity(), 1.0, delta=0.005)
+        self.assertAlmostEqual(effect.opacity(), 0.85, delta=0.005)
+
+        window.setWindowOpacity(0.01)
+
+        self.assertAlmostEqual(window.windowOpacity(), 1.0, delta=0.005)
+        self.assertAlmostEqual(effect.opacity(), 0.01, delta=0.005)
+
     def test_runtime_window_and_components_expose_dynamic_identity_properties(self) -> None:
         _app()
         overlay = FakeOverlayController()