feat: implement overlay architecture with IOverlayLayer interface and telemetry overlay

app/ui/main_window.py

@@ -10,10 +10,11 @@ from PySide6.QtWidgets import QLabel, QMainWindow, QSizePolicy, QStatusBar
 from app.camera.camera_enumerator import CameraEnumerator, CameraInfo
 from app.camera.camera_service import CameraService
 from app.config import APP_NAME, APP_VERSION
+from app.overlay.telemetry_overlay import TelemetryOverlay
 from app.pipeline.frame_dispatcher import FrameDispatcher
 from app.telemetry.telemetry_collector import TelemetryCollector
+from app.ui.camera_view import CameraView
 from app.ui.menu_bar import AppMenuBar
-from app.ui.video_widget import VideoWidget
 
 logger = logging.getLogger(__name__)
 
@@ -23,20 +24,18 @@ class MainWindow(QMainWindow):
     Top-level application window.
 
     Rendering architecture:
-        QVideoWidget is intentionally NOT used.  On Windows its native HWND
-        surface occludes all sibling/child QWidgets regardless of z-order,
-        making overlay rendering impossible.
-
-        Instead, frames are received as QVideoFrame via CameraService.frame_ready,
-        converted to QImage inside VideoWidget.on_frame(), and drawn together with
-        the metrics overlay in a single paintEvent pass.
+        QVideoWidget is intentionally NOT used — on Windows its native HWND
+        surface occludes all sibling/child QWidgets regardless of z-order.
+        CameraView is a plain QWidget that renders frames and overlay layers
+        in a single paintEvent pass.
 
     Signal flow:
         CameraService.frame_ready
             → FrameDispatcher.dispatch
-                → VideoWidget.on_frame          (render)
-                → TelemetryCollector.on_frame   (metrics)
-                    → VideoWidget.update_metrics (overlay data)
+                → CameraView.on_frame           (render frame)
+                → TelemetryCollector.on_frame   (measure metrics)
+                    → TelemetryOverlay.on_metrics_updated  (feed overlay data)
+                    (CameraView repaints and calls TelemetryOverlay.paint())
     """
 
     def __init__(self) -> None:
@@ -46,18 +45,21 @@ class MainWindow(QMainWindow):
         self.setMinimumSize(640, 480)
         self.resize(1280, 720)
 
-        # --- Core components ---
+        # --- Core pipeline components ---
         self._camera_service = CameraService(self)
         self._dispatcher = FrameDispatcher(self)
         self._telemetry = TelemetryCollector(parent=self)
 
-        # --- Video widget (central widget) ---
-        # Plain QWidget — no native surface, overlay rendered in same paintEvent.
-        self._video_widget = VideoWidget(self)
-        self._video_widget.setSizePolicy(
+        # --- Camera view (central widget) ---
+        self._camera_view = CameraView(self)
+        self._camera_view.setSizePolicy(
             QSizePolicy.Policy.Expanding, QSizePolicy.Policy.Expanding
         )
-        self.setCentralWidget(self._video_widget)
+        self.setCentralWidget(self._camera_view)
+
+        # --- Overlay layers ---
+        self._telemetry_overlay = TelemetryOverlay()
+        self._camera_view.add_overlay_layer(self._telemetry_overlay)
 
         # --- Menu bar ---
         self._menu = AppMenuBar(self)
@@ -109,14 +111,14 @@ class MainWindow(QMainWindow):
         # CameraService → FrameDispatcher
         self._camera_service.frame_ready.connect(self._dispatcher.dispatch)
 
-        # FrameDispatcher → VideoWidget (render) — drop if busy: skip frame, keep UI fluid
-        self._dispatcher.subscribe(self._video_widget.on_frame, drop_if_busy=True)
+        # FrameDispatcher → CameraView (render) — drop if busy: stay fluid
+        self._dispatcher.subscribe(self._camera_view.on_frame, drop_if_busy=True)
 
         # FrameDispatcher → TelemetryCollector — never drop, count every frame
         self._dispatcher.subscribe(self._telemetry.on_frame, drop_if_busy=False)
 
-        # TelemetryCollector → VideoWidget overlay
-        self._telemetry.metrics_updated.connect(self._video_widget.update_metrics)
+        # TelemetryCollector → TelemetryOverlay (data only, no repaint trigger here)
+        self._telemetry.metrics_updated.connect(self._telemetry_overlay.on_metrics_updated)
 
         # CameraService status
         self._camera_service.camera_started.connect(self._on_camera_started)
@@ -128,7 +130,7 @@ class MainWindow(QMainWindow):
         self._menu.resolution_selected.connect(self._on_resolution_selected)
         self._menu.fps_selected.connect(self._on_fps_selected)
         self._menu.reconnect_requested.connect(self._camera_service.reconnect)
-        self._menu.overlay_toggled.connect(self._video_widget.set_overlay_visible)
+        self._menu.overlay_toggled.connect(self._camera_view.set_all_overlays_visible)
 
     # ------------------------------------------------------------------
     # Camera status slots