Add FPS display feature and update configuration for display settings

app/main_window.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import time
 from datetime import datetime
 from typing import Any
 
@@ -38,6 +39,9 @@ class MainWindow(QMainWindow):
         self.last_detection: DetectionResult | None = None
         self.detecting = False
         self.detection_frame_count = 0
+        self.fps_frame_count = 0
+        self.fps_last_time = time.monotonic()
+        self.display_fps = 0.0
         self.media_store = MediaStore(self.config, self.app_config)
         self.video_recorder = VideoRecorder(self.config, self.app_config)
 
@@ -162,6 +166,7 @@ class MainWindow(QMainWindow):
 
     @Slot(object)
     def on_frame_ready(self, frame: np.ndarray) -> None:
+        self._update_fps()
         self.last_frame = frame.copy()
         if self.video_recorder.is_recording:
             self.video_recorder.write(frame)
@@ -240,6 +245,17 @@ class MainWindow(QMainWindow):
 
         self.detection_worker.request_detection(frame)
 
+    def _update_fps(self) -> None:
+        self.fps_frame_count += 1
+        now = time.monotonic()
+        elapsed = now - self.fps_last_time
+        if elapsed < 1.0:
+            return
+
+        self.display_fps = self.fps_frame_count / elapsed
+        self.fps_frame_count = 0
+        self.fps_last_time = now
+
     def current_metadata(self, media_type: str) -> dict[str, Any]:
         return {
             "media_type": media_type,
@@ -274,6 +290,8 @@ class MainWindow(QMainWindow):
         display_frame = frame_bgr.copy()
         if self.overlay_result is not None:
             self._draw_detection(display_frame, self.overlay_result)
+        if self.config.get("display", {}).get("show_fps", True):
+            self._draw_fps(display_frame)
 
         frame_rgb = cv2.cvtColor(display_frame, cv2.COLOR_BGR2RGB)
         h, w, channels = frame_rgb.shape
@@ -306,6 +324,20 @@ class MainWindow(QMainWindow):
                 cv2.LINE_AA,
             )
 
+    def _draw_fps(self, frame_bgr: np.ndarray) -> None:
+        label = f"FPS: {self.display_fps:.1f}"
+        cv2.rectangle(frame_bgr, (12, 12), (122, 46), (0, 0, 0), -1)
+        cv2.putText(
+            frame_bgr,
+            label,
+            (20, 36),
+            cv2.FONT_HERSHEY_SIMPLEX,
+            0.7,
+            (255, 255, 255),
+            2,
+            cv2.LINE_AA,
+        )
+
 
 def run_app(app_config: AppConfig) -> int:
     app = QApplication([])