feat(main.py): add timeline UI for video seeking and introduce mouse event handling

main.py

@@ -20,6 +20,16 @@ class MediaGrader:
     MAX_PLAYBACK_SPEED = 100.0
     FAST_SEEK_MULTIPLIER = 60
     IMAGE_DISPLAY_DELAY_MS = 100
+    
+    # Timeline configuration
+    TIMELINE_HEIGHT = 60
+    TIMELINE_MARGIN = 20
+    TIMELINE_BAR_HEIGHT = 12
+    TIMELINE_HANDLE_SIZE = 12
+    TIMELINE_COLOR_BG = (80, 80, 80)
+    TIMELINE_COLOR_PROGRESS = (0, 120, 255)
+    TIMELINE_COLOR_HANDLE = (255, 255, 255)
+    TIMELINE_COLOR_BORDER = (200, 200, 200)
 
     def __init__(
         self, directory: str, seek_frames: int = 30, snap_to_iframe: bool = False
@@ -59,6 +69,12 @@ class MediaGrader:
             ".mov",
             ".mkv",
         ]
+        
+        # Mouse interaction for timeline
+        self.mouse_dragging = False
+        self.timeline_rect = None
+        self.window_width = 800
+        self.window_height = 600
 
         # Create grade directories
         for i in range(1, 6):
@@ -164,9 +180,84 @@ class MediaGrader:
         cv2.putText(
             frame, info_text, (10, 30), cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 0, 0), 1
         )
+        
+        # Draw timeline
+        self.draw_timeline(frame)
 
         cv2.imshow("Media Grader", frame)
 
+    def draw_timeline(self, frame):
+        """Draw timeline at the bottom of the frame"""
+        height, width = frame.shape[:2]
+        self.window_height = height
+        self.window_width = width
+        
+        # Timeline background area
+        timeline_y = height - self.TIMELINE_HEIGHT
+        cv2.rectangle(frame, (0, timeline_y), (width, height), (40, 40, 40), -1)
+        
+        # Calculate timeline bar position
+        bar_y = timeline_y + (self.TIMELINE_HEIGHT - self.TIMELINE_BAR_HEIGHT) // 2
+        bar_x_start = self.TIMELINE_MARGIN
+        bar_x_end = width - self.TIMELINE_MARGIN
+        bar_width = bar_x_end - bar_x_start
+        
+        self.timeline_rect = (bar_x_start, bar_y, bar_width, self.TIMELINE_BAR_HEIGHT)
+        
+        # Draw timeline background
+        cv2.rectangle(frame, (bar_x_start, bar_y), (bar_x_end, bar_y + self.TIMELINE_BAR_HEIGHT), self.TIMELINE_COLOR_BG, -1)
+        cv2.rectangle(frame, (bar_x_start, bar_y), (bar_x_end, bar_y + self.TIMELINE_BAR_HEIGHT), self.TIMELINE_COLOR_BORDER, 1)
+        
+        # Draw progress for videos
+        if self.is_video(self.media_files[self.current_index]) and self.total_frames > 0:
+            progress = self.current_frame / max(1, self.total_frames - 1)
+            progress_width = int(bar_width * progress)
+            if progress_width > 0:
+                cv2.rectangle(frame, (bar_x_start, bar_y), (bar_x_start + progress_width, bar_y + self.TIMELINE_BAR_HEIGHT), self.TIMELINE_COLOR_PROGRESS, -1)
+            
+            # Draw handle
+            handle_x = bar_x_start + progress_width
+            handle_y = bar_y + self.TIMELINE_BAR_HEIGHT // 2
+            cv2.circle(frame, (handle_x, handle_y), self.TIMELINE_HANDLE_SIZE // 2, self.TIMELINE_COLOR_HANDLE, -1)
+            cv2.circle(frame, (handle_x, handle_y), self.TIMELINE_HANDLE_SIZE // 2, self.TIMELINE_COLOR_BORDER, 2)
+
+    def mouse_callback(self, event, x, y, flags, param):
+        """Handle mouse events for timeline interaction"""
+        if not self.timeline_rect or not self.is_video(self.media_files[self.current_index]):
+            return
+            
+        bar_x_start, bar_y, bar_width, bar_height = self.timeline_rect
+        bar_x_end = bar_x_start + bar_width
+        
+        # Check if mouse is over timeline
+        if bar_y <= y <= bar_y + bar_height + 10:  # Add some extra height for easier clicking
+            if event == cv2.EVENT_LBUTTONDOWN:
+                if bar_x_start <= x <= bar_x_end:
+                    self.mouse_dragging = True
+                    self.seek_to_position(x, bar_x_start, bar_width)
+            elif event == cv2.EVENT_MOUSEMOVE and self.mouse_dragging:
+                if bar_x_start <= x <= bar_x_end:
+                    self.seek_to_position(x, bar_x_start, bar_width)
+            elif event == cv2.EVENT_LBUTTONUP:
+                self.mouse_dragging = False
+
+    def seek_to_position(self, mouse_x, bar_x_start, bar_width):
+        """Seek to position based on mouse click/drag on timeline"""
+        if not self.current_cap or not self.is_video(self.media_files[self.current_index]):
+            return
+            
+        # Calculate position ratio
+        relative_x = mouse_x - bar_x_start
+        position_ratio = max(0, min(1, relative_x / bar_width))
+        
+        # Calculate target frame
+        target_frame = int(position_ratio * (self.total_frames - 1))
+        target_frame = max(0, min(target_frame, self.total_frames - 1))
+        
+        # Seek to target frame
+        self.current_cap.set(cv2.CAP_PROP_POS_FRAMES, target_frame)
+        self.load_current_frame()
+
     def advance_frame(self):
         """Advance to next frame(s) based on playback speed"""
         if (
@@ -309,6 +400,7 @@ class MediaGrader:
         print("  Q/ESC: Quit")
 
         cv2.namedWindow("Media Grader", cv2.WINDOW_NORMAL)
+        cv2.setMouseCallback("Media Grader", self.mouse_callback)
 
         while self.media_files and self.current_index < len(self.media_files):
             current_file = self.media_files[self.current_index]