Refine coordinate selector

owocr/screen_coordinate_picker.py

@@ -50,6 +50,9 @@ class ScreenSelector:
 
         def on_release(event):
             nonlocal start_x, start_y
+            if start_x is None or start_y is None:
+                return
+
             end_x, end_y = event.x, event.y
 
             x1 = min(start_x, end_x) 
@@ -64,9 +67,18 @@ class ScreenSelector:
 
             self.on_select(monitor, (x1, y1, x2 - x1, y2 - y1))
 
+        def reset_selection(event):
+            nonlocal start_x, start_y, rect
+            if rect:
+                canvas.delete(rect)
+                rect = None
+            start_x = None
+            start_y = None
+
         canvas.bind('<ButtonPress-1>', on_click)
         canvas.bind('<B1-Motion>', on_drag)
         canvas.bind('<ButtonRelease-1>', on_release)
+        canvas.bind('<Leave>', reset_selection)
 
     def _create_selection_window(self, img, geometry, scale_x=1, scale_y=1, monitor=None):
         window = tk.Toplevel(self.root)