RectSelector in common.py

samples/python2/common.py

@@ -114,4 +114,37 @@ def nothing(*arg, **kw):
     pass
 
 def clock():
-    return cv2.getTickCount() / cv2.getTickFrequency()
\ No newline at end of file
+    return cv2.getTickCount() / cv2.getTickFrequency()
+
+class RectSelector:
+    def __init__(self, win, callback):
+        self.win = win
+        self.callback = callback
+        cv2.setMouseCallback(win, self.onmouse)
+        self.drag_start = None
+        self.drag_rect = None
+    def onmouse(self, event, x, y, flags, param):
+        x, y = np.int16([x, y]) # BUG
+        if event == cv2.EVENT_LBUTTONDOWN:
+            self.drag_start = (x, y)
+        if self.drag_start: 
+            if flags & cv2.EVENT_FLAG_LBUTTON:
+                #h, w = self.frame.shape[:2]
+                xo, yo = self.drag_start
+                x0, y0 = np.minimum([xo, yo], [x, y])
+                x1, y1 = np.maximum([xo, yo], [x, y])
+                #x0, y0 = np.maximum(0, np.minimum([xo, yo], [x, y]))
+                #x1, y1 = np.minimum([w, h], np.maximum([xo, yo], [x, y]))
+                self.drag_rect = None
+                if x1-x0 > 0 and y1-y0 > 0:
+                    self.drag_rect = (x0, y0, x1, y1)
+            else:
+                if self.drag_rect:
+                    self.callback(self.drag_rect)
+                self.drag_start = None
+                self.drag_rect = None
+    def draw(self, vis):
+        if not self.drag_rect:
+            return
+        x0, y0, x1, y1 = self.drag_rect
+        cv2.rectangle(vis, (x0, y0), (x1, y1), (0, 255, 0), 2)