Merge remote-tracking branch 'upstream/3.4' into merge-3.4

Author: alalek

modules/optflow/samples/motempl.py

@@ -11,10 +11,11 @@
 def nothing(dummy):
     pass
 
-def draw_motion_comp(vis, (x, y, w, h), angle, color):
+def draw_motion_comp(vis, rect, angle, color):
+    x, y, w, h = rect
     cv.rectangle(vis, (x, y), (x+w, y+h), (0, 255, 0))
-    r = min(w/2, h/2)
-    cx, cy = x+w/2, y+h/2
+    r = min(w//2, h//2)
+    cx, cy = x+w//2, y+h//2
     angle = angle*np.pi/180
     cv.circle(vis, (cx, cy), r, color, 3)
     cv.line(vis, (cx, cy), (int(cx+np.cos(angle)*r), int(cy+np.sin(angle)*r)), color, 3)
@@ -91,4 +92,6 @@ def draw_motion_comp(vis, (x, y, w, h), angle, color):
         prev_frame = frame.copy()
         if 0xFF & cv.waitKey(5) == 27:
             break
+    # cleanup the camera and close any open windows
+    cam.release()
     cv.destroyAllWindows()