修正了窗口显示的bug

cv2.waitKey(0)会导致第一个窗口一直显示，关闭该窗口之后程序还在堵塞状态，第二个窗口也无法正常显示。改用循环语句和条件语句结合来控制窗口的显示和关闭。

Question_11_20/answers_py/answer_14.py

@@ -58,10 +58,17 @@ def different_filter(img, K_size=3):
 
 # Save result
 cv2.imwrite("out_v.jpg", out_v)
-cv2.imshow("result", out_v)
-cv2.waitKey(0)
+cv2.imshow("result_v", out_v)
+while cv2.waitKey(100) != 27:# loop if not get ESC
+ if cv2.getWindowProperty('result_v',cv2.WND_PROP_VISIBLE) <= 0:
+ break
+cv2.destroyWindow('result_v')
 
 cv2.imwrite("out_h.jpg", out_h)
-cv2.imshow("result", out_h)
-cv2.waitKey(0)
+cv2.imshow("result_h", out_h)
+# loop if not get ESC or click x
+while cv2.waitKey(100) != 27:
+ if cv2.getWindowProperty('result_h',cv2.WND_PROP_VISIBLE) <= 0:
+ break
+cv2.destroyWindow('result_h')
 cv2.destroyAllWindows()