opencv实现的一些简单事件处理，鼠标移动的等的简单操作，便于计算机视觉初学者理解掌握。-opencv implementation of some simple event handling, mouse movements and other simple operation, easy for beginners to understand and grasp of computer vision.

This program creates a rectangle when you click the mouse on the window, and stretches the rectangle until you release the mouse. This requires the creation of a mouse callback. For the main function we use a while loop that keeps redrawing each box

鼠标事件，可以对加载的视屏资料增加一个控制鼠标，实现播放进程的控制-mouse event