OpenCV鼠标操作

Rect g_rectangle;
bool g_bDrawingBox = false;
RNG g_rng(12345);

void DarwRectangle(Mat &img, Rect box)
{
    rectangle(img, box.tl(), box.br(), Scalar(g_rng.uniform(0, 255), g_rng.uniform(0, 255), g_rng.uniform(0, 255)));
}

void on_MouseHandle(int event, int x, int y, int flags, void *param)
{
    Mat &image = *(Mat*)param;
    switch (event)
    {
        case EVENT_MOUSEMOVE: //鼠标移动 0
        {
                                    if (g_bDrawingBox)//绘制矩形，记录长和宽
                                    {
                                        g_rectangle.width = x - g_rectangle.x;
                                        g_rectangle.height = y - g_rectangle.y;
                                    }
        }
            break;
        case EVENT_LBUTTONDOWN: //左键按下 1
        {
                                    g_bDrawingBox = true;
                                    g_rectangle = Rect(x, y, 0, 0);//记录起始点

        }
            break;
        case EVENT_LBUTTONUP: //左键抬起 4
        {
                                  g_bDrawingBox = false;
                                  //对宽和高小于0的处理
                                  if (g_rectangle.width < 0)
                                  {
                                      g_rectangle.x += g_rectangle.width;
                                      g_rectangle.width *= -1;
                                  }
                                  if (g_rectangle.height < 0)
                                  {
                                      g_rectangle.y += g_rectangle.width;
                                      g_rectangle.height *= -1;
                                  }
                                  //调用函数绘制
                                  DarwRectangle(image, g_rectangle);
        }
            break;
    }
}



void runRectangle()
{
     //参数准备
    g_rectangle = Rect(-1, -1, 0, 0);
    Mat srcImage(600, 800, CV_8UC3), tempImage;
    srcImage.copyTo(tempImage);
    srcImage = Scalar::all(0);
    //设置鼠标调用函数
    namedWindow(WINDOW_NAME, 1);
    setMouseCallback(WINDOW_NAME, on_MouseHandle, (void *)&srcImage);
    while (1)
    {
        srcImage.copyTo(tempImage);
        if (g_bDrawingBox)
            DarwRectangle(tempImage, g_rectangle);
        imshow(WINDOW_NAME, tempImage);
        if (waitKey(10) == 27) break;
    }
}