【OpenCV】使用OpenCV画矩形

使用响应事件、回调函数完成利用OpenCV画矩形的功能。

 

CvRect box;
bool drawing_box = false;

void draw_box(IplImage* img, CvRect rect)
{
	cvRectangle(
		img,
		cvPoint(box.x, box.y),
		cvPoint(box.x + box.width, box.y + box.height),
		CvScalar(0xff, 0xff, 0xff)
		);
}

void my_mouse_callback(int event, int x, int y, int flags, void *param)
{
	IplImage *image = (IplImage*)param;
	
	switch (event)
	{
		case CV_EVENT_MOUSEMOVE:
			{
				if (drawing_box)
				{
					box.width = x - box.x;
					box.height = y - box.y;
				}
			}
			break;
		case CV_EVENT_LBUTTONDOWN:
			{
				drawing_box = true;
				box = CvRect(x,y,0,0);
			}
			break;
		case CV_EVENT_LBUTTONUP:
			{
				drawing_box = false;
				if (box.width < 0)
				{
					box.x += box.width;
					box.width *= -1;
				}
				if (box.height < 0)
				{
					box.y += box.height;
					box.height *= -1;
				}
				draw_box(image, box);
			}
			break;
		default:
			break;
	}
}

int main()
{
	box = c