opencv鼠标操作与响应

//鼠标事件
Point sp(-1, -1);
Point ep(-1, -1);
Mat temp;
static void on_draw(int event, int x, int y, int flags, void *userdata) {
	Mat image = *((Mat*)userdata);
	if (event == EVENT_LBUTTONDOWN) {
		sp.x = x;
		sp.y = y;
		std::cout << "start point:"<<sp << std::endl;
		}
	else if (event == EVENT_LBUTTONUP) {
		ep.x = x;
		ep.y = y;
		std::cout << "end point:" << ep << std::endl;
		int dx = ep.x - sp.x;
		int dy = ep.y - sp.y;
		if (dx > 0 && dy > 0) {
			Rect box(sp.x, sp.y, dx, dy);
			imshow("ROI", image(box));
			rectangle(image, box, Scalar(0, 0, 255), 2, 8, 0);
			imshow("鼠标绘制", image);
			
			//为下次绘制做准备
			sp.x = -1;
			sp.y = -1;
		}
	}
	else if (event == EVENT_MOUSEMOVE) {
		if (sp.x > 0 && sp.y > 0) {
			ep.x = x;
			ep.y = y;
			std::cout << "end point:" << ep << std::endl;
			int dx = ep.x - sp.x;
			int dy = ep.y - sp.y;
			if (dx > 0 && dy > 0) {
				Rect box(sp.x, sp.y, dx, dy);
				temp.copyTo(image);
				rectangle(image, box, Scalar(0, 0, 255), 2, 8, 0);
				imshow("鼠标绘制", image);
			}
		}
		
	}
}


void QuickDemo::mouse_drawing_demo(Mat &image) {
	namedWindow("鼠标绘制", WINDOW_AUTOSIZE);
	setMouseCallback("鼠标绘制", on_draw, (void*)(&image));
	imshow("鼠标绘制", image);
	temp = image.clone();
}