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