Mouse callback - I wan't to know what I'm doing
I took function from book to create callback function and it's work. Fuction specifies the location of the mouse on the image and write to console cordinates.
Function looks like:
void mouse_ev (int event, int x, int y, int flags, void* param)
{
Mat *img = ((Mat *)param);
switch (event) {
case EVENT_MOUSEMOVE: cout << "x: " << x << "y: " << y << endl;
break;
}
}
and im main function I use it by this:
setMouseCallback ( window_name, mouse_ev, NULL);
How exactly x and y are sent to mouse_ev function? Is setMouseCallback send all this information to second param of function?
For what is that: Mat *img = ((Mat *)param); line?
My question may seem silly but I want to know 100 percent what I'm doing.