Question

I am working in a project where the images are drag able. In which if i put one image over the other image the image has to be changed.
What i need is
1) I want to check whether both the images are in same place or not.
2) The position of image must not be exact.It may be approximately equal

Answer 1

Here is an approach assuming the images are the same size

// using ints because it is easier for taking the abs value
int dx,dy;

dx = frame1.origin.x - frame2.origin.x;
dy = frame1.origin.y - frame2.origin.y;
dx = abs(dx);
dy = abs(dy);

// overlapping width and height
int ovHeight, ovWidth;

ovWidth = frame1.size.width-dx;
ovHeight = frame1.size.height-dy;

int ovArea = ovWidth*ovHeight;
int imageArea = frame1.width*frame1.height;

int percentOverlap = ovArea*100/imageArea;

if (percentOverlap > 80) {
  // do work here
}