This is a rudimentary question regarding your example in Chapter 2 - First Animation. Just looking over the following code in initializeFramePositions:
rightFramePosition = NSMakeRect(7.0f * frameX / 8.0f, 7.0f *frameY / 16.0f, frameX / 8.0f, frameY/ 8.0f);
I was curious, how did you derive the math to properly position the right frame? Is there a particular geometry algorithm in order to be able to determine how to pin point where you want your NSImageView to end up?
Thanks a bunch!