Why iOS coordinate system is difficult to understand?? only me?

Question

I\'m studying iOS\' UIView! And I found that I can\'t understand how bounds works.

For example,

Please run this code ... and see red box\'s moving. The red

Answer 1

Basically, The bounds of an UIView is the rectangle, expressed as a location (x,y) and size (width,height) relative to its own coordinate system (0,0).

The frame of an UIView is the rectangle, expressed as a location (x,y) and size (width,height) relative to the superview it is contained within.

Please follow this link for clear example. Cocoa: What's the difference between the frame and the bounds?