Where is the (0,0) point of the coordinate system located in UIKit?

In UIKit, the coordinate system for UIView has the point (0,0) at the top-left corner of the view itself.

This means that the coordinates inside a UIView are measured from the top-left corner of that view, with the X axis extending to the right and the Y axis extending downward.

For example, if you have a UIView of size 100x100, then the point (0,0) is the top-left corner, and the point (100,100) is the bottom-right corner of that view.

Important: For UIWindow and the root view of a view controller, the point (0,0) coincides with the top-left corner of the screen (taking into account the device orientation).