coordinate system of mobile phone and pad in iOS

For mobile phones, pad, whether it is a horizontal screen, or vertical screen, the default origin is in the upper left corner of the screen, and then down, right is the positive direction. Look at the picture

Below, depending on the instance

-(void) viewdidload {    [super Viewdidload];     // additional setup after loading the view, typically from a nib.    Self.view.backgroundColor = [Uicolor whitecolor];     *view = [[UIView alloc] Initwithframe:cgrectmake (00)];     = [Uicolor redcolor];    [Self.view Addsubview:view];}

Run separately on iphone and ipad, with the following effects:

First group:

Second group:

Third group:

Group Fourth:

Group Fifth:

Group Sixth:

coordinate system of mobile phone and pad in iOS