I have a ViewController to which I applied the retina 3.5" form factor in the story board. The iOS iPhone 6.1 simulator also has the Retina configured.
When I try to position a UIImageView using SetFrame, its CGRect coordinates are in the non-retina form (i.e. when I position to 320x480, it goes to the bottom right instead of the middle of the screen):
[myImageView setFrame:CGRectMake(320, 480, myImageView.frame.size.width, myImageView.frame.size.height)];
[self.view addSubview:myImageView];
How to have CGRect coordinates for Retina when using SetFrame ?
Thanks.
The reason for this is because iOS uses points instead of pixels. This way, the same code will work on a retina and a non-retina screen. Therefore, when you set the location to (320,480) you are setting it to point (320,480) not pixel (320,480). This way, if the phone is non-retina, that point will end up being pixel (320, 480) and on retina, it will end up being pixel (640,960).
So what it looks like you want is:
[myImageView setFrame:CGRectMake(160, 240, myImageView.frame.size.width, myImageView.frame.size.height)];
[self.view addSubview:myImageView];
which will place the imageView's top-left corner in the same location on both retina and normal display.