Question

Ok, so I realize I can find the scale value from a layer’s CATransform3D like this:

 float scale = [[layer valueForKeyPath: @"transform.scale"] floatValue];

But I can’t for the life of me figure out how I would find the scale value from a CGAffineTransform. Say for instance I have this CGAffineTransform called “cameraTransform”:

UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
CGAffineTransform *cameraTransform =  imagePicker.cameraViewTransform;

Now how do I get the scale value from cameraTransform?

Answer 1

The Quartz 2D Programming Guide tells you where to find the scale values. Compare that with the definition of the CGAffineTransform structure.