I'm using the UIImagePickerController to control the camera and overlay millimeter tick marks in preview for measuring closeup macro shots, and I'd like to be able to detect the current zoom level and scale it properly.
Is there any way to determine the current zoom level in camera preview?
Unfortunately no, since the UIImagePickerController API doesn't give you access to the camera zoom level, nor to any subviews or other properties that might have access to that information.
ReplyDeleteAs Michael Dautermann points out, based on the answer to this question, you could use the cameraViewTransform property of UIImagePickerController to implement your own zoom by setting up the right CGAffineTransform and also the right pinch gesture to zoom in/out. Since you'd be controlling the zoom yourself, you'd always know the zoom level and be able to use it to adjust the tick marks.