Apply CGAffineTransform prior to layer being displayed

Question

I\'m trying to scale an AVCaptureVideoPreviewLayer so it displays a \"zoomed in\" preview from the camera; I can make this work using setAffineTransform:C

Answer 1

Two simple alternative approaches, one (better) for iOS 7.x and one for earlier versions of iOS:

float zoomLevel = 2.0f;
if ([device respondsToSelector:@selector(setVideoZoomFactor:)]
    && device.activeFormat.videoMaxZoomFactor >= zoomLevel) {
  // iOS 7.x with compatible hardware
  if ([device lockForConfiguration:nil]) {
    [device setVideoZoomFactor:zoomLevel];
    [device unlockForConfiguration];
  }
} else {
  // Lesser cases
  CGRect frame = captureVideoPreviewLayer.frame;
  float width = frame.size.width * zoomLevel;
  float height = frame.size.height * zoomLevel;
  float x = (frame.size.width - width)/2;
  float y = (frame.size.height - height)/2;
  captureVideoPreviewLayer.bounds = CGRectMake(x, y, width, height);
}