AVCaptureVideoPreviewLayer Zoomin

gistfile1.m

- (void)handlePinchGesture:(UIPinchGestureRecognizer *)gestureRecognizer {
    
    if([gestureRecognizer state] == UIGestureRecognizerStateBegan) {
        self.lastScale = self.effectiveScale;
    }
    
    self.effectiveScale = self.lastScale * gestureRecognizer.scale;
    if (self.effectiveScale < 1.0) {
        self.effectiveScale = 1.0;
    }
    CGFloat maxScaleAndCropFactor = [[self.stillImageOutput connectionWithMediaType:AVMediaTypeVideo] videoMaxScaleAndCropFactor];
    if (self.effectiveScale > maxScaleAndCropFactor) {
        self.effectiveScale = maxScaleAndCropFactor;
    }
    [CATransaction begin];
    [CATransaction setAnimationDuration:.025];
    [self.previewLayer setAffineTransform:CGAffineTransformMakeScale(self.effectiveScale, self.effectiveScale)];
    [CATransaction commit];
};