Question

Pretty simple Question:

I have a ScrollView and an ImageView. For every pixel scrolled, the ImageView should rotate a certain amount of degrees.

Any ideas how to do this?
Thanks in advance

Answer 1

Implement UIScrollViewDelegate and rotate with an affine transform.

#import <QuartzCore/QuartzCore.h>

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGPoint offset = scrollView.contentOffset;
    CGFloat rotateDegrees = offset.y;
    CGFloat rotateRadians = rotateDegrees * (M_PI / 180);
    _myImage.layer.affineTransform = CGAffineTransformMakeRotation(rotateRadians);
}

To reset the rotation, use _myImage.layer.affineTransform = CGAffineTransformIdentity.