Talks | Ben Clark-Robinson – benclarkrobinson.net

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Today I did a little talk at Cocoaheads Brisbane, Australia. It was on Core Animation and I made a very very very very very simple application which would rotate a single image using CATransform3DIdentity to give it a nice perspective 3D rotation look.

Here’s the full Xcode 3.1 project: Download.

If you’re interested solely in the transformation here’s the code:

float zDistance = 850;
CATransform3D sublayerTransform = CATransform3DIdentity;
sublayerTransform.m34 = 1.0 / -zDistance;
subLayer.transform = sublayerTransform;
 
CABasicAnimation *flipAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.y"];
flipAnimation.toValue = [NSNumber numberWithDouble:1.0f * M_PI];
flipAnimation.autoreverses = YES;
flipAnimation.duration = 2.0f;
flipAnimation.repeatCount = 1e100f;
flipAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
[subLayer addAnimation:flipAnimation forKey:@"flip"];

Where subLayer == your Core Animation layer you want to rotate.

Reference: Core Animation for Mac OS X and the iPhone and Mike Lee.