IrisSegue.mm

@implementation IrisSegue

- (void)perform
{
	CATransition *shutterAnimation = [CATransition animation];
	[shutterAnimation setDelegate:self];
	[shutterAnimation setDuration:0.5];
	
	shutterAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
	[shutterAnimation setType:@"cameraIris"];
	[shutterAnimation setStartProgress:0.5];
	
	CALayer *cameraShutter = [[CALayer alloc]init];
	[cameraShutter setBounds:CGRectMake(0.0, 0.0, 320.0, 425.0)];
	
	UIViewController* destination = self.destinationViewController;
	
	[self.sourceViewController presentViewController:self.destinationViewController animated:NO completion:^{
		// don't ask - it just works with two calls to dispatch_async
		dispatch_async(dispatch_get_main_queue(), ^{
			dispatch_async(dispatch_get_main_queue(), ^{
				[destination.view.layer addSublayer:cameraShutter];
				[destination.view.layer addAnimation:shutterAnimation forKey:@"cameraIris"];
			});
		});
	}];
}

@end