discrete, custom timed (per frame) UIImageView Animation

gistfile1.mm

// keyTimes = array floats for second [(NSNumber)1.2,(NSNumber)2.0] == 2 frames, 1.2 secs for first frame, 2.0 seconds for second frame
- (void) addDiscreteTimedImageAnimation:(NSString *)animationName view:(UIImageView *)imageView images:(NSArray *)images keyTimes:(NSArray *)keyTimes repeatCount:(float)repeatCount onDone:(SEL)callback {
	CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"contents"];
	NSMutableArray *values = [[NSMutableArray alloc] initWithCapacity:[images count]];
	NSMutableArray *keyTimesAsPercent = [[NSMutableArray alloc] initWithCapacity:[keyTimes count]];
	double totalDuration = 0.0;
	
	for(UIImage *image in images) {
		[values addObject:(id)(image.CGImage)];
	}
	
	UIImage *lastImage = [images objectAtIndex:[images count]-1];
	
	[values addObject:(id)(lastImage.CGImage)];
	
	for(NSNumber *frameTime in keyTimes) {
		totalDuration+=[frameTime floatValue];
	}
	
	float totalSoFar = 0.0;
	
	for(NSNumber *frameTime in keyTimes) {
		
		if (totalSoFar == 0.0) // for discrete timing, the first one is always 0.0
		{
			[keyTimesAsPercent addObject:[NSNumber numberWithFloat:0.0]];
			totalSoFar += [frameTime floatValue];
		}
		else 
		{
			[keyTimesAsPercent addObject:[NSNumber numberWithFloat:(totalSoFar/totalDuration)]];
			totalSoFar += [frameTime floatValue];
		}
	}
	
	[keyTimesAsPercent addObject:[NSNumber numberWithFloat:1.0]];
	
	
	animation.values = values;
	[values release];
	
	animation.keyTimes = keyTimesAsPercent;
	[keyTimesAsPercent release];
	
	animation.delegate = self;
	animation.repeatCount = repeatCount;
	animation.duration = totalDuration;
	animation.fillMode = kCAFillModeForwards;
	animation.calculationMode = kCAAnimationDiscrete; // playing
	
	[animation setValue:animationName forKey:@"name"];
	[animation setValue:NSStringFromSelector(callback) forKey:@"onDone"];
	
	[[imageView layer] addAnimation:animation forKey:animationName];
}

- (void) animationDidStop:(CAAnimation *)anim finished:(BOOL)finished {
	if(finished)
	{
		ALog(@"Finished animation: %@", [anim valueForKey:@"name"]);
		
		if ([anim valueForKey:@"onDone"] != nil)
		{
			SEL callback = NSSelectorFromString([anim valueForKey:@"onDone"]);
			[self performSelector:callback];
		}
	}
}

note .... needed this since the animation support built into UIImageView does not support custom timings per frame, and simple callback feature.