Re: CALayer question regarding sequence of animations

FROM : Troy Stephens
DATE : Tue Nov 13 22:25:24 2007

On Nov 13, 2007, at 12:10 PM, Steve Sheets wrote:
> Good evening all...
>
> Using CAAction or CATransaction, can you create a sequence of 
> animation (usually changing a CALayer's property) that occur one 
> after another?
>
> I know you can modify the duration of a single animation using 
> CATransaction, even eliminate the animation all together. You can 
> also group a set of animations, so that each one starts at the same 
> time. However, I want to create a two or more animations that follow 
> one other, without having to resort to a NSTimer or such. I want to 
> be able to create this animation in single code segment (not require 
> timers or callbacks).
>
> For example, I want to create an animation that make a hidden layer 
> appear (aLayer.hidden=FALSE), moves it to a new position (aLayer. 
> position=CGPointMake(100.0,100.0), and then fades it back out 
> (aLayer. hidden=TRUE).
>
> Any thoughts?


See CAAnimation's "beginTime" property (part of the CAMediaTiming 
protocol to which CAAnimation conforms).

By collecting animations in a CAAnimationGroup, and setting the 
"beginTime" and "duration" of each constituent animation as desired, 
you can set the animations up to execute however you like -- in 
contiguous sequence, or even with overlap and/or gaps in between them.

--
Troy Stephens
Cocoa Frameworks
Apple, Inc.