Re: Coordinates used by filter of CALayer

On Sep 15, 2009, at 17:00, Christiaan Hofman wrote:

> I am greatly confused by the different coordinate systems used by  
> CALayer (there are at least three as I see it). In particular, I am  
> trying to use a CATransition with a CIFilter to animate a transition  
> in a layer. I would expect that the coordinate system relevant for  
> the CIFilter would be the one for the layer, i.e. the one used by  
> the layer's bounds. However, it seems to use the coordinate system  
> for the superlayer (the one used by the layer's frame). Can anyone  
> explain why this makes sense?
>
> Christiaan
>

Let me expand a little bit, because now I'm getting even more  
confused. What I see is that when I use a CATransition with a  
CIFilter, the whole animated layer gets shifted so that its bounds  
origin lies at the bounds origin of its superlayer (so the coordinates  
of the layer and its superlayer coincide). I don't get this when I use  
a CATransition without a CIFilter. I even get this with very simple  
transition filters that don't require me to set any input values (i.e.  
the only relevant input values are the ones that should be set  
automatically by the animation). For instance, I would expect that a  
CATransition with type kCATransitionFade would give the exact same  
effect as a CATransition with a CIDissolveTransition filter.

Now this really seems wrong to me. Does anyone else see this? Is this  
a known bug?

thanks,
Christiaan