Re: CAScrollLayer "Contents" Size

FROM : Scott Stevenson
DATE : Wed Mar 12 23:15:57 2008

On Mar 12, 2008, at 5:06 AM, Matt James wrote:

> As a side note, is there any way to setup a layer so that it grows its
> bounds based on sublayers added?  It seems silly to have all this 
> code to
> constantly update the bounds so that references to height and width 
> of a
> given layer are accurate for what I want.


I actually don't think you want to keep growing the parent layer like 
that. It doesn't really have any practical benefit and it eats up 
resources. The parent layer generally only needs to be as big as the 
on-screen display area.


> I'm thinking along the lines of contentsGravity, but for sublayers.


If you want to align sublayers along particular edges of the 
superlayer, you can use the "autoresizingMask", which works like 
springs and struts in NSView. So to keep a sublayer in the lower-left 
corner of the superlayer:

   sublayer.autoresizingMask = ( kCALayerMinXMargin | 
kCALayerMinYMargin );

If you want to position a collection of layers relative to each other 
(such as a grid), you can use CAConstraintLayoutManager.


      - Scott