[webkit-help] Relation between RenderLayer and the rendering tree?

[Maciej Stachowiak]

On Aug 17, 2009, at 11:25 PM, Robin Cao wrote:

> Hi all,
> I'm interested in hacking on WebCore’s rendering system and i'm  
> reading the source.
> What confused me is that what the role does RenderLayer play in the  
> rendering process.
> What's the relation between RenderLayer and the rendering tree?
>

RenderLayer is a tree that, essentially forms a spare subtree of the  
full render tree, which is used to optimize incremental relayout and  
repainting. Opacity and explicit positioning are some of the things  
that can cause a RenderLayer to be created.

Regards,
Maciej