Re: [css3-transitions] transitions and rendering objects vs. DOM nodes

On Jun 28, 2009, at 10:57 PM, Robert O'Callahan wrote:

> On Sun, Jun 28, 2009 at 9:37 AM, David Hyatt <hyatt@apple.com> wrote:
> In WebKit, at the moment we do transitions on rendering objects (and  
> yes this means changes to display:none just kill transitions).  We  
> don't allow transitions to occur on pseudo elements.  Not sure if  
> this is the right decision though, but it's what we have done so far.
>
> What if you have a <span> which fits on one line, a transition on  
> 'color' starts, but halfway through the container width changes so  
> the <span> breaks across two lines? The second box gets the final  
> color immediately? If this happened because the user resized the  
> window, I think it's clearly a bug.
>

Unlike Gecko, our "rendering objects" are not affected by changes in  
line structure.  We create separate objects for lines.  So what you  
describe is not an issue in WebKit.

It's better to think of transitions as happening on nodes and on  
pseudo elements, since obviously the notion of a "rendering object"  
isn't the same in every engine.

I believe we just need to make pseudo elements work in WebKit.

first-line is a particularly thorny case that we'll just need to work  
out.

dave