Hi Matt, If that approach looks reasonable to you, I and Thinker will start working on that.
Kanru [email protected] (Thinker K.F. Li) writes: > After a discussion with Kan-Ru, I get more about the problem itself. > Since the positions of all display items in a nsIScrollableFrame are > relative to nsIScrollableFrame itself. By keeping display itmes in the > cache and applying a translation (shift) to the gfxContext before > calling paint() on display items, we don't need to change the display > items in the cache. Of course, invalidate regions should be translated > too. > > How do you think? > > [email protected] writes: > >> Hi Thinker >> >> Gal and I were discussing this same problem last week, and decided on >> the same solution. >> >> The main problem is that display item positions are relative to the >> screen (or the nearest transformed ancestor) so they change when we >> scroll. This means we'd have to invalidate the cache for all scrolled >> frames, or modify the cached items. >> >> What we decided on instead was to make the scroll root a 'reference >> frame' so that all display items below it have coordinates relative to >> that instead of the screen. This should mean that we no longer have to >> modify the display items when we scroll. >> >> I was planning on working on this in about 2 weeks, once I've finished >> up with my current set of graphics bugs. I'm happy to discuss this >> further though if you want to get started sooner than that. >> >> The rest of the proposal looks good, but you'll at least need to >> invalidate the cached items when we get a style change. Some items >> (like tables) will require special handling too. >> >> - Matt >> >> On Thursday, August 22, 2013 12:52:54 AM UTC+12, Thinker K.F. Li wrote: >>> I am doing profiling for several Apps on b2g, and have found near 1x% ~ >>> >>> 20% of CPU time when scrolling are spent on building display list. So, >>> >>> I think we can use cache for display lists to save time of creating the >>> >>> same display items repeatedly. >>> >>> >>> >>> I just have done some studies, and have a rough idea. My idea is >>> >>> attaching the caches with frames. When a frame is >>> >>> MarkIntrinsicWidthsDirty()ed, the attached cache is deleted if any. For >>> >>> the frames that their parents are MarkIntrinsicWidthsDirty()ed for last >>> >>> reflowing, but not themself, the results of their BuildDisplayList() are >>> >>> kept in the cache. I guess most animation will modify the same set of >>> >>> subtrees repeatedly. So, we can save time for building display lists. >>> >>> >>> >>> Feedback is welcomed! >>> >>> >>> >>> -- >>> >>> Sinker >>> >>> -- >>> >>> 天教懶漫帶疏狂 >> _______________________________________________ dev-tech-layout mailing list [email protected] https://lists.mozilla.org/listinfo/dev-tech-layout
