Re: view gets drawRect called when scrolling into elastic area
Re: view gets drawRect called when scrolling into elastic area
- Subject: Re: view gets drawRect called when scrolling into elastic area
- From: Kyle Sluder <email@hidden>
- Date: Mon, 17 Jun 2013 12:07:09 -0700
On Mon, Jun 17, 2013, at 09:50 AM, Steve Mills wrote:
> Can anyone explain why our view subclass is getting drawRect called when
> I scroll into the elastic area with 2-finger scrolling (OS X, not iOS)?
> The view has at least one CALayer and self.wantsLayer has been set to
> YES. This causes it to draw in tiles. All tiles have been rendered, yet
> when I scroll past the actual bounds of the view into the elastic area,
> we get drawRects for *all* tiles. For a complex document, it brings it to
> a crawl if you happen to swipe aggressively into any elastic area.
Elastic scrolling is pretty rough around the edges. There's no API for
drawing into that area, yet apparently it's willing to invalidate all
your other content.
I guess you could set a breakpoint on -setNeedsDisplay:inRect: to figure
out where to stave off invalidation, but _please_ file a Radar about
improving the API around elastic scrolling.
--Kyle Sluder
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