W3C home > Mailing lists > Public > whatwg@whatwg.org > August 2013

Re: [whatwg] remove resetClip from the Canvas 2D spec

From: Ian Hickson <ian@hixie.ch>
Date: Fri, 9 Aug 2013 20:20:03 +0000 (UTC)
To: Stephen White <senorblanco@chromium.org>
Message-ID: <alpine.DEB.2.00.1308092019440.27623@ps20323.dreamhostps.com>
Cc: WHATWG List <whatwg@whatwg.org>
On Fri, 9 Aug 2013, Stephen White wrote:
>
> Although Skia could support resetClip() via SkRegion::kReplace_Op, it's 
> problematic for the API in general, and I think we should avoid it.
> 
> In particular, it makes it impossible to place a display list (SkPicture 
> in Skia parlance) inside a parent display list containing a clip and be 
> assured that the child will not draw outside the given region, since the 
> child display list can always resetClip() its way out of the parent's 
> clip. It probably also prevents culling optimizations for the same 
> reason.
> 
> For example, if one used Skia to draw the entirety of a browser UI 
> including chrome and content, the resetClip() inside the web page 
> contents would overwrite the browser UI. Obviously we don't do that in 
> Chrome, but it goes some idea of the problem at the API level.

This is a quite widely requested feature. What should we do to address 
this request instead?

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Friday, 9 August 2013 20:20:27 UTC

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