- From: Kenneth Russell <kbr@google.com>
- Date: Tue, 1 Feb 2011 11:13:54 -0800
On Tue, Feb 1, 2011 at 11:08 AM, Tab Atkins Jr. <jackalmage at gmail.com> wrote: > On Tue, Feb 1, 2011 at 10:04 AM, Anne van Kesteren <annevk at opera.com> wrote: >> On Tue, 01 Feb 2011 18:36:19 +0100, Boris Zbarsky <bzbarsky at mit.edu> wrote: >>> >>> On 2/1/11 5:19 AM, Simon Pieters wrote: >>>> >>>> While you're discussing efficient handoff of ArrayBuffer, do you also >>>> keep in mind efficient handoff of other objects (e.g. ImageData) as >>>> discussed in this thread?: >>>> >>>> http://lists.whatwg.org/pipermail/whatwg-whatwg.org/2011-January/029885.html >>> >>> For what it's worth, in Gecko that's the same thing, since imagedata is >>> just a typed array in our implementation. >> >> ImageData.data you mean? I wonder if we can still remove CanvasPixelArray. > > Only if the out-of-bounds behavior for entries in Typed Arrays matches > the current clamping behavior for CanvasPixelArray. ?I don't see any > explicit indication of what should be done in the Typed Array spec, > which I suppose means that they're relying on WebIDL's coercion algos > to keep things in-range for the given view. ?WebIDL has the wrong > behavior here right now (it wraps), though I think heycan is receptive > to changing it. For this reason I think we need to keep CanvasPixelArray distinct. I certainly hope that Web IDL does not change its conversion rules to mimic the clamping behavior in CanvasPixelArray. Right now Web IDL delegates to the ECMA-262 specification for primitive conversions, which have the wrapping behavior of C-style casts rather than clamping behavior. Forcing clamping for out-of-range integer values would impose a significant negative performance constraint on typed arrays. -Ken
Received on Tuesday, 1 February 2011 11:13:54 UTC