- From: Kenneth Russell <kbr@google.com>
- Date: Sun, 29 Nov 2009 10:59:22 -0800
On Sat, Nov 28, 2009 at 9:47 PM, Boris Zbarsky <bzbarsky at mit.edu> wrote: > On 11/29/09 12:15 AM, Kenneth Russell wrote: >>> >>> I assume you meant JS bitwise operators? ?Do we have any indication that >>> this would be faster than four array property sets? ?The bitwise ops in >>> JS >>> are not necessarily particulary fast. >> >> Yes, that's what I meant. I don't have any data on whether this would >> currently be faster than the four separate byte stores. > > Are they even byte stores, necessarily? ?I know in Gecko imagedata is just a > JS array at the moment; it stores each of R,G,B,A as a JS Number (with the > usual "if it's an integer store as an integer" optimization arrays do). > ?That might well change in the future, and I hope it does, but that's the > current code. > > I can't speak to what the behavior is in Webkit, and in particular whether > it's even the same when using V8 vs Nitro. In Chromium (WebKit + V8), CanvasPixelArray property stores write individual bytes to memory. WebGLByteArray and WebGLUnsignedByteArray behave similarly but have simpler clamping semantics. -Ken
Received on Sunday, 29 November 2009 10:59:22 UTC