- From: Philip Taylor <excors+whatwg@gmail.com>
- Date: Mon, 15 Mar 2010 10:46:51 +0000
On Mon, Mar 15, 2010 at 7:05 AM, Maciej Stachowiak <mjs at apple.com> wrote: > Copying from one canvas to another is much faster than copying to/from > ImageData. To make copying to a Worker worthwhile as a responsiveness > improvement for rotations or downscales, in addition to the OffscreenCanvas > proposal we would need a faster way to copy image data to a Worker. One > possibility is to allow an OffscreenCanvas to be copied to and from a > background thread. It seems this would be much much faster than copying via > ImageData. Maybe this indicates that implementations of getImageData/putImageData ought to be optimised? e.g. do the expensive multiplications and divisions in the premultiplication code with SIMD. (A seemingly similar thing at http://bugzilla.openedhand.com/show_bug.cgi?id=1939 suggests SSE2 makes things 3x as fast). That would avoid the need to invent new API, and would also benefit anyone who wants to use ImageData for other purposes. -- Philip Taylor excors at gmail.com
Received on Monday, 15 March 2010 03:46:51 UTC