Thanks for your comments. On Fri, Apr 19, 2013 at 12:53 PM, Rik Cabanier <caban...@gmail.com> wrote:
> Nice! > > The behaviour of putImageData() and putImageDataHD() is to premultiply the > RGB components by the alpha component as usual, but write 1.0 into > destination alpha. In other words, if (r, g, b, a) are the component values > in a given pixel passed to putImageData[HD](), then r' = ar, g' = ag, b' = > ab are the colour components of the resulting canvas pixel, and (r', g', > b', 1.0) is written to the canvas backing store. > > I think that's confusing. Maybe cut that sentence since it isn't needed. > (Having the black backing store implies this behavior) > Do you mean, remove both sentences, or just the last one? I wanted to make it clear that the RGB is still premultiplied with the original alpha, even though the alpha is subsequently ignored. attribute boolean alpha; > > Should it be read-only? Hmm, I have no idea. WebGL's doesn't have it, but I'm not enough of an IDL expert to know whether it's necessary. > > Canvas2DContextAttributes getContextAttributes(); > > Maybe make it an attribute: > > attribute Canvas2DContextAttributes attributes: > > I'm following WebGL syntax here as well. Apparently WebGL's is nullable, though, so I've added ? here. Stephen > > On Fri, Apr 19, 2013 at 9:13 AM, Stephen White > <senorbla...@chromium.org>wrote: > >> Here's a short proposal I've written up for the getContext('2d', { alpha: >> false } ) version of this idea (much of it culled from the mega-thread >> above). >> >> http://wiki.whatwg.org/wiki/CanvasOpaque >> >> Comments are welcome. >> >> Stephen >> > >