[whatwg] Enabling LCD Text and antialiasing in canvas

Rik Cabanier cabanier at gmail.com
Fri Apr 19 09:53:20 PDT 2013


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)

attribute boolean alpha;

Should it be read-only?

Canvas2DContextAttributes getContextAttributes();

Maybe make it an attribute:

attribute Canvas2DContextAttributes attributes:

On Fri, Apr 19, 2013 at 9:13 AM, Stephen White <senorblanco at 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

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