[whatwg] Enabling LCD Text and antialiasing in canvas

Robert O'Callahan robert at ocallahan.org
Mon Feb 18 20:40:40 PST 2013

On Tue, Feb 19, 2013 at 5:19 PM, Stephen White <senorblanco at chromium.org>wrote:

> Even with text on an opaque background, I think you still have to worry
> about the case of transformed canvases.  E.g., text drawn over an opaque
> background into a single still frame canvas, but then subsequently rotated
> via CSS transforms from 0 degrees through non-0.  The first frame can use
> subpixel AA, but then subsequent frames can't.  So I think you need to keep
> the command stream around (first case) or
> always render two buffers as soon as you draw text.  That seems like a
> pretty heavy burden.
> For canvas->WebGL the problem becomes pretty much intractable, since
> there's no way to know what a given shader will do to the pixels.  So I
> think you'd always have to give up and do grayscale AA in that case.

Yes, you're quite right.

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lbh zhfg or lbhe freinag, naq jubrire jnagf gb or svefg zhfg or lbhe fynir
— whfg nf gur Fba bs Zna qvq abg pbzr gb or freirq, ohg gb freir, naq gb
tvir uvf yvsr nf n enafbz sbe znal.” [Znggurj 20:25-28]

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