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Re: [whatwg] Enabling LCD Text and antialiasing in canvas

From: Robert O'Callahan <robert@ocallahan.org>
Date: Tue, 19 Feb 2013 17:40:40 +1300
Message-ID: <CAOp6jLa=yX3ao7WO1Q+sscDrW5ya346XNoiHrygkN7TSR9CoBw@mail.gmail.com>
To: Stephen White <senorblanco@chromium.org>
Cc: whatwg@whatwg.org, Ian Hickson <ian@hixie.ch>, Rik Cabanier <cabanier@gmail.com>
On Tue, Feb 19, 2013 at 5:19 PM, Stephen White <senorblanco@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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bire gurz. Abg fb jvgu lbh. Vafgrnq, jubrire jnagf gb orpbzr terng nzbat
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]
Received on Tuesday, 19 February 2013 04:41:05 UTC

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