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Re: [whatwg] Enabling LCD Text in 2D canvases.

From: Justin Novosad <junov@chromium.org>
Date: Thu, 15 Nov 2012 09:26:06 -0500
Message-ID: <CABpaAqQpFr73BMhYT=VoxxDq0hbmcrLF9-Wk6ikD4myXJaYusw@mail.gmail.com>
To: Fred Andrews <fredandw@live.com>
Cc: whatwg <whatwg@lists.whatwg.org>, "robert@ocallahan.org" <robert@ocallahan.org>
On Wed, Nov 14, 2012 at 8:07 PM, Fred Andrews <fredandw@live.com> wrote:

> The canvas that scripts draw into could be over-sized with the UA down
> sampling this to
> fit the target size and taking into account the sub-pixel screen layout
> when doing so.
Obviously, that would be costly (x3 pixels), but I think it is a very
realistic solution and relatively low hanging fruit. The over-sizing of the
canvas would have to be handled under the hood by the UA though, because it
depends on LCD component ordering and orientation, which means querying the
OS/display driver. A lot of the kinks with the over-sized canvas approach
have already been ironed out for solving the problem of High-DPI support (
put/getImageDataHD ), and I like the idea of unifying the two. Implementing
this would mostly be a matter of adding per color component compositing of
canvases. Also, the pixel aspect ratio would have to be taken into account
for line drawing.

Regarding the concerns about accessibility, I think the problem can be
solved by using HitRegions with labels.  Come to think of it, there should
be an option to make the UA do this automatically: create a HitRegion with
a label every time text is drawn to a canvas.
Received on Thursday, 15 November 2012 14:26:36 UTC

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