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Re: TTML2 wide review comment: styling

From: David Singer <singer@apple.com>
Date: Thu, 05 Oct 2017 09:19:24 -0700
Cc: Glenn Adams <glenn@skynav.com>, David Ronca <dronca@netflix.com>, Timed Text Working Group <public-tt@w3.org>, Pierre-Anthony Lemieux <pal@sandflow.com>
Message-id: <0CD3D7AC-E0A1-4402-A634-C3C28D503E64@apple.com>
To: r12a <ishida@w3.org>
Thank you

I assume also that as it gets more widely implemented, one could use CSS font-variation-settings <https://developer.mozilla.org/en-US/docs/Web/CSS/font-variation-settings> on the ‘slant’ axis <https://www.microsoft.com/typography/otspec/dvaraxisreg.htm>? This would have the advantage that the font designer has some say in the effect of slanting.

I also note that TTML is using a different name, and a different way of specifying the effect (OpenType uses the counter-clockwise angle of shear, TTML uses percentage.)

> On Oct 5, 2017, at 2:01 , r12a <ishida@w3.org> wrote:
> 
> On 04/10/2017 15:42, David Singer wrote:
>>> On Oct 3, 2017, at 22:49 , Glenn Adams <glenn@skynav.com> wrote:
>>> Actually, I was responding to David Singer regarding the CSS WG having discussed oblique. While that is true, I don't know whether they have discussed shear.
>> Yes, I searched for both words, as the usage sometimes overlaps, though oblique is usually used for a designed oblique face, and shear for a generated one. (However, there is plenty of practice that mixes it up; the original Mac did italic by shearing iirc.)
> 
> 
> Here is some relevant text from CSS:
> 
> --
> oblique
>    selects a font that is labeled as an oblique face, or an italic face if one is not
> 
> If no italic or oblique face is available, oblique faces can be synthesized by rendering non-obliqued faces with an artificial obliquing operation. The use of these artificially obliqued faces can be disabled using the ‘font-synthesis’ property. The details of the obliquing operation are not explicitly defined.
> 
> Authors should also be aware that synthesized approaches may not be suitable for scripts like Cyrillic, where italic forms are very different in shape. It is always better to use an actual italic font rather than rely on a synthetic version.
> 
> Many scripts lack the tradition of mixing a cursive form within text rendered with a normal face. Chinese, Japanese and Korean fonts almost always lack italic or oblique faces. Fonts that support a mixture of scripts will sometimes omit specific scripts such as Arabic from the set of glyphs supported in the italic face. User agents should be careful about making character map assumptions across faces when implementing support for system font fallback.
> --
> from https://www.w3.org/TR/css-fonts-3/#oblique
> 
> ri

David Singer
Manager, Software Standards, Apple Inc.
Received on Thursday, 5 October 2017 16:19:49 UTC

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