Re: [css3-writing-modes] inconsistent handling of 'Tr' codepoints in 'text-orientation'

On Oct 1, 2013, at 11:10 AM, John Daggett <jdaggett@mozilla.com> wrote:
> Current spec:
> http://dev.w3.org/csswg/css-writing-modes/#vertical-orientations
>
> # For Tr characters, which are intended to be either transformed or
> # rotated sideways, the UA may assume that appropriate glyphs for
> # upright typesetting are given in the font and render them upright;
> # alternately it may check for such glyphs first, and fall back to
> # typesetting them sideways if the appropriate glyphs are missing.
>
> Revised wording:
>
> # For Tr characters, the user agent should assume that appropriate
> # glyphs for upright typesetting are given in the font and render them
> # upright.

I agree with this for OpenType fonts that provide the 'vert' feature.
However, I would suggest the spec should accomodate working with less
sophisticated font technologies and with fonts that don't provide
vertical alternates.  Something like this:

For Tr characters, which are intended to be either transformed or
rotated sideways:

- if the font declares that it provides alternate glyphs for vertical
typesetting (e.g. it is an OpenType font that provides the 'vert'
feature), the UA must assume that the font provides appropriate glyphs
and render the characters upright;

- otherwise, the UA must render the characters sideways.

James

Received on Tuesday, 1 October 2013 06:26:47 UTC