Re: [css3-writing-modes] eliminate 'sideways' and 'sideways-left' for 'text-orientation'

On 09/09/2014 10:24 PM, John Daggett wrote:
>
> As part of our work on supporting vertical text, we're working on adding
> support for the 'text-orientation' property to Gecko.
>
> There are only three values needed for actual vertical text usage, the
> default, automatic behavior, and explicit overrides for the vertical and
> sideways cases. I'd prefer these be 'auto, vertical, sideways' but the
> spec wants these to be 'mixed, vertical, sideways-right'.
>
> I think we should simply drop the other values, 'sideways' and 'sideways-left'
> for this level ('glyph-orientation' is already optional). The 'sideways-right'
> value is the value used by authors for both Mongolian and CJK vertical text.
>
> fantasai seemed to think there were uses for 'sideways-left' but these
> seem like obscure, unnecessary cases [1]. The 'sideways' keyword is a
> synonym for either 'sideways-right' or 'sideways-left' depending upon
> the writing-mode but there's no need for a value with this behavior,
> it's basically just an synonym for use in the CJK case. As such, it's
> unnecessary and clutters the property design.
>
> For this level, I think I'd prefer it if implementations focused on
> values that are actually used. If use cases arise later that require
> it we can add them back in as needed.

I think you misunderstand here. 'sideways' behaves as 'sideways-right'
in 'vertical-rl' and as 'sideways-left' in 'vertical-lr'. No East Asian
script uses this behavior, they all use 'sideways-right' for things not
typeset upright: regardless of whether they are in a 'vertical-rl' or
'vertical-lr' context, they always tilt rotated text runs 90deg clockwise.

The 'sideways' keyword is intended for horizontal writing systems like
English and Arabic, because it does the right thing for them.  And
'sideways' in 'vertical-lr' is not an obscure case. It's used frequently
for captions, table headings, etc. in these languages.

I said the 'sideways-left' keyword itself is not particularly needed
except in, yes, some fairly obscure cases. But the behavior of
'sideways-left' needs to be implemented for 'sideways' to work
correctly in 'vertical-lr'.

~fantasai

Received on Friday, 12 September 2014 22:32:37 UTC