Re: [css-writing-modes] Propose writing-mode: sideways-left

Jonathan Kew wrote:

> I don't agree that the proposal being considered here would increase
> authoring model complexity. If anything, I'd say it offers authors a
> cleaner and more understandable model. We'd have three modes
> (horizontal-tb, sideways-lr and sideways-rl) that all lay out text in
> the same way, but with a ±90° rotation in the sideways-* cases. In all
> three cases, the text is laid out according to the conventions of
> horizontal writing, even if it is then rotated in its entirety. No
> question of glyph orientation within the line ever arises in these
> modes.

I guess it boils down to this for me: for 99% of the users of the
'writing-mode' property, namely authors in Japan, Taiwan and Hong Kong
laying out vertical text runs, the sideways-* values will be a confusing
addition. As you describe you're basically mixing in the ability to
rotate horizontal text layout into a property used to choose between
horizontal and vertical layout systems. To do so won't be the end of the
world but it will introduce unfortunate confusion.

I do understand that this simplifies implementations details. You no
longer need to be concerned about mixtures of sideways-left and
sideways-right text in the same block. I just am concerned that we're
adding values to a commonly-used property, 'writing-mode', for the sake
of simplifying a less commonly used property, 'text-orientation'.

Florian Rivoal wrote:

> > I'd guess that for CJK authors, the use of text-orientation:sideways
> > will be virtually non-existent, as that simply isn't how these
> > languages are written vertically.
>
> text-orientation:sideways should be used by CJK authors to market small
piece of foreign language embedded in a their text.
>
> article {
>   writing-mode: vertical-rl;
>   text-orientation: upright;
> }
>
> article q:lang(en) {
>   text-orientation: sideways.
> }

I think both of these statements are off the mark. The initial value of
'text-orientation' is 'mixed', such that the contents of vertical text
elements will be laid out based on UTR-50 default orientation data. So
the natural default for vertical text is simply:

article {
  writing-mode: vertical-rl;
  /* default text-orientation: kana/kanji are upright, latin is sideways */
}

No need to use text-orientation or extra markup for small runs of Latin
text.

The text-orientation property provides an override to the default
orientation in cases where a character might be used in either
orientation, such as a symbol:

  <latin> <symbol> <latin>  ==> sideways
  <kanji> <symbol> <kanji>  ==> upright

So its use would be infrequent but not "virtually non-existent".

I really think we need more input from other implementers, specifically
Apple, Microsoft and any other EPUB vendors who support already support
vertical text. Murakami-san seems content with the proposed change.
Other implementers, opinions?

Regards,

John Daggett
Mozilla Japan

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