Re: [css-writing-modes-3] line-under and line-over of text with 'text-orientation: upright'

Hi Gérard,

On Tue, May 12, 2015 at 11:32 AM, Gérard Talbot <www-style@gtalbot.org> wrote:
> Elika, Koji,
>
> Where are line-under and line-over sides when text has its
> 'text-orientation' set to 'upright'?
>
> §7.5 Line-Relative Mappings
> http://dev.w3.org/csswg/css-writing-modes-3/#line-mappings
>
> "
> For the text-decoration property, the underline is drawn on the under side
> of the text; the overline is drawn on the over side of the text.
> "
>
> does *not* provide such information ... which I think it should.
>
> §6.3 Line-relative Directions
> http://dev.w3.org/csswg/css-writing-modes-3/#under
> http://dev.w3.org/csswg/css-writing-modes-3/#over
> does *not* provide such information either.

What probably confused you is that when upright, the baseline does not
change, and you need to assume that the baseline is drawn vertically
on the upright glyph. See these pictures[1][2].

If you think that way, rather than the baseline is horizontal but
characters rotated to upright, I hope it's clear that line-under and
line-over are the same as sideways-right.

> After careful reading,
> §6.4 Abstract-to-Physical Mappings
> http://dev.w3.org/csswg/css-writing-modes-3/#logical-to-physical
> provides such info but, even there, you have to understand that "*right"
> means upright too.

Hm, yeah, it has title attribute if you hover. Interesting...

> So, I suggest/propose to add/insert a sentence in section 7.5 indicating
> that line-under (line-over) for text with 'text-orientation' set to
> 'upright' is at the physical lefthand (righthand) side of text.

Since it's not about "mappings" but how the baseline of upright is
defined, I added a note in 6.3. Hope this makes it clear.

[1] http://partners.adobe.com/public/developer/opentype/index_table_formats2.html
[2] http://www.freetype.org/freetype2/docs/tutorial/step2.html

/koji

Received on Sunday, 17 May 2015 16:14:46 UTC