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RE: CSS3 Text - Edit suggestions

From: Paul Nelson (ATC) <paulnel@winse.microsoft.com>
Date: Tue, 20 Feb 2007 08:56:48 -0800
Message-ID: <49C257E2C13F584790B2E302E021B6F9128C981D@winse-msg-01.segroup.winse.corp.microsoft.com>
To: John Cowan <cowan@ccil.org>
CC: fantasai <fantasai.lists@inkedblade.net>, Bert Bos <bert@w3.org>, <www-style@w3.org>, WWW International <www-international@w3.org>

line-height is a critical measurement that is tied to the font metrics.
If we begin to change the concept we have problems with the core of the
layout system. Vertical text is simply an escapement rotation of
horizontal text. Glyphs in a font are always displayed in a cartesian
format. The glphys always have the 0,0 on the left side of the
horizontal baseline...even if the font is Arabic. The fact that East
Asian glyphs are rotated 90 counter-clockwise does not change the
coordinate system inside of the font file. Mongolian glyphs always
appear like they are written on their side (left-to-right) in a font

If that is what you mean that they are biased towards horizontal, then
that is a fact that brings stability to this entire world of whacking
polyglot text. :-)


-----Original Message-----
From: John Cowan [mailto:cowan@ccil.org] 
Sent: Wednesday, February 21, 2007 12:49 AM
To: Paul Nelson (ATC)
Cc: John Cowan; fantasai; Bert Bos; www-style@w3.org; WWW International
Subject: Re: CSS3 Text - Edit suggestions

Paul Nelson (ATC) scripsit:

> I have seen cases of ancient books where the Arabic baseline was
> 180 degrees so the Arabic text hung from top of the page to the

Doubtless that is what I was thinking of.  My bad.  Of course,
horizontal scripts aren't like this: a horizontal script can validly
run from top to bottom or from bottom to top (to the annoyance
of people who interfile English and German books, for example).

> In fact, line-height is a concept of ascender + descender + leading.
> Regardless of the escapement or glyph orientation of the line the
> ascender is from the baseline to the ascent and from the baseline to
> descent. 

My point is simply that the terms "height", "ascender", and "descender"
are biased towards horizontal layout; they suggest that the characters
displayed in a vertical orientation.  I don't think anything can or
should be done about this.

In politics, obedience and support      John Cowan <cowan@ccil.org>
are the same thing.  --Hannah Arendt    http://www.ccil.org/~cowan
Received on Tuesday, 20 February 2007 16:56:18 UTC

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