Re: CSS1 vertical-align property.

Frank Boumphrey (bckman@ix.netcom.com)
Wed, 26 Nov 1997 19:29:09 -0800


From: "Frank Boumphrey" <bckman@ix.netcom.com>
To: <www-html@w3.org>, <www-style@w3.org>
Date: Wed, 26 Nov 1997 19:29:09 -0800
Message-ID: <01bcfae4$9f834900$94f15ecf@uspppBckman>
Subject: Re: CSS1 vertical-align property.

Has any one any comments on the following, I think the definition of
text-top and text-bottom is clear, althoughI agree with the writers
comments, but I was not sure myself on the definition of sub and super. My
printing Guru told me it could mean either in the printing business.:-

Subject:- CSS1 specification property vertical align.

The W3C Recommendation 17Dec 1996 REC-CSS1-961217 allows the following
values for the element vertical-align:-

 baseline|sub|super|top|text-top|middle|bottom|text-bottom|<percentage>

 The percentage, baseline, & middle definitions are quite clear. Top &
bottom should probably never be used as they have the capacity for forming
an eternal loop.

 The other definitions are not clear and there is some dispute as to their
exact meaning.

 By way of clarification a font character (in a font such as "Times New
Roman")  is usually devided into 5 parts. The top (the FONT-TOP)  that
seperates it from the line of text above, then 20% of the font height down
comes the top of the text proper (the TEXT-TOP) that part that Upper-case
characters rise to (20% down from the top), the top of the textline (the
TEXTLINE-TOP,40% down from the FONT-TOP) where the top of a lowercase m
comes, the middle of the text line(MID-TEXT-LINE) typically the cross of the
lowercases letter x,(60% down from the FONT-TOP), the BASE-LINE 80% down
from the FONT-TOP, and the FONT-BOTTOM ocours where the reach of the lowest
tails come, the remaining 20%, to make 100%.

 Clarification on the following definitions are needed.

 Sub: does this align the TEXTLINE-TOP or the TEXT-TOP with the BASE-LINE.

 Super: does this align the BASE-LINE with the TEXTLINE-TOP or the TEXT-TOP.

 text-top: this is stated to "align the top of the element with the top of
the parent font", however if the element is another font of greater size it
gives a very ragged  appearence,  alignment with the TEXT-TOP rather than
the FONT-TOP is prefered. Incidently text top is the default in Windows
printing methods.

 text-bottom: same comments as text-top.If two fonts are used it gives an
ugly appearence.


      Frank.
-----Original Message-----
From: Chris Lilley <Chris.Lilley@sophia.inria.fr>
To: Andrew n marshall <amarshal@usc.edu>; 'www-html@w3.org'
<www-html@w3.org>; www-style@w3.org <www-style@w3.org>
Date: Tuesday, November 25, 1997 1:49 PM
Subject: Re: Support for Vector Images