CSS3 Text: Text Decoration

umm... underline, overline, and line-through don't
seem to be defined anywhere. That might be a problem.
Certainly their positions--other than for underline--
are not specified anywhere.

Also, there doesn't seem to be a good way to underline
chemical formulas. (An underline would cut through the
subscripts.)

  | If they are specified for (or affects) an inline-level
  | element, it affects all boxes generated by the element.
  | If an element is empty or is a replaced element (e.g.,
  | the IMG element in XHTML), user agents must ignore
  | these properties. Text content also excludes white
  | space characters that are collapsed during the white
  | space processing.

Since text-decoration seems not to affect those descendant
boxes that are empty or replaced, it must be possible to
ignore it based on other computed data. *Please* assign
some syntax for ignoring ancestors' text decoration in CSS3.
It's been requested before, and it would be very useful,
particularly for underlining H<sub>2</sub>O and other
math/science formulae.
   sub {
     text-decoration: ~underline;
   }
or somesuch.

If empty and replaced descendant boxes really /don't/
break the text-decoration line, then that needs to be
made clear. (But I still think there should be a way
to get rid of ancestors' text decoration.)

On a grammar note:
   (affects) should be (affect)

   In "If they are specified for a block-level element, it
   affects", the pronouns don't match.

Style:
   "Text content also excludes white space..."
   The 'also' comes out of nowhere; "text content" is not
   previously mentioned in this section. I recommend
   removing the word.
   Might consider putting that sentence in parentheses.

   The link to CSS2's "ignore" goes to a section on parsing,
   which really isn't appropriate for such computations.

   "All these text decoration properties..."
   Take out either "All" or "All these".


Averaging
---------

   Is averaging done per line, per element, or per block?

   Although averaging underline positions is "based on the
   children text size and baselines", vertical-align doesn't
   seem to affect it. That should be explicit. Also, does
   the size or baseline (before vertical-alignment) of the
   superscript affect averaging? (Is that what the note is
   trying to address?)

   BTW, that should be "children's text size and baselines".
                                ^^

Underline Position
------------------

   Value definitions should probably reference CSS3 Line.

   It would be very helpful if (below) and (above) were given
   in parentheses after the "after"s and "before"s. I keep
   thinking |before and after| rather than ^before and _after--
   even when I imagine vertical text--so it gets quite confusing.

   Whose EM box is all this referring to?
   If I have an overline on a sentence, and one word in the
   sentence has a font twice as big as the rest of the sentence,
   will the line go through the glyph or above it?

   If I have underlined text, both ideographic and alphabetic,
   which baseline gets used for after-baseline?

   I suggest renaming "after-baseline" to "baseline", for
   simplicity.

auto-pos
--------

   | In vertical inline progression, if the language is set to
   | Japanese, the underline if set will appear before the text
   | edge (EM box edge).

   ... I was just wondering if this is specific to the Japanese
   language rather than East Asian ideographic in general. :)

Long thread on text-decoration, if you're interested: (1st post)
http://lists.w3.org/Archives/Public/www-style/2000Mar/0105.html

~fantasai

Received on Thursday, 19 December 2002 03:58:31 UTC