[css3-values] definition of 'ch' should be clearer about "width"

This comment comes from the discussion in
https://bugzilla.mozilla.org/show_bug.cgi?id=493428 .

The definition of the 'ch' unit in
http://www.w3.org/TR/css3-values/#relative0 currently says:
  # The width of the "0" (ZERO, U+0030) glyph found in the font for
  # the font size used to render. If the "0" glyph is not found in
  # the font, the average character width may be used.

I'm not quite sure of the correct terminology here, but this
definition should probably be clearer that the "width" it's talking
about is the advance of the character (i.e., the amount of width it
adds to a string of text if it were inserted in that string,
ignoring kerning) rather than the width of the glyph bounding box
(or the maximal extents of the "ink", or whatever it's called).

-David

-- 
L. David Baron                                 http://dbaron.org/
Mozilla Corporation                       http://www.mozilla.com/

Received on Friday, 10 July 2009 16:20:52 UTC