Why incomplete subscript/superscript alphabet ?
Jukka K. Korpela
jkorpela at cs.tut.fi
Fri Sep 30 10:54:27 CDT 2016
30.9.2016, 18:19, Philippe Verdy wrote:
> Note also that many tools generating documentation from source code
> allow you to insert HTML comments, so you could as well use <sub></sub>,
Yes, but there’s a serious typographic pitfall with this, as well as
with using e.g. subscript or superscript formatting in a word processor.
The problem is that the rendering is almost always simplistic: letters
(or other characters) of the current font are used in reduced size and
in lowered or raised position. The result is that the glyphs have
reduced stroke width too, and the position change very often causes line
spacing to be uneven.
The typographically correct implementation of such formatting or markup
would use subscript or superscript glyphs from the font, designed by the
font creator to match the style of the font. This is more difficult than
the simplistic approach, and of course it is possible only when using a
font that contains such glyphs.
Using HTML, for example, the way to achieve that at present would be to
use markup like <span class="sub">...</span> (to avoid the problems
caused by the default formatting of <sub> and <sup>) and to use a CSS
style sheet that sets font-family suitably and uses OpenType font
feature settings to select subscript or superscript glyphs. In practice,
you would need to use @font-face to embed a suitable OpenType font. So
it’s doable, but not trivial like just slapping <sub> and </sub> around
A practical conclusion is that if you need only e.g. 2 and 3 as
superscripts (a rather general situation in general texts, where you
just need m² or m³), it is much simpler to use the relevant Unicode
superscript characters (instead of e.g. m<sup>2</sup>). This means using
typographer-designer superscript glyphs in a simple and reliable way.
More information about the Unicode