At 05:10 4/15/2002, Lars Marius Garshol wrote:
>I've run into a problem where I need to know what characters don't
>have a specified baseline in a font. It seems that when Latin and Han
>character appear in the same font the font has a baseline, but it only
>applies to the Latin characters. The Han characters all have a
>baseline through their middle, apparently.
>
>The question is, what classes of characters behave like the Han
>characters? Are Hangul the same way? Kana? Yi? Any other characters?
This is a difficult question for which to provide a definitive answer. The
approach taken will vary from font to font, and will depend on both the
technical demands of the font format and on the intent of the developer.
For example, citing your later example of Indic scripts, I have yet to see
a font that sets the nominal baseline to the head stroke of characters in a
script like Devanagari, despite having seen this as a recommendation. I
don't know where this recommendation came from. It is certainly possible,
in the context of a digital font to set the baseline at the head stroke
height, but do you gain anything by doing so? I don't think so, and all you
achieve is Indic type that does not align vertically with other scripts.
Since the intent of most font developers is to provide versatile and useful
fonts, seriously hampering multilingual text setting in this manner seems a
bad idea.
The OpenType font format includes a 'base' table that can contain
script-specific baseline adjustment values. Such information could be used
by an application to optically align different scripts in the same font or
between fonts, regardless of their nominal baselines. This would allow font
developers to set the nominal baseline of an Indic font to the head stroke
height without worrying about the effect on multilingual settings, but I'm
still not clear what the Indic type gains from this approach. Support for
'base' table adjustments has not been implemented in any software of which
I am aware, but I believe Microsoft have plans to support it, and also to
develop a visual tool for adding 'base' table information to fonts.
John Hudson
Tiro Typeworks www.tiro.com
Vancouver, BC tiro@tiro.com
A dinner invitation, once accepted, is a sacred obligation.
If you die before the dinner takes place, your executor
must attend.
- Ward McAllister
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