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Re: Math Arrows and Harpoons


Hello there,

I have deleted the CC's to Hans and Barbara, since I gathered that you
both are on the math-font-discuss (and it's a bit confusing that I get
every message twice, I guess this holds for other people too).

Now then, I agree with Hans in the discussion of Unicode policy rules
(as I think we all do), but I still have to keep raising these
questions. One important reason why we want full characters is MathML:
It's convenient to have as many pre-built characters as possible in
Unicode. This simplifies designing rendering engines for MathML and
consequently the chances of those engines appearing will increase.

I am forced (this is what being hired is all about :-) to include at
least all characters that are in present Unicode + those that are in
the STIX submission. Other than that, in all truth I don't care at all
whether chars are or are not part of Unicode or AFII or whatever
standard and whether or not the basic premisses of these standards are
valid.

The following logic follows: if Barbara says her arrows need to have
angled heads, they will have angled heads. If Hans says he needs flat
heads, I will add glyphs with flat heads. In general, at this moment I
need to know:

1) if the renderings for the Unicode/STIX tables are correct. This is
   of major importance for the validity of the resulting fontset.

2) which of the missing symmetry cases will be adopted into STIX
   submission (since these will also need a glyph slot and I'd rather
   have them filled beforehand). This is important because it will
   save me a lot of work in the future.

3) for the two groups above: what the canonical names of the glyphs
   are supposed to be. This is important because these names will
   ultimately appear in the font file (at least for the Type 1
   version)

4) what other full characters are needed (this list probably includes
   most of the symmetry cases that will not make it into the STIX
   submission, but there may be others as well, like the \leadsto
   style arrows). This is a bonus. I am trying to do a decent job
   for as much software as possible. If e.g. Mathematica needs
   a wide vector accent, then I will add one. 

There is, however, a limit to the amount of full symmetry cases that
can be included. As I said before: I don't want to spend the next five
years on this subject. And I doubt anyone would be happy with three
different fonts that all contain arrows. Also, there is little point
in adding glyphs that will never ever be used.

I think the absolute upper limit on pre-built arrows is 222 (not
counting harpoons). I will probably add a full arrow construction kit
later, but it is more important now to have all needed full characters
and their names decided upon.

Greetings, Taco