[luatex] some bits of opentype math testing

[Ulrik Vieth]

Hi folks,

I've been doing a bit of OpenType math testing once again with
LuaLaTeX, XeLaTeX, and ConTeXt MkIV, all based on the final
(currently frozen) TL2010 pretest version.

Here are a my observations of rendering and font loading issues.

I expect that none of them are serious show stoppers for the
TL2010 release, but they might lead to subsequent online updates
after the TL release.

Regards, Ulrik


Rendering issues (ConTeXt):

- \hbar in math formulas (e.g. quantum mechanics) is incorrectly
   mapped to U+0127 (text upright) instead of U+210F (math italic).

   For Asana-Math you get a missing (disappearing) character.
   For Cambria and XITS-Math you get an incorrect character shape.

   It works OK if you use \hslash, or if you \let\hbar=\hslash.
   (Except for Neo-Euler which doesn't have the glyph.)

- For prime (U+0232), ConTeXt does not use the font substitution
   prime -> prime.ssty, so the raised prime appears too small.

   This problem was recently fixed in luaotfload for LuaLaTeX
   and the fix probably needs to be ported back to ConTeXt now.
   (Or maybe ConTeXt needs to be updated again in TL2010.)


Rendering issues (LuaLaTeX and XeLaTeX):

- \hbar in math formulas is constructed as a macro using
   an 'h' from the current math font and a bar from cmr10 (!).

   It works OK if you use \hslash, or if you \let\hbar=\hslash.
   (Except for Neo-Euler which doesn't have the glyph.)


Rendering issues (LuaLaTeX):

- For Asana-Math and Cambria-Math displaystyle integrals appear
   too small in LuaLaTeX, whereas they are correct in ConTeXt.
   For Neo-Euler and XITS-Math displaystyle integrals appear
   in the same size in LuaLaTeX and ConTeXt (and also in XeLaTeX).

   Does this depend on how many sizes of integrals are available
   or does it depend on the OT parameter DisplayOperatorMinHeight?

Rendering issues (ConTeXt and LuaLaTeX):

- For Asana-Math a straight version of displaystyle parentheses
   (as in the extensible version) is used in LuaLaTeX and ConTeXt,
   whereas a round version is used in XeTeX.

   Does this depend on how many sizes of integrals are available
   or does it depend on the OT parameter DisplayOperatorMinHeight?


Font loading issues (ConTeXt and LuaLaTeX):

- If cambria.ttc is installed in texmf-local/fonts/opentype,
   luaotfload fails to find the font "Cambria" or "Cambria Math".
   If cambria.ttc is installed in texmf-local/fonts/truetype,
   luaotfload correctly resolves the font name.

   With ConTeXt it doesn't matter where cambria.ttc was installed.
   It was correctly found it both locations.

- If euler.otf is installed in texmf-local/fonts/opentype,
   Context fails to find the font, whereas luaotfload does find it.

   Does this depend on specific names in the defintion of typescript
   pagella-euler in type-otf.mkiv?


Font loading issues (XeLaTeX):

- For Asana-Math, you get a messed up PDF file, if the font
   is loaded with \setmathfont{Asana Math}, because there are
   both OTF and TTF versions of the font in the texmf tree.
   If the font is loaded with \setmathfont{Asana-Math.otf}
   (specific type), there are no problems.

   With LuaLaTeX, using the unspecific type works fine.


Font issues:

- It would be nice if Neo-Euler would have a \hslash glpyh (U+210F).
- It would be nice if Neo-Euler would have a bold \nabla (U+1D6C1).
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