[lltx] $n\choose k$-issue with OpenType math fonts

[Philipp Stephani]

Am 05.03.2011 02:13, schrieb Philipp Stephani:
> Or maybe LuaTeX. Unfortunately I have absolutely no time to investigate
> right now, only one observation: C has
> FractionNumeratorDisplayStyleShiftUp = StackTopDisplayStyleShiftUp, but
> the upper part of the binomial is positioned higher than the numerator
> in display style. This may be because the StackDisplayStyleGapMin is too
> large (?).

No, the parameters are fine and I think the only difference is the size
of the delimiters, which is caused by LuaOTFLoad setting the
FractionDelimiterSize parameters which don't really exist in the fonts
(they are LuaTeX-only additions); changing line 116 of luaotfload.lua to
            mc.FractionDelimiterDisplayStyleSize = 1.7 * size
yields much better results. However, that is a font-specific design
issue, and I wonder whether LuaTeX should really use those parameters if
the font doesn't have them.