[luatex] Querying Script and ScriptScriptPercentScaleDown math constants

[taco]

Khaled Hosny wrote:
> Is there a way to the values of ScriptPercentScaleDown and
> ScriptScriptPercentScaleDown either from tex or from lua, other than
> reading the MathConstants table directly?

Not reliably, because LuaTeX itself does not actually use
these parameters.

You can get them directly from font.fonts[] if you know
the right font id, but even then there is no guarantee
that they contain the right values as no checks are done
(and for example, in context mkiv, they are scaled
to the font's load size, just like the other math parameters).

Anyway, here is an iterative loop to demonstrate what
is available:

for i=1,100 do
   if font.fonts[i]
      and font.fonts[i].MathConstants
      and font.fonts[i].MathConstants.ScriptPercentScaleDown then
     texio.write_nl('Font '..i..':')
 
texio.write_nl('Script='..font.fonts[i].MathConstants.ScriptPercentScaleDown)
 
texio.write_nl('ScriptScript='..font.fonts[i].MathConstants.ScriptScriptPercentScaleDown)
   end
end;

Best wishes,
Taco


> Regards,
>  Khaled
>