> What is going on?
OH MY... W... T... H...
% plain XeTeX
\def\tmp#1{\textfont#1\ten \scriptfont#1\seven
\scriptscriptfont#1\five}
\def\showfontdimen#1{\immediate\write-1{#1:
\the\fontdimen#1\textfont2}}
\def\test#1{\font\ten="[#1.otf]:script=math" at 10pt
\font\seven="[#1.otf]:script=math;+ssty=0" at 7pt
\font\five="[#1.otf]:script=math;+ssty=1" at 5pt
\tmp0\tmp1\tmp2\tmp3%
\noindent#1\par
\immediate\write-1{--- #1 ---}%
\showfontdimen{5}%
\showfontdimen{16}%
\showfontdimen{48}%
\showfontdimen{54}%
\showfontdimen{57}%
\showfontdimen{61}%
\setbox0\hbox{$\displaystyle E$}%
\setbox2\hbox{$\displaystyle\kern-\nulldelimiterspace
\Uradical255 0 {E}$}%
\immediate\write-1{displaystyle diff:
\the\dimexpr\ht2-\ht0}%
\showfontdimen{60}%
}
\test{texgyrebonum-math}
\test{texgyredejavu-math}
\test{texgyrepagella-math}
\test{texgyreschola-math}
\test{texgyretermes-math}
\test{STIXTwoMath-Regular}
\bye
yields
--- texgyrebonum-math ---
5: 4.85pt
16: 4.7pt
48: 0.72pt
54: 0.72pt
57: 0.72pt
61: 0.72pt
displaystyle diff: 1.89499pt
60: 1.05pt
--- texgyredejavu-math ---
5: 5.19pt
16: 5.39pt
48: 0.64pt
54: 0.52pt
57: 0.52pt
61: 0.52pt
displaystyle diff: 1.98749pt
60: 0.96pt
--- texgyrepagella-math ---
5: 4.69pt
16: 5.0pt
48: 0.6pt
54: 0.6pt
57: 0.6pt
61: 0.6pt
displaystyle diff: 1.85pt
60: 1.2pt
--- texgyreschola-math ---
5: 4.66pt
16: 4.86pt
48: 0.7pt
54: 0.7pt
57: 0.7pt
61: 0.7pt
displaystyle diff: 1.915pt
60: 1.0pt
--- texgyretermes-math ---
5: 4.5pt
16: 4.7pt
48: 0.52pt
54: 0.52pt
57: 0.52pt
61: 0.52pt
displaystyle diff: 1.69499pt
60: 1.4pt
--- STIXTwoMath-Regular ---
5: 4.73pt
16: 4.8pt
48: 0.68pt
54: 0.68pt
57: 0.68pt
61: 0.68pt
displaystyle diff: 1.87999pt
60: 1.7pt
meaning that when XeTeX constructs radicals in display style, it NEVER
uses \fontdimen60 whatsoever, despite the fact it is LITERALLY Radical
Display Style Vertical Gap. Instead, XeTeX takes a quarter of
\fontdimen16 (not x-height BTW) plus \fontdimen48 (fraction rule
thickness, not radical rule thickness BTW), as the vertical gap for
radicals in display style. WHAT???
If I remember correctly, XeTeX makes the same mistakes when
constructing Overbar and Underbar, which is somewhat documented in the
actuarialangle package manual (pp. 9--10).
I'm in shock...
Rex
