Hans Hagen
these are font properties and using a consistent opentype math versus a bunch of loosely related type one fonts makes a difference
But shouldn't TeXGyrePagellaMath qualify?
I've added:
\starttext
$\displaystyle 1+{2g\over3}+{2\over3}$ \blank
\setupmathfractions[topdistance=0pt]
$\displaystyle 1+{2g\over3}+{2\over3}$ \blank
\setupmathfractions[bottomdistance=0pt]
$\displaystyle 1+{2g\over3}+{2\over3}$ \blank
\setupmathfractions[topdistance=0pt,bottomdistance=0pt]
$\displaystyle 1+{2g\over3}+{2\over3}$ \blank
\stoptext
Thanks, Hans. That is very useful. I also recompiled my textbook draft using the latest beta (2014.05.17), and it works very well. I tried the topdistance and bottomdistance and they are mostly working. To my eye, with topdistance=6pt, the {1\over2} looks very good again. However, the settings don't seem to affect fractions inside square roots. Here's an example (the 20pt setting is to exaggerate the possible effect), using 2014.05.17 beta. \starttext \placeformula\startformula \dfrac{ag}{bcd}\quad{ag\over bcd} \stopformula \placeformula\startformula \sqrt{1\over \dfrac{a}{bcd}} \quad \sqrt{\dfrac{1}{\dfrac{a}{bcd}}} \stopformula \setupmathfractions [topdistance=20pt] \placeformula\startformula \dfrac{ag}{bcd}\quad{ag\over bcd} \stopformula \placeformula\startformula \sqrt{1\over \dfrac{a}{bcd}} \quad \sqrt{\dfrac{1}{\dfrac{a}{bcd}}} \stopformula \stoptext