I read in a book “Book Typography: A Designer’s Manual” that fractions near old style figures should be minimized if they seems to large.
So I think: isn’t it possible with OT features?
So I could make an additional set of numerators and denominators - one.numr.osf etc. and fraction.osf that would be a little bit smaller to harmonize with lowercase glyphs.
Than some changes to the frac feature should be made. And my question is what changes?
It turned out to be very simple. I just added old style glyphs (numerators, denominators, fraction.osf and slash.osf) and hit refresh button on onum feature. Than I made some changes to the frac feature:
lookup FRAC {
sub [slash slash.osf] by [fraction fraction.osf] ;
} FRAC;
lookup HOCH {
sub [zero one two three four five six seven eight nine] by [zero.numr one.numr two.numr three.numr four.numr five.numr six.numr seven.numr eight.numr nine.numr];
} HOCH;
lookup TIEF {
sub [fraction fraction.osf] [zero.numr one.numr two.numr three.numr four.numr five.numr six.numr seven.numr eight.numr nine.numr]’ by [zero.dnom one.dnom two.dnom three.dnom four.dnom five.dnom six.dnom seven.dnom eight.dnom nine.dnom];
sub [zero.dnom one.dnom two.dnom three.dnom four.dnom five.dnom six.dnom seven.dnom eight.dnom nine.dnom] [zero.numr one.numr two.numr three.numr four.numr five.numr six.numr seven.numr eight.numr nine.numr]’ by [zero.dnom one.dnom two.dnom three.dnom four.dnom five.dnom six.dnom seven.dnom eight.dnom nine.dnom];
} TIEF;