[ot-font] Return char-not-found if mapped to gid 0
authorBehdad Esfahbod <behdad@behdad.org>
Sat, 25 Aug 2018 15:44:18 +0000 (08:44 -0700)
committerBehdad Esfahbod <behdad@behdad.org>
Sat, 25 Aug 2018 15:44:18 +0000 (08:44 -0700)
commit531051b8b904cf4eb6a50bacebc11c2d85e40140
tree36d7f3f025fbec1d30c00b984b8885820a0490db
parentaadb2a9188f143126392c0b0f139326dcf7f9c8d
[ot-font] Return char-not-found if mapped to gid 0

OpenType cmap table can use gid=0 to mean "not covered" to produce
more optimized cmap subtables.  Return false from get_nominal_glyph()
for those.  hb-ft already does this.
src/hb-ot-cmap-table.hh