[subset] Fix renumbering of (Chain)ContextFormat2
Jonathan says: "It was broken."
diff --git a/Lib/fontTools/subset.py b/Lib/fontTools/subset.py
index 8bfe705..93af91a 100644
--- a/Lib/fontTools/subset.py
+++ b/Lib/fontTools/subset.py
@@ -557,6 +557,7 @@
self.Intersect = lambda glyphs, c, r: c.intersect_class(glyphs, r)
self.ClassDef = 'InputClassDef' if Chain else 'ClassDef'
+ self.ClassDefIndex = 1 if Chain else 0
self.Input = 'Input' if Chain else 'Class'
if self.Format not in [1, 2, 3]:
@@ -676,12 +677,21 @@
elif self.Format == 2:
if not self.Coverage.subset(s.glyphs):
return False
- indices = getattr(self, c.ClassDef).subset(self.Coverage.glyphs,
- remap=False)
- rss = getattr(self, c.RuleSet)
- rss = [rss[i] for i in indices]
ContextData = c.ContextData(self)
klass_maps = [x.subset(s.glyphs, remap=True) for x in ContextData]
+
+ # Keep rulesets for class numbers that survived.
+ indices = klass_maps[c.ClassDefIndex]
+ rss = getattr(self, c.RuleSet)
+ rssCount = getattr(self, c.RuleSetCount)
+ rss = [rss[i] for i in indices if i < rssCount]
+ del rssCount
+ # Delete, but not renumber, unreachable rulesets.
+ indices = getattr(self, c.ClassDef).intersect(self.Coverage.glyphs)
+ rss = [rss if i in indices else None for i,rss in enumerate(rss)]
+ while rss and rss[-1] == None:
+ del rss[-1]
+
for rs in rss:
if not rs: continue
ss = getattr(rs, c.Rule)
@@ -695,10 +705,6 @@
for r in ss:
c.SetRuleData(r, [[klass_map.index(k) for k in klist]
for klass_map,klist in zip(klass_maps, c.RuleData(r))])
- # Prune empty subrulesets
- rss = [rs for rs in rss if rs and getattr(rs, c.Rule)]
- setattr(self, c.RuleSet, rss)
- setattr(self, c.RuleSetCount, len(rss))
return bool(rss)
elif self.Format == 3:
return all(x.subset(s.glyphs) for x in c.RuleData(self))