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Refactor subtable/lookup record building code

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It's a bit gross, but I'm blaming OpenType for that. I'm doing this now because otherwise it would be even more repetitive once we start adding format 1 Rule and Ruleset subtables.
This commit is contained in:
Simon Cozens 2020-07-07 17:12:09 +01:00
parent 6d4c5fe31c
commit 8c3dfc4e33
1 changed files with 44 additions and 34 deletions
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78
Lib/fontTools/otlLib/builder.py
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@ -358,16 +358,56 @@ class ChainContextualBuilder(LookupBuilder):
raise OpenTypeLibError('Missing index of the specified '
f'lookup, might be a {other} lookup',
self.location)
rec = self.newLookupRecord_()
rec = self.newLookupRecord_(st)
rec.SequenceIndex = sequenceIndex
rec.LookupListIndex = l.lookup_index
self.addLookupRecordToSubtable_(st, rec)
return st
def add_subtable_break(self, location):
self.rules.append((self.SUBTABLE_BREAK_, self.SUBTABLE_BREAK_,
self.SUBTABLE_BREAK_, [self.SUBTABLE_BREAK_]))
def newSubtable_(self, chaining=True):
subtablename = f"Context{self.subtable_type}"
if chaining:
subtablename = "Chain"+subtablename
st = getattr(ot,subtablename)() # ot.ChainContextPos()/ot.ChainSubst()/etc.
setattr(st, f"{self.subtable_type}Count", 0)
setattr(st, f"{self.subtable_type}LookupRecord", [])
return st
def attachSubtableWithCount_(self, st,
subtable_name, count_name,
existing=None,
index=None, chaining=False):
if chaining:
subtable_name = "Chain"+subtable_name
count_name = "Chain"+count_name
if not hasattr(st, count_name):
setattr(st, count_name, 0)
setattr(st, subtable_name, [])
if existing:
new_subtable = existing
else:
# Create a new, empty subtable from otTables
new_subtable = getattr(ot, subtable_name)()
setattr(st, count_name, getattr(st, count_name) + 1)
if index:
getattr(st, subtable_name).insert(index, new_subtable)
else:
getattr(st, subtable_name).append(new_subtable)
return new_subtable
def newLookupRecord_(self, st):
return self.attachSubtableWithCount_(st,
f"{self.subtable_type}LookupRecord",
f"{self.subtable_type}Count",
chaining=False) # Oddly, it isn't ChainSubstLookupRecord
class ChainContextPosBuilder(ChainContextualBuilder):
"""Builds a Chained Contextual Positioning (GPOS8) lookup.
@ -398,22 +438,7 @@ class ChainContextPosBuilder(ChainContextualBuilder):
def __init__(self, font, location):
LookupBuilder.__init__(self, font, location, 'GPOS', 8)
self.rules = [] # (prefix, input, suffix, lookups)
def newSubtable_(self, chaining=True):
if chaining:
st = ot.ChainContextPos()
else:
st = ot.ContextPos()
st.PosCount = 0
st.PosLookupRecord = []
return st
def newLookupRecord_(self):
return ot.PosLookupRecord()
def addLookupRecordToSubtable_(self, st, rec):
st.PosCount += 1
st.PosLookupRecord.append(rec)
self.subtable_type = "Pos"
def find_chainable_single_pos(self, lookups, glyphs, value):
"""Helper for add_single_pos_chained_()"""
@ -456,22 +481,7 @@ class ChainContextSubstBuilder(ChainContextualBuilder):
def __init__(self, font, location):
LookupBuilder.__init__(self, font, location, 'GSUB', 6)
self.rules = [] # (prefix, input, suffix, lookups)
def newSubtable_(self, chaining=True):
if chaining:
st = ot.ChainContextSubst()
else:
st = ot.ContextSubst()
st.SubstCount = 0
st.SubstLookupRecord = []
return st
def newLookupRecord_(self):
return ot.SubstLookupRecord()
def addLookupRecordToSubtable_(self, st, rec):
st.SubstCount += 1
st.SubstLookupRecord.append(rec)
self.subtable_type = "Subst"
def getAlternateGlyphs(self):
result = {}