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Merge pull request #2026 from simoncozens/named-tuple-contextuals

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Use namedtuple to represent contextual rules
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Simon Cozens 2020-07-22 15:35:59 +01:00 committed by GitHub
commit d6ba64fcb6
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 55 additions and 38 deletions
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23
Lib/fontTools/feaLib/builder.py
View File

@ -23,6 +23,7 @@ from fontTools.otlLib.builder import (
ClassPairPosSubtableBuilder,
PairPosBuilder,
SinglePosBuilder,
ChainContextualRule,
)
from fontTools.otlLib.error import OpenTypeLibError
from collections import defaultdict
@ -948,13 +949,17 @@ class Builder(object):
def add_chain_context_pos(self, location, prefix, glyphs, suffix, lookups):
lookup = self.get_lookup_(location, ChainContextPosBuilder)
lookup.rules.append(
(prefix, glyphs, suffix, self.find_lookup_builders_(lookups))
ChainContextualRule(
prefix, glyphs, suffix, self.find_lookup_builders_(lookups)
)
)
def add_chain_context_subst(self, location, prefix, glyphs, suffix, lookups):
lookup = self.get_lookup_(location, ChainContextSubstBuilder)
lookup.rules.append(
(prefix, glyphs, suffix, self.find_lookup_builders_(lookups))
ChainContextualRule(
prefix, glyphs, suffix, self.find_lookup_builders_(lookups)
)
)
def add_alternate_subst(self, location, prefix, glyph, suffix, replacement):
@ -965,7 +970,7 @@ class Builder(object):
if prefix or suffix:
chain = self.get_lookup_(location, ChainContextSubstBuilder)
lookup = self.get_chained_lookup_(location, AlternateSubstBuilder)
chain.rules.append((prefix, [{glyph}], suffix, [lookup]))
chain.rules.append(ChainContextualRule(prefix, [{glyph}], suffix, [lookup]))
else:
lookup = self.get_lookup_(location, AlternateSubstBuilder)
if glyph in lookup.alternates:
@ -1024,7 +1029,7 @@ class Builder(object):
if prefix or suffix or forceChain:
chain = self.get_lookup_(location, ChainContextSubstBuilder)
lookup = self.get_chained_lookup_(location, LigatureSubstBuilder)
chain.rules.append((prefix, glyphs, suffix, [lookup]))
chain.rules.append(ChainContextualRule(prefix, glyphs, suffix, [lookup]))
else:
lookup = self.get_lookup_(location, LigatureSubstBuilder)
@ -1043,7 +1048,7 @@ class Builder(object):
chain = self.get_lookup_(location, ChainContextSubstBuilder)
sub = self.get_chained_lookup_(location, MultipleSubstBuilder)
sub.mapping[glyph] = replacements
chain.rules.append((prefix, [{glyph}], suffix, [sub]))
chain.rules.append(ChainContextualRule(prefix, [{glyph}], suffix, [sub]))
return
lookup = self.get_lookup_(location, MultipleSubstBuilder)
if glyph in lookup.mapping:
@ -1100,7 +1105,9 @@ class Builder(object):
if sub is None:
sub = self.get_chained_lookup_(location, SingleSubstBuilder)
sub.mapping.update(mapping)
chain.rules.append((prefix, [mapping.keys()], suffix, [sub]))
chain.rules.append(
ChainContextualRule(prefix, [list(mapping.keys())], suffix, [sub])
)
def add_cursive_pos(self, location, glyphclass, entryAnchor, exitAnchor):
lookup = self.get_lookup_(location, CursivePosBuilder)
@ -1206,7 +1213,9 @@ class Builder(object):
sub.add_pos(location, glyph, otValue)
subs.append(sub)
assert len(pos) == len(subs), (pos, subs)
chain.rules.append((prefix, [g for g, v in pos], suffix, subs))
chain.rules.append(
ChainContextualRule(prefix, [g for g, v in pos], suffix, subs)
)
def setGlyphClass_(self, location, glyph, glyphClass):
oldClass, oldLocation = self.glyphClassDefs_.get(glyph, (None, None))

53
Lib/fontTools/otlLib/builder.py
View File

@ -257,19 +257,27 @@ class AlternateSubstBuilder(LookupBuilder):
self.alternates[(self.SUBTABLE_BREAK_, location)] = self.SUBTABLE_BREAK_
class ChainContextualRule(
namedtuple("ChainContextualRule", ["prefix", "glyphs", "suffix", "lookups"])
):
@property
def is_subtable_break(self):
return self.prefix == LookupBuilder.SUBTABLE_BREAK_
class ChainContextualRuleset:
def __init__(self):
self.rules = []
def addRule(self, prefix, glyphs, suffix, lookups):
self.rules.append((prefix, glyphs, suffix, lookups))
def addRule(self, rule):
self.rules.append(rule)
@property
def hasPrefixOrSuffix(self):
# Do we have any prefixes/suffixes? If this is False for all
# rulesets, we can express the whole lookup as GPOS5/GSUB7.
for (prefix, glyphs, suffix, lookups) in self.rules:
if len(prefix) > 0 or len(suffix) > 0:
for rule in self.rules:
if len(rule.prefix) > 0 or len(rule.suffix) > 0:
return True
return False
@ -277,8 +285,8 @@ class ChainContextualRuleset:
def hasAnyGlyphClasses(self):
# Do we use glyph classes anywhere in the rules? If this is False
# we can express this subtable as a Format 1.
for (prefix, glyphs, suffix, lookups) in self.rules:
for coverage in (prefix, glyphs, suffix):
for rule in self.rules:
for coverage in (rule.prefix, rule.glyphs, rule.suffix):
if any(len(x) > 1 for x in coverage):
return True
return False
@ -314,11 +322,11 @@ class ChainContextualBuilder(LookupBuilder):
# Return a list of ChainContextRuleset objects, taking explicit
# subtable breaks into account
ruleset = [ChainContextualRuleset()]
for (prefix, glyphs, suffix, lookups) in self.rules:
if prefix == self.SUBTABLE_BREAK_:
for rule in self.rules:
if rule.is_subtable_break:
ruleset.append(ChainContextualRuleset())
continue
ruleset[-1].addRule(prefix, glyphs, suffix, lookups)
ruleset[-1].addRule(rule)
# Squish any empty subtables
return [x for x in ruleset if len(x.rules) > 0]
@ -341,17 +349,16 @@ class ChainContextualBuilder(LookupBuilder):
return self.buildLookup_(subtables)
def buildFormat3Subtable(self, rule, chaining=True):
(prefix, glyphs, suffix, lookups) = rule
st = self.newSubtable_(chaining=chaining)
st.Format = 3
if chaining:
self.setBacktrackCoverage_(prefix, st)
self.setLookAheadCoverage_(suffix, st)
self.setInputCoverage_(glyphs, st)
self.setBacktrackCoverage_(rule.prefix, st)
self.setLookAheadCoverage_(rule.suffix, st)
self.setInputCoverage_(rule.glyphs, st)
else:
self.setCoverage_(glyphs, st)
self.setCoverage_(rule.glyphs, st)
for sequenceIndex, lookupList in enumerate(lookups):
for sequenceIndex, lookupList in enumerate(rule.lookups):
if lookupList is not None:
if not isinstance(lookupList, list):
# Can happen with synthesised lookups
@ -374,7 +381,7 @@ class ChainContextualBuilder(LookupBuilder):
def add_subtable_break(self, location):
self.rules.append(
(
ChainContextualRule(
self.SUBTABLE_BREAK_,
self.SUBTABLE_BREAK_,
self.SUBTABLE_BREAK_,
@ -455,7 +462,7 @@ class ChainContextPosBuilder(ChainContextualBuilder):
def __init__(self, font, location):
LookupBuilder.__init__(self, font, location, "GPOS", 8)
self.rules = [] # (prefix, input, suffix, lookups)
self.rules = []
self.subtable_type = "Pos"
def find_chainable_single_pos(self, lookups, glyphs, value):
@ -505,10 +512,10 @@ class ChainContextSubstBuilder(ChainContextualBuilder):
def getAlternateGlyphs(self):
result = {}
for (prefix, _, _, lookuplist) in self.rules:
if prefix == self.SUBTABLE_BREAK_:
for rule in self.rules:
if rule.is_subtable_break:
continue
for lookups in lookuplist:
for lookups in rule.lookups:
if not isinstance(lookups, list):
lookups = [lookups]
for lookup in lookups:
@ -521,10 +528,10 @@ class ChainContextSubstBuilder(ChainContextualBuilder):
def find_chainable_single_subst(self, glyphs):
"""Helper for add_single_subst_chained_()"""
res = None
for prefix, _, _, rules in self.rules[::-1]:
if prefix == self.SUBTABLE_BREAK_:
for rule in self.rules[::-1]:
if rule.is_subtable_break:
return res
for sub in rules:
for sub in rule.lookups:
if isinstance(sub, SingleSubstBuilder) and not any(
g in glyphs for g in sub.mapping.keys()
):

14
Tests/otlLib/builder_test.py
View File

@ -1398,28 +1398,28 @@ class ChainContextualRulesetTest(object):
font.setGlyphOrder(["a","b","c","d","A","B","C","D","E"])
sb = builder.ChainContextSubstBuilder(font, None)
prefix, input_, suffix, lookups = [["a"], ["b"]], [["c"]], [], [None]
sb.rules.append((prefix, input_, suffix, lookups))
sb.rules.append(builder.ChainContextualRule(prefix, input_, suffix, lookups))
prefix, input_, suffix, lookups = [["a"], ["d"]], [["c"]], [], [None]
sb.rules.append((prefix, input_, suffix, lookups))
sb.rules.append(builder.ChainContextualRule(prefix, input_, suffix, lookups))
sb.add_subtable_break(None)
# Second subtable has some glyph classes
prefix, input_, suffix, lookups = [["A"]], [["E"]], [], [None]
sb.rules.append((prefix, input_, suffix, lookups))
sb.rules.append(builder.ChainContextualRule(prefix, input_, suffix, lookups))
prefix, input_, suffix, lookups = [["A"]], [["C","D"]], [], [None]
sb.rules.append((prefix, input_, suffix, lookups))
sb.rules.append(builder.ChainContextualRule(prefix, input_, suffix, lookups))
prefix, input_, suffix, lookups = [["A", "B"]], [["E"]], [], [None]
sb.rules.append((prefix, input_, suffix, lookups))
sb.rules.append(builder.ChainContextualRule(prefix, input_, suffix, lookups))
sb.add_subtable_break(None)
# Third subtable has no pre/post context
prefix, input_, suffix, lookups = [], [["E"]], [], [None]
sb.rules.append((prefix, input_, suffix, lookups))
sb.rules.append(builder.ChainContextualRule(prefix, input_, suffix, lookups))
prefix, input_, suffix, lookups = [], [["C","D"]], [], [None]
sb.rules.append((prefix, input_, suffix, lookups))
sb.rules.append(builder.ChainContextualRule(prefix, input_, suffix, lookups))
rulesets = sb.rulesets()
assert len(rulesets) == 3

3
Tests/otlLib/mock_builder_test.py
View File

@ -13,6 +13,7 @@ from fontTools.otlLib.builder import (
ClassPairPosSubtableBuilder,
PairPosBuilder,
SinglePosBuilder,
ChainContextualRule
)
from fontTools.otlLib.error import OpenTypeLibError
from fontTools.ttLib import TTFont
@ -79,7 +80,7 @@ def test_chain_pos_references_GSUB_lookup(ttfont):
location = MockBuilderLocation((0, "alpha"))
builder = ChainContextPosBuilder(ttfont, location)
builder2 = SingleSubstBuilder(ttfont, location)
builder.rules.append(([], [], [], [[builder2]]))
builder.rules.append(ChainContextualRule([], [], [], [[builder2]]))
with pytest.raises(OpenTypeLibError, match="0:alpha: Missing index of the specified lookup, might be a substitution lookup"):
builder.build()