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"""GPOSUnparser: Convert binary GPOS lookups to fontFeatures objects."""
from .GTableUnparser import GTableUnparser
import fontFeatures
class GPOSUnparser(GTableUnparser):
"""Unparse a GPOS table into a fontFeatures object. See :py:class:`fontFeatures.ttLib.GTableUnparser`."""
_table = "GPOS"
lookupTypes = {
1: "SinglePositioning",
2: "PairPositioning",
3: "CursiveAttachment",
4: "MarkToBase",
5: "MarkToLigature",
6: "MarkToMark",
7: "Contextual",
8: "ChainedContextual",
9: "Extension",
}
_attrs = {
"lookup": "PosLookupRecord",
"format1_ruleset": "PosRuleSet",
"format1_rule": "PosRule",
"format2_classset": "PosClassSet",
"format2_rule": "PosClassRule",
"chain_format1_ruleset": "ChainPosRuleSet",
"chain_format1_rule": "ChainPosRule",
"chain_format2_classset": "ChainPosClassSet",
"chain_format2_rule": "ChainPosClassRule",
}
def makeValueRecord(self, valueRecord):
"""Helper routine to create ValueRecord instances.
Args:
valueRecord: An ``otTables.ValueRecord`` object.
Returns a ``fontFeatures.ValueRecord`` object."""
valueFormatFlags = (
("XPlacement", 0x0001), # Includes horizontal adjustment for placement
("YPlacement", 0x0002), # Includes vertical adjustment for placement
("XAdvance", 0x0004), # Includes horizontal adjustment for advance
("YAdvance", 0x0008), # Includes vertical adjustment for advance
# Currently we don't have a way to express or represent value records
# with Device tables, whether old-style (ppem adjustment) or new-style
# (VariationIndex). Even if we could represent them, then what? See
# issue #31.
# ("XPlaDevice", 0x0010), # Includes horizontal Device table for placement
# ("YPlaDevice", 0x0020), # Includes vertical Device table for placement
# ("XAdvDevice", 0x0040), # Includes horizontal Device table for advance
# ("YAdvDevice", 0x0080) # Includes vertical Device table for advance
# , 'Reserved': 0xF000 For future use (set to zero)
)
# defaults to 0
values = [getattr(valueRecord, name, 0) or None for name, _ in valueFormatFlags]
return fontFeatures.ValueRecord(*values)
def isChaining(self, lookupType):
"""Returns true if the given lookup type is a chaining lookup."""
return lookupType >= 7
def unparseSinglePositioning(self, lookup):
"""Turn a GPOS1 (single positioning) subtable into a fontFeatures Routine."""
b = fontFeatures.Routine(name=self.getname("SinglePositioning" + self.gensym()))
self._fix_flags(b, lookup)
for subtable in lookup.SubTable:
if subtable.Format == 1:
spos = fontFeatures.Positioning(
[subtable.Coverage.glyphs],
[self.makeValueRecord(subtable.Value)],
address=self.currentLookup,
flags=lookup.LookupFlag,
)
b.addRule(spos)
else:
# Optimize it later
for g, v in zip(subtable.Coverage.glyphs, subtable.Value):
spos = fontFeatures.Positioning(
[[g]],
[self.makeValueRecord(v)],
address=self.currentLookup,
flags=lookup.LookupFlag,
)
b.addRule(spos)
return b, []
def unparsePairPositioning(self, lookup):
"""Turn a GPOS2 (pair adjustment) subtable into a fontFeatures Routine."""
b = fontFeatures.Routine(name=self.getname("PairPositioning" + self.gensym()))
self._fix_flags(b, lookup)
for subtable in lookup.SubTable:
if subtable.Format == 1:
for g, pair in zip(subtable.Coverage.glyphs, subtable.PairSet):
for vr in pair.PairValueRecord:
spos = fontFeatures.Positioning(
[[g], [vr.SecondGlyph]],
[
self.makeValueRecord(vr.Value1),
self.makeValueRecord(vr.Value2),
],
address=self.currentLookup,
flags=lookup.LookupFlag,
)
b.addRule(spos)
else:
class1 = self._invertClassDef(subtable.ClassDef1.classDefs, self.font)
class2 = self._invertClassDef(subtable.ClassDef2.classDefs, self.font)
for ix1, c1 in enumerate(subtable.Class1Record):
if ix1 not in class1:
continue # XXX
for ix2, c2 in enumerate(c1.Class2Record):
if ix2 not in class2:
continue # XXX
vr1 = self.makeValueRecord(c2.Value1)
vr2 = self.makeValueRecord(c2.Value2)
if not vr1 and not vr2:
continue
firstClass = list(
set(class1[ix1]) & set(subtable.Coverage.glyphs)
)
spos = fontFeatures.Positioning(
[firstClass, class2[ix2]],
[vr1, vr2],
address=self.currentLookup,
flags=lookup.LookupFlag,
)
b.addRule(spos)
return b, []
def unparseCursiveAttachment(self, lookup):
"""Turn a GPOS3 (cursive attachment) subtable into a fontFeatures Routine."""
b = fontFeatures.Routine(name=self.getname("CursiveAttachment" + self.gensym()))
self._fix_flags(b, lookup)
entries = {}
exits = {}
for s in lookup.SubTable:
assert s.Format == 1
for glyph, record in zip(s.Coverage.glyphs, s.EntryExitRecord):
if record.EntryAnchor:
entries[glyph] = (
record.EntryAnchor.XCoordinate,
record.EntryAnchor.YCoordinate,
)
if record.ExitAnchor:
exits[glyph] = (
record.ExitAnchor.XCoordinate,
record.ExitAnchor.YCoordinate,
)
b.addRule(
fontFeatures.Attachment(
"cursive_entry",
"cursive_exit",
entries,
exits,
flags=lookup.LookupFlag,
address=self.currentLookup,
)
)
return b, []
def unparseMarkToBase(self, lookup):
"""Turn a GPOS4 (mark to base) subtable into a fontFeatures Routine."""
b = fontFeatures.Routine(name=self.getname("MarkToBase" + self.gensym()))
self._fix_flags(b, lookup)
for subtable in lookup.SubTable: # fontTools.ttLib.tables.otTables.MarkBasePos
assert subtable.Format == 1
for classId in range(0, subtable.ClassCount):
anchorClassPrefix = "Anchor" + self.gensym()
marks = self._formatMarkArray(
subtable.MarkArray, subtable.MarkCoverage, classId
)
bases = self._formatBaseArray(
subtable.BaseArray, subtable.BaseCoverage, classId
)
b.addRule(
fontFeatures.Attachment(
anchorClassPrefix,
"_" + anchorClassPrefix,
bases,
marks,
font=self.font,
address=self.currentLookup,
flags=lookup.LookupFlag,
)
)
return b, []
def _formatMarkArray(self, markArray, markCoverage, classId):
id2Name = markCoverage.glyphs
marks = {}
for i, markRecord in enumerate(markArray.MarkRecord):
if markRecord.Class == classId:
marks[id2Name[i]] = (
markRecord.MarkAnchor.XCoordinate,
markRecord.MarkAnchor.YCoordinate,
# markRecord.Class
)
return marks
def _formatMark2Array(self, markArray, markCoverage, anchorClassPrefix):
id2Name = markCoverage.glyphs
marks = {}
for i, markRecord in enumerate(markArray.Mark2Record):
anchor = markRecord.Mark2Anchor[anchorClassPrefix]
if not anchor:
continue
marks[id2Name[i]] = (
anchor.XCoordinate,
anchor.YCoordinate,
)
return marks
def _formatBaseArray(self, baseArray, baseCoverage, wantedClassId):
id2Name = baseCoverage.glyphs
bases = {}
for i, baseRecord in enumerate(baseArray.BaseRecord):
for classId, anchor in enumerate(baseRecord.BaseAnchor):
if classId != wantedClassId:
continue
if not anchor:
continue
bases[id2Name[i]] = (anchor.XCoordinate, anchor.YCoordinate) # ClassId?
return bases
def unparseMarkToLigature(self, lookup):
"""Turn a GPOS5 (mark to ligature) subtable into a fontFeatures Routine."""
b = fontFeatures.Routine(name=self.getname("MarkToLigature" + self.gensym()))
self._fix_flags(b, lookup)
self.unparsable(b, "Mark to lig pos", lookup)
return b, []
def unparseMarkToMark(self, lookup):
"""Turn a GPOS6 (mark to mark) subtable into a fontFeatures Routine."""
b = fontFeatures.Routine(name=self.getname("MarkToMark" + self.gensym()))
self._fix_flags(b, lookup)
for subtable in lookup.SubTable: # fontTools.ttLib.tables.otTables.MarkBasePos
assert subtable.Format == 1
for classId in range(0, subtable.ClassCount):
anchorClassPrefix = "Anchor" + self.gensym()
marks = self._formatMarkArray(
subtable.Mark1Array, subtable.Mark1Coverage, classId
)
bases = self._formatMark2Array(
subtable.Mark2Array, subtable.Mark2Coverage, classId
)
b.addRule(
fontFeatures.Attachment(
anchorClassPrefix,
anchorClassPrefix + "_",
bases,
marks,
font=self.font,
address=self.currentLookup,
flags=lookup.LookupFlag,
force_markmark=True,
)
)
return b, []
|
