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otTables: try to fix MarkBasePos subtable overflows

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Fixes https://github.com/googlei18n/fontmake/issues/450
This commit is contained in:
Cosimo Lupo 2018-07-19 17:52:00 +01:00
parent 2798bf6d1f
commit 6e8e431dee
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GPG Key ID: 59D54DB0C9976482
1 changed files with 62 additions and 1 deletions
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63
Lib/fontTools/ttLib/tables/otTables.py
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@ -1281,6 +1281,67 @@ def splitPairPos(oldSubTable, newSubTable, overflowRecord):
return ok
def splitMarkBasePos(oldSubTable, newSubTable, overflowRecord):
# split half of the mark classes to the new subtable
classCount = oldSubTable.ClassCount
if classCount < 2:
# oh well, not much left to split...
return False
oldClassCount = classCount // 2
newClassCount = classCount - oldClassCount
oldMarkCoverage, oldMarkRecords = [], []
newMarkCoverage, newMarkRecords = [], []
for glyphName, markRecord in zip(
oldSubTable.MarkCoverage.glyphs,
oldSubTable.MarkArray.MarkRecord
):
if markRecord.Class < oldClassCount:
oldMarkCoverage.append(glyphName)
oldMarkRecords.append(markRecord)
else:
newMarkCoverage.append(glyphName)
newMarkRecords.append(markRecord)
oldBaseRecords, newBaseRecords = [], []
for rec in oldSubTable.BaseArray.BaseRecord:
oldBaseRecord, newBaseRecord = rec.__class__(), rec.__class__()
oldBaseRecord.BaseAnchor = rec.BaseAnchor[:oldClassCount]
newBaseRecord.BaseAnchor = rec.BaseAnchor[oldClassCount:]
oldBaseRecords.append(oldBaseRecord)
newBaseRecords.append(newBaseRecord)
newSubTable.Format = oldSubTable.Format
oldSubTable.MarkCoverage.glyphs = oldMarkCoverage
newSubTable.MarkCoverage = oldSubTable.MarkCoverage.__class__()
newSubTable.MarkCoverage.Format = oldSubTable.MarkCoverage.Format
newSubTable.MarkCoverage.glyphs = newMarkCoverage
# share the same BaseCoverage in both halves
newSubTable.BaseCoverage = oldSubTable.BaseCoverage
oldSubTable.ClassCount = oldClassCount
newSubTable.ClassCount = newClassCount
oldSubTable.MarkArray.MarkRecord = oldMarkRecords
newSubTable.MarkArray = oldSubTable.MarkArray.__class__()
newSubTable.MarkArray.MarkRecord = newMarkRecords
oldSubTable.MarkArray.MarkCount = len(oldMarkRecords)
newSubTable.MarkArray.MarkCount = len(newMarkRecords)
oldSubTable.BaseArray.BaseRecord = oldBaseRecords
newSubTable.BaseArray = oldSubTable.BaseArray.__class__()
newSubTable.BaseArray.BaseRecord = newBaseRecords
oldSubTable.BaseArray.BaseCount = len(oldBaseRecords)
newSubTable.BaseArray.BaseCount = len(newBaseRecords)
return True
splitTable = { 'GSUB': {
# 1: splitSingleSubst,
# 2: splitMultipleSubst,
@ -1295,7 +1356,7 @@ splitTable = { 'GSUB': {
# 1: splitSinglePos,
2: splitPairPos,
# 3: splitCursivePos,
# 4: splitMarkBasePos,
4: splitMarkBasePos,
# 5: splitMarkLigPos,
# 6: splitMarkMarkPos,
# 7: splitContextPos,