added manual implementation for the Coverage subtable to get rid of GlyphID dependencies

git-svn-id: svn://svn.code.sf.net/p/fonttools/code/trunk@341 4cde692c-a291-49d1-8350-778aa11640f8

Lib/fontTools/ttLib/tables/otTables.py

@@ -11,8 +11,85 @@ from otBase import BaseTable, FormatSwitchingBaseTable
 class LookupOrder(BaseTable):
 	"""Dummy class; this table isn't defined, but is used, and is always NULL."""
 
+
 class FeatureParams(BaseTable):
 	"""Dummy class; this table isn't defined, but is used, and is always NULL."""
+	# XXX The above is no longer true; the 'size' feature uses FeatureParams now.
+
+
+class Coverage(FormatSwitchingBaseTable):
+	
+	# manual implementation to get rid of glyphID dependencies
+	
+	def postRead(self, table, font):
+		if self.Format == 1:
+			self.glyphs = table["GlyphArray"]
+		elif self.Format == 2:
+			glyphs = self.glyphs = []
+			ranges = table["RangeRecord"]
+			for r in ranges:
+				assert r.StartCoverageIndex == len(glyphs), \
+					(r.StartCoverageIndex, len(glyphs))
+				start = r.Start
+				end = r.End
+				startID = font.getGlyphID(start)
+				endID = font.getGlyphID(end)
+				glyphs.append(start)
+				for glyphID in range(startID + 1, endID):
+					glyphs.append(font.getGlyphName(glyphID))
+				if start != end:
+					glyphs.append(end)
+		else:
+			assert 0
+	
+	def preWrite(self, font):
+		format = 1
+		table = {"GlyphArray": self.glyphs}
+		if self.glyphs:
+			glyphIDs = []
+			for glyphName in self.glyphs:
+				glyphIDs.append(font.getGlyphID(glyphName))
+			
+			last = glyphIDs[0]
+			ranges = [[last]]
+			for glyphID in glyphIDs[1:]:
+				if glyphID == last + 1:
+					pass
+				else:
+					ranges[-1].append(last)
+					ranges.append([glyphID])
+				last = glyphID
+			ranges[-1].append(last)
+			
+			if len(ranges) * 3 < len(self.glyphs):  # 3 words vs. 1 word
+				# Format 2 is more compact
+				index = 0
+				for i in range(len(ranges)):
+					start, end = ranges[i]
+					r = RangeRecord()
+					r.Start = font.getGlyphName(start)
+					r.End = font.getGlyphName(end)
+					r.StartCoverageIndex = index
+					ranges[i] = r
+					index = index + end - start + 1
+				format = 2
+				table = {"RangeRecord": ranges}
+			#else:
+			#	fallthrough; Format 1 is more compact
+		self.Format = format
+		return table
+	
+	def toXML2(self, xmlWriter, font):
+		for glyphName in self.glyphs:
+			xmlWriter.simpletag("Glyph", value=glyphName)
+			xmlWriter.newline()
+	
+	def fromXML(self, (name, attrs, content), font):
+		glyphs = getattr(self, "glyphs", None)
+		if glyphs is None:
+			glyphs = []
+			self.glyphs = glyphs
+		glyphs.append(attrs["value"])
 
 
 #