[morx] Write AATLookup format 2

Lib/fontTools/ttLib/tables/otConverters.py

@@ -571,10 +571,10 @@ class AATLookup(BaseConverter):
 
 	def write(self, writer, font, tableDict, value, repeatIndex=None):
 		glyphMap = font.getReverseGlyphMap()
-		binSrchHeaderSize = 10
+		# TODO: Also implement format 4 and 8.
-		# TODO: Also implement format 2, 4, and 8.
 		formats = list(sorted(filter(None, [
 			self.buildFormat0(font, value),
+			self.buildFormat2(font, value),
 			self.buildFormat6(font, value),
 		])))
 		# We use the format ID as secondary sort key to make the output
@@ -603,6 +603,36 @@ class AATLookup(BaseConverter):
 		for glyph in font.getGlyphOrder():
 			writer.writeUShort(font.getGlyphID(value[glyph]))
 
+	def buildFormat2(self, font, value):
+		glyphs = [(font.getGlyphID(g), g) for g in value.keys()]
+		glyphs.sort()
+		segStart, glyphName = glyphs[0]
+		segEnd = segStart
+		segValue = value[glyphName]
+		segments = []
+		for glyphID, glyphName in glyphs[1:]:
+			curValue = value[glyphName]
+			if glyphID != segEnd + 1 or curValue != segValue:
+				segments.append((segStart, segEnd, segValue))
+				segStart = segEnd = glyphID
+				segValue = curValue
+			else:
+				segEnd = glyphID
+		segments.append((segStart, segEnd, segValue))
+		segments.append((0xFFFF, 0xFFFF, segValue))
+		return (self.BIN_SEARCH_HEADER_SIZE + len(segments) * 6, 2,
+		        lambda writer:
+		            self.writeFormat2(writer, font, segments))
+
+	def writeFormat2(self, writer, font, segments):
+		writer.writeUShort(2)
+		self.writeBinSearchHeader(writer,
+		                          numUnits=len(segments), unitSize=6)
+		for firstGlyph, lastGlyph, value in segments:
+			writer.writeUShort(lastGlyph)
+			writer.writeUShort(firstGlyph)
+			writer.writeUShort(font.getGlyphID(value))
+
 	def buildFormat6(self, font, value):
 		entries = [(font.getGlyphID(key), font.getGlyphID(value))
 		          for key, value in value.items()]

Tests/ttLib/tables/otConverters_test.py

@@ -261,23 +261,50 @@ class AATLookupTest(unittest.TestCase):
         })
         self.assertEqual(writer.getData(), deHexStr("0000 0000 0003 0003 0001"))
 
+    def test_writeFormat2(self):
+        writer = OTTableWriter()
+        font = FakeFont(".notdef A B C D E F G H".split())
+        self.converter.write(writer, font, {}, {
+            "B": "C",
+            "C": "C",
+            "D": "C",
+            "E": "C",
+            "G": "A",
+            "H": "A",
+        })
+        self.assertEqual(writer.getData(), deHexStr(
+            "0002 "            # format=2
+            "0006 "            # binSrchHeader.unitSize=6
+            "0003 "            # binSrchHeader.nUnits=3
+            "000C "            # binSrchHeader.searchRange=12
+            "0001 "            # binSrchHeader.entrySelector=1
+            "0006 "            # binSrchHeader.rangeShift=6
+            "0005 0002 0003 "  # segments[0].lastGlyph=E, firstGlyph=B, value=C
+            "0008 0007 0001 "  # segments[1].lastGlyph=H, firstGlyph=G, value=A
+            "FFFF FFFF 0001 "  # segments[2]=<END>
+        ))
+
     def test_writeFormat6(self):
         writer = OTTableWriter()
-        font = FakeFont(".notdef A B C".split())
+        font = FakeFont(".notdef A B C D E".split())
         self.converter.write(writer, font, {}, {
             "A": "C",
-            "C": "B"
+            "C": "B",
+            "D": "D",
+            "E": "E",
         })
         self.assertEqual(writer.getData(), deHexStr(
             "0006 "         # format=6
             "0004 "         # binSrchHeader.unitSize=4
-            "0003 "         # binSrchHeader.nUnits=3
+            "0005 "         # binSrchHeader.nUnits=5
-            "0008 "         # binSrchHeader.searchRange=8
+            "0010 "         # binSrchHeader.searchRange=16
-            "0001 "         # binSrchHeader.entrySelector=1
+            "0002 "         # binSrchHeader.entrySelector=2
             "0004 "         # binSrchHeader.rangeShift=4
             "0001 0003 "    # entries[0].glyph=A, .value=C
             "0003 0002 "    # entries[1].glyph=C, .value=B
-            "FFFF FFFF "    # entries[2]=<END>
+            "0004 0004 "    # entries[2].glyph=D, .value=D
+            "0005 0005 "    # entries[3].glyph=E, .value=E
+            "FFFF FFFF "    # entries[4]=<END>
         ))
 
     def test_xmlRead(self):