Add glyf flags bit6 to ttx output (#1316)

* Implement glyf outline flags bit 6 when decompiling/compiling

* Add test data for outline flag bit 6

* Rename flags, use bitwise OR for setting flag bit

* Remove unneeded code

Lib/fontTools/ttLib/tables/_g_l_y_f.py

@@ -260,8 +260,11 @@ flagYShort = 0x04
 flagRepeat = 0x08
 flagXsame =  0x10
 flagYsame = 0x20
-flagReserved1 = 0x40
-flagReserved2 = 0x80
+flagOverlapSimple = 0x40
+flagReserved = 0x80
+
+# These flags are kept for XML output after decompiling the coordinates
+keepFlags = flagOnCurve + flagOverlapSimple
 
 _flagSignBytes = {
 	0: 2,
@@ -408,10 +411,15 @@ class Glyph(object):
 				writer.begintag("contour")
 				writer.newline()
 				for j in range(last, self.endPtsOfContours[i] + 1):
-					writer.simpletag("pt", [
+					attrs = [
 							("x", self.coordinates[j][0]),
 							("y", self.coordinates[j][1]),
-							("on", self.flags[j] & flagOnCurve)])
+							("on", self.flags[j] & flagOnCurve),
+						]
+					if self.flags[j] & flagOverlapSimple:
+						# Apple's rasterizer uses flagOverlapSimple in the first contour/first pt to flag glyphs that contain overlapping contours
+						attrs.append(("overlap", 1))
+					writer.simpletag("pt", attrs)
 					writer.newline()
 				last = self.endPtsOfContours[i] + 1
 				writer.endtag("contour")
@@ -441,7 +449,10 @@ class Glyph(object):
 				if name != "pt":
 					continue  # ignore anything but "pt"
 				coordinates.append((safeEval(attrs["x"]), safeEval(attrs["y"])))
-				flags.append(not not safeEval(attrs["on"]))
+				flag = not not safeEval(attrs["on"])
+				if "overlap" in attrs and bool(safeEval(attrs["overlap"])):
+					flag |= flagOverlapSimple
+				flags.append(flag)
 			flags = array.array("B", flags)
 			if not hasattr(self, "coordinates"):
 				self.coordinates = coordinates
@@ -560,8 +571,8 @@ class Glyph(object):
 		assert xIndex == len(xCoordinates)
 		assert yIndex == len(yCoordinates)
 		coordinates.relativeToAbsolute()
-		# discard all flags but for "flagOnCurve"
-		self.flags = array.array("B", (f & flagOnCurve for f in flags))
+		# discard all flags except "keepFlags"
+		self.flags = array.array("B", (f & keepFlags for f in flags))
 
 	def decompileCoordinatesRaw(self, nCoordinates, data):
 		# unpack flags and prepare unpacking of coordinates

Tests/ttLib/tables/_g_l_y_f_test.py

@@ -1,10 +1,14 @@
 from __future__ import print_function, division, absolute_import
 from fontTools.misc.py23 import *
 from fontTools.misc.fixedTools import otRound
+from fontTools.ttLib import TTFont, newTable
 from fontTools.ttLib.tables._g_l_y_f import GlyphCoordinates
 import sys
 import array
 import pytest
+import re
+import os
+import unittest
 
 
 class GlyphCoordinatesTest(object):
@@ -158,3 +162,60 @@ class GlyphCoordinatesTest(object):
         g.append((0x8000, 0))
         assert g.array.typecode == "d"
         assert g.array == array.array("d", [1.0, 1.0, 32768.0, 0.0])
+
+
+CURR_DIR = os.path.abspath(os.path.dirname(os.path.realpath(__file__)))
+DATA_DIR = os.path.join(CURR_DIR, 'data')
+
+GLYF_TTX = os.path.join(DATA_DIR, "_g_l_y_f_outline_flag_bit6.ttx")
+GLYF_BIN = os.path.join(DATA_DIR, "_g_l_y_f_outline_flag_bit6.glyf.bin")
+HEAD_BIN = os.path.join(DATA_DIR, "_g_l_y_f_outline_flag_bit6.head.bin")
+LOCA_BIN = os.path.join(DATA_DIR, "_g_l_y_f_outline_flag_bit6.loca.bin")
+MAXP_BIN = os.path.join(DATA_DIR, "_g_l_y_f_outline_flag_bit6.maxp.bin")
+
+
+def strip_ttLibVersion(string):
+    return re.sub(' ttLibVersion=".*"', '', string)
+
+
+class glyfTableTest(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        with open(GLYF_BIN, 'rb') as f:
+            cls.glyfData = f.read()
+        with open(HEAD_BIN, 'rb') as f:
+            cls.headData = f.read()
+        with open(LOCA_BIN, 'rb') as f:
+            cls.locaData = f.read()
+        with open(MAXP_BIN, 'rb') as f:
+            cls.maxpData = f.read()
+        with open(GLYF_TTX, 'r') as f:
+            cls.glyfXML = strip_ttLibVersion(f.read()).splitlines()
+
+    def test_toXML(self):
+        font = TTFont(sfntVersion="\x00\x01\x00\x00")
+        glyfTable = font['glyf'] = newTable('glyf')
+        font['head'] = newTable('head')
+        font['loca'] = newTable('loca')
+        font['maxp'] = newTable('maxp')
+        font['maxp'].decompile(self.maxpData, font)
+        font['head'].decompile(self.headData, font)
+        font['loca'].decompile(self.locaData, font)
+        glyfTable.decompile(self.glyfData, font)
+        out = UnicodeIO()
+        font.saveXML(out)
+        glyfXML = strip_ttLibVersion(out.getvalue()).splitlines()
+        self.assertEqual(glyfXML, self.glyfXML)
+
+    def test_fromXML(self):
+        font = TTFont(sfntVersion="\x00\x01\x00\x00")
+        font.importXML(GLYF_TTX)
+        glyfTable = font['glyf']
+        glyfData = glyfTable.compile(font)
+        self.assertEqual(glyfData, self.glyfData)
+
+
+if __name__ == "__main__":
+    import sys
+    sys.exit(unittest.main())

Tests/ttLib/tables/data/_g_l_y_f_outline_flag_bit6.ttx

@@ -0,0 +1,88 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ttFont sfntVersion="\x00\x01\x00\x00" ttLibVersion="3.29">
+
+  <GlyphOrder>
+    <!-- The 'id' attribute is only for humans; it is ignored when parsed. -->
+    <GlyphID id="0" name=".notdef"/>
+    <GlyphID id="1" name="glyph00001"/>
+    <GlyphID id="2" name="glyph00002"/>
+    <GlyphID id="3" name="glyph00003"/>
+  </GlyphOrder>
+
+  <head>
+    <!-- Most of this table will be recalculated by the compiler -->
+    <tableVersion value="1.0"/>
+    <fontRevision value="1.0"/>
+    <checkSumAdjustment value="0x6e4f1ccf"/>
+    <magicNumber value="0x5f0f3cf5"/>
+    <flags value="00100000 00011011"/>
+    <unitsPerEm value="2048"/>
+    <created value="Thu Sep 13 14:22:20 2018"/>
+    <modified value="Fri Sep 14 09:25:13 2018"/>
+    <xMin value="12"/>
+    <yMin value="0"/>
+    <xMax value="1172"/>
+    <yMax value="1430"/>
+    <macStyle value="00000000 00000000"/>
+    <lowestRecPPEM value="9"/>
+    <fontDirectionHint value="2"/>
+    <indexToLocFormat value="0"/>
+    <glyphDataFormat value="0"/>
+  </head>
+
+  <maxp>
+    <!-- Most of this table will be recalculated by the compiler -->
+    <tableVersion value="0x10000"/>
+    <numGlyphs value="4"/>
+    <maxPoints value="11"/>
+    <maxContours value="2"/>
+    <maxCompositePoints value="0"/>
+    <maxCompositeContours value="0"/>
+    <maxZones value="1"/>
+    <maxTwilightPoints value="0"/>
+    <maxStorage value="0"/>
+    <maxFunctionDefs value="10"/>
+    <maxInstructionDefs value="0"/>
+    <maxStackElements value="512"/>
+    <maxSizeOfInstructions value="353"/>
+    <maxComponentElements value="0"/>
+    <maxComponentDepth value="0"/>
+  </maxp>
+
+  <loca>
+    <!-- The 'loca' table will be calculated by the compiler -->
+  </loca>
+
+  <glyf>
+
+    <!-- The xMin, yMin, xMax and yMax values
+         will be recalculated by the compiler. -->
+
+    <TTGlyph name=".notdef"/><!-- contains no outline data -->
+
+    <TTGlyph name="glyph00001"/><!-- contains no outline data -->
+
+    <TTGlyph name="glyph00002"/><!-- contains no outline data -->
+
+    <TTGlyph name="glyph00003" xMin="12" yMin="0" xMax="1172" yMax="1430">
+      <contour>
+        <pt x="501" y="1430" on="1" overlap="1"/>
+        <pt x="683" y="1430" on="1"/>
+        <pt x="1172" y="0" on="1"/>
+        <pt x="983" y="0" on="1"/>
+        <pt x="591" y="1193" on="1"/>
+        <pt x="199" y="0" on="1"/>
+        <pt x="12" y="0" on="1"/>
+      </contour>
+      <contour>
+        <pt x="249" y="514" on="1"/>
+        <pt x="935" y="514" on="1"/>
+        <pt x="935" y="352" on="1"/>
+        <pt x="249" y="352" on="1"/>
+      </contour>
+      <instructions/>
+    </TTGlyph>
+
+  </glyf>
+
+</ttFont>