[glyf] Add optimizeSize option

Set to True by default. Can be turned to False on the table,
or at Glyph() compile time.

Also fixes Glyph's draw() to expand the glyph first. Otherwise
it was failing.

Lib/fontTools/ttLib/tables/_g_l_y_f.py

@@ -713,7 +713,9 @@ class Glyph(object):
         else:
             self.decompileCoordinates(data)
 
-    def compile(self, glyfTable, recalcBBoxes=True, *, boundsDone=None):
+    def compile(
+        self, glyfTable, recalcBBoxes=True, *, boundsDone=None, optimizeSize=None
+    ):
         if hasattr(self, "data"):
             if recalcBBoxes:
                 # must unpack glyph in order to recalculate bounding box
@@ -730,7 +732,9 @@ class Glyph(object):
         if self.isComposite():
             data = data + self.compileComponents(glyfTable)
         else:
-            data = data + self.compileCoordinates()
+            if optimizeSize is None:
+                optimizeSize = getattr(glyfTable, "optimizeSize", True)
+            data = data + self.compileCoordinates(optimizeSize=optimizeSize)
         return data
 
     def toXML(self, writer, ttFont):
@@ -976,7 +980,7 @@ class Glyph(object):
             data = data + struct.pack(">h", len(instructions)) + instructions
         return data
 
-    def compileCoordinates(self):
+    def compileCoordinates(self, *, optimizeSize=True):
         assert len(self.coordinates) == len(self.flags)
         data = []
         endPtsOfContours = array.array("H", self.endPtsOfContours)
@@ -991,9 +995,12 @@ class Glyph(object):
         deltas.toInt()
         deltas.absoluteToRelative()
 
-        # TODO(behdad): Add a configuration option for this?
-        deltas = self.compileDeltasGreedy(self.flags, deltas)
-        # deltas = self.compileDeltasOptimal(self.flags, deltas)
+        if optimizeSize:
+            # TODO(behdad): Add a configuration option for this?
+            deltas = self.compileDeltasGreedy(self.flags, deltas)
+            # deltas = self.compileDeltasOptimal(self.flags, deltas)
+        else:
+            deltas = self.compileDeltasForSpeed(self.flags, deltas)
 
         data.extend(deltas)
         return b"".join(data)
@@ -1110,6 +1117,63 @@ class Glyph(object):
 
         return (compressedFlags, compressedXs, compressedYs)
 
+    def compileDeltasForSpeed(self, flags, deltas):
+        # uses widest representation needed, for all deltas.
+        compressedFlags = bytearray()
+        compressedXs = bytearray()
+        compressedYs = bytearray()
+
+        # Compute the necessary width for each axis
+        xs = [d[0] for d in deltas]
+        ys = [d[1] for d in deltas]
+        minX, minY, maxX, maxY = min(xs), min(ys), max(xs), max(ys)
+        xZero = minX == 0 and maxX == 0
+        yZero = minY == 0 and maxY == 0
+        xShort = -255 <= minX <= maxX <= 255
+        yShort = -255 <= minY <= maxY <= 255
+
+        lastflag = None
+        repeat = 0
+        for flag, (x, y) in zip(flags, deltas):
+            # Oh, the horrors of TrueType
+            # do x
+            if xZero:
+                flag = flag | flagXsame
+            elif xShort:
+                flag = flag | flagXShort
+                if x > 0:
+                    flag = flag | flagXsame
+                else:
+                    x = -x
+                compressedXs.append(x)
+            else:
+                compressedXs.extend(struct.pack(">h", x))
+            # do y
+            if yZero:
+                flag = flag | flagYsame
+            elif yShort:
+                flag = flag | flagYShort
+                if y > 0:
+                    flag = flag | flagYsame
+                else:
+                    y = -y
+                compressedYs.append(y)
+            else:
+                compressedYs.extend(struct.pack(">h", y))
+            # handle repeating flags
+            if flag == lastflag and repeat != 255:
+                repeat = repeat + 1
+                if repeat == 1:
+                    compressedFlags.append(flag)
+                else:
+                    compressedFlags[-2] = flag | flagRepeat
+                    compressedFlags[-1] = repeat
+            else:
+                repeat = 0
+                compressedFlags.append(flag)
+            lastflag = flag
+        return (compressedFlags, compressedXs, compressedYs)
+
     def recalcBounds(self, glyfTable, *, boundsDone=None):
         """Recalculates the bounds of the glyph.
 
@@ -1404,6 +1468,7 @@ class Glyph(object):
                 pen.addComponent(glyphName, transform)
             return
 
+        self.expand(glyfTable)
         coordinates, endPts, flags = self.getCoordinates(glyfTable)
         if offset:
             coordinates = coordinates.copy()

Tests/ttLib/tables/_g_l_y_f_test.py

@@ -707,6 +707,37 @@ class GlyphComponentTest:
             '<component glyphName="a" firstPt="1" secondPt="2" flags="0x0"/>'
         ]
 
+    def test_compile_for_speed(self):
+        glyph = Glyph()
+        glyph.numberOfContours = 1
+        glyph.coordinates = GlyphCoordinates(
+            [(0, 0), (1, 0), (1, 0), (1, 1), (1, 1), (0, 1), (0, 1)]
+        )
+        glyph.flags = array.array("B", [flagOnCurve] + [flagCubic] * 6)
+        glyph.endPtsOfContours = [6]
+        glyph.program = ttProgram.Program()
+
+        glyph.expand(None)
+        sizeBytes = glyph.compile(None, optimizeSize=True)
+        glyph.expand(None)
+        speedBytes = glyph.compile(None, optimizeSize=False)
+
+        assert len(sizeBytes) < len(speedBytes)
+
+        for data in sizeBytes, speedBytes:
+            glyph = Glyph(data)
+
+            pen = RecordingPen()
+            glyph.draw(pen, None)
+
+            assert pen.value == [
+                ("moveTo", ((0, 0),)),
+                ("curveTo", ((1, 0), (1, 0), (1.0, 0.5))),
+                ("curveTo", ((1, 1), (1, 1), (0.5, 1.0))),
+                ("curveTo", ((0, 1), (0, 1), (0, 0))),
+                ("closePath", ()),
+            ]
+
     def test_fromXML_reference_points(self):
         comp = GlyphComponent()
         for name, attrs, content in parseXML(