Merge pull request #1528 from anthrotype/gvar-vmtx-phantom-pts

varLib: use vmtx to compute vertical phantom points, else fall back to ascent - UPEM

Lib/fontTools/varLib/__init__.py

@@ -209,8 +209,40 @@ def _add_stat(font, axes):
 	# TODO make this user-configurable via designspace document
 	stat.ElidedFallbackNameID = 2
 
+
+def _get_phantom_points(font, glyphName, defaultVerticalOrigin=None):
+	glyf = font["glyf"]
+	glyph = glyf[glyphName]
+	horizontalAdvanceWidth, leftSideBearing = font["hmtx"].metrics[glyphName]
+	if not hasattr(glyph, 'xMin'):
+		glyph.recalcBounds(glyf)
+	leftSideX = glyph.xMin - leftSideBearing
+	rightSideX = leftSideX + horizontalAdvanceWidth
+	if "vmtx" in font:
+		verticalAdvanceWidth, topSideBearing = font["vmtx"].metrics[glyphName]
+		topSideY = topSideBearing + glyph.yMax
+	else:
+		# without vmtx, use ascent as vertical origin and UPEM as vertical advance
+		# like HarfBuzz does
+		verticalAdvanceWidth = font["head"].unitsPerEm
+		try:
+			topSideY = font["hhea"].ascent
+		except KeyError:
+			# sparse masters may not contain an hhea table; use the ascent
+			# of the default master as the vertical origin
+			assert defaultVerticalOrigin is not None
+			topSideY = defaultVerticalOrigin
+	bottomSideY = topSideY - verticalAdvanceWidth
+	return [
+		(leftSideX, 0),
+		(rightSideX, 0),
+		(0, topSideY),
+		(0, bottomSideY),
+	]
+
+
 # TODO Move to glyf or gvar table proper
-def _GetCoordinates(font, glyphName):
+def _GetCoordinates(font, glyphName, defaultVerticalOrigin=None):
 	"""font, glyphName --> glyph coordinates as expected by "gvar" table
 
 	The result includes four "phantom points" for the glyph metrics,
@@ -228,19 +260,9 @@ def _GetCoordinates(font, glyphName):
 		control = (glyph.numberOfContours,)+allData[1:]
 
 	# Add phantom points for (left, right, top, bottom) positions.
-	horizontalAdvanceWidth, leftSideBearing = font["hmtx"].metrics[glyphName]
+	phantomPoints = _get_phantom_points(font, glyphName, defaultVerticalOrigin)
-	if not hasattr(glyph, 'xMin'):
-		glyph.recalcBounds(glyf)
-	leftSideX = glyph.xMin - leftSideBearing
-	rightSideX = leftSideX + horizontalAdvanceWidth
-	# XXX these are incorrect.  Load vmtx and fix.
-	topSideY = glyph.yMax
-	bottomSideY = -glyph.yMin
 	coord = coord.copy()
-	coord.extend([(leftSideX, 0),
+	coord.extend(phantomPoints)
-	              (rightSideX, 0),
-	              (0, topSideY),
-	              (0, bottomSideY)])
 
 	return coord, control
 
@@ -297,11 +319,16 @@ def _add_gvar(font, masterModel, master_ttfs, tolerance=0.5, optimize=True):
 
 	glyf = font['glyf']
 
+	# use hhea.ascent of base master as default vertical origin when vmtx is missing
+	defaultVerticalOrigin = font['hhea'].ascent
 	for glyph in font.getGlyphOrder():
 
 		isComposite = glyf[glyph].isComposite()
 
-		allData = [_GetCoordinates(m, glyph) for m in master_ttfs]
+		allData = [
+			_GetCoordinates(m, glyph, defaultVerticalOrigin=defaultVerticalOrigin)
+			for m in master_ttfs
+		]
 		model, allData = masterModel.getSubModel(allData)
 
 		allCoords = [d[0] for d in allData]

Tests/varLib/data/test_results/Build.ttx

@@ -281,7 +281,7 @@
         <delta pt="15" x="0" y="0"/>
         <delta pt="16" x="0" y="0"/>
         <delta pt="17" x="0" y="0"/>
-        <delta pt="18" x="0" y="7"/>
+        <delta pt="18" x="0" y="0"/>
         <delta pt="19" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -304,7 +304,7 @@
         <delta pt="15" x="0" y="0"/>
         <delta pt="16" x="0" y="0"/>
         <delta pt="17" x="0" y="0"/>
-        <delta pt="18" x="0" y="-18"/>
+        <delta pt="18" x="0" y="0"/>
         <delta pt="19" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -424,7 +424,7 @@
         <delta pt="23" x="-2" y="0"/>
         <delta pt="24" x="0" y="0"/>
         <delta pt="25" x="-10" y="0"/>
-        <delta pt="26" x="0" y="9"/>
+        <delta pt="26" x="0" y="0"/>
         <delta pt="27" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -455,7 +455,7 @@
         <delta pt="23" x="12" y="0"/>
         <delta pt="24" x="0" y="0"/>
         <delta pt="25" x="17" y="0"/>
-        <delta pt="26" x="0" y="-23"/>
+        <delta pt="26" x="0" y="0"/>
         <delta pt="27" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -620,7 +620,7 @@
         <delta pt="60" x="33" y="-1"/>
         <delta pt="61" x="0" y="0"/>
         <delta pt="62" x="-3" y="0"/>
-        <delta pt="63" x="0" y="-4"/>
+        <delta pt="63" x="0" y="0"/>
         <delta pt="64" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -688,8 +688,8 @@
         <delta pt="60" x="-25" y="-13"/>
         <delta pt="61" x="0" y="0"/>
         <delta pt="62" x="32" y="0"/>
-        <delta pt="63" x="0" y="16"/>
+        <delta pt="63" x="0" y="0"/>
-        <delta pt="64" x="0" y="3"/>
+        <delta pt="64" x="0" y="0"/>
       </tuple>
       <tuple>
         <coord axis="cntr" value="1.0"/>
@@ -965,7 +965,7 @@
         <delta pt="61" x="-15" y="0"/>
         <delta pt="62" x="0" y="0"/>
         <delta pt="63" x="-7" y="0"/>
-        <delta pt="64" x="0" y="12"/>
+        <delta pt="64" x="0" y="0"/>
         <delta pt="65" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1034,7 +1034,7 @@
         <delta pt="61" x="39" y="0"/>
         <delta pt="62" x="0" y="0"/>
         <delta pt="63" x="63" y="0"/>
-        <delta pt="64" x="0" y="-19"/>
+        <delta pt="64" x="0" y="0"/>
         <delta pt="65" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1314,7 +1314,7 @@
         <delta pt="61" x="-15" y="0"/>
         <delta pt="62" x="0" y="0"/>
         <delta pt="63" x="-7" y="0"/>
-        <delta pt="64" x="0" y="12"/>
+        <delta pt="64" x="0" y="0"/>
         <delta pt="65" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1383,7 +1383,7 @@
         <delta pt="61" x="49" y="0"/>
         <delta pt="62" x="0" y="0"/>
         <delta pt="63" x="63" y="0"/>
-        <delta pt="64" x="0" y="-19"/>
+        <delta pt="64" x="0" y="0"/>
         <delta pt="65" x="0" y="0"/>
       </tuple>
       <tuple>

Tests/varLib/data/test_results/BuildMain.ttx

@@ -927,7 +927,7 @@
         <delta pt="15" x="0" y="0"/>
         <delta pt="16" x="0" y="0"/>
         <delta pt="17" x="0" y="0"/>
-        <delta pt="18" x="0" y="7"/>
+        <delta pt="18" x="0" y="0"/>
         <delta pt="19" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -950,7 +950,7 @@
         <delta pt="15" x="0" y="0"/>
         <delta pt="16" x="0" y="0"/>
         <delta pt="17" x="0" y="0"/>
-        <delta pt="18" x="0" y="-18"/>
+        <delta pt="18" x="0" y="0"/>
         <delta pt="19" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1070,7 +1070,7 @@
         <delta pt="23" x="-2" y="0"/>
         <delta pt="24" x="0" y="0"/>
         <delta pt="25" x="-10" y="0"/>
-        <delta pt="26" x="0" y="9"/>
+        <delta pt="26" x="0" y="0"/>
         <delta pt="27" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1101,7 +1101,7 @@
         <delta pt="23" x="12" y="0"/>
         <delta pt="24" x="0" y="0"/>
         <delta pt="25" x="17" y="0"/>
-        <delta pt="26" x="0" y="-23"/>
+        <delta pt="26" x="0" y="0"/>
         <delta pt="27" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1266,7 +1266,7 @@
         <delta pt="60" x="33" y="-1"/>
         <delta pt="61" x="0" y="0"/>
         <delta pt="62" x="-3" y="0"/>
-        <delta pt="63" x="0" y="-4"/>
+        <delta pt="63" x="0" y="0"/>
         <delta pt="64" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1334,8 +1334,8 @@
         <delta pt="60" x="-25" y="-13"/>
         <delta pt="61" x="0" y="0"/>
         <delta pt="62" x="32" y="0"/>
-        <delta pt="63" x="0" y="16"/>
+        <delta pt="63" x="0" y="0"/>
-        <delta pt="64" x="0" y="3"/>
+        <delta pt="64" x="0" y="0"/>
       </tuple>
       <tuple>
         <coord axis="cntr" value="1.0"/>
@@ -1611,7 +1611,7 @@
         <delta pt="61" x="-15" y="0"/>
         <delta pt="62" x="0" y="0"/>
         <delta pt="63" x="-7" y="0"/>
-        <delta pt="64" x="0" y="12"/>
+        <delta pt="64" x="0" y="0"/>
         <delta pt="65" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1680,7 +1680,7 @@
         <delta pt="61" x="39" y="0"/>
         <delta pt="62" x="0" y="0"/>
         <delta pt="63" x="63" y="0"/>
-        <delta pt="64" x="0" y="-19"/>
+        <delta pt="64" x="0" y="0"/>
         <delta pt="65" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -1960,7 +1960,7 @@
         <delta pt="61" x="-15" y="0"/>
         <delta pt="62" x="0" y="0"/>
         <delta pt="63" x="-7" y="0"/>
-        <delta pt="64" x="0" y="12"/>
+        <delta pt="64" x="0" y="0"/>
         <delta pt="65" x="0" y="0"/>
       </tuple>
       <tuple>
@@ -2029,7 +2029,7 @@
         <delta pt="61" x="49" y="0"/>
         <delta pt="62" x="0" y="0"/>
         <delta pt="63" x="63" y="0"/>
-        <delta pt="64" x="0" y="-19"/>
+        <delta pt="64" x="0" y="0"/>
         <delta pt="65" x="0" y="0"/>
       </tuple>
       <tuple>

Tests/varLib/data/test_results/SparseMasters.ttx

@@ -610,7 +610,7 @@
         <delta pt="12" x="25" y="-1"/>
         <delta pt="13" x="0" y="0"/>
         <delta pt="14" x="0" y="0"/>
-        <delta pt="15" x="0" y="35"/>
+        <delta pt="15" x="0" y="0"/>
         <delta pt="16" x="0" y="0"/>
       </tuple>
     </glyphVariations>
@@ -632,7 +632,7 @@
         <delta pt="12" x="0" y="0"/>
         <delta pt="13" x="0" y="0"/>
         <delta pt="14" x="0" y="0"/>
-        <delta pt="15" x="0" y="45"/>
+        <delta pt="15" x="0" y="0"/>
       </tuple>
     </glyphVariations>
     <glyphVariations glyph="dotabovecomb">
@@ -644,15 +644,14 @@
         <delta pt="3" x="-27" y="-20"/>
         <delta pt="4" x="0" y="0"/>
         <delta pt="5" x="0" y="0"/>
-        <delta pt="6" x="0" y="28"/>
+        <delta pt="6" x="0" y="0"/>
-        <delta pt="7" x="0" y="18"/>
+        <delta pt="7" x="0" y="0"/>
       </tuple>
     </glyphVariations>
     <glyphVariations glyph="edotabove">
       <tuple>
         <coord axis="wght" value="1.0"/>
         <delta pt="1" x="-6" y="91"/>
-        <delta pt="4" x="0" y="119"/>
       </tuple>
     </glyphVariations>
   </gvar>