Merge pull request #2662 from fonttools/varstore-empty

[varLib.varStore] Support NO_VARIATION_INDEX

Lib/fontTools/feaLib/builder.py

@@ -764,7 +764,7 @@ class Builder(object):
         gdef.Version = 0x00010002 if gdef.MarkGlyphSetsDef else 0x00010000
         if self.varstorebuilder:
             store = self.varstorebuilder.finish()
-            if store.VarData:
+            if store:
                 gdef.Version = 0x00010003
                 gdef.VarStore = store
                 varidx_map = store.optimize()

Lib/fontTools/varLib/__init__.py

@@ -486,7 +486,7 @@ def _get_advance_metrics(font, masterModel, master_ttfs,
 			vOrigMap[glyphName] = storeBuilder.storeDeltas(deltas, round=noRound)
 
 	indirectStore = storeBuilder.finish()
-	mapping2 = indirectStore.optimize()
+	mapping2 = indirectStore.optimize(use_NO_VARIATION_INDEX=False)
 	advMapping = [mapping2[advMapping[g]] for g in glyphOrder]
 	advanceMapping = builder.buildVarIdxMap(advMapping, glyphOrder)
 
@@ -606,7 +606,7 @@ def _add_BASE(font, masterModel, master_ttfs, axisTags):
 	merger.mergeTables(font, master_ttfs, ['BASE'])
 	store = merger.store_builder.finish()
 
-	if not store.VarData:
+	if not store:
 		return
 	base = font['BASE'].table
 	assert base.Version == 0x00010000
@@ -621,7 +621,7 @@ def _merge_OTL(font, model, master_fonts, axisTags):
 
 	merger.mergeTables(font, master_fonts, ['GSUB', 'GDEF', 'GPOS'])
 	store = merger.store_builder.finish()
-	if not store.VarData:
+	if not store:
 		return
 	try:
 		GDEF = font['GDEF'].table

Lib/fontTools/varLib/instancer/__init__.py

@@ -633,6 +633,7 @@ def instantiateItemVariationStore(itemVarStore, fvarAxes, axisLimits):
         for major, deltas in enumerate(defaultDeltaArray)
         for minor, delta in enumerate(deltas)
     }
+    defaultDeltas[itemVarStore.NO_VARIATION_INDEX] = 0
     return defaultDeltas
 
 

Lib/fontTools/varLib/varStore.py

@@ -7,6 +7,10 @@ from functools import partial
 from collections import defaultdict
 
 
+NO_VARIATION_INDEX = 0xFFFFFFFF
+ot.VarStore.NO_VARIATION_INDEX = NO_VARIATION_INDEX
+
+
 def _getLocationKey(loc):
 	return tuple(sorted(loc.items(), key=lambda kv: kv[0]))
 
@@ -135,6 +139,11 @@ def VarRegion_get_support(self, fvar_axes):
 
 ot.VarRegion.get_support = VarRegion_get_support
 
+def VarStore___bool__(self):
+    return bool(self.VarData)
+
+ot.VarStore.__bool__ = VarStore___bool__
+
 class VarStoreInstancer(object):
 
 	def __init__(self, varstore, fvar_axes, location={}):
@@ -169,6 +178,7 @@ class VarStoreInstancer(object):
 
 	def __getitem__(self, varidx):
 		major, minor = varidx >> 16, varidx & 0xFFFF
+		if varidx == NO_VARIATION_INDEX: return 0.
 		varData = self._varData
 		scalars = [self._getScalar(ri) for ri in varData[major].VarRegionIndex]
 		deltas = varData[major].Item[minor]
@@ -431,7 +441,7 @@ class _EncodingDict(dict):
 		return chars
 
 
-def VarStore_optimize(self):
+def VarStore_optimize(self, use_NO_VARIATION_INDEX=True):
 	"""Optimize storage. Returns mapping from old VarIdxes to new ones."""
 
 	# TODO
@@ -455,6 +465,10 @@ def VarStore_optimize(self):
 				row[regionIdx] += v
 			row = tuple(row)
 
+			if use_NO_VARIATION_INDEX and not any(row):
+				front_mapping[(major<<16)+minor] = None
+				continue
+
 			encodings.add_row(row)
 			front_mapping[(major<<16)+minor] = row
 
@@ -537,9 +551,9 @@ def VarStore_optimize(self):
 			back_mapping[item] = (major<<16)+minor
 
 	# Compile final mapping.
-	varidx_map = {}
+	varidx_map = {NO_VARIATION_INDEX:NO_VARIATION_INDEX}
 	for k,v in front_mapping.items():
-		varidx_map[k] = back_mapping[v]
+		varidx_map[k] = back_mapping[v] if v is not None else NO_VARIATION_INDEX
 
 	# Remove unused regions.
 	self.prune_regions()

Tests/varLib/instancer/instancer_test.py

@@ -360,7 +360,7 @@ class InstantiateHVARTest(object):
                 assert support == pytest.approx(expectedRegion[axisTag])
 
         assert len(varStore.VarData) == 1
-        assert varStore.VarData[0].ItemCount == 2
+        assert varStore.VarData[0].ItemCount == 1
 
         assert hvar.AdvWidthMap is not None
         advWithMap = hvar.AdvWidthMap.mapping
@@ -368,9 +368,7 @@ class InstantiateHVARTest(object):
         assert advWithMap[".notdef"] == advWithMap["space"]
         varIdx = advWithMap[".notdef"]
         # these glyphs have no metrics variations in the test font
-        assert varStore.VarData[varIdx >> 16].Item[varIdx & 0xFFFF] == (
-            [0] * varStore.VarData[0].VarRegionCount
-        )
+        assert varIdx == varStore.NO_VARIATION_INDEX
 
         varIdx = advWithMap["hyphen"]
         assert varStore.VarData[varIdx >> 16].Item[varIdx & 0xFFFF] == expectedDeltas
@@ -458,6 +456,8 @@ class InstantiateItemVariationStoreTest(object):
 
         defaultDeltaArray = []
         for varidx, delta in sorted(defaultDeltas.items()):
+            if varidx == varStore.NO_VARIATION_INDEX:
+                continue
             major, minor = varidx >> 16, varidx & 0xFFFF
             if major == len(defaultDeltaArray):
                 defaultDeltaArray.append([])

Tests/varLib/varStore_test.py

@@ -13,7 +13,7 @@ from fontTools.ttLib.tables.otTables import VarStore
         (
             [{}, {"a": 1}],
             [
-                [10, 20],
+                [10, 10], # Test NO_VARIATION_INDEX
                 [100, 2000],
                 [100, 22000],
             ],