[subset/VARC] Subset MultiVarStore

Lib/fontTools/subset/__init__.py

@@ -14,7 +14,7 @@ from fontTools.misc.cliTools import makeOutputFileName
 from fontTools.subset.util import _add_method, _uniq_sort
 from fontTools.subset.cff import *
 from fontTools.subset.svg import *
-from fontTools.varLib import varStore  # for subset_varidxes
+from fontTools.varLib import varStore, multiVarStore  # For monkey-patching
 from fontTools.ttLib.tables._n_a_m_e import NameRecordVisitor
 import sys
 import struct
@@ -2629,13 +2629,17 @@ def closure_glyphs(self, s):
 
     s.glyphs.update(variants)
 
+
 @_add_method(ttLib.getTableClass("VARC"))
 def subset_glyphs(self, s):
     indices = self.table.Coverage.subset(s.glyphs)
     # TODO Subset MultiVarStore
-    self.table.VarCompositeGlyphs.glyphs = _list_subset(self.table.VarCompositeGlyphs.glyphs, indices)
+    self.table.VarCompositeGlyphs.glyphs = _list_subset(
+        self.table.VarCompositeGlyphs.glyphs, indices
+    )
     return bool(self.table.VarCompositeGlyphs.glyphs)
 
+
 @_add_method(ttLib.getTableClass("VARC"))
 def closure_glyphs(self, s):
     if self.table.VarCompositeGlyphs:
@@ -2650,6 +2654,30 @@ def closure_glyphs(self, s):
                         glyphs.add(name)
                         new.add(name)
 
+
+@_add_method(ttLib.getTableClass("VARC"))
+def prune_post_subset(self, font, options):
+    table = self.table
+
+    if not hasattr(table, "MultiVarStore"):
+        return True
+
+    store = table.MultiVarStore
+
+    usedVarIdxes = set()
+
+    # Collect.
+    table.collect_varidxes(usedVarIdxes)
+
+    # Subset.
+    varidx_map = store.subset_varidxes(usedVarIdxes)
+
+    # Map.
+    table.remap_varidxes(varidx_map)
+
+    return True
+
+
 @_add_method(ttLib.getTableClass("MATH"))
 def closure_glyphs(self, s):
     if self.table.MathVariants:

Lib/fontTools/varLib/multiVarStore.py

@@ -3,6 +3,7 @@ from fontTools.misc.intTools import bit_count
 from fontTools.misc.vector import Vector
 from fontTools.ttLib.tables import otTables as ot
 from fontTools.varLib.models import supportScalar
+import fontTools.varLib.varStore  # For monkey-patching
 from fontTools.varLib.builder import (
     buildVarRegionList,
     buildVarRegion,
@@ -191,3 +192,29 @@ class MultiVarStoreInstancer(object):
         varData = self._varData
         scalars = [self._getScalar(ri) for ri in varData[varDataIndex].VarRegionIndex]
         return self.interpolateFromDeltasAndScalars(deltas, scalars)
+
+
+def MultiVarStore_subset_varidxes(self, varIdxes):
+    return ot.VarStore.subset_varidxes(self, varIdxes, VarData="MultiVarData")
+
+
+ot.MultiVarStore.prune_regions = ot.VarStore.prune_regions
+ot.MultiVarStore.subset_varidxes = MultiVarStore_subset_varidxes
+
+
+def VARC_collect_varidxes(self, varidxes):
+    for glyph in self.VarCompositeGlyphs.glyphs:
+        for component in glyph.components:
+            varidxes.add(component.locationVarIndex)
+            varidxes.add(component.transformVarIndex)
+
+
+def VARC_remap_varidxes(self, varidxes_map):
+    for glyph in self.VarCompositeGlyphs.glyphs:
+        for component in glyph.components:
+            component.locationVarIndex = varidxes_map[component.locationVarIndex]
+            component.transformVarIndex = varidxes_map[component.transformVarIndex]
+
+
+ot.VARC.collect_varidxes = VARC_collect_varidxes
+ot.VARC.remap_varidxes = VARC_remap_varidxes

Lib/fontTools/varLib/varStore.py

@@ -246,26 +246,29 @@ class VarStoreInstancer(object):
 
 
 def VarStore_subset_varidxes(
-    self, varIdxes, optimize=True, retainFirstMap=False, advIdxes=set()
+    self,
+    varIdxes,
+    optimize=True,
+    retainFirstMap=False,
+    advIdxes=set(),
+    *,
+    VarData="VarData",
 ):
     # Sort out used varIdxes by major/minor.
-    used = {}
+    used = defaultdict(set)
     for varIdx in varIdxes:
         if varIdx == NO_VARIATION_INDEX:
             continue
         major = varIdx >> 16
         minor = varIdx & 0xFFFF
-        d = used.get(major)
-        if d is None:
-            d = used[major] = set()
-        d.add(minor)
+        used[major].add(minor)
     del varIdxes
 
     #
     # Subset VarData
     #
 
-    varData = self.VarData
+    varData = getattr(self, VarData)
     newVarData = []
     varDataMap = {NO_VARIATION_INDEX: NO_VARIATION_INDEX}
     for major, data in enumerate(varData):
@@ -296,12 +299,13 @@ def VarStore_subset_varidxes(
         data.Item = newItems
         data.ItemCount = len(data.Item)
 
-        data.calculateNumShorts(optimize=optimize)
+        if VarData == "VarData":
+            data.calculateNumShorts(optimize=optimize)
 
-    self.VarData = newVarData
-    self.VarDataCount = len(self.VarData)
+    setattr(self, VarData, newVarData)
+    setattr(self, VarData + "Count", len(newVarData))
 
-    self.prune_regions()
+    self.prune_regions(VarData=VarData)
 
     return varDataMap
 
@@ -309,7 +313,7 @@ def VarStore_subset_varidxes(
 ot.VarStore.subset_varidxes = VarStore_subset_varidxes
 
 
-def VarStore_prune_regions(self):
+def VarStore_prune_regions(self, *, VarData="VarData"):
     """Remove unused VarRegions."""
     #
     # Subset VarRegionList
@@ -317,7 +321,7 @@ def VarStore_prune_regions(self):
 
     # Collect.
     usedRegions = set()
-    for data in self.VarData:
+    for data in getattr(self, VarData):
         usedRegions.update(data.VarRegionIndex)
     # Subset.
     regionList = self.VarRegionList
@@ -330,7 +334,7 @@ def VarStore_prune_regions(self):
     regionList.Region = newRegions
     regionList.RegionCount = len(regionList.Region)
     # Map.
-    for data in self.VarData:
+    for data in getattr(self, VarData):
         data.VarRegionIndex = [regionMap[i] for i in data.VarRegionIndex]