From d4d8c4ac5b82a4ad47e1f88444b547eefccffe59 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Fri, 19 Aug 2022 11:03:23 -0600
Subject: [PATCH] [scaleUpem] Support CFF/CFF2

---
 Lib/fontTools/cffLib/__init__.py |  2 ++
 Lib/fontTools/subset/cff.py      |  1 -
 Lib/fontTools/ttLib/scaleUpem.py | 44 +++++++++++++++++++++++++++-----
 3 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/Lib/fontTools/cffLib/__init__.py b/Lib/fontTools/cffLib/__init__.py
index fc82bb27a..3eda9ba48 100644
--- a/Lib/fontTools/cffLib/__init__.py
+++ b/Lib/fontTools/cffLib/__init__.py
@@ -1037,6 +1037,8 @@ class VarStoreData(object):
 		return len(self.data)
 
 	def getNumRegions(self, vsIndex):
+		if vsIndex is None:
+			vsIndex = 0
 		varData = self.otVarStore.VarData[vsIndex]
 		numRegions = varData.VarRegionCount
 		return numRegions
diff --git a/Lib/fontTools/subset/cff.py b/Lib/fontTools/subset/cff.py
index 0dcb79755..532743e35 100644
--- a/Lib/fontTools/subset/cff.py
+++ b/Lib/fontTools/subset/cff.py
@@ -3,7 +3,6 @@ from fontTools import ttLib
 from fontTools.pens.basePen import NullPen
 from fontTools.misc.roundTools import otRound
 from fontTools.misc.loggingTools import deprecateFunction
-from fontTools.varLib.varStore import VarStoreInstancer
 from fontTools.subset.util import _add_method, _uniq_sort
 
 
diff --git a/Lib/fontTools/ttLib/scaleUpem.py b/Lib/fontTools/ttLib/scaleUpem.py
index 02d356996..8282dd71e 100644
--- a/Lib/fontTools/ttLib/scaleUpem.py
+++ b/Lib/fontTools/ttLib/scaleUpem.py
@@ -8,6 +8,8 @@ from fontTools.ttLib.ttVisitor import TTVisitor
 import fontTools.ttLib as ttLib
 import fontTools.ttLib.tables.otBase as otBase
 import fontTools.ttLib.tables.otTables as otTables
+from fontTools.cffLib import VarStoreData
+import fontTools.cffLib.specializer as cffSpecializer
 from fontTools.misc.fixedTools import otRound
 
 
@@ -144,6 +146,41 @@ def visit(visitor, obj, attr, kernTables):
             kernTable[k] = visitor.scale(kernTable[k])
 
 
+def _cff_scale(visitor, args):
+    new_args = []
+    for arg in args:
+        if not isinstance(arg, list):
+            new_args.append(visitor.scale(arg))
+        else:
+            num_blends = arg[-1]
+            _cff_scale(visitor, arg)
+            arg[-1] = num_blends
+            new_args.append(arg)
+    args[:] = new_args
+
+
+@ScalerVisitor.register_attr(
+    (ttLib.getTableClass("CFF "), ttLib.getTableClass("CFF2")), "cff"
+)
+def visit(visitor, obj, attr, cff):
+    cff.desubroutinize()
+    topDict = cff.topDictIndex[0]
+    varStore = getattr(topDict, "VarStore", None)
+    getNumRegions = varStore.getNumRegions if varStore is not None else None
+    for fontname in cff.keys():
+        font = cff[fontname]
+        cs = font.CharStrings
+        for g in font.charset:
+            c, _ = cs.getItemAndSelector(g)
+
+            commands = cffSpecializer.programToCommands(
+                c.program, getNumRegions=getNumRegions
+            )
+            for op, args in commands:
+                _cff_scale(visitor, args)
+            c.program[:] = cffSpecializer.commandsToProgram(commands)
+
+
 # ItemVariationStore
 
 
@@ -229,13 +266,6 @@ def main(args=None):
     font = TTFont(args[0])
     new_upem = int(args[1])
 
-    if "CFF " in font or "CFF2" in font:
-        print(
-            "fonttools ttLib.scaleUpem: CFF/CFF2 fonts are not supported.",
-            file=sys.stderr,
-        )
-        sys.exit(1)
-
     scale_upem(font, new_upem)
 
     print("Writing out.ttf")