[compile] Support for beyond-64k fonts

Lib/ufo2ft/__init__.py

@@ -49,8 +49,9 @@ def compileTTF(ufo, **kwargs):
     in between two off-curves can be dropped when building glyphs (default: False).
 
     *allQuadratic* (bool) specifies whether to convert all curves to quadratic - True
-    by default, builds traditional glyf v0 table. If False, quadratic curves or cubic
-    curves are generated depending on which has fewer points; a glyf v1 is generated.
+    by default, builds traditional glyf v0 table. If False, quadratic or cubic curves
+    are generated depending on which has fewer points, and any cubic outlines are
+    placed in the uppercase GLYF table.
     """
     return TTFCompiler(**kwargs).compile(ufo)
 
@@ -158,8 +159,9 @@ def compileVariableTTFs(designSpaceDoc, **kwargs):
       designspace will by built.
 
     *allQuadratic* (bool) specifies whether to convert all curves to quadratic - True
-      by default, builds traditional glyf v0 table. If False, quadratic curves or cubic
-      curves are generated depending on which has fewer points; a glyf v1 is generated.
+      by default, builds traditional glyf v0 table. If False, quadratic or cubic curves
+      are generated depending on which has fewer points, and any cubic outlines are
+      placed in the uppercase GLYF table.
 
     The rest of the arguments works the same as in the other compile functions.
 
@@ -281,8 +283,9 @@ def compileVariableCFF2s(designSpaceDoc, **kwargs):
       designspace will by built.
 
     *allQuadratic* (bool) specifies whether to convert all curves to quadratic - True
-      by default, builds traditional glyf v0 table. If False, quadratic curves or cubic
-      curves are generated depending on which has fewer points; a glyf v1 is generated.
+      by default, builds traditional glyf v0 table. If False, quadratic or cubic curves
+      are generated depending on which has fewer points, and any cubic outlines are
+      placed in the uppercase GLYF table.
 
     The rest of the arguments works the same as in the other compile functions.
 

Lib/ufo2ft/_compilers/baseCompiler.py

@@ -105,6 +105,13 @@ def postprocess(self, ttf, ufo, glyphSet, info=None):
             )
             kwargs = prune_unknown_kwargs(self.__dict__, postProcessor.process)
             ttf = postProcessor.process(**kwargs)
+            # Upgrade to the beyond-64k companion tables (GLYF/LOCA/MAXP/...)
+            # only on final outputs. While building a variable font,
+            # postProcessorClass is None for the interpolation masters (see
+            # _compileNeededSources), so they keep their lowercase glyf/loca/maxp
+            # tables and varLib sees a consistent table family; the merged VF is
+            # uppercased here when its own postprocess runs.
+            _maybe_uppercase_beyond64k(ttf, getattr(self, "allQuadratic", True))
         return ttf
 
     def compileFeatures(
@@ -481,3 +488,18 @@ def compile_variable_features(self, designSpaceDoc, ttFont, glyphSet):
 
         # Add back feature variations, as the code above would overwrite them.
         varLib.addGSUBFeatureVariations(ttFont, designSpaceDoc)
+
+
+def _maybe_uppercase_beyond64k(ttFont, allQuadratic=True):
+    # maxp.numGlyphs is uint16: a count of 65536 overflows it even though every
+    # gid (0..0xFFFF) still fits. Guard on count > 0xFFFF, not gid width.
+    # allQuadratic=False opts into cubic curves (CUBIC flag is only valid in the
+    # uppercase GLYF, never lowercase glyf), so always upgrade then to make the
+    # compatibility breaking obvious rather than depending on whether a cubic
+    # was emitted, which could be a silent footgun.
+    if len(ttFont.getGlyphOrder()) <= 0xFFFF and allQuadratic:
+        return
+
+    from fontTools.ttLib.beyond64k import upper_tables
+
+    upper_tables(ttFont)

Lib/ufo2ft/_compilers/interpolatableTTFCompiler.py

@@ -28,7 +28,7 @@ class InterpolatableTTFCompiler(BaseInterpolatableCompiler):
 
     def compileOutlines(self, ufo, glyphSet, layerName=None):
         kwargs = prune_unknown_kwargs(self.__dict__, self.outlineCompilerClass)
-        kwargs["glyphDataFormat"] = 0 if self.allQuadratic else 1
+        kwargs["allowCubic"] = not self.allQuadratic
         kwargs["tables"] = SPARSE_TTF_MASTER_TABLES if layerName else None
         # we want to keep coordinates as floats in glyf masters so that fonttools
         # can compute impliable on-curve points from unrounded coordinates before

Lib/ufo2ft/_compilers/ttfCompiler.py

@@ -23,6 +23,6 @@ class TTFCompiler(BaseCompiler):
 
     def compileOutlines(self, ufo, glyphSet):
         kwargs = prune_unknown_kwargs(self.__dict__, self.outlineCompilerClass)
-        kwargs["glyphDataFormat"] = 0 if self.allQuadratic else 1
+        kwargs["allowCubic"] = not self.allQuadratic
         outlineCompiler = self.outlineCompilerClass(ufo, glyphSet=glyphSet, **kwargs)
         return outlineCompiler.compile()

Lib/ufo2ft/outlineCompiler.py

@@ -381,7 +381,7 @@ def setupTable_head(self):
         )
         head.fontDirectionHint = 2
         head.indexToLocFormat = 0
-        head.glyphDataFormat = getattr(self, "glyphDataFormat", 0)
+        head.glyphDataFormat = 0
 
     def setupTable_name(self):
         """
@@ -1673,7 +1673,7 @@ def __init__(
         dropImpliedOnCurves=False,
         autoUseMyMetrics=True,
         roundCoordinates=True,
-        glyphDataFormat=0,
+        allowCubic=False,
         ftConfig=None,
         *,
         compilingVFDefaultSource=True,
@@ -1693,7 +1693,7 @@ def __init__(
         self.autoUseMyMetrics = autoUseMyMetrics
         self.dropImpliedOnCurves = dropImpliedOnCurves
         self.roundCoordinates = roundCoordinates
-        self.glyphDataFormat = glyphDataFormat
+        self.allowCubic = allowCubic
 
     def makeMissingRequiredGlyphs(self, font, glyphSet, sfntVersion, notdefGlyph=None):
         """
@@ -1728,7 +1728,6 @@ def compileGlyphs(self):
         allGlyphs = self.allGlyphs
         ttGlyphs = {}
         round = otRound if self.roundCoordinates else noRound
-        glyphDataFormat = self.glyphDataFormat
         for name in self.glyphOrder:
             glyph = allGlyphs[name]
             pen = TTGlyphPointPen(allGlyphs)
@@ -1743,14 +1742,13 @@ def compileGlyphs(self):
                     round=round,
                 )
                 if (
-                    glyphDataFormat == 0
+                    not self.allowCubic
                     and ttGlyph.numberOfContours > 0
                     and any(f & flagCubic for f in ttGlyph.flags)
                 ):
                     raise ValueError(
-                        f"{name!r} has cubic Bezier curves, but glyphDataFormat=0; "
-                        "either convert to quadratic (convertCubics=True) or use "
-                        "allQuadratic=False so that glyphDataFormat=1."
+                        f"{name!r} has cubic Bezier curves; either convert to "
+                        "quadratic (convertCubics=True) or use allQuadratic=False."
                     )
             ttGlyphs[name] = ttGlyph
         return ttGlyphs