Merge pull request #1832 from googlefonts/kern-gen-fix

Fix kerning feature generation
googlefonts · Dec 2, 2024 · 1b74da5 · 1b74da5
2 parents 73b85a5 + 5743f4e
commit 1b74da5
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Showing 2 changed files with 13 additions and 10 deletions.
diff --git a/src/fontra/workflow/actions/features.py b/src/fontra/workflow/actions/features.py
@@ -195,8 +195,8 @@ def _kernKeySortFunc(self, item):
         return key.startswith(self._kern1Prefix) or key.startswith(self._kern2Prefix)
 
     async def processFeatures(self, features: OpenTypeFeatures) -> OpenTypeFeatures:
-        verticalKerning = (await self.inputKerning).get(self._kernFeatureTag)
-        if verticalKerning is None:
+        kerning = (await self.inputKerning).get(self._kernFeatureTag)
+        if kerning is None:
             return features
 
         glyphMap = await self.inputGlyphMap
@@ -213,24 +213,26 @@ async def processFeatures(self, features: OpenTypeFeatures) -> OpenTypeFeatures:
                     for k, v in mapLocation(sources[sid].location).items()
                 }
             )
-            for sid in verticalKerning.sourceIdentifiers
+            for sid in kerning.sourceIdentifiers
         ]
 
         w = FeatureWriter()
 
-        for groupName, group in sorted(verticalKerning.groups.items()):
+        for groupName, group in sorted(kerning.groups.items()):
             w.addGroup(groupName, group)
 
         fea = w.addFeature(self._kernFeatureTag)
 
         for left, rightDict in sorted(
-            verticalKerning.values.items(), key=self._kernKeySortFunc
+            kerning.values.items(), key=self._kernKeySortFunc
         ):
-            if left.startswith(self._kern1Prefix):
+            leftIsClass = left.startswith(self._kern1Prefix)
+            if leftIsClass:
                 left = "@" + left
 
             for right, values in sorted(rightDict.items(), key=self._kernKeySortFunc):
-                if right.startswith(self._kern2Prefix):
+                rightIsClass = right.startswith(self._kern2Prefix)
+                if rightIsClass:
                     right = "@" + right
 
                 values = [0 if v is None else round(v) for v in values]
@@ -245,7 +247,8 @@ async def processFeatures(self, features: OpenTypeFeatures) -> OpenTypeFeatures:
                     for loc, v in zip(locations, values, strict=True):
                         scalar.add_value(loc, v)
 
-                fea.addLine(f"pos {left} {right} {scalar}")
+                enumStr = "enum " if leftIsClass != rightIsClass else ""
+                fea.addLine(f"{enumStr}pos {left} {right} {scalar}")
 
         featureText = w.asFea()
 

diff --git a/test-py/data/workflow/output-generate-vkrn-feature.fontra/features.txt b/test-py/data/workflow/output-generate-vkrn-feature.fontra/features.txt
@@ -3,7 +3,7 @@
 @kern.bottom.BC = [B C];
 feature vkrn {
     pos C C (wdth=100,wght=400:-5 wdth=100,wght=900:-15 wdth=200,wght=400:-25 wdth=200,wght=900:-35);
-    pos C @kern.bottom.BC (wdth=100,wght=400:-10 wdth=100,wght=900:-20 wdth=200,wght=400:-30 wdth=200,wght=900:-40);
-    pos @kern.top.AB C (wdth=100,wght=400:10 wdth=100,wght=900:20 wdth=200,wght=400:30 wdth=200,wght=900:40);
+    enum pos C @kern.bottom.BC (wdth=100,wght=400:-10 wdth=100,wght=900:-20 wdth=200,wght=400:-30 wdth=200,wght=900:-40);
+    enum pos @kern.top.AB C (wdth=100,wght=400:10 wdth=100,wght=900:20 wdth=200,wght=400:30 wdth=200,wght=900:40);
     pos @kern.top.AB @kern.bottom.BC (wdth=100,wght=400:5 wdth=100,wght=900:15 wdth=200,wght=400:25 wdth=200,wght=900:35);
 } vkrn;