Register lookups under DFLT, too

googlefonts · May 24, 2024 · 9ff6b49 · 9ff6b49
1 parent df592b1
commit 9ff6b49
Show file tree

Hide file tree

Showing 2 changed files with 28 additions and 5 deletions.
diff --git a/Lib/ufo2ft/featureWriters/kernFeatureWriter2.py b/Lib/ufo2ft/featureWriters/kernFeatureWriter2.py
@@ -523,8 +523,28 @@ def _makeFeatureBlocks(self, lookups):
         return features
 
     def _registerKernLookups(self, feature, lookups):
+        # InDesign bugfix: register kerning lookups for all LTR scripts under DFLT
+        # so that the basic composer, without a language selected, will still kern.
+        # Register LTR lookups if any, otherwise RTL lookups.
+        dfltLookups = []
+        ltrLookups = lookups.get("LTR")
+        rtlLookups = lookups.get("RTL")
         if "DFLT" in lookups:
-            ast.addLookupReferences(feature, lookups["DFLT"])
+            dfltLookups.extend(lkp for lkp in lookups["DFLT"])
+            dfltLookups.extend(
+                lkp for lkp in (ltrLookups or rtlLookups) if lkp not in dfltLookups
+            )
+            ast.addLookupReferences(feature, dfltLookups)
+        ltrLookupsRest = (
+            [lkp for lkp in ltrLookups if lkp not in dfltLookups]
+            if ltrLookups
+            else None
+        )
+        rtlLookupsRest = (
+            [lkp for lkp in rtlLookups if lkp not in dfltLookups]
+            if rtlLookups
+            else None
+        )
 
         scriptGroups = self.context.scriptGroups
         if "dist" in self.context.todo:
@@ -535,8 +555,6 @@ def _registerKernLookups(self, feature, lookups):
         ltrScripts = kernScripts.get("LTR", [])
         rtlScripts = kernScripts.get("RTL", [])
 
-        ltrLookups = lookups.get("LTR")
-        rtlLookups = lookups.get("RTL")
         if ltrLookups and rtlLookups:
             if ltrScripts and rtlScripts:
                 for script, langs in ltrScripts:
@@ -560,14 +578,16 @@ def _registerKernLookups(self, feature, lookups):
                     )
         elif ltrLookups:
             if not (rtlScripts or distScripts):
-                ast.addLookupReferences(feature, ltrLookups)
+                if ltrLookupsRest:
+                    ast.addLookupReferences(feature, ltrLookupsRest)
             else:
                 ast.addLookupReferences(feature, ltrLookups, script="DFLT")
                 for script, langs in ltrScripts:
                     ast.addLookupReferences(feature, ltrLookups, script, langs)
         elif rtlLookups:
             if not (ltrScripts or distScripts):
-                ast.addLookupReferences(feature, rtlLookups)
+                if rtlLookupsRest:
+                    ast.addLookupReferences(feature, rtlLookupsRest)
             else:
                 ast.addLookupReferences(feature, rtlLookups, script="DFLT")
                 for script, langs in rtlScripts:

diff --git a/tests/featureWriters/kernFeatureWriter2_test.py b/tests/featureWriters/kernFeatureWriter2_test.py
@@ -694,6 +694,7 @@ def test_kern_LTR_and_RTL(self, FontClass):
 
             feature kern {
                 lookup kern_dflt;
+                lookup kern_ltr;
                 script latn;
                 language dflt;
                 lookup kern_ltr;
@@ -808,6 +809,8 @@ def test_kern_LTR_and_RTL_with_marks(self, FontClass):
 
             feature kern {
                 lookup kern_dflt;
+                lookup kern_ltr;
+                lookup kern_ltr_marks;
                 script latn;
                 language dflt;
                 lookup kern_ltr;