[subset] make glyph-names option match fonttools behavior

Don't encode psNames that are contained in standard glyph names set

src/hb-ot-post-table-v2subset.hh

@@ -76,6 +76,9 @@ HB_INTERNAL bool postV2Tail::subset (hb_subset_context_t *c) const
   hb_map_t old_new_index_map, old_gid_new_index_map;
   unsigned i = 0;
 
+  post::accelerator_t _post;
+  _post.init (c->plan->source);
+
   for (hb_codepoint_t new_gid = 0; new_gid < num_glyphs; new_gid++)
   {
     hb_codepoint_t old_gid = reverse_glyph_map.get (new_gid);
@@ -86,9 +89,24 @@ HB_INTERNAL bool postV2Tail::subset (hb_subset_context_t *c) const
     else if (old_new_index_map.has (old_index)) new_index = old_new_index_map.get (old_index);
     else
     {
-      new_index = 258 + i;
+      hb_bytes_t s = _post.find_glyph_name (old_gid);
+      int standard_glyph_index = -1;
+      for (unsigned i = 0; i < format1_names_length; i++)
+      {
+        if (s == format1_names (i))
+        {
+          standard_glyph_index = i;
+          break;
+        }
+      }
+      if (standard_glyph_index == -1)
+      {
+        new_index = 258 + i;
+        i++;
+      }
+      else
+      { new_index = standard_glyph_index; }
       old_new_index_map.set (old_index, new_index);
-      i++;
     }
     old_gid_new_index_map.set (old_gid, new_index);
   }
@@ -103,8 +121,6 @@ HB_INTERNAL bool postV2Tail::subset (hb_subset_context_t *c) const
                             })
   ;
 
-  post::accelerator_t _post;
-  _post.init (c->plan->source);
   bool ret = serialize (c->serializer, index_iter, &_post);
   _post.fini ();
   return_trace (ret);

test/subset/data/Makefile.am

@@ -41,6 +41,7 @@ EXTRA_DIST += \
 	expected/colr_with_components \
 	expected/cbdt \
 	expected/variable \
+	expected/glyph_names \
 	fonts \
 	profiles \
 	$(NULL)

test/subset/data/Makefile.sources

@@ -33,6 +33,7 @@ TESTS = \
 	tests/layout.tests \
 	tests/sbix.tests \
 	tests/variable.tests \
+	tests/glyph_names.tests \
 	$(NULL)
 
 # TODO: re-enable once colrv1 subsetting is stabilized.

test/subset/data/tests/glyph_names.tests

@@ -0,0 +1,9 @@
+FONTS:
+Ubuntu-Regular.ttf
+
+PROFILES:
+glyph-names.txt
+
+SUBSETS:
+U+0x0,U+0x8,U+0x9,U+0x1d,U+0x20,U+0xb7
+*

test/subset/meson.build

@@ -36,6 +36,7 @@ tests = [
   'colr_with_components',
   'cbdt',
   'variable',
+  'glyph_names',
 ]
 
 repack_tests = [