[subset] Add support for "--gids" option

cmap subsetting now retains entries associated with any glyph ids explicitly requested

src/hb-ot-cmap-table.hh

@@ -56,6 +56,18 @@ struct CmapSubtableFormat0
 	out->add (i);
   }
 
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+                        hb_map_t *mapping /* OUT */) const
+  {
+    for (unsigned i = 0; i < 256; i++)
+      if (glyphIdArray[i])
+      {
+        hb_codepoint_t glyph = glyphIdArray[i];
+        *unicodes << i;
+        *mapping << hb_pair_t<hb_codepoint_t, hb_codepoint_t> (i, glyph);
+      }
+  }
+
   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
@@ -238,8 +250,7 @@ struct CmapSubtableFormat4
 		 { return _.first <= 0xFFFF; })
     ;
 
-    //comment off temporarily while we're working on supporting --gids option
-    //if (format4_iter.len () == 0) return;
+    if (format4_iter.len () == 0) return;
 
     unsigned table_initpos = c->length ();
     if (unlikely (!c->extend_min (*this))) return;
@@ -377,6 +388,45 @@ struct CmapSubtableFormat4
       }
     }
 
+    void collect_mapping (hb_set_t *unicodes, /* OUT */
+                          hb_map_t *mapping /* OUT */) const
+    {
+      unsigned count = this->segCount;
+      if (count && this->startCount[count - 1] == 0xFFFFu)
+        count--; /* Skip sentinel segment. */
+      for (unsigned i = 0; i < count; i++)
+      {
+        hb_codepoint_t start = this->startCount[i];
+        hb_codepoint_t end = this->endCount[i];
+        unsigned rangeOffset = this->idRangeOffset[i];
+        if (rangeOffset == 0)
+        {
+          for (hb_codepoint_t codepoint = start; codepoint <= end; codepoint++)
+          {
+            hb_codepoint_t gid = (codepoint + this->idDelta[i]) & 0xFFFFu;
+            if (unlikely (!gid))
+              continue;
+            *unicodes << codepoint;
+            *mapping << hb_pair_t<hb_codepoint_t, hb_codepoint_t> (codepoint, gid);
+          }
+        }
+        else
+        {
+          for (hb_codepoint_t codepoint = start; codepoint <= end; codepoint++)
+          {
+            unsigned index = rangeOffset / 2 + (codepoint - this->startCount[i]) + i - this->segCount;
+            if (unlikely (index >= this->glyphIdArrayLength))
+              break;
+            hb_codepoint_t gid = this->glyphIdArray[index];
+            if (unlikely (!gid))
+              continue;
+            *unicodes << codepoint;
+            *mapping << hb_pair_t<hb_codepoint_t, hb_codepoint_t> (codepoint, gid);
+          }
+        }
+      }
+    }
+
     const HBUINT16 *endCount;
     const HBUINT16 *startCount;
     const HBUINT16 *idDelta;
@@ -397,6 +447,13 @@ struct CmapSubtableFormat4
     accel.collect_unicodes (out);
   }
 
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+                        hb_map_t *mapping /* OUT */) const
+  {
+    accelerator_t accel (this);
+    accel.collect_mapping (unicodes, mapping);
+  }
+
   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
@@ -499,6 +556,21 @@ struct CmapSubtableTrimmed
 	out->add (start + i);
   }
 
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+                        hb_map_t *mapping /* OUT */) const
+  {
+    hb_codepoint_t start_cp = startCharCode;
+    unsigned count = glyphIdArray.len;
+    for (unsigned i = 0; i < count; i++)
+      if (glyphIdArray[i])
+      {
+        hb_codepoint_t unicode = start_cp + i;
+        hb_codepoint_t glyphid = glyphIdArray[i];
+        *unicodes << unicode;
+        *mapping << hb_pair_t<hb_codepoint_t, hb_codepoint_t> (unicode, glyphid);
+      }
+  }
+
   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
@@ -557,6 +629,36 @@ struct CmapSubtableLongSegmented
     }
   }
 
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+                        hb_map_t *mapping, /* OUT */
+                        unsigned num_glyphs) const
+  {
+    for (unsigned i = 0; i < this->groups.len; i++)
+    {
+      hb_codepoint_t start = this->groups[i].startCharCode;
+      hb_codepoint_t end = hb_min ((hb_codepoint_t) this->groups[i].endCharCode,
+                                   (hb_codepoint_t) HB_UNICODE_MAX);
+      hb_codepoint_t gid = this->groups[i].glyphID;
+      if (!gid)
+      {
+        /* Intention is: if (hb_is_same (T, CmapSubtableFormat13)) continue; */
+        if (! T::group_get_glyph (this->groups[i], end)) continue;
+        start++;
+        gid++;
+      }
+      if (unlikely ((unsigned int) gid >= num_glyphs)) continue;
+      if (unlikely ((unsigned int) (gid + end - start) >= num_glyphs))
+        end = start + (hb_codepoint_t) num_glyphs - gid;
+
+      for (unsigned cp = start; cp <= end; cp++)
+      {
+        *unicodes << cp;
+        *mapping << hb_pair_t<hb_codepoint_t, hb_codepoint_t> (cp, gid);
+        gid++;
+      }
+    }
+  }
+
   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
@@ -783,6 +885,19 @@ struct NonDefaultUVS : SortedArrayOf<UVSMapping, HBUINT32>
       out->add (arrayZ[i].unicodeValue);
   }
 
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    unsigned count = len;
+    for (unsigned i = 0; i < count; i++)
+    {
+      hb_codepoint_t unicode = arrayZ[i].unicodeValue;
+      hb_codepoint_t glyphid = arrayZ[i].glyphID;
+      *unicodes << unicode;
+      *mapping << hb_pair_t<hb_codepoint_t, hb_codepoint_t> (unicode, glyphid);
+    }
+  }
+
   void closure_glyphs (const hb_set_t      *unicodes,
 		       hb_set_t            *glyphset) const
   {
@@ -795,7 +910,7 @@ struct NonDefaultUVS : SortedArrayOf<UVSMapping, HBUINT32>
 
   NonDefaultUVS* copy (hb_serialize_context_t *c,
 		       const hb_set_t *unicodes,
-		       const hb_set_t *glyphs,
+		       const hb_set_t *glyphs_requested,
 		       const hb_map_t *glyph_map) const
   {
     NonDefaultUVS *out = c->start_embed<NonDefaultUVS> ();
@@ -805,7 +920,7 @@ struct NonDefaultUVS : SortedArrayOf<UVSMapping, HBUINT32>
     + as_array ()
     | hb_filter ([&] (const UVSMapping& _)
 		 {
-		   return unicodes->has (_.unicodeValue) || glyphs->has (_.glyphID);
+		   return unicodes->has (_.unicodeValue) || glyphs_requested->has (_.glyphID);
 		 })
     ;
 
@@ -867,6 +982,14 @@ struct VariationSelectorRecord
     (base+nonDefaultUVS).collect_unicodes (out);
   }
 
+  void collect_mapping (const void *base,
+			hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    (base+defaultUVS).collect_unicodes (unicodes);
+    (base+nonDefaultUVS).collect_mapping (unicodes, mapping);
+  }
+
   int cmp (const hb_codepoint_t &variation_selector) const
   { return varSelector.cmp (variation_selector); }
 
@@ -881,7 +1004,7 @@ struct VariationSelectorRecord
   hb_pair_t<unsigned, unsigned>
   copy (hb_serialize_context_t *c,
 	const hb_set_t *unicodes,
-	const hb_set_t *glyphs,
+	const hb_set_t *glyphs_requested,
 	const hb_map_t *glyph_map,
 	const void *base) const
   {
@@ -896,7 +1019,7 @@ struct VariationSelectorRecord
     if (nonDefaultUVS != 0)
     {
       c->push ();
-      if (c->copy (base+nonDefaultUVS, unicodes, glyphs, glyph_map))
+      if (c->copy (base+nonDefaultUVS, unicodes, glyphs_requested, glyph_map))
 	non_default_uvs_objidx = c->pop_pack ();
       else c->pop_discard ();
     }
@@ -945,7 +1068,7 @@ struct CmapSubtableFormat14
 
   void serialize (hb_serialize_context_t *c,
 		  const hb_set_t *unicodes,
-		  const hb_set_t *glyphs,
+		  const hb_set_t *glyphs_requested,
 		  const hb_map_t *glyph_map,
 		  const void *base)
   {
@@ -974,7 +1097,7 @@ struct CmapSubtableFormat14
     hb_vector_t<hb_pair_t<unsigned, unsigned>> obj_indices;
     for (int i = src_tbl->record.len - 1; i >= 0; i--)
     {
-      hb_pair_t<unsigned, unsigned> result = src_tbl->record[i].copy (c, unicodes, glyphs, glyph_map, base);
+      hb_pair_t<unsigned, unsigned> result = src_tbl->record[i].copy (c, unicodes, glyphs_requested, glyph_map, base);
       if (result.first || result.second)
 	obj_indices.push (result);
     }
@@ -1037,6 +1160,13 @@ struct CmapSubtableFormat14
       _.collect_unicodes (out, this);
   }
 
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    for (const VariationSelectorRecord& _ : record)
+      _.collect_mapping (this, unicodes, mapping);
+  }
+
   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
@@ -1086,6 +1216,22 @@ struct CmapSubtable
     }
   }
 
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping, /* OUT */
+			unsigned num_glyphs = UINT_MAX) const
+  {
+    switch (u.format) {
+    case  0: u.format0 .collect_mapping (unicodes, mapping); return;
+    case  4: u.format4 .collect_mapping (unicodes, mapping); return;
+    case  6: u.format6 .collect_mapping (unicodes, mapping); return;
+    case 10: u.format10.collect_mapping (unicodes, mapping); return;
+    case 12: u.format12.collect_mapping (unicodes, mapping, num_glyphs); return;
+    case 13: u.format13.collect_mapping (unicodes, mapping, num_glyphs); return;
+    case 14:
+    default: return;
+    }
+  }
+
   template<typename Iterator,
 	   hb_requires (hb_is_iterator (Iterator))>
   void serialize (hb_serialize_context_t *c,
@@ -1097,7 +1243,7 @@ struct CmapSubtable
     switch (format) {
     case  4: return u.format4.serialize (c, it);
     case 12: return u.format12.serialize (c, it);
-    case 14: return u.format14.serialize (c, plan->unicodes, plan->_glyphset, plan->glyph_map, base);
+    case 14: return u.format14.serialize (c, plan->unicodes, plan->glyphs_requested, plan->glyph_map, base);
     default: return;
     }
   }
@@ -1200,7 +1346,7 @@ struct cmap
   static constexpr hb_tag_t tableTag = HB_OT_TAG_cmap;
 
   template<typename Iterator, typename EncodingRecIter,
-	   hb_requires (hb_is_iterator (Iterator))>
+	   hb_requires (hb_is_iterator (EncodingRecIter))>
   void serialize (hb_serialize_context_t *c,
 		  Iterator it,
 		  EncodingRecIter encodingrec_iter,
@@ -1215,13 +1361,38 @@ struct cmap
     for (const EncodingRecord& _ : encodingrec_iter)
     {
       hb_set_t unicodes_set;
-      (base+_.subtable).collect_unicodes (&unicodes_set);
+      hb_map_t cp_glyphid_map;
+      (base+_.subtable).collect_mapping (&unicodes_set, &cp_glyphid_map);
 
       unsigned format = (base+_.subtable).u.format;
+      if (!plan->glyphs_requested->is_empty ())
+      {
+        auto table_iter =
+        + hb_zip (unicodes_set.iter(), unicodes_set.iter() | hb_map(cp_glyphid_map))
+        | hb_filter (plan->_glyphset, hb_second)
+        | hb_filter ([plan] (const hb_pair_t<hb_codepoint_t, hb_codepoint_t>& p)
+                     {
+                       return plan->unicodes->has (p.first) ||
+                              plan->glyphs_requested->has (p.second);
+                     })
+        | hb_map ([plan] (const hb_pair_t<hb_codepoint_t, hb_codepoint_t>& p_org)
+                  {
+                    return hb_pair_t<hb_codepoint_t, hb_codepoint_t> (p_org.first, plan->glyph_map->get(p_org.second));
+                  })
+        ;
   
-      if (format == 4) c->copy (_, + it | hb_filter (unicodes_set, hb_first), 4u, base, plan, &format4objidx);
-      else if (format == 12) c->copy (_, + it | hb_filter (unicodes_set, hb_first), 12u, base, plan, &format12objidx);
-      else if (format == 14) c->copy (_, it, 14u, base, plan, &format14objidx);
+        if (format == 4) c->copy (_, table_iter, 4u, base, plan, &format4objidx);
+        else if (format == 12) c->copy (_, table_iter, 12u, base, plan, &format12objidx);
+        else if (format == 14) c->copy (_, table_iter, 14u, base, plan, &format14objidx);
+      }
+      /* when --gids option is not used, we iterate input unicodes instead of
+       * all codepoints in each subtable, which is more efficient */
+      else
+      {
+        if (format == 4) c->copy (_, + it | hb_filter (unicodes_set, hb_first), 4u, base, plan, &format4objidx);
+        else if (format == 12) c->copy (_, + it | hb_filter (unicodes_set, hb_first), 12u, base, plan, &format12objidx);
+        else if (format == 14) c->copy (_, it, 14u, base, plan, &format14objidx);
+      }
     }
 
     c->check_assign(this->encodingRecord.len, (c->length () - cmap::min_size)/EncodingRecord::static_size);
@@ -1291,7 +1462,6 @@ struct cmap
     | hb_filter ([&] (const hb_pair_t<hb_codepoint_t, hb_codepoint_t> _)
 		 { return (_.second != HB_MAP_VALUE_INVALID); })
     ;
-
     cmap_prime->serialize (c->serializer, it, encodingrec_iter, this, c->plan);
     return_trace (true);
   }
@@ -1413,6 +1583,9 @@ struct cmap
 
     void collect_unicodes (hb_set_t *out, unsigned int num_glyphs) const
     { subtable->collect_unicodes (out, num_glyphs); }
+    void collect_mapping (hb_set_t *unicodes, hb_map_t *mapping,
+			  unsigned num_glyphs = UINT_MAX) const
+    { subtable->collect_mapping (unicodes, mapping, num_glyphs); }
     void collect_variation_selectors (hb_set_t *out) const
     { subtable_uvs->collect_variation_selectors (out); }
     void collect_variation_unicodes (hb_codepoint_t variation_selector,

src/hb-ot-os2-table.hh

@@ -30,6 +30,7 @@
 
 #include "hb-open-type.hh"
 #include "hb-ot-os2-unicode-ranges.hh"
+#include "hb-ot-cmap-table.hh"
 
 #include "hb-set.hh"
 
@@ -172,12 +173,28 @@ struct OS2
     OS2 *os2_prime = c->serializer->embed (this);
     if (unlikely (!os2_prime)) return_trace (false);
 
+    hb_set_t unicodes;
+    hb_map_t unicode_glyphid_map;
+    
+    OT::cmap::accelerator_t cmap;
+    cmap.init (c->plan->source);
+    cmap.collect_mapping (&unicodes, &unicode_glyphid_map);
+    cmap.fini ();
+    
+    if (c->plan->unicodes->is_empty ()) unicodes.clear ();
+    else hb_set_set (&unicodes, c->plan->unicodes);
+
+    + unicode_glyphid_map.iter ()
+    | hb_filter (c->plan->glyphs_requested, hb_second)
+    | hb_map (hb_first)
+    | hb_sink (unicodes)
+    ;
     uint16_t min_cp, max_cp;
-    find_min_and_max_codepoint (c->plan->unicodes, &min_cp, &max_cp);
+    find_min_and_max_codepoint (&unicodes, &min_cp, &max_cp);
     os2_prime->usFirstCharIndex = min_cp;
     os2_prime->usLastCharIndex = max_cp;
 
-    _update_unicode_ranges (c->plan->unicodes, os2_prime->ulUnicodeRange);
+    _update_unicode_ranges (&unicodes, os2_prime->ulUnicodeRange);
 
     return_trace (true);
   }

src/hb-subset-plan.cc

@@ -294,6 +294,7 @@ hb_subset_plan_create (hb_face_t         *face,
   plan->name_ids = hb_set_reference (input->name_ids);
   _nameid_closure (face, plan->name_ids);
   plan->name_languages = hb_set_reference (input->name_languages);
+  plan->glyphs_requested = hb_set_reference (input->glyphs);
   plan->drop_tables = hb_set_reference (input->drop_tables);
   plan->source = hb_face_reference (face);
   plan->dest = hb_face_builder_create ();
@@ -337,6 +338,7 @@ hb_subset_plan_destroy (hb_subset_plan_t *plan)
   hb_set_destroy (plan->unicodes);
   hb_set_destroy (plan->name_ids);
   hb_set_destroy (plan->name_languages);
+  hb_set_destroy (plan->glyphs_requested);
   hb_set_destroy (plan->drop_tables);
   hb_face_destroy (plan->source);
   hb_face_destroy (plan->dest);

src/hb-subset-plan.hh

@@ -53,6 +53,9 @@ struct hb_subset_plan_t
   // name_languages we would like to retain
   hb_set_t *name_languages;
 
+  //glyph ids requested to retain
+  hb_set_t *glyphs_requested;
+
   // Tables which should be dropped.
   hb_set_t *drop_tables;
 

test/api/test-subset-cmap.c

@@ -113,7 +113,6 @@ test_subset_cmap4_no_exceeding_maximum_codepoint (void)
   hb_face_destroy (face_origin);
 }
 
-/* TEMPORARILY COMMENTED OFF
 static void
 test_subset_cmap_empty_tables (void)
 {
@@ -133,7 +132,6 @@ test_subset_cmap_empty_tables (void)
   hb_face_destroy (face_abc);
   hb_face_destroy (face_empty);
 }
-*/
 
 static void
 test_subset_cmap_noto_color_emoji_noop (void)
@@ -188,7 +186,7 @@ main (int argc, char **argv)
   hb_test_add (test_subset_cmap_noop);
   hb_test_add (test_subset_cmap_non_consecutive_glyphs);
   hb_test_add (test_subset_cmap4_no_exceeding_maximum_codepoint);
-  //hb_test_add (test_subset_cmap_empty_tables);
+  hb_test_add (test_subset_cmap_empty_tables);
   hb_test_add (test_subset_cmap_noto_color_emoji_noop);
   hb_test_add (test_subset_cmap_noto_color_emoji_non_consecutive_glyphs);
 

test/subset/data/Makefile.sources

@@ -4,6 +4,7 @@ TESTS = \
 	tests/cff-full-font.tests \
 	tests/japanese.tests \
 	tests/cff-japanese.tests \
+	tests/cmap.tests \
 	tests/cmap14.tests \
 	tests/sbix.tests \
 	tests/colr.tests \
@@ -20,7 +21,6 @@ DISABLED_TESTS = \
 	tests/layout.gsub3.tests \
 	tests/layout.gsub6.tests \
 	tests/layout.gdef.tests \
-	tests/cmap.tests \
 	$(NULL)
 
 XFAIL_TESTS = \

test/subset/data/profiles/gids.txt

@@ -0,0 +1 @@
+--gids=1,2,3

test/subset/data/tests/basics.tests

@@ -11,6 +11,7 @@ retain-gids.txt
 name-ids.txt
 name-languages.txt
 name-legacy.txt
+gids.txt
 
 SUBSETS:
 abc

test/subset/data/tests/cmap14.tests

@@ -8,6 +8,7 @@ drop-hints.txt
 drop-hints-retain-gids.txt
 retain-gids.txt
 name-ids.txt
+gids.txt
 
 SUBSETS:
 一丂七

test/subset/data/tests/japanese.tests

@@ -13,5 +13,6 @@ acek
 あいうえおか
 あいう珠度輸
 𝜕𝟘AB
+𥝱
 
 

test/subset/meson.build

@@ -13,6 +13,7 @@ tests = [
   'layout.gsub3',
   'layout.gsub6',
   'layout.gdef',
+  'cmap',
   'cmap14',
   'sbix',
   'colr',
@@ -36,7 +37,7 @@ foreach t : tests
     ],
     # as the tests are ran concurrently let's raise acceptable time here
     # ideally better to break and let meson handles them in parallel
-    timeout: 120,
+    timeout: 140,
     workdir: join_paths(meson.current_build_dir(), '..', '..'),
   )
 endforeach

util/options-subset.cc

@@ -28,6 +28,66 @@
 
 #include "hb-subset-input.hh"
 
+static gboolean
+parse_gids (const char *name G_GNUC_UNUSED,
+	    const char *arg,
+	    gpointer    data,
+	    GError    **error G_GNUC_UNUSED)
+{
+  subset_options_t *subset_opts = (subset_options_t *) data;
+  hb_set_t *gids = subset_opts->input->glyphs;
+
+  char *s = (char *) arg;
+  char *p;
+
+  while (s && *s)
+  {
+    while (*s && strchr (", ", *s))
+      s++;
+    if (!*s)
+      break;
+
+    errno = 0;
+    hb_codepoint_t start_code = strtoul (s, &p, 10);
+    if (s[0] == '-' || errno || s == p)
+    {
+      hb_set_destroy (gids);
+      g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
+                   "Failed parsing gids values at: '%s'", s);
+      return false;
+    }
+
+    if (p && p[0] == '-') //gid ranges
+    {
+      s = ++p;
+      hb_codepoint_t end_code = strtoul (s, &p, 10);
+      if (s[0] == '-' || errno || s == p)
+      {
+        hb_set_destroy (gids);
+        g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
+                     "Failed parsing gids values at: '%s'", s);
+        return false;
+      }
+
+      if (end_code < start_code)
+      {
+        hb_set_destroy (gids);
+        g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
+                     "Invalid gids range value %u-%u", start_code, end_code);
+        return false;
+      }
+      hb_set_add_range (gids, start_code, end_code);
+    }
+    else
+    {
+      hb_set_add (gids, start_code);
+    }
+    s = p;
+  }
+
+  return true;
+}
+
 static gboolean
 parse_nameids (const char *name,
 	       const char *arg,
@@ -184,6 +244,7 @@ subset_options_t::add_options (option_parser_t *parser)
   {
     {"no-hinting", 0, 0, G_OPTION_ARG_NONE,  &this->input->drop_hints,   "Whether to drop hints",   nullptr},
     {"retain-gids", 0, 0, G_OPTION_ARG_NONE,  &this->input->retain_gids,   "If set don't renumber glyph ids in the subset.",   nullptr},
+    {"gids", 0, 0, G_OPTION_ARG_CALLBACK,  (gpointer) &parse_gids,  "Specify glyph IDs or ranges to include in the subset", "list of comma/whitespace-separated int numbers or ranges"},
     {"desubroutinize", 0, 0, G_OPTION_ARG_NONE,  &this->input->desubroutinize,   "Remove CFF/CFF2 use of subroutines",   nullptr},
     {"name-IDs", 0, 0, G_OPTION_ARG_CALLBACK,  (gpointer) &parse_nameids,  "Subset specified nameids", "list of int numbers"},
     {"name-legacy", 0, 0, G_OPTION_ARG_NONE,  &this->input->name_legacy,   "Keep legacy (non-Unicode) 'name' table entries",   nullptr},