[subset] Add COLR support

src/hb-ot-color-colr-table.hh

@@ -47,7 +47,7 @@ struct LayerRecord
     return_trace (c->check_struct (this));
   }
 
-  protected:
+  public:
   HBGlyphID	glyphId;	/* Glyph ID of layer glyph */
   Index		colorIdx;	/* Index value to use with a
 				 * selected color palette.
@@ -112,6 +112,48 @@ struct COLR
     return glyph_layers.length;
   }
 
+  struct accelerator_t
+  {
+    accelerator_t () {}
+    ~accelerator_t () { fini(); }
+
+    void init (hb_face_t *face)
+    {
+      colr = hb_sanitize_context_t().reference_table<COLR> (face);
+    }
+
+    void fini ()
+    {
+      this->colr.destroy();
+    }
+
+    bool is_valid ()
+    {
+      return colr.get_blob ()->length;
+    }
+
+    void get_related_glyphs (hb_codepoint_t glyph,
+                             hb_set_t *related_ids /* OUT */) const
+    {
+      colr->get_related_glyphs (glyph, related_ids);
+    }
+
+    private:
+    hb_blob_ptr_t<COLR> colr;
+  };
+
+  void get_related_glyphs (hb_codepoint_t glyph,
+                           hb_set_t *related_ids /* OUT */) const
+  {
+    const BaseGlyphRecord &record = (this+baseGlyphsZ).bsearch (numBaseGlyphs, glyph);
+
+    hb_array_t<const LayerRecord> all_layers = (this+layersZ).as_array (numLayers);
+    hb_array_t<const LayerRecord> glyph_layers = all_layers.sub_array (record.firstLayerIdx,
+                                                                       record.numLayers);
+    for (unsigned int i = 0; i < glyph_layers.length; i++)
+      hb_set_add (related_ids, glyph_layers[i].glyphId);
+  }
+
   bool sanitize (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
@@ -120,6 +162,89 @@ struct COLR
 			  (this+layersZ).sanitize (c, numLayers)));
   }
 
+  template<typename Iterator,
+           hb_requires (hb_is_iterator (Iterator))>
+  bool serialize (hb_subset_context_t *c,
+                  unsigned version,
+                  Iterator it,
+                  hb_array_t<const LayerRecord> all_layers)
+  {
+    TRACE_SERIALIZE (this);
+
+    if (unlikely (!c->serializer->extend_min (this))) return_trace (false);
+    this->version = version;
+    numLayers = 0;
+    numBaseGlyphs = it.len ();
+    baseGlyphsZ = COLR::min_size;
+    layersZ = COLR::min_size + numBaseGlyphs * BaseGlyphRecord::min_size;
+
+    if (unlikely (!c->serializer->allocate_size<HBUINT8> ((unsigned int) layersZ - (unsigned int) baseGlyphsZ)))
+      return_trace (false);
+    hb_sorted_array_t<BaseGlyphRecord> glyph_records = (this+baseGlyphsZ).as_array (numBaseGlyphs);
+
+    unsigned int index = 0;
+    for (const hb_item_type<Iterator>& _ : it.iter ())
+    {
+      const unsigned int new_gid = _.first;
+      const BaseGlyphRecord* record = _.second;
+      if (record->firstLayerIdx >= all_layers.length ||
+          record->firstLayerIdx + record->numLayers > all_layers.length)
+        return_trace (false);
+
+      glyph_records[index].glyphId = new_gid;
+      glyph_records[index].numLayers = record->numLayers;
+      glyph_records[index].firstLayerIdx = numLayers;
+      index += 1;
+
+      hb_array_t<const LayerRecord> layers = all_layers.sub_array (record->firstLayerIdx,
+                                                                   record->numLayers);
+
+      for (unsigned int i = 0; i < layers.length; i++)
+      {
+        hb_codepoint_t new_gid = 0;
+        if (unlikely (!c->plan->new_gid_for_old_gid (layers[i].glyphId, &new_gid))) return_trace(false);
+
+        LayerRecord* out_layer = c->serializer->start_embed<LayerRecord> ();
+        if (unlikely (!c->serializer->extend_min (out_layer))) return_trace (false);
+
+        out_layer->glyphId = new_gid;
+        out_layer->colorIdx = layers[i].colorIdx;
+      }
+      numLayers += record->numLayers;
+    }
+
+    return_trace (true);
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+
+    auto it =
+    + hb_range (1u, c->plan->num_output_glyphs ())  // Skip notdef.
+    | hb_map ([&](unsigned int new_gid)
+        {
+          hb_codepoint_t old_gid = 0;
+          if (unlikely (!c->plan->old_gid_for_new_gid (new_gid, &old_gid)))
+            return hb_pair_t<hb_codepoint_t, const BaseGlyphRecord*>(new_gid, nullptr);
+
+          const BaseGlyphRecord* record = &(this+baseGlyphsZ).bsearch (numBaseGlyphs, old_gid);
+          if (record && (hb_codepoint_t) record->glyphId != old_gid)
+            record = nullptr;
+          return hb_pair_t<hb_codepoint_t, const BaseGlyphRecord*>(new_gid, record);
+        })
+    | hb_filter (hb_second)
+    ;
+
+    if (unlikely (!it.len ())) return_trace (false);
+
+    COLR *colr_prime = c->serializer->start_embed<COLR> ();
+
+    hb_array_t<const LayerRecord> all_layers = (this+layersZ).as_array (numLayers);
+
+    return_trace (colr_prime->serialize (c, version, it, all_layers));
+  }
+
   protected:
   HBUINT16	version;	/* Table version number (starts at 0). */
   HBUINT16	numBaseGlyphs;	/* Number of Base Glyph Records. */

src/hb-subset-plan.cc

@@ -31,6 +31,7 @@
 #include "hb-ot-cmap-table.hh"
 #include "hb-ot-glyf-table.hh"
 #include "hb-ot-cff1-table.hh"
+#include "hb-ot-color-colr-table.hh"
 #include "hb-ot-var-fvar-table.hh"
 #include "hb-ot-stat-table.hh"
 
@@ -156,11 +157,13 @@ _populate_gids_to_retain (hb_subset_plan_t* plan,
 #ifndef HB_NO_SUBSET_CFF
   OT::cff1::accelerator_t cff;
 #endif
+  OT::COLR::accelerator_t colr;
   cmap.init (plan->source);
   glyf.init (plan->source);
 #ifndef HB_NO_SUBSET_CFF
   cff.init (plan->source);
 #endif
+  colr.init (plan->source);
 
   plan->_glyphset_gsub->add (0); // Not-def
   hb_set_union (plan->_glyphset_gsub, input_glyphs_to_retain);
@@ -201,6 +204,8 @@ _populate_gids_to_retain (hb_subset_plan_t* plan,
     if (cff.is_valid ())
       _add_cff_seac_components (cff, gid, plan->_glyphset);
 #endif
+    if (colr.is_valid ())
+      colr.get_related_glyphs (gid, plan->_glyphset);
   }
 
   _remove_invalid_gids (plan->_glyphset, plan->source->get_num_glyphs ());

src/hb-subset.cc

@@ -38,6 +38,7 @@
 #include "hb-ot-hmtx-table.hh"
 #include "hb-ot-maxp-table.hh"
 #include "hb-ot-color-sbix-table.hh"
+#include "hb-ot-color-colr-table.hh"
 #include "hb-ot-os2-table.hh"
 #include "hb-ot-post-table.hh"
 #include "hb-ot-cff1-table.hh"
@@ -203,6 +204,9 @@ _subset_table (hb_subset_plan_t *plan,
     case HB_OT_TAG_post:
       result = _subset2<const OT::post> (plan);
       break;
+    case HB_OT_TAG_COLR:
+      result = _subset2<const OT::COLR> (plan);
+      break;
 
 #ifndef HB_NO_SUBSET_CFF
     case HB_OT_TAG_cff1:

test/api/Makefile.am

@@ -58,6 +58,7 @@ TEST_PROGS = \
 	test-subset-vvar \
 	test-subset-sbix \
 	test-subset-gpos \
+	test-subset-colr \
 	test-unicode \
 	test-version \
 	test-subset-nameids \
@@ -80,6 +81,7 @@ test_subset_vvar_LDADD = $(LDADD) $(top_builddir)/src/libharfbuzz-subset.la
 test_subset_sbix_LDADD = $(LDADD) $(top_builddir)/src/libharfbuzz-subset.la
 test_subset_nameids_LDADD = $(LDADD) $(top_builddir)/src/libharfbuzz-subset.la
 test_subset_gpos_LDADD = $(LDADD) $(top_builddir)/src/libharfbuzz-subset.la
+test_subset_colr_LDADD = $(LDADD) $(top_builddir)/src/libharfbuzz-subset.la
 
 test_unicode_CPPFLAGS = \
 	$(AM_CPPFLAGS) \

test/api/test-subset-colr.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright © 2020  Google, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Google Author(s): Calder Kitagawa
+ */
+
+#include "hb-test.h"
+#include "hb-subset-test.h"
+
+/* Unit tests for COLR subsetting */
+
+static void
+test_subset_colr_noop (void)
+{
+  hb_face_t *face = hb_test_open_font_file ("fonts/TwemojiMozilla.subset.ttf");
+
+  hb_set_t *codepoints = hb_set_create ();
+  hb_face_t *face_subset;
+  hb_set_add (codepoints, '2');
+  hb_set_add (codepoints, 0x3297);
+  hb_set_add (codepoints, 0x3299);
+  face_subset = hb_subset_test_create_subset (face, hb_subset_test_create_input (codepoints));
+  hb_set_destroy (codepoints);
+
+  hb_subset_test_check (face, face_subset, HB_TAG ('C','O','L','R'));
+
+  hb_face_destroy (face_subset);
+  hb_face_destroy (face);
+}
+
+static void
+test_subset_colr_keep_one_colr_glyph (void)
+{
+  hb_face_t *face = hb_test_open_font_file ("fonts/TwemojiMozilla.subset.ttf");
+  hb_face_t *face_expected = hb_test_open_font_file ("fonts/TwemojiMozilla.subset.default.3297.ttf");
+
+  hb_set_t *codepoints = hb_set_create ();
+  hb_face_t *face_subset;
+  hb_set_add (codepoints, 0x3297);
+  face_subset = hb_subset_test_create_subset (face, hb_subset_test_create_input (codepoints));
+  hb_set_destroy (codepoints);
+
+  hb_subset_test_check (face_expected, face_subset, HB_TAG ('C','O','L','R'));
+
+  hb_face_destroy (face_subset);
+  hb_face_destroy (face_expected);
+  hb_face_destroy (face);
+}
+
+static void
+test_subset_colr_keep_no_colr_glyph (void)
+{
+  hb_face_t *face = hb_test_open_font_file ("fonts/TwemojiMozilla.subset.ttf");
+  hb_face_t *face_expected = hb_test_open_font_file ("fonts/TwemojiMozilla.subset.default.32.ttf");
+
+  hb_set_t *codepoints = hb_set_create ();
+  hb_face_t *face_subset;
+  hb_set_add (codepoints, '2');
+  face_subset = hb_subset_test_create_subset (face, hb_subset_test_create_input (codepoints));
+  hb_set_destroy (codepoints);
+
+  hb_subset_test_check (face_expected, face_subset, HB_TAG ('C','O','L','R'));
+
+  hb_face_destroy (face_subset);
+  hb_face_destroy (face_expected);
+  hb_face_destroy (face);
+}
+
+int
+main (int argc, char **argv)
+{
+  hb_test_init (&argc, &argv);
+
+  hb_test_add (test_subset_colr_noop);
+  hb_test_add (test_subset_colr_keep_one_colr_glyph);
+  hb_test_add (test_subset_colr_keep_no_colr_glyph);
+
+  return hb_test_run();
+}

test/subset/data/Makefile.am

@@ -19,6 +19,7 @@ EXTRA_DIST += \
 	expected/layout.gsub6 \
 	expected/cmap14 \
 	expected/sbix \
+	expected/colr \
 	fonts \
 	profiles \
 	$(NULL)

test/subset/data/Makefile.sources

@@ -11,6 +11,7 @@ TESTS = \
 	tests/layout.gsub6.tests \
 	tests/cmap14.tests \
 	tests/sbix.tests \
+	tests/colr.tests \
 	$(NULL)
 
 XFAIL_TESTS = \

test/subset/data/tests/colr.tests

@@ -0,0 +1,17 @@
+FONTS:
+TwemojiMozilla.subset.ttf
+
+PROFILES:
+default.txt
+drop-hints.txt
+drop-hints-retain-gids.txt
+retain-gids.txt
+
+SUBSETS:
+2
+㊗
+㊙
+2㊗
+2㊙
+㊗㊙
+2㊗㊙