Merge pull request #818 from googlefonts/drophints

[subset] Drop hints

src/hb-ot-glyf-table.hh

@@ -275,6 +275,91 @@ struct glyf
 						 composite);
     }
 
+    /* based on FontTools _g_l_y_f.py::trim */
+    inline bool remove_padding(unsigned int start_offset,
+                               unsigned int *end_offset) const
+    {
+      static const int FLAG_X_SHORT = 0x02;
+      static const int FLAG_Y_SHORT = 0x04;
+      static const int FLAG_REPEAT = 0x08;
+      static const int FLAG_X_SAME = 0x10;
+      static const int FLAG_Y_SAME = 0x20;
+
+      if (*end_offset - start_offset < GlyphHeader::static_size)
+        return true;
+
+      const char *glyph = ((const char *) glyf_table) + start_offset;
+      const char * const glyph_end = glyph + (*end_offset - start_offset);
+      const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyph, 0);
+      int16_t num_contours = (int16_t) glyph_header.numberOfContours;
+
+      if (num_contours < 0)
+        /* Trimming for composites not implemented.
+         * If removing hints it falls out of that. */
+        return true;
+      else if (num_contours > 0)
+      {
+        unsigned int glyph_len = *end_offset - start_offset;
+        /* simple glyph w/contours, possibly trimmable */
+        glyph += GlyphHeader::static_size + 2 * num_contours;
+
+        if (unlikely (glyph + 2 >= glyph_end)) return false;
+        uint16_t nCoordinates = (uint16_t) StructAtOffset<HBUINT16>(glyph - 2, 0) + 1;
+        uint16_t nInstructions = (uint16_t) StructAtOffset<HBUINT16>(glyph, 0);
+
+        glyph += 2 + nInstructions;
+        if (unlikely (glyph + 2 >= glyph_end)) return false;
+
+        unsigned int coordBytes = 0;
+        unsigned int coordsWithFlags = 0;
+        while (glyph < glyph_end)
+        {
+          uint8_t flag = (uint8_t) *glyph;
+          glyph++;
+
+          unsigned int repeat = 1;
+          if (flag & FLAG_REPEAT)
+          {
+            if (glyph >= glyph_end)
+            {
+              DEBUG_MSG(SUBSET, nullptr, "Bad flag");
+              return false;
+            }
+            repeat = ((uint8_t) *glyph) + 1;
+            glyph++;
+          }
+
+          unsigned int xBytes, yBytes;
+          xBytes = yBytes = 0;
+          if (flag & FLAG_X_SHORT)
+            xBytes = 1;
+          else if ((flag & FLAG_X_SAME) == 0)
+            xBytes = 2;
+
+          if (flag & FLAG_Y_SHORT)
+            yBytes = 1;
+          else if ((flag & FLAG_Y_SAME) == 0)
+            yBytes = 2;
+
+          coordBytes += (xBytes + yBytes) * repeat;
+          coordsWithFlags += repeat;
+          if (coordsWithFlags >= nCoordinates)
+            break;
+        }
+
+        if (coordsWithFlags != nCoordinates)
+        {
+          DEBUG_MSG(SUBSET, nullptr, "Expect %d coords to have flags, got flags for %d", nCoordinates, coordsWithFlags);
+          return false;
+        }
+        glyph += coordBytes;
+
+        if (glyph < glyph_end)
+          *end_offset -= glyph_end - glyph;
+      }
+      return true;
+    }
+
     inline bool get_offsets (hb_codepoint_t  glyph,
                              unsigned int   *start_offset /* OUT */,
                              unsigned int   *end_offset   /* OUT */) const
@@ -291,6 +376,7 @@ struct glyf
       else
       {
         const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataX;
+
 	*start_offset = offsets[glyph];
 	*end_offset   = offsets[glyph + 1];
       }
@@ -301,6 +387,51 @@ struct glyf
       return true;
     }
 
+    inline bool get_instruction_offsets(unsigned int start_offset,
+                                        unsigned int end_offset,
+                                        unsigned int *instruction_start /* OUT */,
+                                        unsigned int *instruction_end /* OUT */) const
+    {
+      if (end_offset - start_offset < GlyphHeader::static_size)
+      {
+        *instruction_start = 0;
+        *instruction_end = 0;
+        return true; /* Empty glyph; no instructions. */
+      }
+      const GlyphHeader &glyph_header = StructAtOffset<GlyphHeader> (glyf_table, start_offset);
+      int16_t num_contours = (int16_t) glyph_header.numberOfContours;
+      if (num_contours < 0)
+      {
+        CompositeGlyphHeader::Iterator *composite_it;
+        if (unlikely (!CompositeGlyphHeader::get_iterator (
+            (const char*) this->glyf_table + start_offset,
+             end_offset - start_offset, composite_it))) return false;
+        const CompositeGlyphHeader *last;
+        do {
+          last = composite_it->current;
+        } while (composite_it->move_to_next());
+
+        if ( (uint16_t) last->flags & CompositeGlyphHeader::WE_HAVE_INSTRUCTIONS)
+          *instruction_start = start_offset + ((char *) last - (char *) glyf_table->dataX) + last->get_size();
+        else
+          *instruction_start = end_offset;
+        *instruction_end = end_offset;
+        if (unlikely (*instruction_start > *instruction_end))
+        {
+          DEBUG_MSG(SUBSET, nullptr, "Invalid instruction offset, %d is outside [%d, %d]", *instruction_start, start_offset, end_offset);
+          return false;
+        }
+      }
+      else
+      {
+        unsigned int instruction_length_offset = start_offset + GlyphHeader::static_size + 2 * num_contours;
+        const HBUINT16 &instruction_length = StructAtOffset<HBUINT16> (glyf_table, instruction_length_offset);
+        *instruction_start = instruction_length_offset + 2;
+        *instruction_end = *instruction_start + (uint16_t) instruction_length;
+      }
+      return true;
+    }
+
     inline bool get_extents (hb_codepoint_t glyph,
 			     hb_glyph_extents_t *extents) const
     {

src/hb-subset-glyf.cc

@@ -21,7 +21,7 @@
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
- * Google Author(s): Garret Rieger
+ * Google Author(s): Garret Rieger, Roderick Sheeter
  */
 
 #include "hb-open-type-private.hh"
@@ -33,26 +33,49 @@
 static bool
 _calculate_glyf_and_loca_prime_size (const OT::glyf::accelerator_t &glyf,
                                      hb_prealloced_array_t<hb_codepoint_t> &glyph_ids,
-                                     bool *use_short_loca, /* OUT */
+                                     hb_bool_t drop_hints,
-                                     unsigned int *glyf_size, /* OUT */
+                                     bool *use_short_loca /* OUT */,
-                                     unsigned int *loca_size /* OUT */)
+                                     unsigned int *glyf_size /* OUT */,
+                                     unsigned int *loca_size /* OUT */,
+                                     hb_prealloced_array_t<unsigned int> *instruction_ranges /* OUT */)
 {
   unsigned int total = 0;
-  unsigned int count = 0;
   for (unsigned int i = 0; i < glyph_ids.len; i++)
   {
     hb_codepoint_t next_glyph = glyph_ids[i];
-    unsigned int start_offset, end_offset;
+    unsigned int *instruction_start = instruction_ranges->push();
-    if (unlikely (!glyf.get_offsets (next_glyph, &start_offset, &end_offset)))
+    unsigned int *instruction_end = instruction_ranges->push();
-      end_offset = start_offset = 0;
+    *instruction_start = 0;
+    *instruction_end = 0;
 
-    total += end_offset - start_offset;
+    unsigned int start_offset, end_offset;
-    count++;
+    if (unlikely (!(glyf.get_offsets(next_glyph, &start_offset, &end_offset)
+                    && glyf.remove_padding(start_offset, &end_offset))))
+    {
+      DEBUG_MSG(SUBSET, nullptr, "Invalid gid %d", next_glyph);
+      continue;
+    }
+    if (end_offset - start_offset < OT::glyf::GlyphHeader::static_size)
+      continue; /* 0-length glyph */
+
+    if (drop_hints)
+    {
+      if (unlikely (!glyf.get_instruction_offsets(start_offset, end_offset,
+                                                  instruction_start, instruction_end)))
+      {
+        DEBUG_MSG(SUBSET, nullptr, "Unable to get instruction offsets for %d", next_glyph);
+        return false;
+      }
+    }
+
+    total += end_offset - start_offset - (*instruction_end - *instruction_start);
+    /* round2 so short loca will work */
+    total += total % 2;
   }
 
   *glyf_size = total;
   *use_short_loca = (total <= 131070);
-  *loca_size = (count + 1)
+  *loca_size = (glyph_ids.len + 1)
       * (*use_short_loca ? sizeof(OT::HBUINT16) : sizeof(OT::HBUINT32));
 
   DEBUG_MSG(SUBSET, nullptr, "preparing to subset glyf: final size %d, loca size %d, using %s loca",
@@ -118,6 +141,7 @@ _write_glyf_and_loca_prime (hb_subset_plan_t              *plan,
 			    const OT::glyf::accelerator_t &glyf,
                             const char                    *glyf_data,
                             bool                           use_short_loca,
+                            hb_prealloced_array_t<unsigned int> &instruction_ranges,
                             unsigned int                   glyf_prime_size,
                             char                          *glyf_prime_data /* OUT */,
                             unsigned int                   loca_prime_size,
@@ -130,27 +154,44 @@ _write_glyf_and_loca_prime (hb_subset_plan_t              *plan,
   for (unsigned int i = 0; i < glyph_ids.len; i++)
   {
     unsigned int start_offset, end_offset;
-    if (unlikely (!glyf.get_offsets (glyph_ids[i], &start_offset, &end_offset)))
+    if (unlikely (!(glyf.get_offsets (glyph_ids[i], &start_offset, &end_offset)
+                    && glyf.remove_padding(start_offset, &end_offset))))
       end_offset = start_offset = 0;
+    unsigned int instruction_start = instruction_ranges[i * 2];
+    unsigned int instruction_end = instruction_ranges[i * 2 + 1];
 
-    int length = end_offset - start_offset;
+    int length = end_offset - start_offset - (instruction_end - instruction_start);
+    length += length % 2;
 
     if (glyf_prime_data_next + length > glyf_prime_data + glyf_prime_size)
     {
       DEBUG_MSG (SUBSET,
                  nullptr,
-                 "WARNING: Attempted to write an out of bounds glyph entry for gid %d",
+                 "WARNING: Attempted to write an out of bounds glyph entry for gid %d (length %d)",
-                 i);
+                 i, length);
       return false;
     }
-    memcpy (glyf_prime_data_next, glyf_data + start_offset, length);
+
+    if (instruction_start == instruction_end)
+      memcpy (glyf_prime_data_next, glyf_data + start_offset, length);
+    else
+    {
+      memcpy (glyf_prime_data_next, glyf_data + start_offset, instruction_start - start_offset);
+      memcpy (glyf_prime_data_next + instruction_start - start_offset, glyf_data + instruction_end, end_offset - instruction_end);
+      /* if the instructions end at the end this was a composite glyph */
+      if (instruction_end == end_offset)
+        ; // TODO(rsheeter) remove WE_HAVE_INSTRUCTIONS from last flags
+      else
+        /* zero instruction length, which is just before instruction_start */
+        memset (glyf_prime_data_next + instruction_start - start_offset - 2, 0, 2);
+    }
 
     success = success && _write_loca_entry (i,
                                             glyf_prime_data_next - glyf_prime_data,
                                             use_short_loca,
                                             loca_prime_data,
                                             loca_prime_size);
-    _update_components (plan, glyf_prime_data_next, end_offset - start_offset);
+    _update_components (plan, glyf_prime_data_next, length);
 
     glyf_prime_data_next += length;
   }
@@ -166,7 +207,7 @@ _write_glyf_and_loca_prime (hb_subset_plan_t              *plan,
 static bool
 _hb_subset_glyf_and_loca (const OT::glyf::accelerator_t  &glyf,
                           const char                     *glyf_data,
-			  hb_subset_plan_t               *plan,
+                          hb_subset_plan_t               *plan,
                           bool                           *use_short_loca,
                           hb_blob_t                     **glyf_prime /* OUT */,
                           hb_blob_t                     **loca_prime /* OUT */)
@@ -176,25 +217,33 @@ _hb_subset_glyf_and_loca (const OT::glyf::accelerator_t  &glyf,
 
   unsigned int glyf_prime_size;
   unsigned int loca_prime_size;
+  hb_prealloced_array_t<unsigned int> instruction_ranges;
+  instruction_ranges.init();
 
   if (unlikely (!_calculate_glyf_and_loca_prime_size (glyf,
                                                       glyphs_to_retain,
+                                                      plan->drop_hints,
                                                       use_short_loca,
                                                       &glyf_prime_size,
-                                                      &loca_prime_size))) {
+                                                      &loca_prime_size,
+                                                      &instruction_ranges))) {
+    instruction_ranges.finish();
     return false;
   }
 
-  char *glyf_prime_data = (char *) malloc (glyf_prime_size);
+  char *glyf_prime_data = (char *) calloc (1, glyf_prime_size);
-  char *loca_prime_data = (char *) malloc (loca_prime_size);
+  char *loca_prime_data = (char *) calloc (1, loca_prime_size);
   if (unlikely (!_write_glyf_and_loca_prime (plan, glyf, glyf_data,
                                              *use_short_loca,
+                                             instruction_ranges,
                                              glyf_prime_size, glyf_prime_data,
                                              loca_prime_size, loca_prime_data))) {
     free (glyf_prime_data);
     free (loca_prime_data);
+    instruction_ranges.finish();
     return false;
   }
+  instruction_ranges.finish();
 
   *glyf_prime = hb_blob_create (glyf_prime_data,
                                 glyf_prime_size,

src/hb-subset-input.cc

@@ -53,9 +53,9 @@ hb_subset_input_create_or_fail (void)
  * hb_subset_input_reference: (skip)
  * @subset_input: a subset_input.
  *
- * 
  *
- * Return value: 
+ *
+ * Return value:
  *
  * Since: 1.8.0
  **/
@@ -105,3 +105,15 @@ hb_subset_input_glyph_set (hb_subset_input_t *subset_input)
 {
   return subset_input->glyphs;
 }
+
+/**
+ * hb_subset_input_drop_hints:
+ * @subset_input: a subset_input.
+ *
+ * Since: 1.8.0
+ **/
+HB_EXTERN hb_bool_t *
+hb_subset_input_drop_hints (hb_subset_input_t *subset_input)
+{
+  return &subset_input->drop_hints;
+}

src/hb-subset-plan.cc

@@ -79,6 +79,9 @@ hb_subset_plan_add_table (hb_subset_plan_t *plan,
                           hb_tag_t tag,
                           hb_blob_t *contents)
 {
+  hb_blob_t *source_blob = plan->source->reference_table (tag);
+  DEBUG_MSG(SUBSET, nullptr, "add table %c%c%c%c, dest %d bytes, source %d bytes", HB_UNTAG(tag), hb_blob_get_length (contents), hb_blob_get_length (source_blob));
+  hb_blob_destroy (source_blob);
   return hb_subset_face_add_table(plan->dest, tag, contents);
 }
 
@@ -192,6 +195,7 @@ hb_subset_plan_create (hb_face_t           *face,
   plan->gids_to_retain_sorted.init();
   plan->source = hb_face_reference (face);
   plan->dest = hb_subset_face_create ();
+  plan->drop_hints = input->drop_hints;
 
   _populate_codepoints (input->unicodes, plan->codepoints);
   _populate_gids_to_retain (face,

src/hb-subset-plan.hh

@@ -37,6 +37,8 @@ struct hb_subset_plan_t {
   hb_object_header_t header;
   ASSERT_POD ();
 
+  hb_bool_t drop_hints;
+
   // TODO(Q1) actual map, drop this crap
   // Look at me ma, I'm a poor mans map codepoint : new gid
   // codepoints is sorted and aligned with gids_to_retain.

src/hb-subset-private.hh

@@ -43,6 +43,7 @@ struct hb_subset_input_t {
   hb_set_t *unicodes;
   hb_set_t *glyphs;
 
+  hb_bool_t drop_hints;
   /* TODO
    *
    * features

src/hb-subset.cc

@@ -242,11 +242,12 @@ _subset_table (hb_subset_plan_t *plan,
       result = _subset<const OT::hdmx> (plan);
       break;
     case HB_OT_TAG_head:
-      // SKIP head, it's handled by glyf
+      // TODO that won't work well if there is no glyf
+      DEBUG_MSG(SUBSET, nullptr, "skip head, handled by glyf");
       result = true;
       break;
     case HB_OT_TAG_hhea:
-      // SKIP hhea, it's handled by hmtx
+      DEBUG_MSG(SUBSET, nullptr, "skip hhea handled by hmtx");
       return true;
     case HB_OT_TAG_hmtx:
       result = _subset<const OT::hmtx> (plan);
@@ -255,7 +256,7 @@ _subset_table (hb_subset_plan_t *plan,
       result = _subset<const OT::maxp> (plan);
       break;
     case HB_OT_TAG_loca:
-      // SKIP loca, it's handle by glyf
+      DEBUG_MSG(SUBSET, nullptr, "skip loca handled by glyf");
       return true;
     case HB_OT_TAG_cmap:
       result = _subset<const OT::cmap> (plan);
@@ -277,9 +278,16 @@ _subset_table (hb_subset_plan_t *plan,
 }
 
 static bool
-_should_drop_table(hb_tag_t tag)
+_should_drop_table(hb_subset_plan_t *plan, hb_tag_t tag)
 {
     switch (tag) {
+      case HB_TAG ('c', 'v', 'a', 'r'): /* hint table, fallthrough */
+      case HB_TAG ('c', 'v', 't', ' '): /* hint table, fallthrough */
+      case HB_TAG ('f', 'p', 'g', 'm'): /* hint table, fallthrough */
+      case HB_TAG ('p', 'r', 'e', 'p'): /* hint table, fallthrough */
+      case HB_TAG ('h', 'd', 'm', 'x'): /* hint table, fallthrough */
+      case HB_TAG ('V', 'D', 'M', 'X'): /* hint table, fallthrough */
+        return plan->drop_hints;
       case HB_TAG ('G', 'D', 'E', 'F'): /* temporary */
       case HB_TAG ('G', 'P', 'O', 'S'): /* temporary */
       case HB_TAG ('G', 'S', 'U', 'B'): /* temporary */
@@ -316,7 +324,7 @@ hb_subset (hb_face_t *source,
     for (unsigned int i = 0; i < count; i++)
     {
       hb_tag_t tag = table_tags[i];
-      if (_should_drop_table(tag))
+      if (_should_drop_table(plan, tag))
       {
         DEBUG_MSG(SUBSET, nullptr, "drop %c%c%c%c", HB_UNTAG(tag));
         continue;

src/hb-subset.h

@@ -68,6 +68,8 @@ hb_subset_input_unicode_set (hb_subset_input_t *subset_input);
 HB_EXTERN hb_set_t *
 hb_subset_input_glyph_set (hb_subset_input_t *subset_input);
 
+HB_EXTERN hb_bool_t *
+hb_subset_input_drop_hints (hb_subset_input_t *subset_input);
 
 /* hb_subset() */
 

test/api/hb-subset-test.h

@@ -95,17 +95,20 @@ hb_subset_test_open_font (const char *font_path)
   return NULL; /* Shut up, compiler! */
 }
 
+static inline hb_subset_input_t *
+hb_subset_test_create_input(const hb_set_t  *codepoints)
+{
+  hb_subset_input_t *input = hb_subset_input_create_or_fail ();
+  hb_set_t * input_codepoints = hb_subset_input_unicode_set (input);
+  hb_set_union (input_codepoints, codepoints);
+  return input;
+}
+
 static inline hb_face_t *
 hb_subset_test_create_subset (hb_face_t *source,
-                              const hb_set_t  *codepoints)
+                              hb_subset_input_t *input)
 {
   hb_subset_profile_t *profile = hb_subset_profile_create();
-  hb_subset_input_t *input = hb_subset_input_create_or_fail ();
-
-  hb_set_t * input_codepoints = hb_subset_input_unicode_set (input);
-
-  hb_set_union (input_codepoints, codepoints);
-
   hb_face_t *subset = hb_subset (source, profile, input);
   g_assert (subset);
 
@@ -119,6 +122,7 @@ hb_subset_test_check (hb_face_t *expected,
                       hb_face_t *actual,
                       hb_tag_t   table)
 {
+  fprintf(stderr, "compare %c%c%c%c\n", HB_UNTAG(table));
   hb_blob_t *expected_blob = hb_face_reference_table (expected, table);
   hb_blob_t *actual_blob = hb_face_reference_table (actual, table);
   hb_test_assert_blobs_equal (expected_blob, actual_blob);

test/api/test-subset-cmap.c

@@ -40,7 +40,7 @@ test_subset_cmap (void)
   hb_set_t *codepoints = hb_set_create ();
   hb_set_add (codepoints, 97);
   hb_set_add (codepoints, 99);
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('c','m','a','p'));
@@ -59,7 +59,7 @@ test_subset_cmap_noop (void)
   hb_set_add (codepoints, 97);
   hb_set_add (codepoints, 98);
   hb_set_add (codepoints, 99);
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   hb_subset_test_check (face_abc, face_abc_subset, HB_TAG ('c','m','a','p'));

test/api/test-subset-glyf.c

@@ -31,6 +31,18 @@
 
 /* Unit tests for hb-subset-glyf.h */
 
+static void check_maxp_num_glyphs (hb_face_t *face, uint16_t expected_num_glyphs)
+{
+  hb_blob_t *maxp_blob = hb_face_reference_table (face, HB_TAG ('m','a','x', 'p'));
+
+  unsigned int maxp_len;
+  uint8_t *raw_maxp = (uint8_t *) hb_blob_get_data(maxp_blob, &maxp_len);
+  uint16_t num_glyphs = (raw_maxp[4] << 8) + raw_maxp[5];
+  g_assert_cmpuint(expected_num_glyphs, ==, num_glyphs);
+
+  hb_blob_destroy (maxp_blob);
+}
+
 static void
 test_subset_glyf (void)
 {
@@ -40,12 +52,12 @@ test_subset_glyf (void)
   hb_set_t *codepoints = hb_set_create();
   hb_set_add (codepoints, 97);
   hb_set_add (codepoints, 99);
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('g','l','y','f'));
   hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('l','o','c', 'a'));
-  hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('m','a','x', 'p'));
+  check_maxp_num_glyphs(face_abc_subset, 3);
 
   hb_face_destroy (face_abc_subset);
   hb_face_destroy (face_abc);
@@ -60,12 +72,12 @@ test_subset_glyf_with_components (void)
 
   hb_set_t *codepoints = hb_set_create();
   hb_set_add (codepoints, 0x1fc);
-  hb_face_t *face_generated_subset = hb_subset_test_create_subset (face_components, codepoints);
+  hb_face_t *face_generated_subset = hb_subset_test_create_subset (face_components, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   hb_subset_test_check (face_subset, face_generated_subset, HB_TAG ('g','l','y','f'));
   hb_subset_test_check (face_subset, face_generated_subset, HB_TAG ('l','o','c', 'a'));
-  hb_subset_test_check (face_subset, face_generated_subset, HB_TAG ('m','a','x', 'p'));
+  check_maxp_num_glyphs(face_generated_subset, 4);
 
   hb_face_destroy (face_generated_subset);
   hb_face_destroy (face_subset);
@@ -81,16 +93,42 @@ test_subset_glyf_noop (void)
   hb_set_add (codepoints, 97);
   hb_set_add (codepoints, 98);
   hb_set_add (codepoints, 99);
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   hb_subset_test_check (face_abc, face_abc_subset, HB_TAG ('g','l','y','f'));
   hb_subset_test_check (face_abc, face_abc_subset, HB_TAG ('l','o','c', 'a'));
+  check_maxp_num_glyphs(face_abc_subset, 4);
 
   hb_face_destroy (face_abc_subset);
   hb_face_destroy (face_abc);
 }
 
+static void
+test_subset_glyf_strip_hints (void)
+{
+  hb_face_t *face_abc = hb_subset_test_open_font ("fonts/Roboto-Regular.abc.ttf");
+  hb_face_t *face_ac = hb_subset_test_open_font ("fonts/Roboto-Regular.ac.nohints.ttf");
+
+  hb_set_t *codepoints = hb_set_create();
+  hb_set_add (codepoints, 'a');
+  hb_set_add (codepoints, 'c');
+  hb_subset_input_t *input = hb_subset_test_create_input (codepoints);
+  *hb_subset_input_drop_hints(input) = true;
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, input);
+  hb_set_destroy (codepoints);
+
+  hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('l','o','c', 'a'));
+  hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('g','l','y','f'));
+  check_maxp_num_glyphs(face_abc_subset, 3);
+
+  hb_face_destroy (face_abc_subset);
+  hb_face_destroy (face_abc);
+  hb_face_destroy (face_ac);
+}
+
+// TODO(rsheeter): test strip hints from composite
+
 // TODO(grieger): test for long loca generation.
 
 int
@@ -98,9 +136,10 @@ main (int argc, char **argv)
 {
   hb_test_init (&argc, &argv);
 
-  hb_test_add (test_subset_glyf);
-  hb_test_add (test_subset_glyf_with_components);
   hb_test_add (test_subset_glyf_noop);
+  hb_test_add (test_subset_glyf);
+  hb_test_add (test_subset_glyf_strip_hints);
+  hb_test_add (test_subset_glyf_with_components);
 
   return hb_test_run();
 }

test/api/test-subset-hdmx.c

@@ -41,7 +41,7 @@ test_subset_hdmx_simple_subset (void)
   hb_set_t *codepoints = hb_set_create ();
   hb_set_add (codepoints, 'a');
   hb_set_add (codepoints, 'c');
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   hb_subset_test_check (face_ac, face_abc_subset, HB_TAG ('h','d','m','x'));
@@ -60,7 +60,7 @@ test_subset_hdmx_noop (void)
   hb_set_add (codepoints, 'a');
   hb_set_add (codepoints, 'b');
   hb_set_add (codepoints, 'c');
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   hb_subset_test_check (face_abc, face_abc_subset, HB_TAG ('h','d','m','x'));

test/api/test-subset-hmtx.c

@@ -55,7 +55,7 @@ test_subset_hmtx_simple_subset (void)
   hb_set_t *codepoints = hb_set_create ();
   hb_set_add (codepoints, 'a');
   hb_set_add (codepoints, 'c');
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   check_num_hmetrics(face_abc_subset, 3); /* nothing has same width */
@@ -76,7 +76,7 @@ test_subset_hmtx_monospace (void)
   hb_set_t *codepoints = hb_set_create ();
   hb_set_add (codepoints, 'a');
   hb_set_add (codepoints, 'c');
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   check_num_hmetrics(face_abc_subset, 1); /* everything has same width */
@@ -97,7 +97,7 @@ test_subset_hmtx_keep_num_metrics (void)
   hb_set_t *codepoints = hb_set_create ();
   hb_set_add (codepoints, 'a');
   hb_set_add (codepoints, 'c');
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   check_num_hmetrics(face_abc_subset, 3); /* c is wider */
@@ -117,7 +117,7 @@ test_subset_hmtx_decrease_num_metrics (void)
   hb_set_t *codepoints = hb_set_create ();
   hb_set_add (codepoints, 'a');
   hb_set_add (codepoints, 'b');
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   check_num_hmetrics(face_abc_subset, 1); /* everything left has same width */
@@ -137,7 +137,7 @@ test_subset_hmtx_noop (void)
   hb_set_add (codepoints, 'a');
   hb_set_add (codepoints, 'b');
   hb_set_add (codepoints, 'c');
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   check_num_hmetrics(face_abc_subset, 4); /* nothing has same width */

test/api/test-subset-os2.c

@@ -37,7 +37,7 @@ test_subset_os2 (void)
 
   hb_set_t *codepoints = hb_set_create();
   hb_set_add (codepoints, 98);
-  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, codepoints);
+  hb_face_t *face_abc_subset = hb_subset_test_create_subset (face_abc, hb_subset_test_create_input (codepoints));
   hb_set_destroy (codepoints);
 
   hb_subset_test_check (face_b, face_abc_subset, HB_TAG ('O','S','/','2'));

util/hb-subset.cc

@@ -29,6 +29,7 @@
 
 #include "main-font-text.hh"
 #include "hb-subset.h"
+#include "hb-subset-private.hh"
 
 /*
  * Command line interface to the harfbuzz font subsetter.
@@ -37,7 +38,7 @@
 struct subset_consumer_t
 {
   subset_consumer_t (option_parser_t *parser)
-      : failed (false), options (parser), font (nullptr), input (nullptr) {}
+      : failed (false), options (parser), subset_options (parser), font (nullptr), input (nullptr) {}
 
   void init (hb_buffer_t  *buffer_,
              const font_options_t *font_opts)
@@ -89,6 +90,8 @@ struct subset_consumer_t
 
   void finish (const font_options_t *font_opts)
   {
+    input->drop_hints = subset_options.drop_hints;
+
     hb_subset_profile_t *subset_profile = hb_subset_profile_create();
     hb_face_t *face = hb_font_get_face (font);
 
@@ -111,6 +114,7 @@ struct subset_consumer_t
 
   private:
   output_options_t options;
+  subset_options_t subset_options;
   hb_font_t *font;
   hb_subset_input_t *input;
 };

util/options.cc

@@ -1009,3 +1009,18 @@ format_options_t::serialize_buffer_of_glyphs (hb_buffer_t  *buffer,
   serialize_glyphs (buffer, font, output_format, format_flags, gs);
   g_string_append_c (gs, '\n');
 }
+
+void
+subset_options_t::add_options (option_parser_t *parser)
+{
+  GOptionEntry entries[] =
+  {
+    {"no-hinting", 0, 0, G_OPTION_ARG_NONE,  &this->drop_hints,   "Whether to drop hints",   nullptr},
+    {nullptr}
+  };
+  parser->add_group (entries,
+         "subset",
+         "Subset options:",
+         "Options subsetting",
+         this);
+}

util/options.hh

@@ -655,6 +655,20 @@ struct format_options_t : option_group_t
   hb_bool_t trace;
 };
 
+struct subset_options_t : option_group_t
+{
+  subset_options_t (option_parser_t *parser)
+  {
+    drop_hints = false;
+
+    add_options (parser);
+  }
+
+  void add_options (option_parser_t *parser);
+
+  hb_bool_t drop_hints;
+};
+
 /* fallback implementation for scalbn()/scalbnf() for pre-2013 MSVC */
 #if defined (_MSC_VER) && (_MSC_VER < 1800)