Imported Upstream version 8.2.2
[platform/upstream/harfbuzz.git] / src / hb-ot-hmtx-table.hh
index b94337d..89640b4 100644 (file)
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
- * Google Author(s): Behdad Esfahbod
+ * Google Author(s): Behdad Esfahbod, Roderick Sheeter
  */
 
 #ifndef HB_OT_HMTX_TABLE_HH
 #define HB_OT_HMTX_TABLE_HH
 
-#include "hb-open-type-private.hh"
+#include "hb-open-type.hh"
+#include "hb-ot-maxp-table.hh"
+#include "hb-ot-hhea-table.hh"
+#include "hb-ot-var-hvar-table.hh"
+#include "hb-ot-var-mvar-table.hh"
+#include "hb-ot-metrics.hh"
 
+/*
+ * hmtx -- Horizontal Metrics
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/hmtx
+ * vmtx -- Vertical Metrics
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/vmtx
+ */
+#define HB_OT_TAG_hmtx HB_TAG('h','m','t','x')
+#define HB_OT_TAG_vmtx HB_TAG('v','m','t','x')
 
-namespace OT {
 
+HB_INTERNAL bool
+_glyf_get_leading_bearing_with_var_unscaled (hb_font_t *font, hb_codepoint_t glyph, bool is_vertical, int *lsb);
 
-/*
- * hmtx -- The Horizontal Metrics Table
- */
+HB_INTERNAL unsigned
+_glyf_get_advance_with_var_unscaled (hb_font_t *font, hb_codepoint_t glyph, bool is_vertical);
 
-#define HB_OT_TAG_hmtx HB_TAG('h','m','t','x')
+HB_INTERNAL bool
+_glyf_get_leading_bearing_without_var_unscaled (hb_face_t *face, hb_codepoint_t gid, bool is_vertical, int *lsb);
+
+
+namespace OT {
 
 
-struct LongHorMetric
+struct LongMetric
 {
-  USHORT       advanceWidth;
-  SHORT                lsb;
+  UFWORD       advance; /* Advance width/height. */
+  FWORD                sb; /* Leading (left/top) side bearing. */
   public:
   DEFINE_SIZE_STATIC (4);
 };
 
-struct hmtx
-{
-  static const hb_tag_t Tag    = HB_OT_TAG_hmtx;
 
-  inline bool sanitize (hb_sanitize_context_t *c) {
+template <typename T/*Data table type*/, typename H/*Header table type*/, typename V/*Var table type*/>
+struct hmtxvmtx
+{
+  bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const
+  {
     TRACE_SANITIZE (this);
     /* We don't check for anything specific here.  The users of the
      * struct do all the hard work... */
-    return TRACE_RETURN (true);
+    return_trace (true);
+  }
+
+  const hb_hashmap_t<hb_codepoint_t, hb_pair_t<unsigned, int>>* get_mtx_map (const hb_subset_plan_t *plan) const
+  { return T::is_horizontal ? &plan->hmtx_map : &plan->vmtx_map; }
+
+  bool subset_update_header (hb_subset_context_t *c,
+                            unsigned int num_hmetrics,
+                            const hb_hashmap_t<hb_codepoint_t, hb_pair_t<unsigned, int>> *mtx_map,
+                            const hb_vector_t<unsigned> &bounds_vec) const
+  {
+    hb_blob_t *src_blob = hb_sanitize_context_t ().reference_table<H> (c->plan->source, H::tableTag);
+    hb_blob_t *dest_blob = hb_blob_copy_writable_or_fail (src_blob);
+    hb_blob_destroy (src_blob);
+
+    if (unlikely (!dest_blob)) {
+      return false;
+    }
+
+    unsigned int length;
+    H *table = (H *) hb_blob_get_data (dest_blob, &length);
+    c->serializer->check_assign (table->numberOfLongMetrics, num_hmetrics, HB_SERIALIZE_ERROR_INT_OVERFLOW);
+
+#ifndef HB_NO_VAR
+    if (c->plan->normalized_coords)
+    {
+      auto &MVAR = *c->plan->source->table.MVAR;
+      if (T::is_horizontal)
+      {
+       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE,   caretSlopeRise);
+       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_CARET_RUN,    caretSlopeRun);
+       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_HORIZONTAL_CARET_OFFSET, caretOffset);
+      }
+      else
+      {
+       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_VERTICAL_CARET_RISE,     caretSlopeRise);
+       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_VERTICAL_CARET_RUN,      caretSlopeRun);
+       HB_ADD_MVAR_VAR (HB_OT_METRICS_TAG_VERTICAL_CARET_OFFSET,   caretOffset);
+      }
+
+      bool empty = true;
+      int min_lsb = 0x7FFF;
+      int min_rsb = 0x7FFF;
+      int max_extent = -0x7FFF;
+      unsigned max_adv = 0;
+      for (const auto _ : *mtx_map)
+      {
+        hb_codepoint_t gid = _.first;
+        unsigned adv = _.second.first;
+        int lsb = _.second.second;
+        max_adv = hb_max (max_adv, adv);
+
+        if (bounds_vec[gid] != 0xFFFFFFFF)
+        {
+         empty = false;
+          unsigned bound_width = bounds_vec[gid];
+          int rsb = adv - lsb - bound_width;
+          int extent = lsb + bound_width;
+          min_lsb = hb_min (min_lsb, lsb);
+          min_rsb = hb_min (min_rsb, rsb);
+          max_extent = hb_max (max_extent, extent);
+        }
+      }
+
+      table->advanceMax = max_adv;
+      if (!empty)
+      {
+        table->minLeadingBearing = min_lsb;
+        table->minTrailingBearing = min_rsb;
+        table->maxExtent = max_extent;
+      }
+    }
+#endif
+
+    bool result = c->plan->add_table (H::tableTag, dest_blob);
+    hb_blob_destroy (dest_blob);
+
+    return result;
+  }
+
+  template<typename Iterator,
+          hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_serialize_context_t *c,
+                 Iterator it,
+                 const hb_vector_t<hb_codepoint_pair_t> new_to_old_gid_list,
+                 unsigned num_long_metrics,
+                  unsigned total_num_metrics)
+  {
+    LongMetric* long_metrics = c->allocate_size<LongMetric> (num_long_metrics * LongMetric::static_size);
+    FWORD* short_metrics = c->allocate_size<FWORD> ((total_num_metrics - num_long_metrics) * FWORD::static_size);
+    if (!long_metrics || !short_metrics) return;
+
+    short_metrics -= num_long_metrics;
+
+    for (auto _ : new_to_old_gid_list)
+    {
+      hb_codepoint_t gid = _.first;
+      auto mtx = *it++;
+
+      if (gid < num_long_metrics)
+      {
+       LongMetric& lm = long_metrics[gid];
+       lm.advance = mtx.first;
+       lm.sb = mtx.second;
+      }
+      // TODO(beyond-64k): This assumes that maxp.numGlyphs is 0xFFFF.
+      else if (gid < 0x10000u)
+        short_metrics[gid] = mtx.second;
+      else
+        ((UFWORD*) short_metrics)[gid] = mtx.first;
+    }
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+
+    auto *table_prime = c->serializer->start_embed <T> ();
+
+    accelerator_t _mtx (c->plan->source);
+    unsigned num_long_metrics;
+    const hb_hashmap_t<hb_codepoint_t, hb_pair_t<unsigned, int>> *mtx_map = get_mtx_map (c->plan);
+    {
+      /* Determine num_long_metrics to encode. */
+      auto& plan = c->plan;
+
+      // TODO Don't consider retaingid holes here.
+
+      num_long_metrics = hb_min (plan->num_output_glyphs (), 0xFFFFu);
+      unsigned int last_advance = get_new_gid_advance_unscaled (plan, mtx_map, num_long_metrics - 1, _mtx);
+      while (num_long_metrics > 1 &&
+            last_advance == get_new_gid_advance_unscaled (plan, mtx_map, num_long_metrics - 2, _mtx))
+      {
+       num_long_metrics--;
+      }
+    }
+
+    auto it =
+    + hb_iter (c->plan->new_to_old_gid_list)
+    | hb_map ([c, &_mtx, mtx_map] (hb_codepoint_pair_t _)
+             {
+               hb_codepoint_t new_gid = _.first;
+               hb_codepoint_t old_gid = _.second;
+
+               hb_pair_t<unsigned, int> *v = nullptr;
+               if (!mtx_map->has (new_gid, &v))
+               {
+                 int lsb = 0;
+                 if (!_mtx.get_leading_bearing_without_var_unscaled (old_gid, &lsb))
+                   (void) _glyf_get_leading_bearing_without_var_unscaled (c->plan->source, old_gid, !T::is_horizontal, &lsb);
+                 return hb_pair (_mtx.get_advance_without_var_unscaled (old_gid), +lsb);
+               }
+               return *v;
+             })
+    ;
+
+    table_prime->serialize (c->serializer,
+                           it,
+                           c->plan->new_to_old_gid_list,
+                           num_long_metrics,
+                           c->plan->num_output_glyphs ());
+
+    if (unlikely (c->serializer->in_error ()))
+      return_trace (false);
+
+    // Amend header num hmetrics
+    if (unlikely (!subset_update_header (c, num_long_metrics, mtx_map,
+                                         T::is_horizontal ? c->plan->bounds_width_vec : c->plan->bounds_height_vec)))
+      return_trace (false);
+
+    return_trace (true);
+  }
+
+  struct accelerator_t
+  {
+    friend struct hmtxvmtx;
+
+    accelerator_t (hb_face_t *face)
+    {
+      table = hb_sanitize_context_t ().reference_table<hmtxvmtx> (face, T::tableTag);
+      var_table = hb_sanitize_context_t ().reference_table<V> (face, T::variationsTag);
+
+      default_advance = T::is_horizontal ? hb_face_get_upem (face) / 2 : hb_face_get_upem (face);
+
+      /* Populate count variables and sort them out as we go */
+
+      unsigned int len = table.get_length ();
+      if (len & 1)
+        len--;
+
+      num_long_metrics = T::is_horizontal ?
+                        face->table.hhea->numberOfLongMetrics :
+#ifndef HB_NO_VERTICAL
+                        face->table.vhea->numberOfLongMetrics
+#else
+                        0
+#endif
+                        ;
+      if (unlikely (num_long_metrics * 4 > len))
+       num_long_metrics = len / 4;
+      len -= num_long_metrics * 4;
+
+      num_bearings = face->table.maxp->get_num_glyphs ();
+
+      if (unlikely (num_bearings < num_long_metrics))
+        num_bearings = num_long_metrics;
+      if (unlikely ((num_bearings - num_long_metrics) * 2 > len))
+        num_bearings = num_long_metrics + len / 2;
+      len -= (num_bearings - num_long_metrics) * 2;
+
+      /* We MUST set num_bearings to zero if num_long_metrics is zero.
+       * Our get_advance() depends on that. */
+      if (unlikely (!num_long_metrics))
+       num_bearings = num_long_metrics = 0;
+
+      num_advances = num_bearings + len / 2;
+      num_glyphs = face->get_num_glyphs ();
+      if (num_glyphs < num_advances)
+        num_glyphs = num_advances;
+    }
+    ~accelerator_t ()
+    {
+      table.destroy ();
+      var_table.destroy ();
+    }
+
+    bool has_data () const { return (bool) num_bearings; }
+
+    bool get_leading_bearing_without_var_unscaled (hb_codepoint_t glyph,
+                                                  int *lsb) const
+    {
+      if (glyph < num_long_metrics)
+      {
+       *lsb = table->longMetricZ[glyph].sb;
+       return true;
+      }
+
+      if (unlikely (glyph >= num_bearings))
+       return false;
+
+      const FWORD *bearings = (const FWORD *) &table->longMetricZ[num_long_metrics];
+      *lsb = bearings[glyph - num_long_metrics];
+      return true;
+    }
+
+    bool get_leading_bearing_with_var_unscaled (hb_font_t *font,
+                                               hb_codepoint_t glyph,
+                                               int *lsb) const
+    {
+      if (!font->num_coords)
+       return get_leading_bearing_without_var_unscaled (glyph, lsb);
+
+#ifndef HB_NO_VAR
+      float delta;
+      if (var_table->get_lsb_delta_unscaled (glyph, font->coords, font->num_coords, &delta) &&
+         get_leading_bearing_without_var_unscaled (glyph, lsb))
+      {
+       *lsb += roundf (delta);
+       return true;
+      }
+
+      return _glyf_get_leading_bearing_with_var_unscaled (font, glyph, T::tableTag == HB_OT_TAG_vmtx, lsb);
+#else
+      return false;
+#endif
+    }
+
+    unsigned int get_advance_without_var_unscaled (hb_codepoint_t glyph) const
+    {
+      /* OpenType case. */
+      if (glyph < num_bearings)
+       return table->longMetricZ[hb_min (glyph, (uint32_t) num_long_metrics - 1)].advance;
+
+      /* If num_advances is zero, it means we don't have the metrics table
+       * for this direction: return default advance.  Otherwise, there's a
+       * well-defined answer. */
+      if (unlikely (!num_advances))
+       return default_advance;
+
+#ifdef HB_NO_BEYOND_64K
+      return 0;
+#endif
+
+      if (unlikely (glyph >= num_glyphs))
+        return 0;
+
+      /* num_bearings <= glyph < num_glyphs;
+       * num_bearings <= num_advances */
+
+      if (num_bearings == num_advances)
+        return get_advance_without_var_unscaled (num_bearings - 1);
+
+      const FWORD *bearings = (const FWORD *) &table->longMetricZ[num_long_metrics];
+      const UFWORD *advances = (const UFWORD *) &bearings[num_bearings - num_long_metrics];
+
+      return advances[hb_min (glyph - num_bearings, num_advances - num_bearings - 1)];
+    }
+
+    unsigned get_advance_with_var_unscaled (hb_codepoint_t  glyph,
+                                           hb_font_t      *font,
+                                           VariationStore::cache_t *store_cache = nullptr) const
+    {
+      unsigned int advance = get_advance_without_var_unscaled (glyph);
+
+#ifndef HB_NO_VAR
+      if (unlikely (glyph >= num_bearings) || !font->num_coords)
+       return advance;
+
+      if (var_table.get_length ())
+       return advance + roundf (var_table->get_advance_delta_unscaled (glyph,
+                                                                       font->coords, font->num_coords,
+                                                                       store_cache));
+
+      return _glyf_get_advance_with_var_unscaled (font, glyph, T::tableTag == HB_OT_TAG_vmtx);
+#else
+      return advance;
+#endif
+    }
+
+    protected:
+    // 0 <= num_long_metrics <= num_bearings <= num_advances <= num_glyphs
+    unsigned num_long_metrics;
+    unsigned num_bearings;
+    unsigned num_advances;
+    unsigned num_glyphs;
+
+    unsigned int default_advance;
+
+    public:
+    hb_blob_ptr_t<hmtxvmtx> table;
+    hb_blob_ptr_t<V> var_table;
+  };
+
+  /* get advance: when no variations, call get_advance_without_var_unscaled.
+   * when there're variations, get advance value from mtx_map in subset_plan*/
+  unsigned get_new_gid_advance_unscaled (const hb_subset_plan_t *plan,
+                                         const hb_hashmap_t<hb_codepoint_t, hb_pair_t<unsigned, int>> *mtx_map,
+                                         unsigned new_gid,
+                                         const accelerator_t &_mtx) const
+  {
+    if (mtx_map->is_empty ())
+    {
+      hb_codepoint_t old_gid = 0;
+      return plan->old_gid_for_new_gid (new_gid, &old_gid) ?
+             _mtx.get_advance_without_var_unscaled (old_gid) : 0;
+    }
+    return mtx_map->get (new_gid).first;
   }
 
   protected:
-  LongHorMetric        longHorMetric[VAR];     /* Paired advance width and left side
-                                        * bearing values for each glyph. The
-                                        * value numOfHMetrics comes from
-                                        * the 'hhea' table. If the font is
-                                        * monospaced, only one entry need
-                                        * be in the array, but that entry is
-                                        * required. The last entry applies to
-                                        * all subsequent glyphs. */
-  SHORT                leftSideBearingX[VAR];  /* Here the advanceWidth is assumed
-                                        * to be the same as the advanceWidth
-                                        * for the last entry above. The
-                                        * number of entries in this array is
-                                        * derived from numGlyphs (from 'maxp'
-                                        * table) minus numberOfHMetrics. This
-                                        * generally is used with a run of
-                                        * monospaced glyphs (e.g., Kanji
-                                        * fonts or Courier fonts). Only one
-                                        * run is allowed and it must be at
-                                        * the end. This allows a monospaced
-                                        * font to vary the left side bearing
-                                        * values for each glyph. */
+  UnsizedArrayOf<LongMetric>
+               longMetricZ;    /* Paired advance width and leading
+                                * bearing values for each glyph. The
+                                * value numOfHMetrics comes from
+                                * the 'hhea' table. If the font is
+                                * monospaced, only one entry need
+                                * be in the array, but that entry is
+                                * required. The last entry applies to
+                                * all subsequent glyphs. */
+/*UnsizedArrayOf<FWORD>        leadingBearingX;*/
+                               /* Here the advance is assumed
+                                * to be the same as the advance
+                                * for the last entry above. The
+                                * number of entries in this array is
+                                * derived from numGlyphs (from 'maxp'
+                                * table) minus numberOfLongMetrics.
+                                * This generally is used with a run
+                                * of monospaced glyphs (e.g., Kanji
+                                * fonts or Courier fonts). Only one
+                                * run is allowed and it must be at
+                                * the end. This allows a monospaced
+                                * font to vary the side bearing
+                                * values for each glyph. */
+/*UnsizedArrayOf<UFWORD>advancesX;*/
+                               /* TODO Document. */
   public:
-  DEFINE_SIZE_ARRAY2 (0, longHorMetric, leftSideBearingX);
+  DEFINE_SIZE_ARRAY (0, longMetricZ);
 };
 
+struct hmtx : hmtxvmtx<hmtx, hhea, HVAR> {
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_hmtx;
+  static constexpr hb_tag_t variationsTag = HB_OT_TAG_HVAR;
+  static constexpr bool is_horizontal = true;
+};
+struct vmtx : hmtxvmtx<vmtx, vhea, VVAR> {
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_vmtx;
+  static constexpr hb_tag_t variationsTag = HB_OT_TAG_VVAR;
+  static constexpr bool is_horizontal = false;
+};
+
+struct hmtx_accelerator_t : hmtx::accelerator_t {
+  hmtx_accelerator_t (hb_face_t *face) : hmtx::accelerator_t (face) {}
+};
+struct vmtx_accelerator_t : vmtx::accelerator_t {
+  vmtx_accelerator_t (hb_face_t *face) : vmtx::accelerator_t (face) {}
+};
 
 } /* namespace OT */