src/hb-ot-var-gvar-table.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2019  Adobe Inc.
  * Copyright © 2019  Ebrahim Byagowi
  *
  *  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.
  *
  * Adobe Author(s): Michiharu Ariza
  */

 #ifndef HB_OT_VAR_GVAR_TABLE_HH
 #define HB_OT_VAR_GVAR_TABLE_HH

 #include "hb-open-type.hh"
 #include "hb-ot-var-common.hh"

 /*
  * gvar -- Glyph Variation Table
  * https://docs.microsoft.com/en-us/typography/opentype/spec/gvar
  */
 #define HB_OT_TAG_gvar HB_TAG('g','v','a','r')

 namespace OT {

 struct contour_point_t
 {
   void init (float x_ = 0.f, float y_ = 0.f, bool is_end_point_ = false)
   { flag = 0; x = x_; y = y_; is_end_point = is_end_point_; }

   void transform (const float (&matrix)[4])
   {
     float x_ = x * matrix[0] + y * matrix[2];
 	  y  = x * matrix[1] + y * matrix[3];
     x  = x_;
   }
   HB_ALWAYS_INLINE
   void translate (const contour_point_t &p) { x += p.x; y += p.y; }


   float x;
   float y;
   uint8_t flag;
   bool is_end_point;
 };

 struct contour_point_vector_t : hb_vector_t<contour_point_t>
 {
   void extend (const hb_array_t<contour_point_t> &a)
   {
     unsigned int old_len = length;
     if (unlikely (!resize (old_len + a.length, false)))
       return;
     auto arrayZ = this->arrayZ + old_len;
     unsigned count = a.length;
     hb_memcpy (arrayZ, a.arrayZ, count * sizeof (arrayZ[0]));
   }
 };

 struct GlyphVariationData : TupleVariationData
 {};

 struct gvar
 {
   static constexpr hb_tag_t tableTag = HB_OT_TAG_gvar;

   bool sanitize_shallow (hb_sanitize_context_t *c) const
   {
     TRACE_SANITIZE (this);
     return_trace (c->check_struct (this) && (version.major == 1) &&
 		  sharedTuples.sanitize (c, this, axisCount * sharedTupleCount) &&
 		  (is_long_offset () ?
 		     c->check_array (get_long_offset_array (), c->get_num_glyphs () + 1) :
 		     c->check_array (get_short_offset_array (), c->get_num_glyphs () + 1)));
   }

   /* GlyphVariationData not sanitized here; must be checked while accessing each glyph variation data */
   bool sanitize (hb_sanitize_context_t *c) const
   { return sanitize_shallow (c); }

   bool subset (hb_subset_context_t *c) const
   {
     TRACE_SUBSET (this);

     unsigned glyph_count = version.to_int () ? c->plan->source->get_num_glyphs () : 0;

     gvar *out = c->serializer->allocate_min<gvar> ();
     if (unlikely (!out)) return_trace (false);

     out->version.major = 1;
     out->version.minor = 0;
     out->axisCount = axisCount;
     out->sharedTupleCount = sharedTupleCount;

     unsigned int num_glyphs = c->plan->num_output_glyphs ();
     out->glyphCountX = hb_min (0xFFFFu, num_glyphs);

     auto it = hb_iter (c->plan->new_to_old_gid_list);
     if (it->first == 0 && !(c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE))
       it++;
     unsigned int subset_data_size = 0;
     for (auto &_ : it)
     {
       hb_codepoint_t old_gid = _.second;
       subset_data_size += get_glyph_var_data_bytes (c->source_blob, glyph_count, old_gid).length;
     }

     bool long_offset = subset_data_size & ~0xFFFFu;
     out->flags = long_offset ? 1 : 0;

     HBUINT8 *subset_offsets = c->serializer->allocate_size<HBUINT8> ((long_offset ? 4 : 2) * (num_glyphs + 1), false);
     if (!subset_offsets) return_trace (false);

     /* shared tuples */
     if (!sharedTupleCount || !sharedTuples)
       out->sharedTuples = 0;
     else
     {
       unsigned int shared_tuple_size = F2DOT14::static_size * axisCount * sharedTupleCount;
       F2DOT14 *tuples = c->serializer->allocate_size<F2DOT14> (shared_tuple_size);
       if (!tuples) return_trace (false);
       out->sharedTuples = (char *) tuples - (char *) out;
       hb_memcpy (tuples, this+sharedTuples, shared_tuple_size);
     }

     char *subset_data = c->serializer->allocate_size<char> (subset_data_size, false);
     if (!subset_data) return_trace (false);
     out->dataZ = subset_data - (char *) out;


     if (long_offset)
     {
       ((HBUINT32 *) subset_offsets)[0] = 0;
       subset_offsets += 4;
     }
     else
     {
       ((HBUINT16 *) subset_offsets)[0] = 0;
       subset_offsets += 2;
     }
     unsigned int glyph_offset = 0;

     hb_codepoint_t last = 0;
     it = hb_iter (c->plan->new_to_old_gid_list);
     if (it->first == 0 && !(c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE))
       it++;
     for (auto &_ : it)
     {
       hb_codepoint_t gid = _.first;
       hb_codepoint_t old_gid = _.second;

       if (long_offset)
 	for (; last < gid; last++)
 	  ((HBUINT32 *) subset_offsets)[last] = glyph_offset;
       else
 	for (; last < gid; last++)
 	  ((HBUINT16 *) subset_offsets)[last] = glyph_offset / 2;

       hb_bytes_t var_data_bytes = get_glyph_var_data_bytes (c->source_blob,
 							    glyph_count,
 							    old_gid);

       hb_memcpy (subset_data, var_data_bytes.arrayZ, var_data_bytes.length);
       subset_data += var_data_bytes.length;
       glyph_offset += var_data_bytes.length;

       if (long_offset)
 	((HBUINT32 *) subset_offsets)[gid] = glyph_offset;
       else
 	((HBUINT16 *) subset_offsets)[gid] = glyph_offset / 2;

       last++; // Skip over gid
     }

     if (long_offset)
       for (; last < num_glyphs; last++)
 	((HBUINT32 *) subset_offsets)[last] = glyph_offset;
     else
       for (; last < num_glyphs; last++)
 	((HBUINT16 *) subset_offsets)[last] = glyph_offset / 2;

     return_trace (true);
   }

   protected:
   const hb_bytes_t get_glyph_var_data_bytes (hb_blob_t *blob,
 					     unsigned glyph_count,
 					     hb_codepoint_t glyph) const
   {
     unsigned start_offset = get_offset (glyph_count, glyph);
     unsigned end_offset = get_offset (glyph_count, glyph+1);
     if (unlikely (end_offset < start_offset)) return hb_bytes_t ();
     unsigned length = end_offset - start_offset;
     hb_bytes_t var_data = blob->as_bytes ().sub_array (((unsigned) dataZ) + start_offset, length);
     return likely (var_data.length >= GlyphVariationData::min_size) ? var_data : hb_bytes_t ();
   }

   bool is_long_offset () const { return flags & 1; }

   unsigned get_offset (unsigned glyph_count, unsigned i) const
   {
     if (unlikely (i > glyph_count)) return 0;
     _hb_compiler_memory_r_barrier ();
     return is_long_offset () ? get_long_offset_array ()[i] : get_short_offset_array ()[i] * 2;
   }

   const HBUINT32 * get_long_offset_array () const { return (const HBUINT32 *) &offsetZ; }
   const HBUINT16 *get_short_offset_array () const { return (const HBUINT16 *) &offsetZ; }

   public:
   struct accelerator_t
   {
     accelerator_t (hb_face_t *face)
     {
       table = hb_sanitize_context_t ().reference_table<gvar> (face);
       /* If sanitize failed, set glyphCount to 0. */
       glyphCount = table->version.to_int () ? face->get_num_glyphs () : 0;

       /* For shared tuples that only have one axis active, shared the index of
        * that axis as a cache. This will speed up caclulate_scalar() a lot
        * for fonts with lots of axes and many "monovar" tuples. */
       hb_array_t<const F2DOT14> shared_tuples = (table+table->sharedTuples).as_array (table->sharedTupleCount * table->axisCount);
       unsigned count = table->sharedTupleCount;
       if (unlikely (!shared_tuple_active_idx.resize (count, false))) return;
       unsigned axis_count = table->axisCount;
       for (unsigned i = 0; i < count; i++)
       {
 	hb_array_t<const F2DOT14> tuple = shared_tuples.sub_array (axis_count * i, axis_count);
 	int idx1 = -1, idx2 = -1;
 	for (unsigned j = 0; j < axis_count; j++)
 	{
 	  const F2DOT14 &peak = tuple.arrayZ[j];
 	  if (peak.to_int () != 0)
 	  {
 	    if (idx1 == -1)
 	      idx1 = j;
 	    else if (idx2 == -1)
 	      idx2 = j;
 	    else
 	    {
 	      idx1 = idx2 = -1;
 	      break;
 	    }
 	  }
 	}
 	shared_tuple_active_idx.arrayZ[i] = {idx1, idx2};
       }
     }
     ~accelerator_t () { table.destroy (); }

     private:

     static float infer_delta (const hb_array_t<contour_point_t> points,
 			      const hb_array_t<contour_point_t> deltas,
 			      unsigned int target, unsigned int prev, unsigned int next,
 			      float contour_point_t::*m)
     {
       float target_val = points.arrayZ[target].*m;
       float prev_val = points.arrayZ[prev].*m;
       float next_val = points.arrayZ[next].*m;
       float prev_delta =  deltas.arrayZ[prev].*m;
       float next_delta =  deltas.arrayZ[next].*m;

       if (prev_val == next_val)
 	return (prev_delta == next_delta) ? prev_delta : 0.f;
       else if (target_val <= hb_min (prev_val, next_val))
 	return (prev_val < next_val) ? prev_delta : next_delta;
       else if (target_val >= hb_max (prev_val, next_val))
 	return (prev_val > next_val) ? prev_delta : next_delta;

       /* linear interpolation */
       float r = (target_val - prev_val) / (next_val - prev_val);
       return prev_delta + r * (next_delta - prev_delta);
     }

     static unsigned int next_index (unsigned int i, unsigned int start, unsigned int end)
     { return (i >= end) ? start : (i + 1); }

     public:
     bool apply_deltas_to_points (hb_codepoint_t glyph,
 				 hb_array_t<int> coords,
 				 const hb_array_t<contour_point_t> points,
 				 bool phantom_only = false) const
     {
       if (unlikely (glyph >= glyphCount)) return true;

       hb_bytes_t var_data_bytes = table->get_glyph_var_data_bytes (table.get_blob (), glyphCount, glyph);
       if (!var_data_bytes.as<GlyphVariationData> ()->has_data ()) return true;
       hb_vector_t<unsigned int> shared_indices;
       GlyphVariationData::tuple_iterator_t iterator;
       if (!GlyphVariationData::get_tuple_iterator (var_data_bytes, table->axisCount,
 						   var_data_bytes.arrayZ,
 						   shared_indices, &iterator))
 	return true; /* so isn't applied at all */

       /* Save original points for inferred delta calculation */
       contour_point_vector_t orig_points_vec; // Populated lazily
       auto orig_points = orig_points_vec.as_array ();

       /* flag is used to indicate referenced point */
       contour_point_vector_t deltas_vec; // Populated lazily
       auto deltas = deltas_vec.as_array ();

       hb_vector_t<unsigned> end_points; // Populated lazily

       unsigned num_coords = table->axisCount;
       hb_array_t<const F2DOT14> shared_tuples = (table+table->sharedTuples).as_array (table->sharedTupleCount * num_coords);

       hb_vector_t<unsigned int> private_indices;
       hb_vector_t<int> x_deltas;
       hb_vector_t<int> y_deltas;
       unsigned count = points.length;
       bool flush = false;
       do
       {
 	float scalar = iterator.current_tuple->calculate_scalar (coords, num_coords, shared_tuples,
 								 &shared_tuple_active_idx);
 	if (scalar == 0.f) continue;
 	const HBUINT8 *p = iterator.get_serialized_data ();
 	unsigned int length = iterator.current_tuple->get_data_size ();
 	if (unlikely (!iterator.var_data_bytes.check_range (p, length)))
 	  return false;

 	if (!deltas)
 	{
 	  if (unlikely (!deltas_vec.resize (count, false))) return false;
 	  deltas = deltas_vec.as_array ();
 	  hb_memset (deltas.arrayZ + (phantom_only ? count - 4 : 0), 0,
 		     (phantom_only ? 4 : count) * sizeof (deltas[0]));
 	}

 	const HBUINT8 *end = p + length;

 	bool has_private_points = iterator.current_tuple->has_private_points ();
 	if (has_private_points &&
 	    !GlyphVariationData::unpack_points (p, private_indices, end))
 	  return false;
 	const hb_array_t<unsigned int> &indices = has_private_points ? private_indices : shared_indices;

 	bool apply_to_all = (indices.length == 0);
 	unsigned int num_deltas = apply_to_all ? points.length : indices.length;
 	if (unlikely (!x_deltas.resize (num_deltas, false))) return false;
 	if (unlikely (!GlyphVariationData::unpack_deltas (p, x_deltas, end))) return false;
 	if (unlikely (!y_deltas.resize (num_deltas, false))) return false;
 	if (unlikely (!GlyphVariationData::unpack_deltas (p, y_deltas, end))) return false;

 	if (!apply_to_all)
 	{
 	  if (!orig_points && !phantom_only)
 	  {
 	    orig_points_vec.extend (points);
 	    if (unlikely (orig_points_vec.in_error ())) return false;
 	    orig_points = orig_points_vec.as_array ();
 	  }

 	  if (flush)
 	  {
 	    for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
 	      points.arrayZ[i].translate (deltas.arrayZ[i]);
 	    flush = false;

 	  }
 	  hb_memset (deltas.arrayZ + (phantom_only ? count - 4 : 0), 0,
 		     (phantom_only ? 4 : count) * sizeof (deltas[0]));
 	}

 	if (HB_OPTIMIZE_SIZE_VAL)
 	{
 	  for (unsigned int i = 0; i < num_deltas; i++)
 	  {
 	    unsigned int pt_index;
 	    if (apply_to_all)
 	      pt_index = i;
 	    else
 	    {
 	      pt_index = indices[i];
 	      if (unlikely (pt_index >= deltas.length)) continue;
 	    }
 	    if (phantom_only && pt_index < count - 4) continue;
 	    auto &delta = deltas.arrayZ[pt_index];
 	    delta.flag = 1;	/* this point is referenced, i.e., explicit deltas specified */
 	    delta.x += x_deltas.arrayZ[i] * scalar;
 	    delta.y += y_deltas.arrayZ[i] * scalar;
 	  }
 	}
 	else
 	{
 	  /* Ouch. Four cases... for optimization. */
 	  if (scalar != 1.0f)
 	  {
 	    if (apply_to_all)
 	      for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
 	      {
 		unsigned int pt_index = i;
 		auto &delta = deltas.arrayZ[pt_index];
 		delta.x += x_deltas.arrayZ[i] * scalar;
 		delta.y += y_deltas.arrayZ[i] * scalar;
 	      }
 	    else
 	      for (unsigned int i = 0; i < num_deltas; i++)
 	      {
 		unsigned int pt_index = indices[i];
 		if (unlikely (pt_index >= deltas.length)) continue;
 		if (phantom_only && pt_index < count - 4) continue;
 		auto &delta = deltas.arrayZ[pt_index];
 		delta.flag = 1;	/* this point is referenced, i.e., explicit deltas specified */
 		delta.x += x_deltas.arrayZ[i] * scalar;
 		delta.y += y_deltas.arrayZ[i] * scalar;
 	      }
 	  }
 	  else
 	  {
 	    if (apply_to_all)
 	      for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
 	      {
 		unsigned int pt_index = i;
 		auto &delta = deltas.arrayZ[pt_index];
 		delta.x += x_deltas.arrayZ[i];
 		delta.y += y_deltas.arrayZ[i];
 	      }
 	    else
 	      for (unsigned int i = 0; i < num_deltas; i++)
 	      {
 		unsigned int pt_index = indices[i];
 		if (unlikely (pt_index >= deltas.length)) continue;
 		if (phantom_only && pt_index < count - 4) continue;
 		auto &delta = deltas.arrayZ[pt_index];
 		delta.flag = 1;	/* this point is referenced, i.e., explicit deltas specified */
 		delta.x += x_deltas.arrayZ[i];
 		delta.y += y_deltas.arrayZ[i];
 	      }
 	  }
 	}

 	/* infer deltas for unreferenced points */
 	if (!apply_to_all && !phantom_only)
 	{
 	  if (!end_points)
 	  {
 	    for (unsigned i = 0; i < count; ++i)
 	      if (points.arrayZ[i].is_end_point)
 		end_points.push (i);
 	    if (unlikely (end_points.in_error ())) return false;
 	  }

 	  unsigned start_point = 0;
 	  for (unsigned end_point : end_points)
 	  {
 	    /* Check the number of unreferenced points in a contour. If no unref points or no ref points, nothing to do. */
 	    unsigned unref_count = 0;
 	    for (unsigned i = start_point; i < end_point + 1; i++)
 	      unref_count += deltas.arrayZ[i].flag;
 	    unref_count = (end_point - start_point + 1) - unref_count;

 	    unsigned j = start_point;
 	    if (unref_count == 0 || unref_count > end_point - start_point)
 	      goto no_more_gaps;

 	    for (;;)
 	    {
 	      /* Locate the next gap of unreferenced points between two referenced points prev and next.
 	       * Note that a gap may wrap around at left (start_point) and/or at right (end_point).
 	       */
 	      unsigned int prev, next, i;
 	      for (;;)
 	      {
 		i = j;
 		j = next_index (i, start_point, end_point);
 		if (deltas.arrayZ[i].flag && !deltas.arrayZ[j].flag) break;
 	      }
 	      prev = j = i;
 	      for (;;)
 	      {
 		i = j;
 		j = next_index (i, start_point, end_point);
 		if (!deltas.arrayZ[i].flag && deltas.arrayZ[j].flag) break;
 	      }
 	      next = j;
 	      /* Infer deltas for all unref points in the gap between prev and next */
 	      i = prev;
 	      for (;;)
 	      {
 		i = next_index (i, start_point, end_point);
 		if (i == next) break;
 		deltas.arrayZ[i].x = infer_delta (orig_points, deltas, i, prev, next, &contour_point_t::x);
 		deltas.arrayZ[i].y = infer_delta (orig_points, deltas, i, prev, next, &contour_point_t::y);
 		if (--unref_count == 0) goto no_more_gaps;
 	      }
 	    }
 	  no_more_gaps:
 	    start_point = end_point + 1;
 	  }
 	}

 	flush = true;

       } while (iterator.move_to_next ());

       if (flush)
       {
 	for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
 	  points.arrayZ[i].translate (deltas.arrayZ[i]);
       }

       return true;
     }

     unsigned int get_axis_count () const { return table->axisCount; }

     private:
     hb_blob_ptr_t<gvar> table;
     unsigned glyphCount;
     hb_vector_t<hb_pair_t<int, int>> shared_tuple_active_idx;
   };

   protected:
   FixedVersion<>version;	/* Version number of the glyph variations table
 				 * Set to 0x00010000u. */
   HBUINT16	axisCount;	/* The number of variation axes for this font. This must be
 				 * the same number as axisCount in the 'fvar' table. */
   HBUINT16	sharedTupleCount;
 				/* The number of shared tuple records. Shared tuple records
 				 * can be referenced within glyph variation data tables for
 				 * multiple glyphs, as opposed to other tuple records stored
 				 * directly within a glyph variation data table. */
   NNOffset32To<UnsizedArrayOf<F2DOT14>>
 		sharedTuples;	/* Offset from the start of this table to the shared tuple records.
 				 * Array of tuple records shared across all glyph variation data tables. */
   HBUINT16	glyphCountX;	/* The number of glyphs in this font. This must match the number of
 				 * glyphs stored elsewhere in the font. */
   HBUINT16	flags;		/* Bit-field that gives the format of the offset array that follows.
 				 * If bit 0 is clear, the offsets are uint16; if bit 0 is set, the
 				 * offsets are uint32. */
   Offset32To<GlyphVariationData>
 		dataZ;		/* Offset from the start of this table to the array of
 				 * GlyphVariationData tables. */
   UnsizedArrayOf<HBUINT8>
 		offsetZ;	/* Offsets from the start of the GlyphVariationData array
 				 * to each GlyphVariationData table. */
   public:
   DEFINE_SIZE_ARRAY (20, offsetZ);
 };

 struct gvar_accelerator_t : gvar::accelerator_t {
   gvar_accelerator_t (hb_face_t *face) : gvar::accelerator_t (face) {}
 };

 } /* namespace OT */

 #endif /* HB_OT_VAR_GVAR_TABLE_HH */
	/*
	* Copyright © 2019 Adobe Inc.
	* Copyright © 2019 Ebrahim Byagowi
	*
	* 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.
	*
	* Adobe Author(s): Michiharu Ariza
	*/

	#ifndef HB_OT_VAR_GVAR_TABLE_HH
	#define HB_OT_VAR_GVAR_TABLE_HH

	#include "hb-open-type.hh"
	#include "hb-ot-var-common.hh"

	/*
	* gvar -- Glyph Variation Table
	* https://docs.microsoft.com/en-us/typography/opentype/spec/gvar
	*/
	#define HB_OT_TAG_gvar HB_TAG('g','v','a','r')

	namespace OT {

	struct contour_point_t
	{
	void init (float x_ = 0.f, float y_ = 0.f, bool is_end_point_ = false)
	{ flag = 0; x = x_; y = y_; is_end_point = is_end_point_; }

	void transform (const float (&matrix)[4])
	{
	float x_ = x * matrix[0] + y * matrix[2];
	y = x * matrix[1] + y * matrix[3];
	x = x_;
	}
	HB_ALWAYS_INLINE
	void translate (const contour_point_t &p) { x += p.x; y += p.y; }


	float x;
	float y;
	uint8_t flag;
	bool is_end_point;
	};

	struct contour_point_vector_t : hb_vector_t<contour_point_t>
	{
	void extend (const hb_array_t<contour_point_t> &a)
	{
	unsigned int old_len = length;
	if (unlikely (!resize (old_len + a.length, false)))
	return;
	auto arrayZ = this->arrayZ + old_len;
	unsigned count = a.length;
	hb_memcpy (arrayZ, a.arrayZ, count * sizeof (arrayZ[0]));
	}
	};

	struct GlyphVariationData : TupleVariationData
	{};

	struct gvar
	{
	static constexpr hb_tag_t tableTag = HB_OT_TAG_gvar;

	bool sanitize_shallow (hb_sanitize_context_t *c) const
	{
	TRACE_SANITIZE (this);
	return_trace (c->check_struct (this) && (version.major == 1) &&
	sharedTuples.sanitize (c, this, axisCount * sharedTupleCount) &&
	(is_long_offset () ?
	c->check_array (get_long_offset_array (), c->get_num_glyphs () + 1) :
	c->check_array (get_short_offset_array (), c->get_num_glyphs () + 1)));
	}

	/* GlyphVariationData not sanitized here; must be checked while accessing each glyph variation data */
	bool sanitize (hb_sanitize_context_t *c) const
	{ return sanitize_shallow (c); }

	bool subset (hb_subset_context_t *c) const
	{
	TRACE_SUBSET (this);

	unsigned glyph_count = version.to_int () ? c->plan->source->get_num_glyphs () : 0;

	gvar *out = c->serializer->allocate_min<gvar> ();
	if (unlikely (!out)) return_trace (false);

	out->version.major = 1;
	out->version.minor = 0;
	out->axisCount = axisCount;
	out->sharedTupleCount = sharedTupleCount;

	unsigned int num_glyphs = c->plan->num_output_glyphs ();
	out->glyphCountX = hb_min (0xFFFFu, num_glyphs);

	auto it = hb_iter (c->plan->new_to_old_gid_list);
	if (it->first == 0 && !(c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE))
	it++;
	unsigned int subset_data_size = 0;
	for (auto &_ : it)
	{
	hb_codepoint_t old_gid = _.second;
	subset_data_size += get_glyph_var_data_bytes (c->source_blob, glyph_count, old_gid).length;
	}

	bool long_offset = subset_data_size & ~0xFFFFu;
	out->flags = long_offset ? 1 : 0;

	HBUINT8 subset_offsets = c->serializer->allocate_size<HBUINT8> ((long_offset ? 4 : 2) (num_glyphs + 1), false);
	if (!subset_offsets) return_trace (false);

	/* shared tuples */
	if (!sharedTupleCount \|\| !sharedTuples)
	out->sharedTuples = 0;
	else
	{
	unsigned int shared_tuple_size = F2DOT14::static_size * axisCount * sharedTupleCount;
	F2DOT14 *tuples = c->serializer->allocate_size<F2DOT14> (shared_tuple_size);
	if (!tuples) return_trace (false);
	out->sharedTuples = (char ) tuples - (char ) out;
	hb_memcpy (tuples, this+sharedTuples, shared_tuple_size);
	}

	char *subset_data = c->serializer->allocate_size<char> (subset_data_size, false);
	if (!subset_data) return_trace (false);
	out->dataZ = subset_data - (char *) out;


	if (long_offset)
	{
	((HBUINT32 *) subset_offsets)[0] = 0;
	subset_offsets += 4;
	}
	else
	{
	((HBUINT16 *) subset_offsets)[0] = 0;
	subset_offsets += 2;
	}
	unsigned int glyph_offset = 0;

	hb_codepoint_t last = 0;
	it = hb_iter (c->plan->new_to_old_gid_list);
	if (it->first == 0 && !(c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE))
	it++;
	for (auto &_ : it)
	{
	hb_codepoint_t gid = _.first;
	hb_codepoint_t old_gid = _.second;

	if (long_offset)
	for (; last < gid; last++)
	((HBUINT32 *) subset_offsets)[last] = glyph_offset;
	else
	for (; last < gid; last++)
	((HBUINT16 *) subset_offsets)[last] = glyph_offset / 2;

	hb_bytes_t var_data_bytes = get_glyph_var_data_bytes (c->source_blob,
	glyph_count,
	old_gid);

	hb_memcpy (subset_data, var_data_bytes.arrayZ, var_data_bytes.length);
	subset_data += var_data_bytes.length;
	glyph_offset += var_data_bytes.length;

	if (long_offset)
	((HBUINT32 *) subset_offsets)[gid] = glyph_offset;
	else
	((HBUINT16 *) subset_offsets)[gid] = glyph_offset / 2;

	last++; // Skip over gid
	}

	if (long_offset)
	for (; last < num_glyphs; last++)
	((HBUINT32 *) subset_offsets)[last] = glyph_offset;
	else
	for (; last < num_glyphs; last++)
	((HBUINT16 *) subset_offsets)[last] = glyph_offset / 2;

	return_trace (true);
	}

	protected:
	const hb_bytes_t get_glyph_var_data_bytes (hb_blob_t *blob,
	unsigned glyph_count,
	hb_codepoint_t glyph) const
	{
	unsigned start_offset = get_offset (glyph_count, glyph);
	unsigned end_offset = get_offset (glyph_count, glyph+1);
	if (unlikely (end_offset < start_offset)) return hb_bytes_t ();
	unsigned length = end_offset - start_offset;
	hb_bytes_t var_data = blob->as_bytes ().sub_array (((unsigned) dataZ) + start_offset, length);
	return likely (var_data.length >= GlyphVariationData::min_size) ? var_data : hb_bytes_t ();
	}

	bool is_long_offset () const { return flags & 1; }

	unsigned get_offset (unsigned glyph_count, unsigned i) const
	{
	if (unlikely (i > glyph_count)) return 0;
	_hb_compiler_memory_r_barrier ();
	return is_long_offset () ? get_long_offset_array ()[i] : get_short_offset_array ()[i] * 2;
	}

	const HBUINT32 * get_long_offset_array () const { return (const HBUINT32 *) &offsetZ; }
	const HBUINT16 get_short_offset_array () const { return (const HBUINT16 ) &offsetZ; }

	public:
	struct accelerator_t
	{
	accelerator_t (hb_face_t *face)
	{
	table = hb_sanitize_context_t ().reference_table<gvar> (face);
	/* If sanitize failed, set glyphCount to 0. */
	glyphCount = table->version.to_int () ? face->get_num_glyphs () : 0;

	/* For shared tuples that only have one axis active, shared the index of
	* that axis as a cache. This will speed up caclulate_scalar() a lot
	* for fonts with lots of axes and many "monovar" tuples. */
	hb_array_t<const F2DOT14> shared_tuples = (table+table->sharedTuples).as_array (table->sharedTupleCount * table->axisCount);
	unsigned count = table->sharedTupleCount;
	if (unlikely (!shared_tuple_active_idx.resize (count, false))) return;
	unsigned axis_count = table->axisCount;
	for (unsigned i = 0; i < count; i++)
	{
	hb_array_t<const F2DOT14> tuple = shared_tuples.sub_array (axis_count * i, axis_count);
	int idx1 = -1, idx2 = -1;
	for (unsigned j = 0; j < axis_count; j++)
	{
	const F2DOT14 &peak = tuple.arrayZ[j];
	if (peak.to_int () != 0)
	{
	if (idx1 == -1)
	idx1 = j;
	else if (idx2 == -1)
	idx2 = j;
	else
	{
	idx1 = idx2 = -1;
	break;
	}
	}
	}
	shared_tuple_active_idx.arrayZ[i] = {idx1, idx2};
	}
	}
	~accelerator_t () { table.destroy (); }

	private:

	static float infer_delta (const hb_array_t<contour_point_t> points,
	const hb_array_t<contour_point_t> deltas,
	unsigned int target, unsigned int prev, unsigned int next,
	float contour_point_t::*m)
	{
	float target_val = points.arrayZ[target].*m;
	float prev_val = points.arrayZ[prev].*m;
	float next_val = points.arrayZ[next].*m;
	float prev_delta = deltas.arrayZ[prev].*m;
	float next_delta = deltas.arrayZ[next].*m;

	if (prev_val == next_val)
	return (prev_delta == next_delta) ? prev_delta : 0.f;
	else if (target_val <= hb_min (prev_val, next_val))
	return (prev_val < next_val) ? prev_delta : next_delta;
	else if (target_val >= hb_max (prev_val, next_val))
	return (prev_val > next_val) ? prev_delta : next_delta;

	/* linear interpolation */
	float r = (target_val - prev_val) / (next_val - prev_val);
	return prev_delta + r * (next_delta - prev_delta);
	}

	static unsigned int next_index (unsigned int i, unsigned int start, unsigned int end)
	{ return (i >= end) ? start : (i + 1); }

	public:
	bool apply_deltas_to_points (hb_codepoint_t glyph,
	hb_array_t<int> coords,
	const hb_array_t<contour_point_t> points,
	bool phantom_only = false) const
	{
	if (unlikely (glyph >= glyphCount)) return true;

	hb_bytes_t var_data_bytes = table->get_glyph_var_data_bytes (table.get_blob (), glyphCount, glyph);
	if (!var_data_bytes.as<GlyphVariationData> ()->has_data ()) return true;
	hb_vector_t<unsigned int> shared_indices;
	GlyphVariationData::tuple_iterator_t iterator;
	if (!GlyphVariationData::get_tuple_iterator (var_data_bytes, table->axisCount,
	var_data_bytes.arrayZ,
	shared_indices, &iterator))
	return true; /* so isn't applied at all */

	/* Save original points for inferred delta calculation */
	contour_point_vector_t orig_points_vec; // Populated lazily
	auto orig_points = orig_points_vec.as_array ();

	/* flag is used to indicate referenced point */
	contour_point_vector_t deltas_vec; // Populated lazily
	auto deltas = deltas_vec.as_array ();

	hb_vector_t<unsigned> end_points; // Populated lazily

	unsigned num_coords = table->axisCount;
	hb_array_t<const F2DOT14> shared_tuples = (table+table->sharedTuples).as_array (table->sharedTupleCount * num_coords);

	hb_vector_t<unsigned int> private_indices;
	hb_vector_t<int> x_deltas;
	hb_vector_t<int> y_deltas;
	unsigned count = points.length;
	bool flush = false;
	do
	{
	float scalar = iterator.current_tuple->calculate_scalar (coords, num_coords, shared_tuples,
	&shared_tuple_active_idx);
	if (scalar == 0.f) continue;
	const HBUINT8 *p = iterator.get_serialized_data ();
	unsigned int length = iterator.current_tuple->get_data_size ();
	if (unlikely (!iterator.var_data_bytes.check_range (p, length)))
	return false;

	if (!deltas)
	{
	if (unlikely (!deltas_vec.resize (count, false))) return false;
	deltas = deltas_vec.as_array ();
	hb_memset (deltas.arrayZ + (phantom_only ? count - 4 : 0), 0,
	(phantom_only ? 4 : count) * sizeof (deltas[0]));
	}

	const HBUINT8 *end = p + length;

	bool has_private_points = iterator.current_tuple->has_private_points ();
	if (has_private_points &&
	!GlyphVariationData::unpack_points (p, private_indices, end))
	return false;
	const hb_array_t<unsigned int> &indices = has_private_points ? private_indices : shared_indices;

	bool apply_to_all = (indices.length == 0);
	unsigned int num_deltas = apply_to_all ? points.length : indices.length;
	if (unlikely (!x_deltas.resize (num_deltas, false))) return false;
	if (unlikely (!GlyphVariationData::unpack_deltas (p, x_deltas, end))) return false;
	if (unlikely (!y_deltas.resize (num_deltas, false))) return false;
	if (unlikely (!GlyphVariationData::unpack_deltas (p, y_deltas, end))) return false;

	if (!apply_to_all)
	{
	if (!orig_points && !phantom_only)
	{
	orig_points_vec.extend (points);
	if (unlikely (orig_points_vec.in_error ())) return false;
	orig_points = orig_points_vec.as_array ();
	}

	if (flush)
	{
	for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
	points.arrayZ[i].translate (deltas.arrayZ[i]);
	flush = false;

	}
	hb_memset (deltas.arrayZ + (phantom_only ? count - 4 : 0), 0,
	(phantom_only ? 4 : count) * sizeof (deltas[0]));
	}

	if (HB_OPTIMIZE_SIZE_VAL)
	{
	for (unsigned int i = 0; i < num_deltas; i++)
	{
	unsigned int pt_index;
	if (apply_to_all)
	pt_index = i;
	else
	{
	pt_index = indices[i];
	if (unlikely (pt_index >= deltas.length)) continue;
	}
	if (phantom_only && pt_index < count - 4) continue;
	auto &delta = deltas.arrayZ[pt_index];
	delta.flag = 1; /* this point is referenced, i.e., explicit deltas specified */
	delta.x += x_deltas.arrayZ[i] * scalar;
	delta.y += y_deltas.arrayZ[i] * scalar;
	}
	}
	else
	{
	/* Ouch. Four cases... for optimization. */
	if (scalar != 1.0f)
	{
	if (apply_to_all)
	for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
	{
	unsigned int pt_index = i;
	auto &delta = deltas.arrayZ[pt_index];
	delta.x += x_deltas.arrayZ[i] * scalar;
	delta.y += y_deltas.arrayZ[i] * scalar;
	}
	else
	for (unsigned int i = 0; i < num_deltas; i++)
	{
	unsigned int pt_index = indices[i];
	if (unlikely (pt_index >= deltas.length)) continue;
	if (phantom_only && pt_index < count - 4) continue;
	auto &delta = deltas.arrayZ[pt_index];
	delta.flag = 1; /* this point is referenced, i.e., explicit deltas specified */
	delta.x += x_deltas.arrayZ[i] * scalar;
	delta.y += y_deltas.arrayZ[i] * scalar;
	}
	}
	else
	{
	if (apply_to_all)
	for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
	{
	unsigned int pt_index = i;
	auto &delta = deltas.arrayZ[pt_index];
	delta.x += x_deltas.arrayZ[i];
	delta.y += y_deltas.arrayZ[i];
	}
	else
	for (unsigned int i = 0; i < num_deltas; i++)
	{
	unsigned int pt_index = indices[i];
	if (unlikely (pt_index >= deltas.length)) continue;
	if (phantom_only && pt_index < count - 4) continue;
	auto &delta = deltas.arrayZ[pt_index];
	delta.flag = 1; /* this point is referenced, i.e., explicit deltas specified */
	delta.x += x_deltas.arrayZ[i];
	delta.y += y_deltas.arrayZ[i];
	}
	}
	}

	/* infer deltas for unreferenced points */
	if (!apply_to_all && !phantom_only)
	{
	if (!end_points)
	{
	for (unsigned i = 0; i < count; ++i)
	if (points.arrayZ[i].is_end_point)
	end_points.push (i);
	if (unlikely (end_points.in_error ())) return false;
	}

	unsigned start_point = 0;
	for (unsigned end_point : end_points)
	{
	/* Check the number of unreferenced points in a contour. If no unref points or no ref points, nothing to do. */
	unsigned unref_count = 0;
	for (unsigned i = start_point; i < end_point + 1; i++)
	unref_count += deltas.arrayZ[i].flag;
	unref_count = (end_point - start_point + 1) - unref_count;

	unsigned j = start_point;
	if (unref_count == 0 \|\| unref_count > end_point - start_point)
	goto no_more_gaps;

	for (;;)
	{
	/* Locate the next gap of unreferenced points between two referenced points prev and next.
	* Note that a gap may wrap around at left (start_point) and/or at right (end_point).
	*/
	unsigned int prev, next, i;
	for (;;)
	{
	i = j;
	j = next_index (i, start_point, end_point);
	if (deltas.arrayZ[i].flag && !deltas.arrayZ[j].flag) break;
	}
	prev = j = i;
	for (;;)
	{
	i = j;
	j = next_index (i, start_point, end_point);
	if (!deltas.arrayZ[i].flag && deltas.arrayZ[j].flag) break;
	}
	next = j;
	/* Infer deltas for all unref points in the gap between prev and next */
	i = prev;
	for (;;)
	{
	i = next_index (i, start_point, end_point);
	if (i == next) break;
	deltas.arrayZ[i].x = infer_delta (orig_points, deltas, i, prev, next, &contour_point_t::x);
	deltas.arrayZ[i].y = infer_delta (orig_points, deltas, i, prev, next, &contour_point_t::y);
	if (--unref_count == 0) goto no_more_gaps;
	}
	}
	no_more_gaps:
	start_point = end_point + 1;
	}
	}

	flush = true;

	} while (iterator.move_to_next ());

	if (flush)
	{
	for (unsigned int i = phantom_only ? count - 4 : 0; i < count; i++)
	points.arrayZ[i].translate (deltas.arrayZ[i]);
	}

	return true;
	}

	unsigned int get_axis_count () const { return table->axisCount; }

	private:
	hb_blob_ptr_t<gvar> table;
	unsigned glyphCount;
	hb_vector_t<hb_pair_t<int, int>> shared_tuple_active_idx;
	};

	protected:
	FixedVersion<>version; /* Version number of the glyph variations table
	* Set to 0x00010000u. */
	HBUINT16 axisCount; /* The number of variation axes for this font. This must be
	* the same number as axisCount in the 'fvar' table. */
	HBUINT16 sharedTupleCount;
	/* The number of shared tuple records. Shared tuple records
	* can be referenced within glyph variation data tables for
	* multiple glyphs, as opposed to other tuple records stored
	* directly within a glyph variation data table. */
	NNOffset32To<UnsizedArrayOf<F2DOT14>>
	sharedTuples; /* Offset from the start of this table to the shared tuple records.
	* Array of tuple records shared across all glyph variation data tables. */
	HBUINT16 glyphCountX; /* The number of glyphs in this font. This must match the number of
	* glyphs stored elsewhere in the font. */
	HBUINT16 flags; /* Bit-field that gives the format of the offset array that follows.
	* If bit 0 is clear, the offsets are uint16; if bit 0 is set, the
	* offsets are uint32. */
	Offset32To<GlyphVariationData>
	dataZ; /* Offset from the start of this table to the array of
	* GlyphVariationData tables. */
	UnsizedArrayOf<HBUINT8>
	offsetZ; /* Offsets from the start of the GlyphVariationData array
	* to each GlyphVariationData table. */
	public:
	DEFINE_SIZE_ARRAY (20, offsetZ);
	};

	struct gvar_accelerator_t : gvar::accelerator_t {
	gvar_accelerator_t (hb_face_t *face) : gvar::accelerator_t (face) {}
	};

	} /* namespace OT */

	#endif /* HB_OT_VAR_GVAR_TABLE_HH */