tor-browser

glyf.hh (17527B)

---

#ifndef OT_GLYF_GLYF_HH
#define OT_GLYF_GLYF_HH


#include "../../hb-open-type.hh"
#include "../../hb-ot-head-table.hh"
#include "../../hb-ot-hmtx-table.hh"
#include "../../hb-ot-var-gvar-table.hh"
#include "../../hb-draw.hh"
#include "../../hb-paint.hh"

#include "glyf-helpers.hh"
#include "Glyph.hh"
#include "SubsetGlyph.hh"
#include "loca.hh"
#include "path-builder.hh"


namespace OT {


/*
* glyf -- TrueType Glyph Data
* https://docs.microsoft.com/en-us/typography/opentype/spec/glyf
*/
#define HB_OT_TAG_glyf HB_TAG('g','l','y','f')

struct glyf
{
 friend struct glyf_accelerator_t;

 static constexpr hb_tag_t tableTag = HB_OT_TAG_glyf;

 static bool has_valid_glyf_format(const hb_face_t* face)
 {
   const OT::head &head = *face->table.head;
   return head.indexToLocFormat <= 1 && head.glyphDataFormat <= 1;
 }

 bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const
 {
   TRACE_SANITIZE (this);
   /* Runtime checks as eager sanitizing each glyph is costy */
   return_trace (true);
 }

 /* requires source of SubsetGlyph complains the identifier isn't declared */
 template <typename Iterator>
 bool serialize (hb_serialize_context_t *c,
	  Iterator it,
                 bool use_short_loca,
	  const hb_subset_plan_t *plan)
 {
   TRACE_SERIALIZE (this);

   unsigned init_len = c->length ();
   for (auto &_ : it)
     if (unlikely (!_.serialize (c, use_short_loca, plan)))
       return false;

   /* As a special case when all glyph in the font are empty, add a zero byte
    * to the table, so that OTS doesn’t reject it, and to make the table work
    * on Windows as well.
    * See https://github.com/khaledhosny/ots/issues/52 */
   if (init_len == c->length ())
   {
     HBUINT8 empty_byte;
     empty_byte = 0;
     c->copy (empty_byte);
   }
   return_trace (true);
 }

 /* Byte region(s) per glyph to output
    unpadded, hints removed if so requested
    If we fail to process a glyph we produce an empty (0-length) glyph */
 bool subset (hb_subset_context_t *c) const
 {
   TRACE_SUBSET (this);

   if (!has_valid_glyf_format (c->plan->source)) {
     // glyf format is unknown don't attempt to subset it.
     DEBUG_MSG (SUBSET, nullptr,
                "unkown glyf format, dropping from subset.");
     return_trace (false);
   }

   hb_font_t *font = nullptr;
   if (c->plan->normalized_coords)
   {
     font = _create_font_for_instancing (c->plan);
     if (unlikely (!font))
return_trace (false);
   }

   hb_vector_t<unsigned> padded_offsets;
   if (unlikely (!padded_offsets.alloc_exact (c->plan->new_to_old_gid_list.length)))
     return_trace (false);

   hb_vector_t<glyf_impl::SubsetGlyph> glyphs;
   if (!_populate_subset_glyphs (c->plan, font, glyphs))
   {
     hb_font_destroy (font);
     return_trace (false);
   }

   if (font)
     hb_font_destroy (font);

   unsigned max_offset = 0;
   for (auto &g : glyphs)
   {
     unsigned size = g.padded_size ();
     padded_offsets.push (size);
     max_offset += size;
   }

   bool use_short_loca = false;
   if (likely (!c->plan->force_long_loca))
     use_short_loca = max_offset < 0x1FFFF;

   if (!use_short_loca)
   {
     padded_offsets.resize (0);
     for (auto &g : glyphs)
padded_offsets.push (g.length ());
   }

   auto *glyf_prime = c->serializer->start_embed <glyf> ();
   bool result = glyf_prime->serialize (c->serializer, hb_iter (glyphs), use_short_loca, c->plan);
   if (c->plan->normalized_coords && !c->plan->pinned_at_default)
     _free_compiled_subset_glyphs (glyphs);

   if (unlikely (!c->serializer->check_success (glyf_impl::_add_loca_and_head (c,
					 padded_offsets.iter (),
					 use_short_loca))))
     return_trace (false);

   return result;
 }

 bool
 _populate_subset_glyphs (const hb_subset_plan_t   *plan,
		   hb_font_t                *font,
		   hb_vector_t<glyf_impl::SubsetGlyph>& glyphs /* OUT */) const;

 hb_font_t *
 _create_font_for_instancing (const hb_subset_plan_t *plan) const;

 void _free_compiled_subset_glyphs (hb_vector_t<glyf_impl::SubsetGlyph> &glyphs) const
 {
   for (auto &g : glyphs)
     g.free_compiled_bytes ();
 }

 protected:
 UnsizedArrayOf<HBUINT8>
	dataZ;	/* Glyphs data. */
 public:
 DEFINE_SIZE_MIN (0);	/* In reality, this is UNBOUNDED() type; but since we always
		 * check the size externally, allow Null() object of it by
		 * defining it _MIN instead. */
};

struct glyf_accelerator_t
{
 glyf_accelerator_t (hb_face_t *face)
 {
   short_offset = false;
   num_glyphs = 0;
   loca_table = nullptr;
   glyf_table = nullptr;
#ifndef HB_NO_VAR
   gvar = nullptr;
#ifndef HB_NO_BEYOND_64K
   GVAR = nullptr;
#endif
#endif
   hmtx = nullptr;
#ifndef HB_NO_VERTICAL
   vmtx = nullptr;
#endif
   const OT::head &head = *face->table.head;
   if (!glyf::has_valid_glyf_format (face))
     /* Unknown format.  Leave num_glyphs=0, that takes care of disabling us. */
     return;
   short_offset = 0 == head.indexToLocFormat;

   loca_table = face->table.loca.get_blob (); // Needs no destruct!
   glyf_table = hb_sanitize_context_t ().reference_table<glyf> (face);
#ifndef HB_NO_VAR
   gvar = face->table.gvar;
#ifndef HB_NO_BEYOND_64K
   GVAR = face->table.GVAR;
#endif
#endif
   hmtx = face->table.hmtx;
#ifndef HB_NO_VERTICAL
   vmtx = face->table.vmtx;
#endif

   num_glyphs = hb_max (1u, loca_table.get_length () / (short_offset ? 2 : 4)) - 1;
   num_glyphs = hb_min (num_glyphs, face->get_num_glyphs ());
 }
 ~glyf_accelerator_t ()
 {
   auto *scratch = cached_scratch.get_relaxed ();
   if (scratch)
   {
     scratch->~hb_glyf_scratch_t ();
     hb_free (scratch);
   }

   glyf_table.destroy ();
 }

 bool has_data () const { return num_glyphs; }

 protected:
 template<typename T>
 bool get_points (hb_font_t *font, hb_codepoint_t gid, T consumer,
	   hb_array_t<const int> coords,
	   hb_glyf_scratch_t &scratch,
	   hb_scalar_cache_t *gvar_cache = nullptr) const
 {
   if (gid >= num_glyphs) return false;

   auto &all_points = scratch.all_points;
   all_points.resize (0);

   bool phantom_only = !consumer.is_consuming_contour_points ();
   if (unlikely (!glyph_for_gid (gid).get_points (font, *this, all_points, scratch, nullptr, nullptr, nullptr, true, true, phantom_only, coords, gvar_cache)))
     return false;

   unsigned count = all_points.length;
   assert (count >= glyf_impl::PHANTOM_COUNT);
   count -= glyf_impl::PHANTOM_COUNT;

   if (consumer.is_consuming_contour_points ())
   {
     auto *points = all_points.arrayZ;

     if (false)
     {
/* Our path-builder was designed to work with this simple loop.
 * But FreeType and CoreText do it differently, so we match those
 * with the other, more complicated, code branch below. */
for (unsigned i = 0; i < count; i++)
{
  consumer.consume_point (points[i]);
  if (points[i].is_end_point)
    consumer.contour_end ();
}
     }
     else
     {
for (unsigned i = 0; i < count; i++)
{
  // Start of a contour.
  if (points[i].flag & glyf_impl::SimpleGlyph::FLAG_ON_CURVE)
  {
    // First point is on-curve. Draw the contour.
    for (; i < count; i++)
    {
      consumer.consume_point (points[i]);
      if (points[i].is_end_point)
      {
	consumer.contour_end ();
	break;
      }
    }
  }
  else
  {
    unsigned start = i;

    // Find end of the contour.
    for (; i < count; i++)
      if (points[i].is_end_point)
	break;

    unsigned end = i;

    // Enough to start from the end. Our path-builder takes care of the rest.
    if (likely (end < count)) // Can only fail in case of alloc failure *maybe*.
      consumer.consume_point (points[end]);

    for (i = start; i < end; i++)
      consumer.consume_point (points[i]);

    consumer.contour_end ();
  }
}
     }

     consumer.points_end ();
   }

   /* Where to write phantoms, nullptr if not requested */
   contour_point_t *phantoms = consumer.get_phantoms_sink ();
   if (phantoms)
     for (unsigned i = 0; i < glyf_impl::PHANTOM_COUNT; ++i)
phantoms[i] = all_points.arrayZ[count + i];

   return true;
 }

 public:

#ifndef HB_NO_VAR
 struct points_aggregator_t
 {
   hb_font_t *font;
   hb_glyph_extents_t *extents;
   contour_point_t *phantoms;
   bool scaled;

   struct contour_bounds_t
   {
     contour_bounds_t () { min_x = min_y = FLT_MAX; max_x = max_y = -FLT_MAX; }

     void add (const contour_point_t &p)
     {
min_x = hb_min (min_x, p.x);
min_y = hb_min (min_y, p.y);
max_x = hb_max (max_x, p.x);
max_y = hb_max (max_y, p.y);
     }

     bool empty () const { return (min_x >= max_x) || (min_y >= max_y); }

     void get_extents (hb_font_t *font, hb_glyph_extents_t *extents, bool scaled)
     {
if (unlikely (empty ()))
{
  extents->width = 0;
  extents->x_bearing = 0;
  extents->height = 0;
  extents->y_bearing = 0;
  return;
}
{
  extents->x_bearing = roundf (min_x);
  extents->width = roundf (max_x - extents->x_bearing);
  extents->y_bearing = roundf (max_y);
  extents->height = roundf (min_y - extents->y_bearing);

  if (scaled)
    font->scale_glyph_extents (extents);
}
     }

     protected:
     float min_x, min_y, max_x, max_y;
   } bounds;

   points_aggregator_t (hb_font_t *font_, hb_glyph_extents_t *extents_, contour_point_t *phantoms_, bool scaled_)
   {
     font = font_;
     extents = extents_;
     phantoms = phantoms_;
     scaled = scaled_;
     if (extents) bounds = contour_bounds_t ();
   }

   HB_ALWAYS_INLINE
   void consume_point (const contour_point_t &point) { bounds.add (point); }
   void contour_end () {}
   void points_end () { bounds.get_extents (font, extents, scaled); }

   bool is_consuming_contour_points () { return extents; }
   contour_point_t *get_phantoms_sink () { return phantoms; }
 };

#ifndef HB_NO_VAR
 unsigned
 get_advance_with_var_unscaled (hb_codepoint_t gid,
			 hb_font_t *font,
			 bool is_vertical,
			  hb_glyf_scratch_t &scratch,
			 hb_scalar_cache_t *gvar_cache = nullptr) const
 {
   if (unlikely (gid >= num_glyphs)) return 0;

   bool success = false;

   contour_point_t phantoms[glyf_impl::PHANTOM_COUNT];
   success = get_points (font, gid, points_aggregator_t (font, nullptr, phantoms, false),
		  hb_array (font->coords,
			    font->has_nonzero_coords ? font->num_coords : 0),
		  scratch, gvar_cache);
   if (unlikely (!success))
   {
     unsigned upem = font->face->get_upem ();
     return is_vertical ? upem : upem / 2;
   }

   float result = is_vertical
	 ? phantoms[glyf_impl::PHANTOM_TOP].y - phantoms[glyf_impl::PHANTOM_BOTTOM].y
	 : phantoms[glyf_impl::PHANTOM_RIGHT].x - phantoms[glyf_impl::PHANTOM_LEFT].x;
   return hb_clamp (roundf (result), 0.f, (float) UINT_MAX / 2);
 }

 float
 get_v_origin_with_var_unscaled (hb_codepoint_t gid,
			  hb_font_t *font,
			  hb_glyf_scratch_t &scratch,
			  hb_scalar_cache_t *gvar_cache = nullptr) const
 {
   if (unlikely (gid >= num_glyphs)) return 0;

   bool success = false;

   contour_point_t phantoms[glyf_impl::PHANTOM_COUNT];
   success = get_points (font, gid, points_aggregator_t (font, nullptr, phantoms, false),
		  hb_array (font->coords,
			    font->has_nonzero_coords ? font->num_coords : 0),
		  scratch, gvar_cache);
   if (unlikely (!success))
   {
     return font->face->get_upem ();
   }

   return phantoms[glyf_impl::PHANTOM_TOP].y;
 }
#endif
#endif

 public:

 bool get_extents (hb_font_t *font,
	    hb_codepoint_t gid,
	    hb_glyph_extents_t *extents) const
 { return get_extents_at (font, gid, extents, hb_array (font->coords,
						 font->has_nonzero_coords ? font->num_coords : 0)); }

 bool get_extents_at (hb_font_t *font,
	       hb_codepoint_t gid,
	       hb_glyph_extents_t *extents,
	       hb_array_t<const int> coords) const
 {
   if (unlikely (gid >= num_glyphs)) return false;

#ifndef HB_NO_VAR
   if (coords)
   {
     hb_glyf_scratch_t *scratch = acquire_scratch ();
     if (unlikely (!scratch)) return false;
     bool ret = get_points (font,
		     gid,
		     points_aggregator_t (font, extents, nullptr, true),
		     coords,
		     *scratch);
     release_scratch (scratch);
     return ret;
   }
#endif
   return glyph_for_gid (gid).get_extents_without_var_scaled (font, *this, extents);
 }

 const glyf_impl::Glyph
 glyph_for_gid (hb_codepoint_t gid, bool needs_padding_removal = false) const
 {
   if (unlikely (gid >= num_glyphs)) return glyf_impl::Glyph ();

   unsigned int start_offset, end_offset;

   if (short_offset)
   {
     const HBUINT16 *offsets = (const HBUINT16 *) loca_table->dataZ.arrayZ;
     start_offset = 2 * offsets[gid];
     end_offset   = 2 * offsets[gid + 1];
   }
   else
   {
     const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataZ.arrayZ;
     start_offset = offsets[gid];
     end_offset   = offsets[gid + 1];
   }

   if (unlikely (start_offset > end_offset || end_offset > glyf_table.get_length ()))
     return glyf_impl::Glyph ();

   glyf_impl::Glyph glyph (hb_bytes_t ((const char *) this->glyf_table + start_offset,
		     end_offset - start_offset), gid);
   return needs_padding_removal ? glyf_impl::Glyph (glyph.trim_padding (), gid) : glyph;
 }

 bool
 get_path (hb_font_t *font, hb_codepoint_t gid, hb_draw_session_t &draw_session, hb_scalar_cache_t *gvar_cache = nullptr) const
 {
   if (!has_data ()) return false;

   hb_glyf_scratch_t *scratch = acquire_scratch ();
   if (unlikely (!scratch)) return true;

   bool ret = get_points (font, gid, glyf_impl::path_builder_t (font, draw_session),
		   hb_array (font->coords,
			     font->has_nonzero_coords ? font->num_coords : 0),
		   *scratch,
		    gvar_cache);

   release_scratch (scratch);

   return ret;
 }

 bool
 get_path_at (hb_font_t *font, hb_codepoint_t gid, hb_draw_session_t &draw_session,
       hb_array_t<const int> coords,
       hb_glyf_scratch_t &scratch,
       hb_scalar_cache_t *gvar_cache = nullptr) const
 {
   if (!has_data ()) return false;
   return get_points (font, gid, glyf_impl::path_builder_t (font, draw_session),
	       coords,
	       scratch,
	       gvar_cache);
 }


 hb_glyf_scratch_t *acquire_scratch () const
 {
   if (!has_data ()) return nullptr;
   hb_glyf_scratch_t *scratch = cached_scratch.get_acquire ();
   if (!scratch || unlikely (!cached_scratch.cmpexch (scratch, nullptr)))
   {
     scratch = (hb_glyf_scratch_t *) hb_calloc (1, sizeof (hb_glyf_scratch_t));
     if (unlikely (!scratch))
return nullptr;
   }
   return scratch;
 }
 void release_scratch (hb_glyf_scratch_t *scratch) const
 {
   if (!scratch)
     return;
   if (!cached_scratch.cmpexch (nullptr, scratch))
   {
     scratch->~hb_glyf_scratch_t ();
     hb_free (scratch);
   }
 }

#ifndef HB_NO_VAR
 const gvar_accelerator_t *gvar;
#ifndef HB_NO_BEYOND_64K
 const GVAR_accelerator_t *GVAR;
#endif
#endif
 const hmtx_accelerator_t *hmtx;
#ifndef HB_NO_VERTICAL
 const vmtx_accelerator_t *vmtx;
#endif

 private:
 bool short_offset;
 unsigned int num_glyphs;
 hb_blob_ptr_t<loca> loca_table;
 hb_blob_ptr_t<glyf> glyf_table;
 mutable hb_atomic_t<hb_glyf_scratch_t *> cached_scratch;
};


inline bool
glyf::_populate_subset_glyphs (const hb_subset_plan_t   *plan,
		       hb_font_t *font,
		       hb_vector_t<glyf_impl::SubsetGlyph>& glyphs /* OUT */) const
{
 OT::glyf_accelerator_t glyf (plan->source);
 if (!glyphs.alloc_exact (plan->new_to_old_gid_list.length)) return false;

 for (const auto &pair : plan->new_to_old_gid_list)
 {
   hb_codepoint_t new_gid = pair.first;
   hb_codepoint_t old_gid = pair.second;
   glyf_impl::SubsetGlyph *p = glyphs.push ();
   glyf_impl::SubsetGlyph& subset_glyph = *p;
   subset_glyph.old_gid = old_gid;

   if (unlikely (old_gid == 0 && new_gid == 0 &&
                 !(plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE)) &&
                 !plan->normalized_coords)
     subset_glyph.source_glyph = glyf_impl::Glyph ();
   else
   {
     /* If plan has an accelerator, the preprocessing step already trimmed glyphs.
      * Don't trim them again! */
     subset_glyph.source_glyph = glyf.glyph_for_gid (subset_glyph.old_gid, !plan->accelerator);
   }

   if (plan->flags & HB_SUBSET_FLAGS_NO_HINTING)
     subset_glyph.drop_hints_bytes ();
   else
     subset_glyph.dest_start = subset_glyph.source_glyph.get_bytes ();

   if (font)
   {
     if (unlikely (!subset_glyph.compile_bytes_with_deltas (plan, font, glyf)))
     {
       // when pinned at default, only bounds are updated, thus no need to free
       if (!plan->pinned_at_default)
         _free_compiled_subset_glyphs (glyphs);
       return false;
     }
   }
 }
 return true;
}

inline hb_font_t *
glyf::_create_font_for_instancing (const hb_subset_plan_t *plan) const
{
 hb_font_t *font = hb_font_create (plan->source);
 if (unlikely (font == hb_font_get_empty ())) return nullptr;

 hb_vector_t<hb_variation_t> vars;
 if (unlikely (!vars.alloc (plan->user_axes_location.get_population (), true)))
 {
   hb_font_destroy (font);
   return nullptr;
 }

 for (auto _ : plan->user_axes_location)
 {
   hb_variation_t var;
   var.tag = _.first;
   var.value = _.second.middle;
   vars.push (var);
 }

#ifndef HB_NO_VAR
 hb_font_set_variations (font, vars.arrayZ, plan->user_axes_location.get_population ());
#endif
 return font;
}


} /* namespace OT */


#endif /* OT_GLYF_GLYF_HH */