hb-ft.cc

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/*
 * Copyright © 2009  Red Hat, Inc.
 * Copyright © 2009  Keith Stribley
 * Copyright © 2015  Google, Inc.
 *
 *  This is part of HarfBuzz, a text shaping library.
 *
 * Permission is hereby granted, without written agreement and without
 * license or royalty fees, to use, copy, modify, and distribute this
 * software and its documentation for any purpose, provided that the
 * above copyright notice and the following two paragraphs appear in
 * all copies of this software.
 *
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 *
 * Red Hat Author(s): Behdad Esfahbod
 * Google Author(s): Behdad Esfahbod
 */
 
#include "hb.hh"
 
#ifdef HAVE_FREETYPE
 
#include "hb-ft.h"
 
#include "hb-draw.hh"
#include "hb-font.hh"
#include "hb-machinery.hh"
#include "hb-cache.hh"
 
#include FT_ADVANCES_H
#include FT_MULTIPLE_MASTERS_H
#include FT_OUTLINE_H
#include FT_TRUETYPE_TABLES_H
 
 
/* TODO:
 *
 * In general, this file does a fine job of what it's supposed to do.
 * There are, however, things that need more work:
 *
 *   - FreeType works in 26.6 mode.  Clients can decide to use that mode, and everything
 *     would work fine.  However, we also abuse this API for performing in font-space,
 *     but don't pass the correct flags to FreeType.  We just abuse the no-hinting mode
 *     for that, such that no rounding etc happens.  As such, we don't set ppem, and
 *     pass NO_HINTING as load_flags.  Would be much better to use NO_SCALE, and scale
 *     ourselves.
 *
 *   - We don't handle / allow for emboldening / obliqueing.
 *
 *   - In the future, we should add constructors to create fonts in font space?
 */
 
 
struct hb_ft_font_t
{
  mutable hb_mutex_t lock;
  FT_Face ft_face;
  int load_flags;
  bool symbol; /* Whether selected cmap is symbol cmap. */
  bool unref; /* Whether to destroy ft_face when done. */
 
  mutable int cached_x_scale;
  mutable hb_advance_cache_t advance_cache;
};
 
static hb_ft_font_t *
_hb_ft_font_create (FT_Face ft_face, bool symbol, bool unref)
{
  hb_ft_font_t *ft_font = (hb_ft_font_t *) hb_calloc (1, sizeof (hb_ft_font_t));
  if (unlikely (!ft_font)) return nullptr;
 
  ft_font->lock.init ();
  ft_font->ft_face = ft_face;
  ft_font->symbol = symbol;
  ft_font->unref = unref;
 
  ft_font->load_flags = FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING;
 
  ft_font->cached_x_scale = 0;
  ft_font->advance_cache.init ();
 
  return ft_font;
}
 
static void
_hb_ft_face_destroy (void *data)
{
  FT_Done_Face ((FT_Face) data);
}
 
static void
_hb_ft_font_destroy (void *data)
{
  hb_ft_font_t *ft_font = (hb_ft_font_t *) data;
 
  ft_font->advance_cache.fini ();
 
  if (ft_font->unref)
    _hb_ft_face_destroy (ft_font->ft_face);
 
  ft_font->lock.fini ();
 
  hb_free (ft_font);
}
 
void
hb_ft_font_set_load_flags (hb_font_t *font, int load_flags)
{
  if (hb_object_is_immutable (font))
    return;
 
  if (unlikely (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy))
    return;
 
  hb_ft_font_t *ft_font = (hb_ft_font_t *) font->user_data;
 
  ft_font->load_flags = load_flags;
}
 
int
hb_ft_font_get_load_flags (hb_font_t *font)
{
  if (unlikely (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy))
    return 0;
 
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font->user_data;
 
  return ft_font->load_flags;
}
 
FT_Face
hb_ft_font_get_face (hb_font_t *font)
{
  if (unlikely (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy))
    return nullptr;
 
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font->user_data;
 
  return ft_font->ft_face;
}
 
FT_Face
hb_ft_font_lock_face (hb_font_t *font)
{
  if (unlikely (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy))
    return nullptr;
 
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font->user_data;
 
  ft_font->lock.lock ();
 
  return ft_font->ft_face;
}
 
void
hb_ft_font_unlock_face (hb_font_t *font)
{
  if (unlikely (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy))
    return;
 
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font->user_data;
 
  ft_font->lock.unlock ();
}
 
 
static hb_bool_t
hb_ft_get_nominal_glyph (hb_font_t *font HB_UNUSED,
             void *font_data,
             hb_codepoint_t unicode,
             hb_codepoint_t *glyph,
             void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  unsigned int g = FT_Get_Char_Index (ft_font->ft_face, unicode);
 
  if (unlikely (!g))
  {
    if (unlikely (ft_font->symbol) && unicode <= 0x00FFu)
    {
      /* For symbol-encoded OpenType fonts, we duplicate the
       * U+F000..F0FF range at U+0000..U+00FF.  That's what
       * Windows seems to do, and that's hinted about at:
       * https://docs.microsoft.com/en-us/typography/opentype/spec/recom
       * under "Non-Standard (Symbol) Fonts". */
      g = FT_Get_Char_Index (ft_font->ft_face, 0xF000u + unicode);
      if (!g)
    return false;
    }
    else
      return false;
  }
 
  *glyph = g;
  return true;
}
 
static unsigned int
hb_ft_get_nominal_glyphs (hb_font_t *font HB_UNUSED,
              void *font_data,
              unsigned int count,
              const hb_codepoint_t *first_unicode,
              unsigned int unicode_stride,
              hb_codepoint_t *first_glyph,
              unsigned int glyph_stride,
              void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  unsigned int done;
  for (done = 0;
       done < count && (*first_glyph = FT_Get_Char_Index (ft_font->ft_face, *first_unicode));
       done++)
  {
    first_unicode = &StructAtOffsetUnaligned<hb_codepoint_t> (first_unicode, unicode_stride);
    first_glyph = &StructAtOffsetUnaligned<hb_codepoint_t> (first_glyph, glyph_stride);
  }
  /* We don't need to do ft_font->symbol dance here, since HB calls the singular
   * nominal_glyph() for what we don't handle here. */
  return done;
}
 
 
static hb_bool_t
hb_ft_get_variation_glyph (hb_font_t *font HB_UNUSED,
               void *font_data,
               hb_codepoint_t unicode,
               hb_codepoint_t variation_selector,
               hb_codepoint_t *glyph,
               void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  unsigned int g = FT_Face_GetCharVariantIndex (ft_font->ft_face, unicode, variation_selector);
 
  if (unlikely (!g))
    return false;
 
  *glyph = g;
  return true;
}
 
static void
hb_ft_get_glyph_h_advances (hb_font_t* font, void* font_data,
                unsigned count,
                const hb_codepoint_t *first_glyph,
                unsigned glyph_stride,
                hb_position_t *first_advance,
                unsigned advance_stride,
                void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Face ft_face = ft_font->ft_face;
  int load_flags = ft_font->load_flags;
  int mult = font->x_scale < 0 ? -1 : +1;
 
  if (font->x_scale != ft_font->cached_x_scale)
  {
    ft_font->advance_cache.clear ();
    ft_font->cached_x_scale = font->x_scale;
  }
 
  for (unsigned int i = 0; i < count; i++)
  {
    FT_Fixed v = 0;
    hb_codepoint_t glyph = *first_glyph;
 
    unsigned int cv;
    if (ft_font->advance_cache.get (glyph, &cv))
      v = cv;
    else
    {
      FT_Get_Advance (ft_face, glyph, load_flags, &v);
      ft_font->advance_cache.set (glyph, v);
    }
 
    *first_advance = (v * mult + (1<<9)) >> 10;
    first_glyph = &StructAtOffsetUnaligned<hb_codepoint_t> (first_glyph, glyph_stride);
    first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride);
  }
}
 
#ifndef HB_NO_VERTICAL
static hb_position_t
hb_ft_get_glyph_v_advance (hb_font_t *font,
               void *font_data,
               hb_codepoint_t glyph,
               void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Fixed v;
 
  if (unlikely (FT_Get_Advance (ft_font->ft_face, glyph, ft_font->load_flags | FT_LOAD_VERTICAL_LAYOUT, &v)))
    return 0;
 
  if (font->y_scale < 0)
    v = -v;
 
  /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
   * have a Y growing upward.  Hence the extra negation. */
 
  return (-v + (1<<9)) >> 10;
}
#endif
 
#ifndef HB_NO_VERTICAL
static hb_bool_t
hb_ft_get_glyph_v_origin (hb_font_t *font,
              void *font_data,
              hb_codepoint_t glyph,
              hb_position_t *x,
              hb_position_t *y,
              void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Face ft_face = ft_font->ft_face;
 
  if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))
    return false;
 
  /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
   * have a Y growing upward.  Hence the extra negation. */
  *x = ft_face->glyph->metrics.horiBearingX -   ft_face->glyph->metrics.vertBearingX;
  *y = ft_face->glyph->metrics.horiBearingY - (-ft_face->glyph->metrics.vertBearingY);
 
  if (font->x_scale < 0)
    *x = -*x;
  if (font->y_scale < 0)
    *y = -*y;
 
  return true;
}
#endif
 
#ifndef HB_NO_OT_SHAPE_FALLBACK
static hb_position_t
hb_ft_get_glyph_h_kerning (hb_font_t *font,
               void *font_data,
               hb_codepoint_t left_glyph,
               hb_codepoint_t right_glyph,
               void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  FT_Vector kerningv;
 
  FT_Kerning_Mode mode = font->x_ppem ? FT_KERNING_DEFAULT : FT_KERNING_UNFITTED;
  if (FT_Get_Kerning (ft_font->ft_face, left_glyph, right_glyph, mode, &kerningv))
    return 0;
 
  return kerningv.x;
}
#endif
 
static hb_bool_t
hb_ft_get_glyph_extents (hb_font_t *font,
             void *font_data,
             hb_codepoint_t glyph,
             hb_glyph_extents_t *extents,
             void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Face ft_face = ft_font->ft_face;
 
  if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))
    return false;
 
  extents->x_bearing = ft_face->glyph->metrics.horiBearingX;
  extents->y_bearing = ft_face->glyph->metrics.horiBearingY;
  extents->width = ft_face->glyph->metrics.width;
  extents->height = -ft_face->glyph->metrics.height;
  if (font->x_scale < 0)
  {
    extents->x_bearing = -extents->x_bearing;
    extents->width = -extents->width;
  }
  if (font->y_scale < 0)
  {
    extents->y_bearing = -extents->y_bearing;
    extents->height = -extents->height;
  }
  return true;
}
 
static hb_bool_t
hb_ft_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
                   void *font_data,
                   hb_codepoint_t glyph,
                   unsigned int point_index,
                   hb_position_t *x,
                   hb_position_t *y,
                   void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Face ft_face = ft_font->ft_face;
 
  if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))
      return false;
 
  if (unlikely (ft_face->glyph->format != FT_GLYPH_FORMAT_OUTLINE))
      return false;
 
  if (unlikely (point_index >= (unsigned int) ft_face->glyph->outline.n_points))
      return false;
 
  *x = ft_face->glyph->outline.points[point_index].x;
  *y = ft_face->glyph->outline.points[point_index].y;
 
  return true;
}
 
static hb_bool_t
hb_ft_get_glyph_name (hb_font_t *font HB_UNUSED,
              void *font_data,
              hb_codepoint_t glyph,
              char *name, unsigned int size,
              void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Face ft_face = ft_font->ft_face;
 
  hb_bool_t ret = !FT_Get_Glyph_Name (ft_face, glyph, name, size);
  if (ret && (size && !*name))
    ret = false;
 
  return ret;
}
 
static hb_bool_t
hb_ft_get_glyph_from_name (hb_font_t *font HB_UNUSED,
               void *font_data,
               const char *name, int len, /* -1 means nul-terminated */
               hb_codepoint_t *glyph,
               void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Face ft_face = ft_font->ft_face;
 
  if (len < 0)
    *glyph = FT_Get_Name_Index (ft_face, (FT_String *) name);
  else {
    /* Make a nul-terminated version. */
    char buf[128];
    len = hb_min (len, (int) sizeof (buf) - 1);
    strncpy (buf, name, len);
    buf[len] = '\0';
    *glyph = FT_Get_Name_Index (ft_face, buf);
  }
 
  if (*glyph == 0)
  {
    /* Check whether the given name was actually the name of glyph 0. */
    char buf[128];
    if (!FT_Get_Glyph_Name(ft_face, 0, buf, sizeof (buf)) &&
    len < 0 ? !strcmp (buf, name) : !strncmp (buf, name, len))
      return true;
  }
 
  return *glyph != 0;
}
 
static hb_bool_t
hb_ft_get_font_h_extents (hb_font_t *font HB_UNUSED,
              void *font_data,
              hb_font_extents_t *metrics,
              void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Face ft_face = ft_font->ft_face;
  metrics->ascender = FT_MulFix(ft_face->ascender, ft_face->size->metrics.y_scale);
  metrics->descender = FT_MulFix(ft_face->descender, ft_face->size->metrics.y_scale);
  metrics->line_gap = FT_MulFix( ft_face->height, ft_face->size->metrics.y_scale ) - (metrics->ascender - metrics->descender);
  if (font->y_scale < 0)
  {
    metrics->ascender = -metrics->ascender;
    metrics->descender = -metrics->descender;
    metrics->line_gap = -metrics->line_gap;
  }
  return true;
}
 
#ifndef HB_NO_DRAW
 
static int
_hb_ft_move_to (const FT_Vector *to,
        hb_draw_session_t *drawing)
{
  drawing->move_to (to->x, to->y);
  return FT_Err_Ok;
}
 
static int
_hb_ft_line_to (const FT_Vector *to,
        hb_draw_session_t *drawing)
{
  drawing->line_to (to->x, to->y);
  return FT_Err_Ok;
}
 
static int
_hb_ft_conic_to (const FT_Vector *control,
         const FT_Vector *to,
         hb_draw_session_t *drawing)
{
  drawing->quadratic_to (control->x, control->y,
             to->x, to->y);
  return FT_Err_Ok;
}
 
static int
_hb_ft_cubic_to (const FT_Vector *control1,
         const FT_Vector *control2,
         const FT_Vector *to,
         hb_draw_session_t *drawing)
{
  drawing->cubic_to (control1->x, control1->y,
             control2->x, control2->y,
             to->x, to->y);
  return FT_Err_Ok;
}
 
static void
hb_ft_get_glyph_shape (hb_font_t *font HB_UNUSED,
               void *font_data,
               hb_codepoint_t glyph,
               hb_draw_funcs_t *draw_funcs, void *draw_data,
               void *user_data HB_UNUSED)
{
  const hb_ft_font_t *ft_font = (const hb_ft_font_t *) font_data;
  hb_lock_t lock (ft_font->lock);
  FT_Face ft_face = ft_font->ft_face;
 
  if (unlikely (FT_Load_Glyph (ft_face, glyph,
                   FT_LOAD_NO_BITMAP | ft_font->load_flags)))
    return;
 
  if (ft_face->glyph->format != FT_GLYPH_FORMAT_OUTLINE)
    return;
 
  const FT_Outline_Funcs outline_funcs = {
    (FT_Outline_MoveToFunc) _hb_ft_move_to,
    (FT_Outline_LineToFunc) _hb_ft_line_to,
    (FT_Outline_ConicToFunc) _hb_ft_conic_to,
    (FT_Outline_CubicToFunc) _hb_ft_cubic_to,
    0, /* shift */
    0, /* delta */
  };
 
  hb_draw_session_t draw_session (draw_funcs, draw_data, font->slant_xy);
 
  FT_Outline_Decompose (&ft_face->glyph->outline,
            &outline_funcs,
            &draw_session);
}
#endif
 
 
static inline void free_static_ft_funcs ();
 
static struct hb_ft_font_funcs_lazy_loader_t : hb_font_funcs_lazy_loader_t<hb_ft_font_funcs_lazy_loader_t>
{
  static hb_font_funcs_t *create ()
  {
    hb_font_funcs_t *funcs = hb_font_funcs_create ();
 
    hb_font_funcs_set_nominal_glyph_func (funcs, hb_ft_get_nominal_glyph, nullptr, nullptr);
    hb_font_funcs_set_nominal_glyphs_func (funcs, hb_ft_get_nominal_glyphs, nullptr, nullptr);
    hb_font_funcs_set_variation_glyph_func (funcs, hb_ft_get_variation_glyph, nullptr, nullptr);
 
    hb_font_funcs_set_font_h_extents_func (funcs, hb_ft_get_font_h_extents, nullptr, nullptr);
    hb_font_funcs_set_glyph_h_advances_func (funcs, hb_ft_get_glyph_h_advances, nullptr, nullptr);
    //hb_font_funcs_set_glyph_h_origin_func (funcs, hb_ft_get_glyph_h_origin, nullptr, nullptr);
 
#ifndef HB_NO_VERTICAL
    //hb_font_funcs_set_font_v_extents_func (funcs, hb_ft_get_font_v_extents, nullptr, nullptr);
    hb_font_funcs_set_glyph_v_advance_func (funcs, hb_ft_get_glyph_v_advance, nullptr, nullptr);
    hb_font_funcs_set_glyph_v_origin_func (funcs, hb_ft_get_glyph_v_origin, nullptr, nullptr);
#endif
 
#ifndef HB_NO_OT_SHAPE_FALLBACK
    hb_font_funcs_set_glyph_h_kerning_func (funcs, hb_ft_get_glyph_h_kerning, nullptr, nullptr);
#endif
    //hb_font_funcs_set_glyph_v_kerning_func (funcs, hb_ft_get_glyph_v_kerning, nullptr, nullptr);
    hb_font_funcs_set_glyph_extents_func (funcs, hb_ft_get_glyph_extents, nullptr, nullptr);
    hb_font_funcs_set_glyph_contour_point_func (funcs, hb_ft_get_glyph_contour_point, nullptr, nullptr);
    hb_font_funcs_set_glyph_name_func (funcs, hb_ft_get_glyph_name, nullptr, nullptr);
    hb_font_funcs_set_glyph_from_name_func (funcs, hb_ft_get_glyph_from_name, nullptr, nullptr);
 
#ifndef HB_NO_DRAW
    hb_font_funcs_set_glyph_shape_func (funcs, hb_ft_get_glyph_shape, nullptr, nullptr);
#endif
 
    hb_font_funcs_make_immutable (funcs);
 
    hb_atexit (free_static_ft_funcs);
 
    return funcs;
  }
} static_ft_funcs;
 
static inline
void free_static_ft_funcs ()
{
  static_ft_funcs.free_instance ();
}
 
static hb_font_funcs_t *
_hb_ft_get_font_funcs ()
{
  return static_ft_funcs.get_unconst ();
}
 
static void
_hb_ft_font_set_funcs (hb_font_t *font, FT_Face ft_face, bool unref)
{
  bool symbol = ft_face->charmap && ft_face->charmap->encoding == FT_ENCODING_MS_SYMBOL;
 
  hb_ft_font_t *ft_font = _hb_ft_font_create (ft_face, symbol, unref);
  if (unlikely (!ft_font)) return;
 
  hb_font_set_funcs (font,
             _hb_ft_get_font_funcs (),
             ft_font,
             _hb_ft_font_destroy);
}
 
 
static hb_blob_t *
_hb_ft_reference_table (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)
{
  FT_Face ft_face = (FT_Face) user_data;
  FT_Byte *buffer;
  FT_ULong  length = 0;
  FT_Error error;
 
  /* Note: FreeType like HarfBuzz uses the NONE tag for fetching the entire blob */
 
  error = FT_Load_Sfnt_Table (ft_face, tag, 0, nullptr, &length);
  if (error)
    return nullptr;
 
  buffer = (FT_Byte *) hb_malloc (length);
  if (!buffer)
    return nullptr;
 
  error = FT_Load_Sfnt_Table (ft_face, tag, 0, buffer, &length);
  if (error)
  {
    hb_free (buffer);
    return nullptr;
  }
 
  return hb_blob_create ((const char *) buffer, length,
             HB_MEMORY_MODE_WRITABLE,
             buffer, hb_free);
}
 
hb_face_t *
hb_ft_face_create (FT_Face           ft_face,
           hb_destroy_func_t destroy)
{
  hb_face_t *face;
 
  if (!ft_face->stream->read) {
    hb_blob_t *blob;
 
    blob = hb_blob_create ((const char *) ft_face->stream->base,
               (unsigned int) ft_face->stream->size,
               HB_MEMORY_MODE_READONLY,
               ft_face, destroy);
    face = hb_face_create (blob, ft_face->face_index);
    hb_blob_destroy (blob);
  } else {
    face = hb_face_create_for_tables (_hb_ft_reference_table, ft_face, destroy);
  }
 
  hb_face_set_index (face, ft_face->face_index);
  hb_face_set_upem (face, ft_face->units_per_EM);
 
  return face;
}
 
hb_face_t *
hb_ft_face_create_referenced (FT_Face ft_face)
{
  FT_Reference_Face (ft_face);
  return hb_ft_face_create (ft_face, _hb_ft_face_destroy);
}
 
static void
hb_ft_face_finalize (FT_Face ft_face)
{
  hb_face_destroy ((hb_face_t *) ft_face->generic.data);
}
 
hb_face_t *
hb_ft_face_create_cached (FT_Face ft_face)
{
  if (unlikely (!ft_face->generic.data || ft_face->generic.finalizer != (FT_Generic_Finalizer) hb_ft_face_finalize))
  {
    if (ft_face->generic.finalizer)
      ft_face->generic.finalizer (ft_face);
 
    ft_face->generic.data = hb_ft_face_create (ft_face, nullptr);
    ft_face->generic.finalizer = (FT_Generic_Finalizer) hb_ft_face_finalize;
  }
 
  return hb_face_reference ((hb_face_t *) ft_face->generic.data);
}
 
hb_font_t *
hb_ft_font_create (FT_Face           ft_face,
           hb_destroy_func_t destroy)
{
  hb_font_t *font;
  hb_face_t *face;
 
  face = hb_ft_face_create (ft_face, destroy);
  font = hb_font_create (face);
  hb_face_destroy (face);
  _hb_ft_font_set_funcs (font, ft_face, false);
  hb_ft_font_changed (font);
  return font;
}
 
void
hb_ft_font_changed (hb_font_t *font)
{
  if (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy)
    return;
 
  hb_ft_font_t *ft_font = (hb_ft_font_t *) font->user_data;
 
  FT_Face ft_face = ft_font->ft_face;
 
  hb_font_set_scale (font,
             (int) (((uint64_t) ft_face->size->metrics.x_scale * (uint64_t) ft_face->units_per_EM + (1u<<15)) >> 16),
             (int) (((uint64_t) ft_face->size->metrics.y_scale * (uint64_t) ft_face->units_per_EM + (1u<<15)) >> 16));
#if 0 /* hb-ft works in no-hinting model */
  hb_font_set_ppem (font,
            ft_face->size->metrics.x_ppem,
            ft_face->size->metrics.y_ppem);
#endif
 
#if defined(HAVE_FT_GET_VAR_BLEND_COORDINATES) && !defined(HB_NO_VAR)
  FT_MM_Var *mm_var = nullptr;
  if (!FT_Get_MM_Var (ft_face, &mm_var))
  {
    FT_Fixed *ft_coords = (FT_Fixed *) hb_calloc (mm_var->num_axis, sizeof (FT_Fixed));
    int *coords = (int *) hb_calloc (mm_var->num_axis, sizeof (int));
    if (coords && ft_coords)
    {
      if (!FT_Get_Var_Blend_Coordinates (ft_face, mm_var->num_axis, ft_coords))
      {
    bool nonzero = false;
 
    for (unsigned int i = 0; i < mm_var->num_axis; ++i)
     {
      coords[i] = ft_coords[i] >>= 2;
      nonzero = nonzero || coords[i];
     }
 
    if (nonzero)
      hb_font_set_var_coords_normalized (font, coords, mm_var->num_axis);
    else
      hb_font_set_var_coords_normalized (font, nullptr, 0);
      }
    }
    hb_free (coords);
    hb_free (ft_coords);
#ifdef HAVE_FT_DONE_MM_VAR
    FT_Done_MM_Var (ft_face->glyph->library, mm_var);
#else
    hb_free (mm_var);
#endif
  }
#endif
}
 
hb_font_t *
hb_ft_font_create_referenced (FT_Face ft_face)
{
  FT_Reference_Face (ft_face);
  return hb_ft_font_create (ft_face, _hb_ft_face_destroy);
}
 
static inline void free_static_ft_library ();
 
static struct hb_ft_library_lazy_loader_t : hb_lazy_loader_t<hb_remove_pointer<FT_Library>,
                                 hb_ft_library_lazy_loader_t>
{
  static FT_Library create ()
  {
    FT_Library l;
    if (FT_Init_FreeType (&l))
      return nullptr;
 
    hb_atexit (free_static_ft_library);
 
    return l;
  }
  static void destroy (FT_Library l)
  {
    FT_Done_FreeType (l);
  }
  static FT_Library get_null ()
  {
    return nullptr;
  }
} static_ft_library;
 
static inline
void free_static_ft_library ()
{
  static_ft_library.free_instance ();
}
 
static FT_Library
get_ft_library ()
{
  return static_ft_library.get_unconst ();
}
 
static void
_release_blob (FT_Face ft_face)
{
  hb_blob_destroy ((hb_blob_t *) ft_face->generic.data);
}
 
void
hb_ft_font_set_funcs (hb_font_t *font)
{
  hb_blob_t *blob = hb_face_reference_blob (font->face);
  unsigned int blob_length;
  const char *blob_data = hb_blob_get_data (blob, &blob_length);
  if (unlikely (!blob_length))
    DEBUG_MSG (FT, font, "Font face has empty blob");
 
  FT_Face ft_face = nullptr;
  FT_Error err = FT_New_Memory_Face (get_ft_library (),
                     (const FT_Byte *) blob_data,
                     blob_length,
                     hb_face_get_index (font->face),
                     &ft_face);
 
  if (unlikely (err)) {
    hb_blob_destroy (blob);
    DEBUG_MSG (FT, font, "Font face FT_New_Memory_Face() failed");
    return;
  }
 
  if (FT_Select_Charmap (ft_face, FT_ENCODING_MS_SYMBOL))
    FT_Select_Charmap (ft_face, FT_ENCODING_UNICODE);
 
  FT_Set_Char_Size (ft_face,
            abs (font->x_scale), abs (font->y_scale),
            0, 0);
#if 0
            font->x_ppem * 72 * 64 / font->x_scale,
            font->y_ppem * 72 * 64 / font->y_scale);
#endif
  if (font->x_scale < 0 || font->y_scale < 0)
  {
    FT_Matrix matrix = { font->x_scale < 0 ? -1 : +1, 0,
              0, font->y_scale < 0 ? -1 : +1};
    FT_Set_Transform (ft_face, &matrix, nullptr);
  }
 
#if defined(HAVE_FT_GET_VAR_BLEND_COORDINATES) && !defined(HB_NO_VAR)
  unsigned int num_coords;
  const int *coords = hb_font_get_var_coords_normalized (font, &num_coords);
  if (num_coords)
  {
    FT_Fixed *ft_coords = (FT_Fixed *) hb_calloc (num_coords, sizeof (FT_Fixed));
    if (ft_coords)
    {
      for (unsigned int i = 0; i < num_coords; i++)
    ft_coords[i] = coords[i] * 4;
      FT_Set_Var_Blend_Coordinates (ft_face, num_coords, ft_coords);
      hb_free (ft_coords);
    }
  }
#endif
 
  ft_face->generic.data = blob;
  ft_face->generic.finalizer = (FT_Generic_Finalizer) _release_blob;
 
  _hb_ft_font_set_funcs (font, ft_face, true);
  hb_ft_font_set_load_flags (font, FT_LOAD_DEFAULT | FT_LOAD_NO_HINTING);
}
 
 
#endif