Quelle hb-ft.cc Sprache: C

/*
* 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 "hb-ot-os2-table.hh"
#include "hb-ot-shaper-arabic-pua.hh"

#include FT_ADVANCES_H
#include FT_MULTIPLE_MASTERS_H
#include FT_OUTLINE_H
#include FT_TRUETYPE_TABLES_H

/**
* SECTION:hb-ft
* @title: hb-ft
* @short_description: FreeType integration
* @include: hb-ft.h
*
* Functions for using HarfBuzz with the FreeType library.
*
* HarfBuzz supports using FreeType to provide face and
* font data.
*
* <note>Note that FreeType is not thread-safe, therefore these
* functions are not thread-safe either.</note>
**/

/* 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
{
  int load_flags;
  bool symbol; /* Whether selected cmap is symbol cmap. */
  bool unref; /* Whether to destroy ft_face when done. */

  mutable hb_mutex_t lock;
  FT_Face ft_face;
  mutable unsigned cached_serial;
  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_serial = (unsigned) -1;
  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);
}

/* hb_font changed, update FT_Face. */
static void _hb_ft_hb_font_changed (hb_font_t *font, FT_Face ft_face)
{

  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
}

/* Check if hb_font changed, update FT_Face. */
static inline bool
_hb_ft_hb_font_check_changed (hb_font_t *font,
                              const hb_ft_font_t *ft_font)
{
  if (font->serial != ft_font->cached_serial)
  {
    _hb_ft_hb_font_changed (font, ft_font->ft_face);
    ft_font->advance_cache.clear ();
    ft_font->cached_serial = font->serial;
    return true;
  }
  return false;
}

/**
* hb_ft_font_set_load_flags:
* @font: #hb_font_t to work upon
* @load_flags: The FreeType load flags to set
*
* Sets the FT_Load_Glyph load flags for the specified #hb_font_t.
*
* For more information, see
* https://www.freetype.org/freetype2/docs/reference/ft2-base_interface.html#ft_load_xxx
*
* Since: 1.0.5
**/
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;
}

/**
* hb_ft_font_get_load_flags:
* @font: #hb_font_t to work upon
*
* Fetches the FT_Load_Glyph load flags of the specified #hb_font_t.
*
* For more information, see
* https://www.freetype.org/freetype2/docs/reference/ft2-base_interface.html#ft_load_xxx
*
* Return value: FT_Load_Glyph flags found
*
* Since: 1.0.5
**/
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;
}

/**
* hb_ft_font_get_face: (skip)
* @font: #hb_font_t to work upon
*
* Fetches the FT_Face associated with the specified #hb_font_t
* font object.
*
* Return value: (nullable): the FT_Face found or %NULL
*
* Since: 0.9.2
**/
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;
}

/**
* hb_ft_font_lock_face: (skip)
* @font: #hb_font_t to work upon
*
* Gets the FT_Face associated with @font, This face will be kept around until
* you call hb_ft_font_unlock_face().
*
* Return value: (nullable): the FT_Face associated with @font or %NULL
* Since: 2.6.5
**/
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;
}

/**
* hb_ft_font_unlock_face:
* @font: #hb_font_t to work upon
*
* Releases an FT_Face previously obtained with hb_ft_font_lock_face().
*
* Since: 2.6.5
**/
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,
                         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))
    {
      switch ((unsigned) font->face->table.OS2->get_font_page ()) {
      case OT::OS2::font_page_t::FONT_PAGE_NONE:
        if (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);
        break;
#ifndef HB_NO_OT_SHAPER_ARABIC_FALLBACK
      case OT::OS2::font_page_t::FONT_PAGE_SIMP_ARABIC:
        g = FT_Get_Char_Index (ft_font->ft_face, _hb_arabic_pua_simp_map (unicode));
        break;
      case OT::OS2::font_page_t::FONT_PAGE_TRAD_ARABIC:
        g = FT_Get_Char_Index (ft_font->ft_face, _hb_arabic_pua_trad_map (unicode));
        break;
#endif
      default:
        break;
      }
      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;

  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;
  hb_lock_t lock (ft_font->lock);
  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;

  _hb_ft_hb_font_check_changed (font, ft_font);

  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_ft_face_create:
* @ft_face: (destroy destroy) (scope notified): FT_Face to work upon
* @destroy: (nullable): A callback to call when the face object is not needed anymore
*
* Creates an #hb_face_t face object from the specified FT_Face.
*
* This variant of the function does not provide any life-cycle management.
*
* Most client programs should use hb_ft_face_create_referenced()
* (or, perhaps, hb_ft_face_create_cached()) instead.
*
* If you know you have valid reasons not to use hb_ft_face_create_referenced(),
* then it is the client program's responsibility to destroy @ft_face
* after the #hb_face_t face object has been destroyed.
*
* Return value: (transfer full): the new #hb_face_t face object
*
* Since: 0.9.2
**/
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_ft_face_create_referenced:
* @ft_face: FT_Face to work upon
*
* Creates an #hb_face_t face object from the specified FT_Face.
*
* This is the preferred variant of the hb_ft_face_create*
* function family, because it calls FT_Reference_Face() on @ft_face,
* ensuring that @ft_face remains alive as long as the resulting
* #hb_face_t face object remains alive. Also calls FT_Done_Face()
* when the #hb_face_t face object is destroyed.
*
* Use this version unless you know you have good reasons not to.
*
* Return value: (transfer full): the new #hb_face_t face object
*
* Since: 0.9.38
**/
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_ft_face_create_cached:
* @ft_face: FT_Face to work upon
*
* Creates an #hb_face_t face object from the specified FT_Face.
*
* This variant of the function caches the newly created #hb_face_t
* face object, using the @generic pointer of @ft_face. Subsequent function
* calls that are passed the same @ft_face parameter will have the same
* #hb_face_t returned to them, and that #hb_face_t will be correctly
* reference counted.
*
* However, client programs are still responsible for destroying
* @ft_face after the last #hb_face_t face object has been destroyed.
*
* Return value: (transfer full): the new #hb_face_t face object
*
* Since: 0.9.2
**/
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_ft_font_create:
* @ft_face: (destroy destroy) (scope notified): FT_Face to work upon
* @destroy: (nullable): A callback to call when the font object is not needed anymore
*
* Creates an #hb_font_t font object from the specified FT_Face.
*
* <note>Note: You must set the face size on @ft_face before calling
* hb_ft_font_create() on it. HarfBuzz assumes size is always set and will
* access `size` member of FT_Face unconditionally.</note>
*
* This variant of the function does not provide any life-cycle management.
*
* Most client programs should use hb_ft_font_create_referenced()
* instead.
*
* If you know you have valid reasons not to use hb_ft_font_create_referenced(),
* then it is the client program's responsibility to destroy @ft_face
* after the #hb_font_t font object has been destroyed.
*
* HarfBuzz will use the @destroy callback on the #hb_font_t font object
* if it is supplied when you use this function. However, even if @destroy
* is provided, it is the client program's responsibility to destroy @ft_face,
* and it is the client program's responsibility to ensure that @ft_face is
* destroyed only after the #hb_font_t font object has been destroyed.
*
* Return value: (transfer full): the new #hb_font_t font object
*
* Since: 0.9.2
**/
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;
}

/**
* hb_ft_font_changed:
* @font: #hb_font_t to work upon
*
* Refreshes the state of @font when the underlying FT_Face has changed.
* This function should be called after changing the size or
* variation-axis settings on the FT_Face.
*
* Since: 1.0.5
**/
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_ft_hb_font_changed:
* @font: #hb_font_t to work upon
*
* Refreshes the state of the underlying FT_Face of @font when the hb_font_t
* @font has changed.
* This function should be called after changing the size or
* variation-axis settings on the @font.
* This call is fast if nothing has changed on @font.
*
* Return value: true if changed, false otherwise
*
* Since: 4.4.0
**/
hb_bool_t
hb_ft_hb_font_changed (hb_font_t *font)
{
  if (font->destroy != (hb_destroy_func_t) _hb_ft_font_destroy)
    return false;

  hb_ft_font_t *ft_font = (hb_ft_font_t *) font->user_data;

  return _hb_ft_hb_font_check_changed (font, ft_font);
}

/**
* hb_ft_font_create_referenced:
* @ft_face: FT_Face to work upon
*
* Creates an #hb_font_t font object from the specified FT_Face.
*
* <note>Note: You must set the face size on @ft_face before calling
* hb_ft_font_create_referenced() on it. HarfBuzz assumes size is always set
* and will access `size` member of FT_Face unconditionally.</note>
*
* This is the preferred variant of the hb_ft_font_create*
* function family, because it calls FT_Reference_Face() on @ft_face,
* ensuring that @ft_face remains alive as long as the resulting
* #hb_font_t font object remains alive.
*
* Use this version unless you know you have good reasons not to.
*
* Return value: (transfer full): the new #hb_font_t font object
*
* Since: 0.9.38
**/
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);
}

/**
* hb_ft_font_set_funcs:
* @font: #hb_font_t to work upon
*
* Configures the font-functions structure of the specified
* #hb_font_t font object to use FreeType font functions.
*
* In particular, you can use this function to configure an
* existing #hb_face_t face object for use with FreeType font
* functions even if that #hb_face_t face object was initially
* created with hb_face_create(), and therefore was not
* initially configured to use FreeType font functions.
*
* An #hb_face_t face object created with hb_ft_face_create()
* is preconfigured for FreeType font functions and does not
* require this function to be used.
*
* <note>Note: Internally, this function creates an FT_Face.
* </note>
*
* Since: 1.0.5
**/
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);

  _hb_ft_hb_font_changed (font, ft_face);

  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

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