Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1500 insertions, 0 deletions

diff --git a/gfx/harfbuzz/src/hb-ft.cc b/gfx/harfbuzz/src/hb-ft.cc
new file mode 100644
index 0000000000..1105862fbc
--- /dev/null
+++ b/gfx/harfbuzz/src/hb-ft.cc
@@ -0,0 +1,1500 @@
+/*
+ * 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-cache.hh"
+#include "hb-draw.hh"
+#include "hb-font.hh"
+#include "hb-machinery.hh"
+#include "hb-ot-os2-table.hh"
+#include "hb-ot-shaper-arabic-pua.hh"
+#include "hb-paint.hh"
+
+#include FT_ADVANCES_H
+#include FT_MULTIPLE_MASTERS_H
+#include FT_OUTLINE_H
+#include FT_TRUETYPE_TABLES_H
+#include FT_SYNTHESIS_H
+#if (FREETYPE_MAJOR*10000 + FREETYPE_MINOR*100 + FREETYPE_PATCH) >= 21300
+#include FT_COLOR_H
+#endif
+
+
+/**
+ * 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?
+ */
+
+
+using hb_ft_advance_cache_t = hb_cache_t<16, 24, 8, false>;
+
+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. */
+  bool transform; /* Whether to apply FT_Face's transform. */
+
+  mutable hb_mutex_t lock; /* Protects members below. */
+  FT_Face ft_face;
+  mutable unsigned cached_serial;
+  mutable hb_ft_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;
+
+  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)
+{
+  hb_ft_font_t *ft_font = (hb_ft_font_t *) font->user_data;
+
+  float x_mult = 1.f, y_mult = 1.f;
+
+  if (font->x_scale < 0) x_mult = -x_mult;
+  if (font->y_scale < 0) y_mult = -y_mult;
+
+  if (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
+     ) && ft_face->num_fixed_sizes)
+  {
+#ifdef HAVE_FT_GET_TRANSFORM
+    /* Bitmap font, eg. bitmap color emoji. */
+    /* Pick largest size? */
+    int x_scale  = ft_face->available_sizes[ft_face->num_fixed_sizes - 1].x_ppem;
+    int y_scale = ft_face->available_sizes[ft_face->num_fixed_sizes - 1].y_ppem;
+    FT_Set_Char_Size (ft_face,
+		      x_scale, y_scale,
+		      0, 0);
+
+    /* This contains the sign that was previously in x_mult/y_mult. */
+    x_mult = (float) font->x_scale / x_scale;
+    y_mult = (float) font->y_scale / y_scale;
+#endif
+  }
+  else
+  { /* Shrug */ }
+
+
+  if (x_mult != 1.f || y_mult != 1.f)
+  {
+    FT_Matrix matrix = { (int) roundf (x_mult * (1<<16)), 0,
+			  0, (int) roundf (y_mult * (1<<16))};
+    FT_Set_Transform (ft_face, &matrix, nullptr);
+    ft_font->transform = true;
+  }
+
+#if defined(HAVE_FT_GET_VAR_BLEND_COORDINATES) && !defined(HB_NO_VAR)
+  unsigned int num_coords;
+  const float *coords = hb_font_get_var_coords_design (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] * 65536.f;
+      FT_Set_Var_Design_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
+ *
+ * This function works with #hb_font_t objects created by
+ * hb_ft_font_create() or hb_ft_font_create_referenced().
+ *
+ * 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
+ *
+ * This function works with #hb_font_t objects created by
+ * hb_ft_font_create() or hb_ft_font_create_referenced().
+ *
+ * Return value: FT_Load_Glyph flags found, or 0
+ *
+ * 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.
+ *
+ * This function works with #hb_font_t objects created by
+ * hb_ft_font_create() or hb_ft_font_create_referenced().
+ *
+ * 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 and access to the FT_Face object
+ * from other HarfBuzz API wil be blocked until you call hb_ft_font_unlock_face().
+ *
+ * This function works with #hb_font_t objects created by
+ * hb_ft_font_create() or hb_ft_font_create_referenced().
+ *
+ * Return value: (nullable) (transfer none): 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: (skip)
+ * @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_position_t *orig_first_advance = first_advance;
+  hb_lock_t lock (ft_font->lock);
+  FT_Face ft_face = ft_font->ft_face;
+  int load_flags = ft_font->load_flags;
+  float x_mult;
+#ifdef HAVE_FT_GET_TRANSFORM
+  if (ft_font->transform)
+  {
+    FT_Matrix matrix;
+    FT_Get_Transform (ft_face, &matrix, nullptr);
+    x_mult = sqrtf ((float)matrix.xx * matrix.xx + (float)matrix.xy * matrix.xy) / 65536.f;
+    x_mult *= font->x_scale < 0 ? -1 : +1;
+  }
+  else
+#endif
+  {
+    x_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);
+      /* Work around bug that FreeType seems to return negative advance
+       * for variable-set fonts if x_scale is negative! */
+      v = abs (v);
+      v = (int) (v * x_mult + (1<<9)) >> 10;
+      ft_font->advance_cache.set (glyph, v);
+    }
+
+    *first_advance = v;
+    first_glyph = &StructAtOffsetUnaligned<hb_codepoint_t> (first_glyph, glyph_stride);
+    first_advance = &StructAtOffsetUnaligned<hb_position_t> (first_advance, advance_stride);
+  }
+
+  if (font->x_strength && !font->embolden_in_place)
+  {
+    /* Emboldening. */
+    hb_position_t x_strength = font->x_scale >= 0 ? font->x_strength : -font->x_strength;
+    first_advance = orig_first_advance;
+    for (unsigned int i = 0; i < count; i++)
+    {
+      *first_advance += *first_advance ? x_strength : 0;
+      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;
+  float y_mult;
+#ifdef HAVE_FT_GET_TRANSFORM
+  if (ft_font->transform)
+  {
+    FT_Matrix matrix;
+    FT_Get_Transform (ft_font->ft_face, &matrix, nullptr);
+    y_mult = sqrtf ((float)matrix.yx * matrix.yx + (float)matrix.yy * matrix.yy) / 65536.f;
+    y_mult *= font->y_scale < 0 ? -1 : +1;
+  }
+  else
+#endif
+  {
+    y_mult = font->y_scale < 0 ? -1 : +1;
+  }
+
+  if (unlikely (FT_Get_Advance (ft_font->ft_face, glyph, ft_font->load_flags | FT_LOAD_VERTICAL_LAYOUT, &v)))
+    return 0;
+
+  v = (int) (y_mult * v);
+
+  /* Note: FreeType's vertical metrics grows downward while other FreeType coordinates
+   * have a Y growing upward.  Hence the extra negation. */
+
+  hb_position_t y_strength = font->y_scale >= 0 ? font->y_strength : -font->y_strength;
+  return ((-v + (1<<9)) >> 10) + (font->embolden_in_place ? 0 : y_strength);
+}
+#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;
+  float x_mult, y_mult;
+#ifdef HAVE_FT_GET_TRANSFORM
+  if (ft_font->transform)
+  {
+    FT_Matrix matrix;
+    FT_Get_Transform (ft_face, &matrix, nullptr);
+    x_mult = sqrtf ((float)matrix.xx * matrix.xx + (float)matrix.xy * matrix.xy) / 65536.f;
+    x_mult *= font->x_scale < 0 ? -1 : +1;
+    y_mult = sqrtf ((float)matrix.yx * matrix.yx + (float)matrix.yy * matrix.yy) / 65536.f;
+    y_mult *= font->y_scale < 0 ? -1 : +1;
+  }
+  else
+#endif
+  {
+    x_mult = font->x_scale < 0 ? -1 : +1;
+    y_mult = font->y_scale < 0 ? -1 : +1;
+  }
+
+  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);
+
+  *x = (hb_position_t) (x_mult * *x);
+  *y = (hb_position_t) (y_mult * *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;
+  float x_mult, y_mult;
+  float slant_xy = font->slant_xy;
+#ifdef HAVE_FT_GET_TRANSFORM
+  if (ft_font->transform)
+  {
+    FT_Matrix matrix;
+    FT_Get_Transform (ft_face, &matrix, nullptr);
+    x_mult = sqrtf ((float)matrix.xx * matrix.xx + (float)matrix.xy * matrix.xy) / 65536.f;
+    x_mult *= font->x_scale < 0 ? -1 : +1;
+    y_mult = sqrtf ((float)matrix.yx * matrix.yx + (float)matrix.yy * matrix.yy) / 65536.f;
+    y_mult *= font->y_scale < 0 ? -1 : +1;
+  }
+  else
+#endif
+  {
+    x_mult = font->x_scale < 0 ? -1 : +1;
+    y_mult = font->y_scale < 0 ? -1 : +1;
+  }
+
+  if (unlikely (FT_Load_Glyph (ft_face, glyph, ft_font->load_flags)))
+    return false;
+
+  /* Copied from hb_font_t::scale_glyph_extents. */
+
+  float x1 = x_mult * ft_face->glyph->metrics.horiBearingX;
+  float y1 = y_mult * ft_face->glyph->metrics.horiBearingY;
+  float x2 = x1 + x_mult *  ft_face->glyph->metrics.width;
+  float y2 = y1 + y_mult * -ft_face->glyph->metrics.height;
+
+  /* Apply slant. */
+  if (slant_xy)
+  {
+    x1 += hb_min (y1 * slant_xy, y2 * slant_xy);
+    x2 += hb_max (y1 * slant_xy, y2 * slant_xy);
+  }
+
+  extents->x_bearing = floorf (x1);
+  extents->y_bearing = floorf (y1);
+  extents->width = ceilf (x2) - extents->x_bearing;
+  extents->height = ceilf (y2) - extents->y_bearing;
+
+  if (font->x_strength || font->y_strength)
+  {
+    /* Y */
+    int y_shift = font->y_strength;
+    if (font->y_scale < 0) y_shift = -y_shift;
+    extents->y_bearing += y_shift;
+    extents->height -= y_shift;
+
+    /* X */
+    int x_shift = font->x_strength;
+    if (font->x_scale < 0) x_shift = -x_shift;
+    if (font->embolden_in_place)
+      extents->x_bearing -= x_shift / 2;
+    extents->width += x_shift;
+  }
+
+  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;
+  float y_mult;
+#ifdef HAVE_FT_GET_TRANSFORM
+  if (ft_font->transform)
+  {
+    FT_Matrix matrix;
+    FT_Get_Transform (ft_face, &matrix, nullptr);
+    y_mult = sqrtf ((float)matrix.yx * matrix.yx + (float)matrix.yy * matrix.yy) / 65536.f;
+    y_mult *= font->y_scale < 0 ? -1 : +1;
+  }
+  else
+#endif
+  {
+    y_mult = font->y_scale < 0 ? -1 : +1;
+  }
+
+  if (ft_face->units_per_EM != 0)
+  {
+    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);
+  }
+  else
+  {
+    /* Bitmap-only font, eg. color bitmap font. */
+    metrics->ascender = ft_face->size->metrics.ascender;
+    metrics->descender = ft_face->size->metrics.descender;
+    metrics->line_gap = ft_face->size->metrics.height - (metrics->ascender - metrics->descender);
+  }
+
+  metrics->ascender  = (hb_position_t) (y_mult * (metrics->ascender + font->y_strength));
+  metrics->descender = (hb_position_t) (y_mult * metrics->descender);
+  metrics->line_gap  = (hb_position_t) (y_mult * metrics->line_gap);
+
+  return true;
+}
+
+#ifndef HB_NO_DRAW
+
+static int
+_hb_ft_move_to (const FT_Vector *to,
+		void *arg)
+{
+  hb_draw_session_t *drawing = (hb_draw_session_t *) arg;
+  drawing->move_to (to->x, to->y);
+  return FT_Err_Ok;
+}
+
+static int
+_hb_ft_line_to (const FT_Vector *to,
+		void *arg)
+{
+  hb_draw_session_t *drawing = (hb_draw_session_t *) arg;
+  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,
+		 void *arg)
+{
+  hb_draw_session_t *drawing = (hb_draw_session_t *) arg;
+  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,
+		 void *arg)
+{
+  hb_draw_session_t *drawing = (hb_draw_session_t *) arg;
+  drawing->cubic_to (control1->x, control1->y,
+		     control2->x, control2->y,
+		     to->x, to->y);
+  return FT_Err_Ok;
+}
+
+static void
+hb_ft_draw_glyph (hb_font_t *font,
+		  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 = {
+    _hb_ft_move_to,
+    _hb_ft_line_to,
+    _hb_ft_conic_to,
+    _hb_ft_cubic_to,
+    0, /* shift */
+    0, /* delta */
+  };
+
+  hb_draw_session_t draw_session (draw_funcs, draw_data, font->slant_xy);
+
+  /* Embolden */
+  if (font->x_strength || font->y_strength)
+  {
+    FT_Outline_EmboldenXY (&ft_face->glyph->outline, font->x_strength, font->y_strength);
+
+    int x_shift = 0;
+    int y_shift = 0;
+    if (font->embolden_in_place)
+    {
+      /* Undo the FreeType shift. */
+      x_shift = -font->x_strength / 2;
+      y_shift = 0;
+      if (font->y_scale < 0) y_shift = -font->y_strength;
+    }
+    else
+    {
+      /* FreeType applied things in the wrong direction for negative scale; fix up. */
+      if (font->x_scale < 0) x_shift = -font->x_strength;
+      if (font->y_scale < 0) y_shift = -font->y_strength;
+    }
+    if (x_shift || y_shift)
+    {
+      auto &outline = ft_face->glyph->outline;
+      for (auto &point : hb_iter (outline.points, outline.contours[outline.n_contours - 1] + 1))
+      {
+	point.x += x_shift;
+	point.y += y_shift;
+      }
+    }
+  }
+
+
+  FT_Outline_Decompose (&ft_face->glyph->outline,
+			&outline_funcs,
+			&draw_session);
+}
+#endif
+
+#ifndef HB_NO_PAINT
+#if (FREETYPE_MAJOR*10000 + FREETYPE_MINOR*100 + FREETYPE_PATCH) >= 21300
+
+#include "hb-ft-colr.hh"
+
+static void
+hb_ft_paint_glyph (hb_font_t *font,
+                   void *font_data,
+                   hb_codepoint_t gid,
+                   hb_paint_funcs_t *paint_funcs, void *paint_data,
+                   unsigned int palette_index,
+                   hb_color_t foreground,
+                   void *user_data)
+{
+  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;
+
+  /* We release the lock before calling into glyph callbacks, such that
+   * eg. draw API can call back into the face.*/
+
+  if (unlikely (FT_Load_Glyph (ft_face, gid,
+			       ft_font->load_flags | FT_LOAD_COLOR)))
+    return;
+
+  if (ft_face->glyph->format == FT_GLYPH_FORMAT_OUTLINE)
+  {
+    if (hb_ft_paint_glyph_colr (font, font_data, gid,
+				paint_funcs, paint_data,
+				palette_index, foreground,
+				user_data))
+      return;
+
+    /* Simple outline. */
+    ft_font->lock.unlock ();
+    paint_funcs->push_clip_glyph (paint_data, gid, font);
+    ft_font->lock.lock ();
+    paint_funcs->color (paint_data, true, foreground);
+    paint_funcs->pop_clip (paint_data);
+
+    return;
+  }
+
+  auto *glyph = ft_face->glyph;
+  if (glyph->format == FT_GLYPH_FORMAT_BITMAP)
+  {
+    auto &bitmap = glyph->bitmap;
+    if (bitmap.pixel_mode == FT_PIXEL_MODE_BGRA)
+    {
+      if (bitmap.pitch != (signed) bitmap.width * 4)
+        return;
+
+      ft_font->lock.unlock ();
+
+      hb_blob_t *blob = hb_blob_create ((const char *) bitmap.buffer,
+					bitmap.pitch * bitmap.rows,
+					HB_MEMORY_MODE_DUPLICATE,
+					nullptr, nullptr);
+
+      hb_glyph_extents_t extents;
+      if (!hb_font_get_glyph_extents (font, gid, &extents))
+	goto out;
+
+      if (!paint_funcs->image (paint_data,
+			       blob,
+			       bitmap.width,
+			       bitmap.rows,
+			       HB_PAINT_IMAGE_FORMAT_BGRA,
+			       font->slant_xy,
+			       &extents))
+      {
+        /* TODO Try a forced outline load and paint? */
+      }
+
+    out:
+      hb_blob_destroy (blob);
+      ft_font->lock.lock ();
+    }
+
+    return;
+  }
+}
+#endif
+#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_draw_glyph_func (funcs, hb_ft_draw_glyph, nullptr, nullptr);
+#endif
+
+#ifndef HB_NO_PAINT
+#if (FREETYPE_MAJOR*10000 + FREETYPE_MINOR*100 + FREETYPE_PATCH) >= 21300
+    hb_font_funcs_set_paint_glyph_func (funcs, hb_ft_paint_glyph, nullptr, nullptr);
+#endif
+#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.
+ *
+ * Note that this is using the FT_Face object just to get at the underlying
+ * font data, and fonts created from the returned #hb_face_t will use the native
+ * HarfBuzz font implementation, unless you call hb_ft_font_set_funcs() on them.
+ *
+ * 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.
+ *
+ * Note that this is using the FT_Face object just to get at the underlying
+ * font data, and fonts created from the returned #hb_face_t will use the native
+ * HarfBuzz font implementation, unless you call hb_ft_font_set_funcs() on them.
+ *
+ * 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 (void *arg)
+{
+  FT_Face ft_face = (FT_Face) arg;
+  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.
+ *
+ * Note that this is using the FT_Face object just to get at the underlying
+ * font data, and fonts created from the returned #hb_face_t will use the native
+ * HarfBuzz font implementation, unless you call hb_ft_font_set_funcs() on them.
+ *
+ * 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 = 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
+
+  ft_font->advance_cache.clear ();
+  ft_font->cached_serial = font->serial;
+}
+
+/**
+ * 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 (void *arg)
+{
+  FT_Face ft_face = (FT_Face) arg;
+  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_font_t object created with hb_ft_font_create()
+ * is preconfigured for FreeType font functions and does not
+ * require this function to be used.
+ *
+ * Note that if you modify the underlying #hb_font_t after
+ * calling this function, you need to call hb_ft_hb_font_changed()
+ * to update the underlying FT_Face.
+ *
+ * <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);
+
+
+  ft_face->generic.data = blob;
+  ft_face->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);
+
+  _hb_ft_hb_font_changed (font, ft_face);
+}
+
+#endif