/* ftcrfont.c -- FreeType font driver on cairo.
   Copyright (C) 2015-2020 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */


#include <config.h>
#include <math.h>
#include <cairo-ft.h>

#include "lisp.h"
#include "xterm.h"
#include "blockinput.h"
#include "charset.h"
#include "composite.h"
#include "font.h"
#include "ftfont.h"
#include "pdumper.h"

#define METRICS_NCOLS_PER_ROW	(128)

enum metrics_status
  {
    METRICS_INVALID = -1,    /* metrics entry is invalid */
  };

#define METRICS_STATUS(metrics)	((metrics)->ascent + (metrics)->descent)
#define METRICS_SET_STATUS(metrics, status) \
  ((metrics)->ascent = 0, (metrics)->descent = (status))

static int
ftcrfont_glyph_extents (struct font *font,
                        unsigned glyph,
                        struct font_metrics *metrics)
{
  struct font_info *ftcrfont_info = (struct font_info *) font;
  int row, col;
  struct font_metrics *cache;

  row = glyph / METRICS_NCOLS_PER_ROW;
  col = glyph % METRICS_NCOLS_PER_ROW;
  if (row >= ftcrfont_info->metrics_nrows)
    {
      ftcrfont_info->metrics =
	xrealloc (ftcrfont_info->metrics,
		  sizeof (struct font_metrics *) * (row + 1));
      memset (ftcrfont_info->metrics + ftcrfont_info->metrics_nrows, 0,
	      (sizeof (struct font_metrics *)
	       * (row + 1 - ftcrfont_info->metrics_nrows)));
      ftcrfont_info->metrics_nrows = row + 1;
    }
  if (ftcrfont_info->metrics[row] == NULL)
    {
      struct font_metrics *new;
      int i;

      new = xmalloc (sizeof (struct font_metrics) * METRICS_NCOLS_PER_ROW);
      for (i = 0; i < METRICS_NCOLS_PER_ROW; i++)
	METRICS_SET_STATUS (new + i, METRICS_INVALID);
      ftcrfont_info->metrics[row] = new;
    }
  cache = ftcrfont_info->metrics[row] + col;

  if (METRICS_STATUS (cache) == METRICS_INVALID)
    {
      cairo_glyph_t cr_glyph = {.index = glyph};
      cairo_text_extents_t extents;

      cairo_scaled_font_glyph_extents (ftcrfont_info->cr_scaled_font,
				       &cr_glyph, 1, &extents);
      cache->lbearing = floor (extents.x_bearing);
      cache->rbearing = ceil (extents.width + extents.x_bearing);
      cache->width = lround (extents.x_advance);
      cache->ascent = ceil (- extents.y_bearing);
      cache->descent = ceil (extents.height + extents.y_bearing);
    }

  if (metrics)
    *metrics = *cache;

  return cache->width;
}

static Lisp_Object
ftcrfont_list (struct frame *f, Lisp_Object spec)
{
  return ftfont_list2 (f, spec, Qftcr);
}

static Lisp_Object
ftcrfont_match (struct frame *f, Lisp_Object spec)
{
  return ftfont_match2 (f, spec, Qftcr);
}

static Lisp_Object
ftcrfont_open (struct frame *f, Lisp_Object entity, int pixel_size)
{
  FcResult result;
  Lisp_Object val, filename, font_object;
  FcPattern *pat, *match;
  struct font_info *ftcrfont_info;
  struct font *font;
  double size = 0;
  cairo_font_face_t *font_face;
  cairo_font_extents_t extents;
  FT_Face ft_face;
  FcMatrix *matrix;

  val = assq_no_quit (QCfont_entity, AREF (entity, FONT_EXTRA_INDEX));
  if (! CONSP (val))
    return Qnil;
  val = XCDR (val);
  filename = XCAR (val);
  size = XFIXNUM (AREF (entity, FONT_SIZE_INDEX));
  if (size == 0)
    size = pixel_size;

  block_input ();

  pat = ftfont_entity_pattern (entity, pixel_size);
  FcConfigSubstitute (NULL, pat, FcMatchPattern);
  FcDefaultSubstitute (pat);
  match = FcFontMatch (NULL, pat, &result);
  ftfont_fix_match (pat, match);

  FcPatternDestroy (pat);
  font_face = cairo_ft_font_face_create_for_pattern (match);
  if (!font_face)
    {
      unblock_input ();
      FcPatternDestroy (match);
      return Qnil;
    }
  cairo_matrix_t font_matrix, ctm;
  cairo_matrix_init_scale (&font_matrix, pixel_size, pixel_size);
  cairo_matrix_init_identity (&ctm);
  cairo_font_options_t *options = cairo_font_options_create ();
  cairo_scaled_font_t *scaled_font
    = cairo_scaled_font_create (font_face, &font_matrix, &ctm, options);
  cairo_font_face_destroy (font_face);
  cairo_font_options_destroy (options);
  unblock_input ();

  font_object = font_build_object (VECSIZE (struct font_info),
				   AREF (entity, FONT_TYPE_INDEX),
				   entity, size);
  ASET (font_object, FONT_FILE_INDEX, filename);
  font = XFONT_OBJECT (font_object);
  font->pixel_size = size;
#ifdef HAVE_HARFBUZZ
  if (EQ (AREF (font_object, FONT_TYPE_INDEX), Qftcrhb))
    font->driver = &ftcrhbfont_driver;
  else
#endif	/* HAVE_HARFBUZZ */
  font->driver = &ftcrfont_driver;
  font->encoding_charset = font->repertory_charset = -1;

  ftcrfont_info = (struct font_info *) font;
  ftcrfont_info->cr_scaled_font = scaled_font;

  /* This means that there's no need of transformation.  */
  ftcrfont_info->matrix.xx = 0;
  if (FcPatternGetMatrix (match, FC_MATRIX, 0, &matrix) == FcResultMatch)
    {
      ftcrfont_info->matrix.xx = 0x10000L * matrix->xx;
      ftcrfont_info->matrix.yy = 0x10000L * matrix->yy;
      ftcrfont_info->matrix.xy = 0x10000L * matrix->xy;
      ftcrfont_info->matrix.yx = 0x10000L * matrix->yx;
    }

  ftcrfont_info->metrics = NULL;
  ftcrfont_info->metrics_nrows = 0;

  block_input ();
  cairo_glyph_t stack_glyph;
  font->min_width = font->average_width = font->space_width = 0;
  for (char c = 32; c < 127; c++)
    {
      cairo_glyph_t *glyphs = &stack_glyph;
      int num_glyphs = 1;
      cairo_status_t status =
	cairo_scaled_font_text_to_glyphs (ftcrfont_info->cr_scaled_font,
					  0, 0, &c, 1, &glyphs, &num_glyphs,
					  NULL, NULL, NULL);

      /* In order to simulate the Xft behavior, we use metrics of
	 glyph ID 0 if there is no glyph for an ASCII printable.  */
      if (status != CAIRO_STATUS_SUCCESS)
	stack_glyph.index = 0;
      else if (glyphs != &stack_glyph)
	{
	  cairo_glyph_free (glyphs);
	  stack_glyph.index = 0;
	}
      int this_width = ftcrfont_glyph_extents (font, stack_glyph.index, NULL);
      if (this_width > 0
	  && (! font->min_width
	      || font->min_width > this_width))
	font->min_width = this_width;
      if (c == 32)
	font->space_width = this_width;
      font->average_width += this_width;
    }
  font->average_width /= 95;

  cairo_scaled_font_extents (ftcrfont_info->cr_scaled_font, &extents);
  font->ascent = ceil (extents.ascent);
  val = assq_no_quit (QCminspace, AREF (entity, FONT_EXTRA_INDEX));
  if (!(CONSP (val) && NILP (XCDR (val))))
    {
      font->descent = lround (extents.descent);
      font->height = font->ascent + font->descent;
    }
  else
    {
      font->height = lround (extents.height);
      font->descent = font->height - font->ascent;
    }

  ft_face = cairo_ft_scaled_font_lock_face (scaled_font);
  if (XFIXNUM (AREF (entity, FONT_SIZE_INDEX)) == 0)
    {
      int upEM = ft_face->units_per_EM;

      font->underline_position = -ft_face->underline_position * size / upEM;
      font->underline_thickness = ft_face->underline_thickness * size / upEM;
      if (font->underline_thickness > 2)
	font->underline_position -= font->underline_thickness / 2;
    }
  else
    {
      font->underline_position = -1;
      font->underline_thickness = 0;
    }
#ifdef HAVE_LIBOTF
  ftcrfont_info->maybe_otf = (ft_face->face_flags & FT_FACE_FLAG_SFNT) != 0;
  ftcrfont_info->otf = NULL;
#endif	/* HAVE_LIBOTF */
#ifdef HAVE_HARFBUZZ
  ftcrfont_info->hb_font = NULL;
#endif	/* HAVE_HARFBUZZ */
  if (ft_face->units_per_EM)
    ftcrfont_info->bitmap_position_unit = 0;
  else
    ftcrfont_info->bitmap_position_unit = (extents.height
					   / ft_face->size->metrics.height);
  cairo_ft_scaled_font_unlock_face (scaled_font);
  ftcrfont_info->ft_size = NULL;
  unblock_input ();

  font->baseline_offset = 0;
  font->relative_compose = 0;
  font->default_ascent = 0;
  font->vertical_centering = false;

  return font_object;
}

static void
ftcrfont_close (struct font *font)
{
  if (font_data_structures_may_be_ill_formed ())
    return;

  struct font_info *ftcrfont_info = (struct font_info *) font;

  block_input ();
#ifdef HAVE_LIBOTF
  if (ftcrfont_info->otf)
    {
      OTF_close (ftcrfont_info->otf);
      ftcrfont_info->otf = NULL;
    }
#endif
#ifdef HAVE_HARFBUZZ
  if (ftcrfont_info->hb_font)
    {
      hb_font_destroy (ftcrfont_info->hb_font);
      ftcrfont_info->hb_font = NULL;
    }
#endif
  for (int i = 0; i < ftcrfont_info->metrics_nrows; i++)
    if (ftcrfont_info->metrics[i])
      xfree (ftcrfont_info->metrics[i]);
  if (ftcrfont_info->metrics)
    xfree (ftcrfont_info->metrics);
  cairo_scaled_font_destroy (ftcrfont_info->cr_scaled_font);
  unblock_input ();
}

static int
ftcrfont_has_char (Lisp_Object font, int c)
{
  if (FONT_ENTITY_P (font))
    return ftfont_has_char (font, c);

  struct charset *cs = NULL;

  if (EQ (AREF (font, FONT_ADSTYLE_INDEX), Qja)
      && charset_jisx0208 >= 0)
    cs = CHARSET_FROM_ID (charset_jisx0208);
  else if (EQ (AREF (font, FONT_ADSTYLE_INDEX), Qko)
      && charset_ksc5601 >= 0)
    cs = CHARSET_FROM_ID (charset_ksc5601);
  if (cs)
    return (ENCODE_CHAR (cs, c) != CHARSET_INVALID_CODE (cs));

  return -1;
}

static Lisp_Object
ftcrfont_guess_script (struct font *font, int c)
{
  block_input ();
  hb_buffer_t *hb_buf = hb_buffer_create ();
  hb_buffer_set_content_type (hb_buf, HB_BUFFER_CONTENT_TYPE_UNICODE);
  hb_buffer_add (hb_buf, c, 0);
  hb_buffer_guess_segment_properties (hb_buf);
  /* Force the language to a known and system-independent value, so as
     not to make Emacs's behavior depend on LC_CTYPE. */
  hb_buffer_set_language (hb_buf, hb_language_from_string ("en", -1));
  hb_script_t script =
    hb_buffer_get_script (hb_buf);
  Lisp_Object ret;

  if (script == HB_SCRIPT_UNKNOWN ||
      script == HB_SCRIPT_COMMON ||
      script == HB_SCRIPT_INHERITED ||
      script == HB_SCRIPT_INVALID)
    ret = Qnil;
  else
    {
      char string[5];
      string[4] = 0;
      string[3] = script & 0xff;
      string[2] = (script>>8) & 0xff;
      string[1] = (script>>16) & 0xff;
      string[0] = (script>>24) & 0xff;
      ret = build_string (string);
    }

  unblock_input ();

  return ret;
}

static hb_codepoint_t
hb_mirror (hb_unicode_funcs_t *ufuncs,
	   hb_codepoint_t codepoint,
	   void *user_data)
{
  /* HarfBuzz expects unmirrored codepoints, so if we mirrored it,
     don't mirror it again.  */
  if (bidi_mirror_char (codepoint) != codepoint)
    return codepoint;
  return hb_unicode_mirroring (hb_unicode_funcs_get_parent (ufuncs), codepoint);
}

static Lisp_Object
get_shaped_context (struct font *font, Lisp_Object string, Lisp_Object script)
{
  struct font_info *ftcrfont_info = (struct font_info *) font;
  if (NILP (font->hb_cache))
    font->hb_cache = CALLN (Fmake_hash_table, QCtest, Qequal, QCweakness, Qkey);

  Lisp_Object cached = Fgethash (Fcons (string, script), font->hb_cache, Qnil);

  if (!NILP (cached))
    return cached;
  block_input ();
  unsigned int num_glyphs = 0;
  hb_buffer_t *hb_buf = hb_buffer_create ();
  hb_unicode_funcs_t *ufuncs = hb_unicode_funcs_create (hb_buffer_get_unicode_funcs (hb_buf));
  hb_unicode_funcs_set_mirroring_func (ufuncs, hb_mirror, NULL, NULL);
  hb_buffer_set_unicode_funcs (hb_buf, ufuncs);
  hb_buffer_set_cluster_level (hb_buf, HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
  bool rtl = false;
  for (int i = 0; i < SCHARS (string); i++)
    {
      int c = XFIXNUM (Faref (string, make_fixnum (i)));
      hb_buffer_add (hb_buf, c, i);
    }
  hb_buffer_set_content_type (hb_buf, HB_BUFFER_CONTENT_TYPE_UNICODE);
  if (STRINGP (script) && SBYTES (script) >= 4)
    {
      hb_script_t scriptint = 0;
      scriptint += SREF (script, 0) << 24;
      scriptint += SREF (script, 1) << 16;
      scriptint += SREF (script, 2) <<  8;
      scriptint += SREF (script, 3);
      hb_buffer_set_script (hb_buf, scriptint);
    }
  hb_buffer_guess_segment_properties (hb_buf);
  /* Force the language to a known and system-independent value, so as
     not to make Emacs's behavior depend on LC_CTYPE. */
  hb_buffer_set_language (hb_buf, hb_language_from_string ("en", -1));
  rtl = hb_buffer_get_direction (hb_buf) == HB_DIRECTION_RTL;
  hb_font_t *hb_font = hb_ft_font_create_referenced
    (cairo_ft_scaled_font_lock_face (ftcrfont_info->cr_scaled_font));
  hb_shape (hb_font, hb_buf, NULL, 0);
  hb_glyph_info_t *glyph_info = hb_buffer_get_glyph_infos
    (hb_buf, &num_glyphs);
  hb_glyph_position_t *glyph_pos = hb_buffer_get_glyph_positions
    (hb_buf, &num_glyphs);

  /* Reverse glyphs for RTL. This is because HarfBuzz reverses them,
     not because we want to bypass the code in bidi.c. */
  if (rtl)
    {
      for (int i = 0; i < num_glyphs/2; i++)
	{
	  hb_glyph_position_t temp_pos = glyph_pos[num_glyphs - i - 1];
	  glyph_pos[num_glyphs - i - 1] = glyph_pos[i];
	  glyph_pos[i] = temp_pos;

	  hb_glyph_info_t temp_info = glyph_info[num_glyphs - i - 1];
	  glyph_info[num_glyphs - i - 1] = glyph_info[i];
	  glyph_info[i] = temp_info;
	}
    }

  /* Merge non-spacing glyphs into the previous cluster. */
  int last_spacing_cluster = 0;
  for (int i = 0; i < num_glyphs; i++)
    {
      if (glyph_pos[i].x_advance == 0
	  && glyph_info[i].cluster > last_spacing_cluster)
	glyph_info[i].cluster = last_spacing_cluster;
      else
	last_spacing_cluster = glyph_info[i].cluster;
    }

  /* For RTL, un-reverse glyphs that ended up forming a cluster. */
  if (rtl)
    {
      for (int i = 0; i < num_glyphs;)
	{
	  int j;
	  for (j = i + 1; j < num_glyphs; j++)
	    {
	      if (glyph_info[j].cluster != glyph_info[i].cluster)
		break;
	    }
	  for (int k = i; k < i + (j - i)/2; k++)
	    {
	      int k2 = i + j - k - 1;
	      hb_glyph_position_t temp_pos = glyph_pos[k2];
	      glyph_pos[k2] = glyph_pos[k];
	      glyph_pos[k] = temp_pos;

	      hb_glyph_info_t temp_info = glyph_info[k2];
	      glyph_info[k2] = glyph_info[k];
	      glyph_info[k] = temp_info;
	    }
	  i = j;
	}
    }

  Lisp_Object ret = make_nil_vector (num_glyphs);
  for (int i = 0; i < num_glyphs; i++)
    {
      Lisp_Object glyph = make_nil_vector (HB_SHAPED_LENGTH);
      ASET (glyph, HB_SHAPED_CODE, make_fixnum (glyph_info[i].codepoint));
      ASET (glyph, HB_SHAPED_CLUSTER, make_fixnum (glyph_info[i].cluster));
      {
	Lisp_Object v = make_nil_vector (HB_SHAPED_METRICS_LENGTH);
	ASET (v, HB_SHAPED_METRICS_X_ADVANCE,
	      make_fixnum ((glyph_pos[i].x_advance + 32)/ 64));
	ASET (v, HB_SHAPED_METRICS_Y_ADVANCE,
	      make_fixnum ((glyph_pos[i].y_advance + 32) / 64));
	ASET (v, HB_SHAPED_METRICS_X_OFFSET,
	      make_fixnum ((glyph_pos[i].x_offset) / 64));
	ASET (v, HB_SHAPED_METRICS_Y_OFFSET,
	      make_fixnum ((glyph_pos[i].y_offset) / 64));
	ASET (glyph, HB_SHAPED_METRICS, v);
      }
#if 0
      Lisp_Object v = Qnil;
      if (false) {
	hb_position_t carets[1024];
	unsigned int caret_count = 1022;
	if (hb_ot_layout_get_ligature_carets
	    (hb_font, HB_DIRECTION_LTR /* XXX */,
	     glyph_info[i].codepoint, 0,
	     &caret_count, carets + 1))
	  {
	    carets[0] = 0;
	    caret_count++;
	    carets[caret_count++] = glyph_pos[i].x_advance;
	    v = make_nil_vector (caret_count);
	    for (ptrdiff_t i = 0; i < caret_count; i++)
	      ASET (v, i, make_fixnum (carets[i]));
	  }
      }
#endif
      ASET (glyph, HB_SHAPED_CARETS, Qnil);
      ASET (glyph, HB_SHAPED_RTL, rtl ? Qt : Qnil);
      ASET (ret, i, glyph);
    }

  Fputhash (Fcons (string, script), ret, font->hb_cache);
  unblock_input ();
  return ret;
}

static Lisp_Object
ftcrfont_encode_char (struct font *font, int c, struct glyph_context *context)
{
  Lisp_Object code = Qnil;

  if (context == NULL)
    {
      context = ALLOCATE_PSEUDOVECTOR (struct glyph_context, position, PVEC_GLYPH_CONTEXT);
      context->script = Qnil;
      context->string = CALLN (Fstring, make_fixnum (c));
      context->position = make_fixnum (0);
    }

  bool rtl = false;
  Lisp_Object shaped = get_shaped_context (font, context->string, context->script);
  unsigned int num_glyphs = ASIZE (shaped);
  rtl = ! NILP (AREF (AREF (shaped, 0), HB_SHAPED_RTL));
  int glyph0 = 0, glyph1 = num_glyphs;
  int cluster0 = 0, cluster1 = XFIXNUM (Flength (context->string));
  int char0 = 0, char1 = XFIXNUM (Flength (context->string));
  for (int i = 0; i < num_glyphs; i++)
    if (XFIXNUM (AREF (AREF (shaped, i), HB_SHAPED_CLUSTER))
	<= XFIXNUM (context->position))
      {
	cluster0 = XFIXNUM (AREF (AREF (shaped, i), HB_SHAPED_CLUSTER));
	int i1 = i;
	while (i1 > 0
	       && XFIXNUM (AREF (AREF (shaped, i1 - 1), HB_SHAPED_CLUSTER))
	       == cluster0)
	  i1--;
	glyph0 = i1;
	char0 = cluster0;
      }
  for (int i = 0; i < num_glyphs; i++)
    if (XFIXNUM (AREF (AREF (shaped, i), HB_SHAPED_CLUSTER))
	> XFIXNUM (context->position))
      {
	glyph1 = i;
	cluster1 = XFIXNUM (AREF (AREF (shaped, i), HB_SHAPED_CLUSTER));
	char1 = cluster1;
	break;
      }
  int i = XFIXNUM (context->position) - char0;
  if (rtl)
    i = char1 - char0 - 1 - i;
  Lisp_Object glyphs = make_nil_vector (glyph1 - glyph0);
  int x_advance = 0;
  for (ptrdiff_t i = glyph0; i < glyph1; i++)
    {
      Lisp_Object glyph = make_nil_vector (HB_GLYPH_LENGTH);
      ASET (glyph, HB_GLYPH_GLYPH, Qglyph);
      Lisp_Object code = AREF (AREF (shaped, i), HB_SHAPED_CODE);
      /* This appears to be the only sign from HarfBuzz that our font
	 is missing a glyph ... */
      if (XFIXNUM (code) == 0)
	return Qnil;
      ASET (glyph, HB_GLYPH_CODE, AREF (AREF (shaped, i), HB_SHAPED_CODE));
      ASET (glyph, HB_GLYPH_X_OFF, AREF (AREF (AREF (shaped, i), 2), 2));
      ASET (glyph, HB_GLYPH_Y_OFF, CALLN (Fminus, AREF (AREF (AREF (shaped, i), 2), 3)));
      ASET (glyph, HB_GLYPH_CODEPOINT, make_fixnum (c));
      ASET (glyph, HB_GLYPH_X_ADVANCE, AREF (AREF (AREF (shaped, i), 2), 0));
      ASET (glyphs, i - glyph0, glyph);
      x_advance += XFIXNUM (AREF (AREF (AREF (shaped, i), 2), 0));
    }

  code = make_nil_vector (HB_SLICE_LENGTH);
  ASET (code, HB_SLICE_SLICE, Qslice);
  ASET (code, HB_SLICE_I, make_fixnum (i));
  ASET (code, HB_SLICE_N, make_fixnum (char1 - char0));
  int x0 = (char1 - char0 - i - 1) * x_advance / (char1 - char0);
  int x1 = (char1 - char0 - i) * x_advance / (char1 - char0);
  ASET (code, HB_SLICE_X_ADVANCE, make_fixnum (x1 - x0));
  ASET (code, HB_SLICE_X_OFFSET, make_fixnum (x_advance - x1));
  ASET (code, HB_SLICE_GLYPHS, glyphs);

  return code;
}

static void
ftcrfont_text_extents (struct font *font,
                       const Lisp_Object *code,
                       int nglyphs,
                       struct font_metrics *metrics)
{
  int width = 0;

  block_input ();
  if (metrics)
    {
      for (int i = 0; i < nglyphs; i++)
	{
	  if (VECTORP (code[i]) && EQ (AREF (code[i], 0), Qslice))
	    {
	      int slice_ascent = 0;
	      int slice_descent = 0;
	      int slice_lbearing = 0;
	      int slice_rbearing = 0;
	      int slice_i = XFIXNUM (AREF (code[i], HB_SLICE_I));
	      int slice_n = XFIXNUM (AREF (code[i], HB_SLICE_N));
	      Lisp_Object glyphs = AREF (code[i], HB_SLICE_GLYPHS);
	      int slice_width = 0;
	      for (ptrdiff_t gi = 0; gi < ASIZE (glyphs); gi++)
		{
		  Lisp_Object glyph = AREF (glyphs, gi);
		  struct font_metrics m;
		  ftcrfont_glyph_extents (font, XFIXNUM (AREF (glyph, HB_GLYPH_CODE)), &m);
		  int glyph_lbearing =
		    slice_width + m.lbearing + XFIXNUM (AREF (glyph, HB_GLYPH_X_OFF));
		  int glyph_rbearing =
		    slice_width + m.rbearing + XFIXNUM (AREF (glyph, HB_GLYPH_X_OFF));
		  int glyph_ascent =
		    m.ascent + XFIXNUM (AREF (glyph, HB_GLYPH_Y_OFF)); // XXX -?

		  int glyph_descent =
		    m.descent + XFIXNUM (AREF (glyph, HB_GLYPH_Y_OFF)); // XXX -?

		  if (gi == 0 || glyph_lbearing < slice_lbearing)
		    slice_lbearing = glyph_lbearing;
		  if (gi == 0 || glyph_rbearing > slice_rbearing)
		    slice_rbearing = glyph_rbearing;
		  if (gi == 0 || glyph_ascent > slice_ascent)
		    slice_ascent = glyph_ascent;
		  if (gi == 0 || glyph_descent > slice_descent)
		    slice_descent = glyph_descent;

		  slice_width += XFIXNUM (AREF (glyph, HB_GLYPH_X_ADVANCE));
		}

	      slice_width = XFIXNUM (AREF (code[i], HB_SLICE_X_ADVANCE));
	      if (slice_i < slice_n - 1)
		slice_rbearing = XFIXNUM (AREF (code[i], HB_SLICE_X_ADVANCE))
		  + XFIXNUM (AREF (code[i], HB_SLICE_X_OFFSET));
	      if (slice_i > 0)
		slice_lbearing = XFIXNUM (AREF (code[i], HB_SLICE_X_OFFSET));

	      if (i == 0 || slice_lbearing < metrics->lbearing)
		metrics->lbearing = slice_lbearing;
	      if (i == 0 || slice_rbearing > metrics->rbearing)
		metrics->rbearing = slice_rbearing;
	      if (i == 0 || slice_ascent > metrics->ascent)
		metrics->ascent = slice_ascent;
	      if (i == 0 || slice_descent > metrics->descent)
		metrics->descent = slice_descent;
	      width += slice_width;
	    }
	  else if (FIXNUMP (code[i]))
	    {
	    }
	}
      metrics->width = width;
    }
  unblock_input ();
}

static int
ftcrfont_get_bitmap (struct font *font, unsigned int code,
		     struct font_bitmap *bitmap, int bits_per_pixel)
{
  struct font_info *ftcrfont_info = (struct font_info *) font;

  if (ftcrfont_info->bitmap_position_unit)
    return -1;

  cairo_scaled_font_t *scaled_font = ftcrfont_info->cr_scaled_font;
  FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);

  ftcrfont_info->ft_size = ft_face->size;
  int result = ftfont_get_bitmap (font, code, bitmap, bits_per_pixel);
  cairo_ft_scaled_font_unlock_face (scaled_font);
  ftcrfont_info->ft_size = NULL;

  return result;
}

static int
ftcrfont_anchor_point (struct font *font, unsigned int code, int idx,
		       int *x, int *y)
{
  struct font_info *ftcrfont_info = (struct font_info *) font;

  if (ftcrfont_info->bitmap_position_unit)
    return -1;

  cairo_scaled_font_t *scaled_font = ftcrfont_info->cr_scaled_font;
  FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);

  ftcrfont_info->ft_size = ft_face->size;
  int result = ftfont_anchor_point (font, code, idx, x, y);
  cairo_ft_scaled_font_unlock_face (scaled_font);
  ftcrfont_info->ft_size = NULL;

  return result;
}

#ifdef HAVE_LIBOTF
static Lisp_Object
ftcrfont_otf_capability (struct font *font)
{
  struct font_info *ftcrfont_info = (struct font_info *) font;
  cairo_scaled_font_t *scaled_font = ftcrfont_info->cr_scaled_font;
  FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);

  ftcrfont_info->ft_size = ft_face->size;
  Lisp_Object result = ftfont_otf_capability (font);
  cairo_ft_scaled_font_unlock_face (scaled_font);
  ftcrfont_info->ft_size = NULL;

  return result;
}
#endif

#if defined HAVE_M17N_FLT && defined HAVE_LIBOTF
static Lisp_Object
ftcrfont_shape (Lisp_Object lgstring, Lisp_Object direction)
{
  struct font *font = CHECK_FONT_GET_OBJECT (LGSTRING_FONT (lgstring));
  struct font_info *ftcrfont_info = (struct font_info *) font;

  if (ftcrfont_info->bitmap_position_unit)
    return make_fixnum (0);

  cairo_scaled_font_t *scaled_font = ftcrfont_info->cr_scaled_font;
  FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);

  ftcrfont_info->ft_size = ft_face->size;
  Lisp_Object result = ftfont_shape (lgstring, direction);
  cairo_ft_scaled_font_unlock_face (scaled_font);
  ftcrfont_info->ft_size = NULL;

  return result;
}
#endif

#if defined HAVE_OTF_GET_VARIATION_GLYPHS || defined HAVE_FT_FACE_GETCHARVARIANTINDEX
static int
ftcrfont_variation_glyphs (struct font *font, int c, unsigned variations[256])
{
  struct font_info *ftcrfont_info = (struct font_info *) font;
  cairo_scaled_font_t *scaled_font = ftcrfont_info->cr_scaled_font;
  FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);

  ftcrfont_info->ft_size = ft_face->size;
  int result = ftfont_variation_glyphs (font, c, variations);
  cairo_ft_scaled_font_unlock_face (scaled_font);
  ftcrfont_info->ft_size = NULL;

  return result;
}
#endif	/* HAVE_OTF_GET_VARIATION_GLYPHS || HAVE_FT_FACE_GETCHARVARIANTINDEX */

static int
ftcrfont_draw (struct glyph_string *s,
               int from, int to, int x, int y, bool with_background)
{
  struct frame *f = s->f;
  struct face *face = s->face;
  struct font_info *ftcrfont_info = (struct font_info *) s->font;
  cairo_t *cr;
  int len = to - from;
  int i;

  block_input ();

  cr = x_begin_cr_clip (f, s->gc);

  if (with_background)
    {
      x_set_cr_source_with_gc_background (f, s->gc);
      cairo_rectangle (cr, x, y - FONT_BASE (face->font),
		       s->width, FONT_HEIGHT (face->font));
      cairo_fill (cr);
    }

  x_set_cr_source_with_gc_foreground (f, s->gc);
  cairo_set_scaled_font (cr, ftcrfont_info->cr_scaled_font);
  for (i = 0; i < len; i++)
    {
      Lisp_Object code = s->char2b[from + i];
      if (VECTORP (code))
	{
	  if (EQ (AREF (code, 0), Qslice))
	    {
	      int xtmp = x;
	      cairo_save (cr);
	      struct font_metrics metrics;
	      ftcrfont_text_extents (s->font, &code, 1, &metrics);
	      double x0 = x + metrics.lbearing - XFIXNUM (AREF (code, HB_SLICE_X_OFFSET));
	      double x1 = x + metrics.rbearing - XFIXNUM (AREF (code, HB_SLICE_X_OFFSET));
	      double y0 = y - metrics.ascent;
	      double y1 = y + metrics.descent;
	      x0--; y0--; x1++; y1++; /* FIXME */
	      cairo_rectangle (cr, x0, y0, x1 - x0, y1 - y0);
	      cairo_clip (cr);

	      Lisp_Object glyphs = AREF (code, HB_SLICE_GLYPHS);
	      for (ptrdiff_t gi = 0; gi < ASIZE (glyphs); gi++)
		{
		  Lisp_Object glyph = AREF (glyphs, gi);
		  cairo_glyph_t cglyph;
		  cglyph.index = XFIXNUM (AREF (glyph, HB_GLYPH_CODE));
		  cglyph.x = x + XFIXNUM (AREF (glyph, HB_GLYPH_X_OFF));
		  cglyph.y = y + XFIXNUM (AREF (glyph, HB_GLYPH_Y_OFF));
		  cglyph.x -= XFIXNUM (AREF (code, HB_SLICE_X_OFFSET));
		  x += XFIXNUM (AREF (glyph, HB_GLYPH_X_ADVANCE));
		  cairo_show_glyphs (cr, &cglyph, 1);
		}
	      cairo_restore (cr);
	      x = xtmp + XFIXNUM (AREF (code, HB_SLICE_X_ADVANCE));
	    }
	}
      else if (FIXNUMP (code))
	{
	  cairo_glyph_t cglyph;
	  cglyph.index = XFIXNUM (code);
	  cglyph.x = x;
	  cglyph.y = y;
	  x += (s->padding_p ? 0 : 0);
	  cairo_show_glyphs (cr, &cglyph, 1);
	}
    }


  x_end_cr_clip (f);

  unblock_input ();

  return len;
}

#ifdef HAVE_HARFBUZZ

static Lisp_Object
ftcrhbfont_list (struct frame *f, Lisp_Object spec)
{
  return ftfont_list2 (f, spec, Qftcrhb);
}

static Lisp_Object
ftcrhbfont_match (struct frame *f, Lisp_Object spec)
{
  return ftfont_match2 (f, spec, Qftcrhb);
}

static hb_font_t *
ftcrhbfont_begin_hb_font (struct font *font, double *position_unit)
{
  struct font_info *ftcrfont_info = (struct font_info *) font;
  cairo_scaled_font_t *scaled_font = ftcrfont_info->cr_scaled_font;
  FT_Face ft_face = cairo_ft_scaled_font_lock_face (scaled_font);

  ftcrfont_info->ft_size = ft_face->size;
  hb_font_t *hb_font = fthbfont_begin_hb_font (font, position_unit);
  if (ftcrfont_info->bitmap_position_unit)
    *position_unit = ftcrfont_info->bitmap_position_unit;

  return hb_font;
}

static void
ftcrhbfont_end_hb_font (struct font *font, hb_font_t *hb_font)
{
  struct font_info *ftcrfont_info = (struct font_info *) font;
  cairo_scaled_font_t *scaled_font = ftcrfont_info->cr_scaled_font;

  cairo_ft_scaled_font_unlock_face (scaled_font);
  ftcrfont_info->ft_size = NULL;
}

#endif	/* HAVE_HARFBUZZ */
\f

static void syms_of_ftcrfont_for_pdumper (void);

struct font_driver const ftcrfont_driver =
  {
  .type = LISPSYM_INITIALLY (Qftcr),
  .get_cache = ftfont_get_cache,
  .list = ftcrfont_list,
  .match = ftcrfont_match,
  .list_family = ftfont_list_family,
  .open_font = ftcrfont_open,
  .close_font = ftcrfont_close,
  .has_char = ftcrfont_has_char,
  .encode_char = ftcrfont_encode_char,
  .text_extents = ftcrfont_text_extents,
  .draw = ftcrfont_draw,
  .get_bitmap = ftcrfont_get_bitmap,
  .anchor_point = ftcrfont_anchor_point,
  .guess_script = ftcrfont_guess_script,
#ifdef HAVE_LIBOTF
  .otf_capability = ftcrfont_otf_capability,
#endif
#if defined HAVE_M17N_FLT && defined HAVE_LIBOTF
  .shape = ftcrfont_shape,
#endif
#if defined HAVE_OTF_GET_VARIATION_GLYPHS || defined HAVE_FT_FACE_GETCHARVARIANTINDEX
  .get_variation_glyphs = ftcrfont_variation_glyphs,
#endif
  .filter_properties = ftfont_filter_properties,
  .combining_capability = ftfont_combining_capability,
  };
#ifdef HAVE_HARFBUZZ
struct font_driver ftcrhbfont_driver;
#endif	/* HAVE_HARFBUZZ */

void
syms_of_ftcrfont (void)
{
  DEFSYM (Qftcr, "ftcr");
#ifdef HAVE_HARFBUZZ
  DEFSYM (Qftcrhb, "ftcrhb");
  Fput (Qftcr, Qfont_driver_superseded_by, Qftcrhb);
#endif	/* HAVE_HARFBUZZ */
  pdumper_do_now_and_after_load (syms_of_ftcrfont_for_pdumper);
}

static void
syms_of_ftcrfont_for_pdumper (void)
{
  register_font_driver (&ftcrfont_driver, NULL);
#ifdef HAVE_HARFBUZZ
  ftcrhbfont_driver = ftcrfont_driver;
  ftcrhbfont_driver.type = Qftcrhb;
  ftcrhbfont_driver.list = ftcrhbfont_list;
  ftcrhbfont_driver.match = ftcrhbfont_match;
  ftcrhbfont_driver.otf_capability = hbfont_otf_capability;
  ftcrhbfont_driver.shape = hbfont_shape;
  ftcrhbfont_driver.combining_capability = hbfont_combining_capability;
  ftcrhbfont_driver.begin_hb_font = ftcrhbfont_begin_hb_font;
  ftcrhbfont_driver.end_hb_font = ftcrhbfont_end_hb_font;
  register_font_driver (&ftcrhbfont_driver, NULL);
#endif	/* HAVE_HARFBUZZ */
}