ftcrfont.c 8.79 KB
Newer Older
Jan D's avatar
Jan D committed
1
/* ftcrfont.c -- FreeType font driver on cairo.
Paul Eggert's avatar
Paul Eggert committed
2
   Copyright (C) 2015-2019 Free Software Foundation, Inc.
Jan D's avatar
Jan D committed
3 4 5 6 7

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
8 9
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
Jan D's avatar
Jan D committed
10 11 12 13 14 15 16

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
17
along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
Jan D's avatar
Jan D committed
18 19 20 21 22 23 24 25 26 27 28 29 30 31


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

#include "lisp.h"
#include "xterm.h"
#include "blockinput.h"
#include "font.h"
#include "ftfont.h"

/* FTCR font driver.  */

Paul Eggert's avatar
Paul Eggert committed
32 33
/* The actual structure for FTCR font.  A pointer to this structure
   can be cast to struct font *.  */
Jan D's avatar
Jan D committed
34 35 36 37

struct ftcrfont_info
{
  struct font font;
38 39 40
  /* The following members up to and including 'matrix' must be here
     in this order to be compatible with struct ftfont_info (in
     ftfont.c).  */
Jan D's avatar
Jan D committed
41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84
#ifdef HAVE_LIBOTF
  bool maybe_otf;	  /* Flag to tell if this may be OTF or not.  */
  OTF *otf;
#endif	/* HAVE_LIBOTF */
  FT_Size ft_size;
  int index;
  FT_Matrix matrix;

  cairo_font_face_t *cr_font_face;
  /* To prevent cairo from cluttering the activated FT_Size maintained
     in ftfont.c, we activate this special FT_Size before drawing.  */
  FT_Size ft_size_draw;
  /* Font metrics cache.  */
  struct font_metrics **metrics;
  short metrics_nrows;
};

#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 ftcrfont_info *ftcrfont_info = (struct ftcrfont_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));
Paul Eggert's avatar
Paul Eggert committed
85 86 87
      memset (ftcrfont_info->metrics + ftcrfont_info->metrics_nrows, 0,
	      (sizeof (struct font_metrics *)
	       * (row + 1 - ftcrfont_info->metrics_nrows)));
Jan D's avatar
Jan D committed
88 89 90 91 92 93 94 95 96 97 98 99 100 101 102
      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)
103
    ftfont_text_extents (font, &glyph, 1, cache);
Jan D's avatar
Jan D committed
104 105 106 107 108 109 110 111 112 113

  if (metrics)
    *metrics = *cache;

  return cache->width;
}

static Lisp_Object
ftcrfont_list (struct frame *f, Lisp_Object spec)
{
114
  Lisp_Object list = ftfont_list (f, spec), tail;
Jan D's avatar
Jan D committed
115 116 117 118 119 120 121 122 123

  for (tail = list; CONSP (tail); tail = XCDR (tail))
    ASET (XCAR (tail), FONT_TYPE_INDEX, Qftcr);
  return list;
}

static Lisp_Object
ftcrfont_match (struct frame *f, Lisp_Object spec)
{
124
  Lisp_Object entity = ftfont_match (f, spec);
Jan D's avatar
Jan D committed
125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167

  if (VECTORP (entity))
    ASET (entity, FONT_TYPE_INDEX, Qftcr);
  return entity;
}

static Lisp_Object
ftcrfont_open (struct frame *f, Lisp_Object entity, int pixel_size)
{
  Lisp_Object font_object;
  struct font *font;
  struct ftcrfont_info *ftcrfont_info;
  FT_Face ft_face;
  FT_UInt size;

  block_input ();
  size = XINT (AREF (entity, FONT_SIZE_INDEX));
  if (size == 0)
    size = pixel_size;
  font_object = font_build_object (VECSIZE (struct ftcrfont_info),
				   Qftcr, entity, size);
  font_object = ftfont_open2 (f, entity, pixel_size, font_object);
  if (NILP (font_object)) return Qnil;

  font = XFONT_OBJECT (font_object);
  font->driver = &ftcrfont_driver;
  ftcrfont_info = (struct ftcrfont_info *) font;
  ft_face = ftcrfont_info->ft_size->face;
  FT_New_Size (ft_face, &ftcrfont_info->ft_size_draw);
  FT_Activate_Size (ftcrfont_info->ft_size_draw);
  FT_Set_Pixel_Sizes (ft_face, 0, font->pixel_size);
  ftcrfont_info->cr_font_face =
    cairo_ft_font_face_create_for_ft_face (ft_face, 0);
  ftcrfont_info->metrics = NULL;
  ftcrfont_info->metrics_nrows = 0;
  unblock_input ();

  return font_object;
}

static void
ftcrfont_close (struct font *font)
{
Paul Eggert's avatar
Paul Eggert committed
168 169 170
  if (font_data_structures_may_be_ill_formed ())
    return;

Jan D's avatar
Jan D committed
171 172 173 174 175 176 177 178 179 180 181 182 183
  struct ftcrfont_info *ftcrfont_info = (struct ftcrfont_info *) font;
  int i;

  block_input ();
  for (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);
  FT_Done_Size (ftcrfont_info->ft_size_draw);
  cairo_font_face_destroy (ftcrfont_info->cr_font_face);
  unblock_input ();

184
  ftfont_close (font);
Jan D's avatar
Jan D committed
185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230
}

static void
ftcrfont_text_extents (struct font *font,
                       unsigned *code,
                       int nglyphs,
                       struct font_metrics *metrics)
{
  int width, i;

  block_input ();
  width = ftcrfont_glyph_extents (font, code[0], metrics);
  for (i = 1; i < nglyphs; i++)
    {
      struct font_metrics m;
      int w = ftcrfont_glyph_extents (font, code[i], metrics ? &m : NULL);

      if (metrics)
	{
	  if (width + m.lbearing < metrics->lbearing)
	    metrics->lbearing = width + m.lbearing;
	  if (width + m.rbearing > metrics->rbearing)
	    metrics->rbearing = width + m.rbearing;
	  if (m.ascent > metrics->ascent)
	    metrics->ascent = m.ascent;
	  if (m.descent > metrics->descent)
	    metrics->descent = m.descent;
	}
      width += w;
    }
  unblock_input ();

  if (metrics)
    metrics->width = width;
}

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 ftcrfont_info *ftcrfont_info = (struct ftcrfont_info *) s->font;
  cairo_t *cr;
  cairo_glyph_t *glyphs;
  cairo_surface_t *surface;
231
  cairo_surface_type_t surface_type;
Jan D's avatar
Jan D committed
232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267
  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);
    }

  glyphs = alloca (sizeof (cairo_glyph_t) * len);
  for (i = 0; i < len; i++)
    {
      unsigned code = ((XCHAR2B_BYTE1 (s->char2b + from + i) << 8)
		       | XCHAR2B_BYTE2 (s->char2b + from + i));

      glyphs[i].index = code;
      glyphs[i].x = x;
      glyphs[i].y = y;
      x += (s->padding_p ? 1 : ftcrfont_glyph_extents (s->font, code, NULL));
    }

  x_set_cr_source_with_gc_foreground (f, s->gc);
  cairo_set_font_face (cr, ftcrfont_info->cr_font_face);
  cairo_set_font_size (cr, s->font->pixel_size);
  /* cairo_set_font_matrix */
  /* cairo_set_font_options */

  FT_Activate_Size (ftcrfont_info->ft_size_draw);
  cairo_show_glyphs (cr, glyphs, len);
  surface = cairo_get_target (cr);
268 269 270 271 272 273
  /* XXX: It used to be necessary to flush when exporting.  It might
     be the case that this is no longer necessary.  */
  surface_type = cairo_surface_get_type (surface);
  if (surface_type != CAIRO_SURFACE_TYPE_XLIB
      && (surface_type != CAIRO_SURFACE_TYPE_IMAGE
	  || cairo_image_surface_get_format (surface) != CAIRO_FORMAT_ARGB32))
Jan D's avatar
Jan D committed
274 275 276 277 278 279 280 281 282 283 284
    cairo_surface_flush (surface);

  x_end_cr_clip (f);

  unblock_input ();

  return len;
}



285 286
struct font_driver const ftcrfont_driver =
  {
Paul Eggert's avatar
Paul Eggert committed
287 288 289 290 291 292 293 294 295 296 297 298 299
  .type = LISPSYM_INITIALLY (Qftcr),
  .get_cache = ftfont_get_cache,
  .list = ftcrfont_list,
  .match = ftcrfont_match,
  .list_family = ftfont_list_family,
  .open = ftcrfont_open,
  .close = ftcrfont_close,
  .has_char = ftfont_has_char,
  .encode_char = ftfont_encode_char,
  .text_extents = ftcrfont_text_extents,
  .draw = ftcrfont_draw,
  .get_bitmap = ftfont_get_bitmap,
  .anchor_point = ftfont_anchor_point,
300
#ifdef HAVE_LIBOTF
Paul Eggert's avatar
Paul Eggert committed
301
  .otf_capability = ftfont_otf_capability,
302 303
#endif
#if defined HAVE_M17N_FLT && defined HAVE_LIBOTF
Paul Eggert's avatar
Paul Eggert committed
304
  .shape = ftfont_shape,
305 306
#endif
#ifdef HAVE_OTF_GET_VARIATION_GLYPHS
Paul Eggert's avatar
Paul Eggert committed
307
  .get_variation_glyphs = ftfont_variation_glyphs,
308
#endif
Paul Eggert's avatar
Paul Eggert committed
309 310
  .filter_properties = ftfont_filter_properties,
  .combining_capability = ftfont_combining_capability,
311 312
  };

Jan D's avatar
Jan D committed
313 314 315 316 317 318 319 320 321
void
syms_of_ftcrfont (void)
{
  if (ftfont_info_size != offsetof (struct ftcrfont_info, cr_font_face))
    abort ();

  DEFSYM (Qftcr, "ftcr");
  register_font_driver (&ftcrfont_driver, NULL);
}