/src/cairo/src/cairo-user-font.c

Source
/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
/* cairo - a vector graphics library with display and print output
 *
 * Copyright © 2006, 2008 Red Hat, Inc
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Red Hat, Inc.
 *
 * Contributor(s):
 *      Kristian Høgsberg <krh@redhat.com>
 *      Behdad Esfahbod <behdad@behdad.org>
 */

#include "cairoint.h"
#include "cairo-user-font-private.h"
#include "cairo-recording-surface-private.h"
#include "cairo-analysis-surface-private.h"
#include "cairo-error-private.h"

/**
 * SECTION:cairo-user-fonts
 * @Title:User Fonts
 * @Short_Description: Font support with font data provided by the user
 *
 * The user-font feature allows the cairo user to provide drawings for glyphs
 * in a font.  This is most useful in implementing fonts in non-standard
 * formats, like SVG fonts and Flash fonts, but can also be used by games and
 * other application to draw "funky" fonts.
 **/

/**
 * CAIRO_HAS_USER_FONT:
 *
 * Defined if the user font backend is available.
 * This macro can be used to conditionally compile backend-specific code.
 * The user font backend is always built in versions of cairo that support
 * this feature (1.8 and later).
 *
 * Since: 1.8
 **/

typedef struct _cairo_user_scaled_font_methods {
    cairo_user_scaled_font_init_func_t      init;
    cairo_user_scaled_font_render_glyph_func_t    render_color_glyph;
    cairo_user_scaled_font_render_glyph_func_t    render_glyph;
    cairo_user_scaled_font_unicode_to_glyph_func_t  unicode_to_glyph;
    cairo_user_scaled_font_text_to_glyphs_func_t  text_to_glyphs;
} cairo_user_scaled_font_methods_t;

typedef struct _cairo_user_font_face {
    cairo_font_face_t              base;

    /* Set to true after first scaled font is created.  At that point,
     * the scaled_font_methods cannot change anymore. */
    cairo_bool_t         immutable;
    cairo_bool_t                     has_color;
    cairo_user_scaled_font_methods_t scaled_font_methods;
} cairo_user_font_face_t;

typedef struct _cairo_user_scaled_font {
    cairo_scaled_font_t  base;

    cairo_text_extents_t default_glyph_extents;

    /* space to compute extents in, and factors to convert back to user space */
    cairo_matrix_t extent_scale;
    double extent_x_scale;
    double extent_y_scale;

    /* multiplier for metrics hinting */
    double snap_x_scale;
    double snap_y_scale;

    cairo_pattern_t *foreground_marker;
    cairo_pattern_t *foreground_pattern;
    cairo_bool_t foreground_marker_used;
    cairo_bool_t foreground_colors_used;

} cairo_user_scaled_font_t;

/* #cairo_user_scaled_font_t */

static cairo_surface_t *
_cairo_user_scaled_font_create_recording_surface (cairo_user_scaled_font_t *scaled_font,
              cairo_bool_t              color,
              const cairo_color_t      *foreground_color)
{
    cairo_content_t content;

    if (color) {
  content = CAIRO_CONTENT_COLOR_ALPHA;
    } else {
  content = scaled_font->base.options.antialias == CAIRO_ANTIALIAS_SUBPIXEL ?
                     CAIRO_CONTENT_COLOR_ALPHA :
                     CAIRO_CONTENT_ALPHA;
    }

    if (scaled_font->foreground_pattern)
  cairo_pattern_destroy (scaled_font->foreground_pattern);

    scaled_font->foreground_marker_used = FALSE;
    scaled_font->foreground_colors_used = FALSE;
    if (foreground_color) {
  scaled_font->foreground_pattern = _cairo_pattern_create_solid (foreground_color);
    } else {
  scaled_font->foreground_pattern = cairo_pattern_create_rgb (0, 0, 0);
    }

    return cairo_recording_surface_create (content, NULL);
}

static cairo_t *
_cairo_user_scaled_font_create_recording_context (const cairo_user_scaled_font_t *scaled_font,
              cairo_surface_t                *recording_surface,
              cairo_bool_t                    color)
{
    cairo_t *cr;

    cr = cairo_create (recording_surface);

    if (!_cairo_matrix_is_scale_0 (&scaled_font->base.scale)) {
        cairo_matrix_t scale;
  scale = scaled_font->base.scale;
  scale.x0 = scale.y0 = 0.;
  cairo_set_matrix (cr, &scale);
    }

    cairo_set_font_size (cr, 1.0);
    cairo_set_font_options (cr, &scaled_font->base.options);
    if (!color)
  cairo_set_source_rgb (cr, 1., 1., 1.);

    return cr;
}

static cairo_int_status_t
_cairo_user_scaled_glyph_init_record_glyph (cairo_user_scaled_font_t *scaled_font,
              cairo_scaled_glyph_t     *scaled_glyph,
              const cairo_color_t      *foreground_color)
{
    cairo_user_font_face_t *face =
  (cairo_user_font_face_t *) scaled_font->base.font_face;
    cairo_text_extents_t extents = scaled_font->default_glyph_extents;
    cairo_surface_t *recording_surface = NULL;
    cairo_int_status_t status = CAIRO_STATUS_SUCCESS;
    cairo_t *cr;
    cairo_bool_t foreground_used = FALSE;

    if (!face->scaled_font_methods.render_color_glyph && !face->scaled_font_methods.render_glyph)
  return CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;

    /* special case for 0 rank matrix (as in _cairo_scaled_font_init): empty surface */
    if (_cairo_matrix_is_scale_0 (&scaled_font->base.scale)) {
  recording_surface = _cairo_user_scaled_font_create_recording_surface (scaled_font, FALSE, foreground_color);
  _cairo_scaled_glyph_set_recording_surface (scaled_glyph,
               &scaled_font->base,
               recording_surface,
               NULL);
    } else {
  status = CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED;

  if (face->scaled_font_methods.render_color_glyph &&
      scaled_font->base.options.color_mode != CAIRO_COLOR_MODE_NO_COLOR)
  {
      recording_surface = _cairo_user_scaled_font_create_recording_surface (scaled_font, TRUE, foreground_color);

      cr = _cairo_user_scaled_font_create_recording_context (scaled_font, recording_surface, TRUE);
      status = face->scaled_font_methods.render_color_glyph ((cairo_scaled_font_t *)scaled_font,
                   _cairo_scaled_glyph_index(scaled_glyph),
                   cr, &extents);
      if (status == CAIRO_INT_STATUS_SUCCESS) {
    status = cairo_status (cr);
    scaled_glyph->color_glyph = TRUE;
    scaled_glyph->color_glyph_set = TRUE;
      }

      cairo_destroy (cr);
      foreground_used = scaled_font->foreground_marker_used || scaled_font->foreground_colors_used;
  }

  if (status == (cairo_int_status_t)CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED &&
      face->scaled_font_methods.render_glyph) {
      if (recording_surface)
    cairo_surface_destroy (recording_surface);
      recording_surface = _cairo_user_scaled_font_create_recording_surface (scaled_font, FALSE, foreground_color);
      recording_surface->device_transform.x0 = .25 * _cairo_scaled_glyph_xphase (scaled_glyph);
      recording_surface->device_transform.y0 = .25 * _cairo_scaled_glyph_yphase (scaled_glyph);

      cr = _cairo_user_scaled_font_create_recording_context (scaled_font, recording_surface, FALSE);

      status = face->scaled_font_methods.render_glyph ((cairo_scaled_font_t *)scaled_font,
                   _cairo_scaled_glyph_index(scaled_glyph),
                   cr, &extents);
      if (status == CAIRO_INT_STATUS_SUCCESS) {
    status = cairo_status (cr);
    scaled_glyph->color_glyph = FALSE;
    scaled_glyph->color_glyph_set = TRUE;
      }

      cairo_destroy (cr);
      foreground_used = FALSE;
  }

  if (status != CAIRO_INT_STATUS_SUCCESS) {
      if (recording_surface)
    cairo_surface_destroy (recording_surface);
      return status;
  }

  _cairo_scaled_glyph_set_recording_surface (scaled_glyph,
               &scaled_font->base,
               recording_surface,
               foreground_used ? foreground_color : NULL);
    }

    /* set metrics */

    if (extents.width == 0.) {
  cairo_box_t bbox;
  double x1, y1, x2, y2;
  double x_scale, y_scale;

  /* Compute extents.x/y/width/height from recording_surface,
   * in font space.
   */
  status = _cairo_recording_surface_get_bbox ((cairo_recording_surface_t *) recording_surface,
                &bbox,
                &scaled_font->extent_scale);
  if (unlikely (status))
      return status;

  _cairo_box_to_doubles (&bbox, &x1, &y1, &x2, &y2);

  x_scale = scaled_font->extent_x_scale;
  y_scale = scaled_font->extent_y_scale;
  extents.x_bearing = x1 * x_scale;
  extents.y_bearing = y1 * y_scale;
  extents.width     = (x2 - x1) * x_scale;
  extents.height    = (y2 - y1) * y_scale;
    }

    if (scaled_font->base.options.hint_metrics != CAIRO_HINT_METRICS_OFF) {
  extents.x_advance = _cairo_lround (extents.x_advance / scaled_font->snap_x_scale) * scaled_font->snap_x_scale;
  extents.y_advance = _cairo_lround (extents.y_advance / scaled_font->snap_y_scale) * scaled_font->snap_y_scale;
    }

    _cairo_scaled_glyph_set_metrics (scaled_glyph,
             &scaled_font->base,
             &extents);

    return status;
}

static cairo_int_status_t
_cairo_user_scaled_glyph_init_surface (cairo_user_scaled_font_t  *scaled_font,
               cairo_scaled_glyph_t  *scaled_glyph,
               cairo_scaled_glyph_info_t  info,
               const cairo_color_t       *foreground_color)
{
    cairo_surface_t *surface;
    cairo_format_t format;
    int width, height;
    cairo_int_status_t status = CAIRO_STATUS_SUCCESS;
    cairo_bool_t foreground_used;

    /* TODO
     * extend the glyph cache to support argb glyphs.
     * need to figure out the semantics and interaction with subpixel
     * rendering first.
     */

    /* Only one info type at a time handled in this function */
    assert (info == CAIRO_SCALED_GLYPH_INFO_COLOR_SURFACE || info == CAIRO_SCALED_GLYPH_INFO_SURFACE);

    width = _cairo_fixed_integer_ceil (scaled_glyph->bbox.p2.x) -
  _cairo_fixed_integer_floor (scaled_glyph->bbox.p1.x);
    height = _cairo_fixed_integer_ceil (scaled_glyph->bbox.p2.y) -
  _cairo_fixed_integer_floor (scaled_glyph->bbox.p1.y);

    if (info == CAIRO_SCALED_GLYPH_INFO_COLOR_SURFACE) {
  format = CAIRO_FORMAT_ARGB32;
    } else {
  switch (scaled_font->base.options.antialias) {
      default:
      case CAIRO_ANTIALIAS_DEFAULT:
      case CAIRO_ANTIALIAS_FAST:
      case CAIRO_ANTIALIAS_GOOD:
      case CAIRO_ANTIALIAS_GRAY:
    format = CAIRO_FORMAT_A8;
    break;
      case CAIRO_ANTIALIAS_NONE:
    format = CAIRO_FORMAT_A1;
    break;
      case CAIRO_ANTIALIAS_BEST:
      case CAIRO_ANTIALIAS_SUBPIXEL:
    format = CAIRO_FORMAT_ARGB32;
    break;
  }
    }
    surface = cairo_image_surface_create (format, width, height);

    cairo_surface_set_device_offset (surface,
             - _cairo_fixed_integer_floor (scaled_glyph->bbox.p1.x),
             - _cairo_fixed_integer_floor (scaled_glyph->bbox.p1.y));

    if (info == CAIRO_SCALED_GLYPH_INFO_COLOR_SURFACE) {
  status = _cairo_recording_surface_replay_with_foreground_color (scaled_glyph->recording_surface,
                  surface,
                  foreground_color,
                  &foreground_used);
  
    } else {
  status = _cairo_recording_surface_replay (scaled_glyph->recording_surface, surface);
  foreground_used = FALSE;
    }
    if (unlikely (status)) {
  cairo_surface_destroy(surface);
  return status;
    }

    foreground_used = foreground_used || scaled_glyph->recording_uses_foreground_color;
    
    if (info == CAIRO_SCALED_GLYPH_INFO_COLOR_SURFACE) {
  _cairo_scaled_glyph_set_color_surface (scaled_glyph,
                 &scaled_font->base,
                 (cairo_image_surface_t *)surface,
                 foreground_used ? foreground_color : NULL);
  surface = NULL;
    } else {
  _cairo_scaled_glyph_set_surface (scaled_glyph,
           &scaled_font->base,
           (cairo_image_surface_t *) surface);
  surface = NULL;
    }

    if (surface)
  cairo_surface_destroy (surface);

    return status;
}

static void
_cairo_user_scaled_glyph_fini (void      *abstract_font)
{
    cairo_user_scaled_font_t *scaled_font = abstract_font;

    if (scaled_font->foreground_pattern)
  cairo_pattern_destroy (scaled_font->foreground_pattern);

    if (scaled_font->foreground_marker)
  cairo_pattern_destroy (scaled_font->foreground_marker);
}

static cairo_int_status_t
_cairo_user_scaled_glyph_init (void      *abstract_font,
             cairo_scaled_glyph_t  *scaled_glyph,
             cairo_scaled_glyph_info_t  info,
             const cairo_color_t       *foreground_color)
{
    cairo_int_status_t status = CAIRO_STATUS_SUCCESS;
    cairo_user_scaled_font_t *scaled_font = abstract_font;

    if (!scaled_glyph->recording_surface || (info & CAIRO_SCALED_GLYPH_INFO_RECORDING_SURFACE)) {
  status = _cairo_user_scaled_glyph_init_record_glyph (scaled_font, scaled_glyph, foreground_color);
  if (status)
      return status;
    }

    if (info & CAIRO_SCALED_GLYPH_INFO_COLOR_SURFACE) {
  if (!scaled_glyph->color_glyph )
      return CAIRO_INT_STATUS_UNSUPPORTED;

  status = _cairo_user_scaled_glyph_init_surface (scaled_font,
              scaled_glyph,
              CAIRO_SCALED_GLYPH_INFO_COLOR_SURFACE,
              foreground_color);
  if (status)
      return status;
    }

    if (info & CAIRO_SCALED_GLYPH_INFO_SURFACE) {
  status = _cairo_user_scaled_glyph_init_surface (scaled_font,
              scaled_glyph,
              CAIRO_SCALED_GLYPH_INFO_SURFACE,
              NULL);
  if (status)
      return status;
    }

    if (info & CAIRO_SCALED_GLYPH_INFO_PATH) {
  cairo_path_fixed_t *path = _cairo_path_fixed_create ();
  if (!path)
      return _cairo_error (CAIRO_STATUS_NO_MEMORY);

  status = _cairo_recording_surface_get_path (scaled_glyph->recording_surface, path);
  if (unlikely (status)) {
      _cairo_path_fixed_destroy (path);
      return status;
  }

  _cairo_scaled_glyph_set_path (scaled_glyph,
              &scaled_font->base,
              path);
    }

    return status;
}

static unsigned long
_cairo_user_ucs4_to_index (void     *abstract_font,
         uint32_t  ucs4)
{
    cairo_user_scaled_font_t *scaled_font = abstract_font;
    cairo_user_font_face_t *face =
  (cairo_user_font_face_t *) scaled_font->base.font_face;
    unsigned long glyph = 0;

    if (face->scaled_font_methods.unicode_to_glyph) {
  cairo_status_t status;

  status = face->scaled_font_methods.unicode_to_glyph (&scaled_font->base,
                   ucs4, &glyph);

  if (status == CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
      goto not_implemented;

  if (status != CAIRO_STATUS_SUCCESS) {
      status = _cairo_scaled_font_set_error (&scaled_font->base, status);
      glyph = 0;
  }

    } else {
not_implemented:
  glyph = ucs4;
    }

    return glyph;
}

static cairo_bool_t
_cairo_user_has_color_glyphs (void         *abstract_font)
{
    cairo_user_scaled_font_t *scaled_font = abstract_font;
    cairo_user_font_face_t *face =
  (cairo_user_font_face_t *) scaled_font->base.font_face;

    return face->has_color;
}

static cairo_int_status_t
_cairo_user_text_to_glyphs (void          *abstract_font,
          double           x,
          double           y,
          const char          *utf8,
          int            utf8_len,
          cairo_glyph_t      **glyphs,
          int            *num_glyphs,
          cairo_text_cluster_t      **clusters,
          int            *num_clusters,
          cairo_text_cluster_flags_t *cluster_flags)
{
    cairo_int_status_t status = CAIRO_INT_STATUS_UNSUPPORTED;

    cairo_user_scaled_font_t *scaled_font = abstract_font;
    cairo_user_font_face_t *face =
  (cairo_user_font_face_t *) scaled_font->base.font_face;

    if (face->scaled_font_methods.text_to_glyphs) {
  int i;
  cairo_glyph_t *orig_glyphs = *glyphs;
  int orig_num_glyphs = *num_glyphs;

  status = face->scaled_font_methods.text_to_glyphs (&scaled_font->base,
                 utf8, utf8_len,
                 glyphs, num_glyphs,
                 clusters, num_clusters, cluster_flags);

  if (status != CAIRO_INT_STATUS_SUCCESS &&
      status != CAIRO_INT_STATUS_USER_FONT_NOT_IMPLEMENTED)
      return status;

  if (status == CAIRO_INT_STATUS_USER_FONT_NOT_IMPLEMENTED ||
      *num_glyphs < 0) {
      if (orig_glyphs != *glyphs) {
    cairo_glyph_free (*glyphs);
    *glyphs = orig_glyphs;
      }
      *num_glyphs = orig_num_glyphs;
      return CAIRO_INT_STATUS_UNSUPPORTED;
  }

  /* Convert from font space to user space and add x,y */
  for (i = 0; i < *num_glyphs; i++) {
      double gx = (*glyphs)[i].x;
      double gy = (*glyphs)[i].y;

      cairo_matrix_transform_point (&scaled_font->base.font_matrix,
            &gx, &gy);

      (*glyphs)[i].x = gx + x;
      (*glyphs)[i].y = gy + y;
  }
    }

    return status;
}

static cairo_status_t
_cairo_user_font_face_scaled_font_create (void                        *abstract_face,
            const cairo_matrix_t        *font_matrix,
            const cairo_matrix_t        *ctm,
            const cairo_font_options_t  *options,
            cairo_scaled_font_t        **scaled_font);

static cairo_status_t
_cairo_user_font_face_create_for_toy (cairo_toy_font_face_t   *toy_face,
              cairo_font_face_t      **font_face)
{
    return _cairo_font_face_twin_create_for_toy (toy_face, font_face);
}

static const cairo_scaled_font_backend_t _cairo_user_scaled_font_backend = {
    CAIRO_FONT_TYPE_USER,
    _cairo_user_scaled_glyph_fini,
    _cairo_user_scaled_glyph_init,
    _cairo_user_text_to_glyphs,
    _cairo_user_ucs4_to_index,
    NULL, /* load_truetype_table */
    NULL, /* index_to_ucs4 */
    NULL,       /* is_synthetic */
    NULL,       /* index_to_glyph_name */
    NULL,       /* load_type1_data */
    _cairo_user_has_color_glyphs,
};

/* #cairo_user_font_face_t */

static cairo_status_t
_cairo_user_font_face_scaled_font_create (void                        *abstract_face,
            const cairo_matrix_t        *font_matrix,
            const cairo_matrix_t        *ctm,
            const cairo_font_options_t  *options,
            cairo_scaled_font_t        **scaled_font)
{
    cairo_status_t status = CAIRO_STATUS_SUCCESS;
    cairo_user_font_face_t *font_face = abstract_face;
    cairo_user_scaled_font_t *user_scaled_font = NULL;
    cairo_font_extents_t font_extents = {1., 0., 1., 1., 0.};

    font_face->immutable = TRUE;

    user_scaled_font = _cairo_calloc (sizeof (cairo_user_scaled_font_t));
    if (unlikely (user_scaled_font == NULL))
  return _cairo_error (CAIRO_STATUS_NO_MEMORY);

    status = _cairo_scaled_font_init (&user_scaled_font->base,
              &font_face->base,
              font_matrix, ctm, options,
              &_cairo_user_scaled_font_backend);

    if (unlikely (status)) {
  free (user_scaled_font);
  return status;
    }

    user_scaled_font->foreground_pattern = NULL;
    user_scaled_font->foreground_marker = _cairo_pattern_create_foreground_marker ();

    /* XXX metrics hinting? */

    /* compute a normalized version of font scale matrix to compute
     * extents in.  This is to minimize error caused by the cairo_fixed_t
     * representation. */
    {
  double fixed_scale, x_scale, y_scale;

  user_scaled_font->snap_x_scale = 1.0;
  user_scaled_font->snap_y_scale = 1.0;
  user_scaled_font->extent_scale = user_scaled_font->base.scale_inverse;
  status = _cairo_matrix_compute_basis_scale_factors (&user_scaled_font->extent_scale,
                  &x_scale, &y_scale,
                  1);
  if (status == CAIRO_STATUS_SUCCESS) {

      if (x_scale == 0) x_scale = 1.;
      if (y_scale == 0) y_scale = 1.;

      user_scaled_font->snap_x_scale = x_scale;
      user_scaled_font->snap_y_scale = y_scale;

      /* since glyphs are pretty much 1.0x1.0, we can reduce error by
       * scaling to a larger square.  say, 1024.x1024. */
      fixed_scale = 1024.;
      x_scale /= fixed_scale;
      y_scale /= fixed_scale;

      cairo_matrix_scale (&user_scaled_font->extent_scale, 1. / x_scale, 1. / y_scale);

      user_scaled_font->extent_x_scale = x_scale;
      user_scaled_font->extent_y_scale = y_scale;
  }
    }

    if (status == CAIRO_STATUS_SUCCESS &&
  font_face->scaled_font_methods.init != NULL)
    {
  /* Lock the scaled_font mutex such that user doesn't accidentally try
         * to use it just yet. */
  CAIRO_MUTEX_LOCK (user_scaled_font->base.mutex);

  /* Give away fontmap lock such that user-font can use other fonts */
  status = _cairo_scaled_font_register_placeholder_and_unlock_font_map (&user_scaled_font->base);
  if (status == CAIRO_STATUS_SUCCESS) {
      cairo_surface_t *recording_surface;
      cairo_t *cr;

      recording_surface = _cairo_user_scaled_font_create_recording_surface (user_scaled_font, FALSE, NULL);
      cr = _cairo_user_scaled_font_create_recording_context (user_scaled_font, recording_surface, FALSE);
      cairo_surface_destroy (recording_surface);

      status = font_face->scaled_font_methods.init (&user_scaled_font->base,
                cr,
                &font_extents);

      if (status == CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED)
    status = CAIRO_STATUS_SUCCESS;

      if (status == CAIRO_STATUS_SUCCESS)
    status = cairo_status (cr);

      cairo_destroy (cr);

      _cairo_scaled_font_unregister_placeholder_and_lock_font_map (&user_scaled_font->base);
  }

  CAIRO_MUTEX_UNLOCK (user_scaled_font->base.mutex);
    }

    if (status == CAIRO_STATUS_SUCCESS)
  status = _cairo_scaled_font_set_metrics (&user_scaled_font->base, &font_extents);

    if (status != CAIRO_STATUS_SUCCESS) {
        _cairo_scaled_font_fini (&user_scaled_font->base);
  free (user_scaled_font);
    } else {
        user_scaled_font->default_glyph_extents.x_bearing = 0.;
        user_scaled_font->default_glyph_extents.y_bearing = -font_extents.ascent;
        user_scaled_font->default_glyph_extents.width = 0.;
        user_scaled_font->default_glyph_extents.height = font_extents.ascent + font_extents.descent;
        user_scaled_font->default_glyph_extents.x_advance = font_extents.max_x_advance;
        user_scaled_font->default_glyph_extents.y_advance = 0.;

  *scaled_font = &user_scaled_font->base;
    }

    return status;
}

const cairo_font_face_backend_t _cairo_user_font_face_backend = {
    CAIRO_FONT_TYPE_USER,
    _cairo_user_font_face_create_for_toy,
    _cairo_font_face_destroy,
    _cairo_user_font_face_scaled_font_create
};


cairo_bool_t
_cairo_font_face_is_user (cairo_font_face_t *font_face)
{
    return font_face->backend == &_cairo_user_font_face_backend;
}

/* Implement the public interface */

/**
 * cairo_user_font_face_create:
 *
 * Creates a new user font-face.
 *
 * Use the setter functions to associate callbacks with the returned
 * user font.  The only mandatory callback is render_glyph.
 *
 * After the font-face is created, the user can attach arbitrary data
 * (the actual font data) to it using cairo_font_face_set_user_data()
 * and access it from the user-font callbacks by using
 * cairo_scaled_font_get_font_face() followed by
 * cairo_font_face_get_user_data().
 *
 * Return value: a newly created #cairo_font_face_t. Free with
 *  cairo_font_face_destroy() when you are done using it.
 *
 * Since: 1.8
 **/
cairo_font_face_t *
cairo_user_font_face_create (void)
{
    cairo_user_font_face_t *font_face;

    font_face = _cairo_calloc (sizeof (cairo_user_font_face_t));
    if (!font_face) {
  _cairo_error_throw (CAIRO_STATUS_NO_MEMORY);
  return (cairo_font_face_t *)&_cairo_font_face_nil;
    }

    _cairo_font_face_init (&font_face->base, &_cairo_user_font_face_backend);

    font_face->immutable = FALSE;
    font_face->has_color = FALSE;
    memset (&font_face->scaled_font_methods, 0, sizeof (font_face->scaled_font_methods));

    return &font_face->base;
}

/* User-font method setters */


/**
 * cairo_user_font_face_set_init_func:
 * @font_face: A user font face
 * @init_func: The init callback, or %NULL
 *
 * Sets the scaled-font initialization function of a user-font.
 * See #cairo_user_scaled_font_init_func_t for details of how the callback
 * works.
 *
 * The font-face should not be immutable or a %CAIRO_STATUS_USER_FONT_IMMUTABLE
 * error will occur.  A user font-face is immutable as soon as a scaled-font
 * is created from it.
 *
 * Since: 1.8
 **/
void
cairo_user_font_face_set_init_func (cairo_font_face_t                  *font_face,
            cairo_user_scaled_font_init_func_t  init_func)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    if (user_font_face->immutable) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_USER_FONT_IMMUTABLE))
      return;
    }
    user_font_face->scaled_font_methods.init = init_func;
}

/**
 * cairo_user_font_face_set_render_color_glyph_func:
 * @font_face: A user font face
 * @render_glyph_func: The render_glyph callback, or %NULL
 *
 * Sets the color glyph rendering function of a user-font.
 * See #cairo_user_scaled_font_render_glyph_func_t for details of how the callback
 * works.
 *
 * The font-face should not be immutable or a %CAIRO_STATUS_USER_FONT_IMMUTABLE
 * error will occur.  A user font-face is immutable as soon as a scaled-font
 * is created from it.
 *
 * The render_glyph callback is the only mandatory callback of a
 * user-font. At least one of
 * cairo_user_font_face_set_render_color_glyph_func() or
 * cairo_user_font_face_set_render_glyph_func() must be called to set
 * a render callback. If both callbacks are set, the color glyph
 * render callback is invoked first. If the color glyph render
 * callback returns %CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED, the
 * non-color version of the callback is invoked.
 *
 * If the callback is %NULL and a glyph is tried to be rendered using
 * @font_face, a %CAIRO_STATUS_USER_FONT_ERROR will occur.
 *
 * Since: 1.18
 **/
void
cairo_user_font_face_set_render_color_glyph_func (cairo_font_face_t                          *font_face,
                                                  cairo_user_scaled_font_render_glyph_func_t  render_glyph_func)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    if (user_font_face->immutable) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_USER_FONT_IMMUTABLE))
      return;
    }
    user_font_face->scaled_font_methods.render_color_glyph = render_glyph_func;
    user_font_face->has_color = render_glyph_func ? TRUE : FALSE;
}

/**
 * cairo_user_font_face_set_render_glyph_func:
 * @font_face: A user font face
 * @render_glyph_func: The render_glyph callback, or %NULL
 *
 * Sets the glyph rendering function of a user-font.
 * See #cairo_user_scaled_font_render_glyph_func_t for details of how the callback
 * works.
 *
 * The font-face should not be immutable or a %CAIRO_STATUS_USER_FONT_IMMUTABLE
 * error will occur.  A user font-face is immutable as soon as a scaled-font
 * is created from it.
 *
 * The render_glyph callback is the only mandatory callback of a
 * user-font. At least one of
 * cairo_user_font_face_set_render_color_glyph_func() or
 * cairo_user_font_face_set_render_glyph_func() must be called to set
 * a render callback. If both callbacks are set, the color glyph
 * render callback is invoked first. If the color glyph render
 * callback returns %CAIRO_STATUS_USER_FONT_NOT_IMPLEMENTED, the
 * non-color version of the callback is invoked.
 *
 * If the callback is %NULL and a glyph is tried to be rendered using
 * @font_face, a %CAIRO_STATUS_USER_FONT_ERROR will occur.
 *
 * Since: 1.8
 **/
void
cairo_user_font_face_set_render_glyph_func (cairo_font_face_t                          *font_face,
              cairo_user_scaled_font_render_glyph_func_t  render_glyph_func)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    if (user_font_face->immutable) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_USER_FONT_IMMUTABLE))
      return;
    }
    user_font_face->scaled_font_methods.render_glyph = render_glyph_func;
}

/**
 * cairo_user_font_face_set_text_to_glyphs_func:
 * @font_face: A user font face
 * @text_to_glyphs_func: The text_to_glyphs callback, or %NULL
 *
 * Sets th text-to-glyphs conversion function of a user-font.
 * See #cairo_user_scaled_font_text_to_glyphs_func_t for details of how the callback
 * works.
 *
 * The font-face should not be immutable or a %CAIRO_STATUS_USER_FONT_IMMUTABLE
 * error will occur.  A user font-face is immutable as soon as a scaled-font
 * is created from it.
 *
 * Since: 1.8
 **/
void
cairo_user_font_face_set_text_to_glyphs_func (cairo_font_face_t                            *font_face,
                cairo_user_scaled_font_text_to_glyphs_func_t  text_to_glyphs_func)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    if (user_font_face->immutable) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_USER_FONT_IMMUTABLE))
      return;
    }
    user_font_face->scaled_font_methods.text_to_glyphs = text_to_glyphs_func;
}

/**
 * cairo_user_font_face_set_unicode_to_glyph_func:
 * @font_face: A user font face
 * @unicode_to_glyph_func: The unicode_to_glyph callback, or %NULL
 *
 * Sets the unicode-to-glyph conversion function of a user-font.
 * See #cairo_user_scaled_font_unicode_to_glyph_func_t for details of how the callback
 * works.
 *
 * The font-face should not be immutable or a %CAIRO_STATUS_USER_FONT_IMMUTABLE
 * error will occur.  A user font-face is immutable as soon as a scaled-font
 * is created from it.
 *
 * Since: 1.8
 **/
void
cairo_user_font_face_set_unicode_to_glyph_func (cairo_font_face_t                              *font_face,
            cairo_user_scaled_font_unicode_to_glyph_func_t  unicode_to_glyph_func)
{
    cairo_user_font_face_t *user_font_face;
    if (font_face->status)
  return;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    if (user_font_face->immutable) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_USER_FONT_IMMUTABLE))
      return;
    }
    user_font_face->scaled_font_methods.unicode_to_glyph = unicode_to_glyph_func;
}

/* User-font method getters */

/**
 * cairo_user_font_face_get_init_func:
 * @font_face: A user font face
 *
 * Gets the scaled-font initialization function of a user-font.
 *
 * Return value: The init callback of @font_face
 * or %NULL if none set or an error has occurred.
 *
 * Since: 1.8
 **/
cairo_user_scaled_font_init_func_t
cairo_user_font_face_get_init_func (cairo_font_face_t *font_face)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return NULL;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return NULL;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    return user_font_face->scaled_font_methods.init;
}

/**
 * cairo_user_font_face_get_render_color_glyph_func:
 * @font_face: A user font face
 *
 * Gets the color glyph rendering function of a user-font.
 *
 * Return value: The render_glyph callback of @font_face
 * or %NULL if none set or an error has occurred.
 *
 * Since: 1.18
 **/
cairo_user_scaled_font_render_glyph_func_t
cairo_user_font_face_get_render_color_glyph_func (cairo_font_face_t *font_face)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return NULL;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return NULL;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    return user_font_face->scaled_font_methods.render_color_glyph;
}

/**
 * cairo_user_font_face_get_render_glyph_func:
 * @font_face: A user font face
 *
 * Gets the glyph rendering function of a user-font.
 *
 * Return value: The render_glyph callback of @font_face
 * or %NULL if none set or an error has occurred.
 *
 * Since: 1.8
 **/
cairo_user_scaled_font_render_glyph_func_t
cairo_user_font_face_get_render_glyph_func (cairo_font_face_t *font_face)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return NULL;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return NULL;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    return user_font_face->scaled_font_methods.render_glyph;
}

/**
 * cairo_user_font_face_get_text_to_glyphs_func:
 * @font_face: A user font face
 *
 * Gets the text-to-glyphs conversion function of a user-font.
 *
 * Return value: The text_to_glyphs callback of @font_face
 * or %NULL if none set or an error occurred.
 *
 * Since: 1.8
 **/
cairo_user_scaled_font_text_to_glyphs_func_t
cairo_user_font_face_get_text_to_glyphs_func (cairo_font_face_t *font_face)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return NULL;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return NULL;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    return user_font_face->scaled_font_methods.text_to_glyphs;
}

/**
 * cairo_user_font_face_get_unicode_to_glyph_func:
 * @font_face: A user font face
 *
 * Gets the unicode-to-glyph conversion function of a user-font.
 *
 * Return value: The unicode_to_glyph callback of @font_face
 * or %NULL if none set or an error occurred.
 *
 * Since: 1.8
 **/
cairo_user_scaled_font_unicode_to_glyph_func_t
cairo_user_font_face_get_unicode_to_glyph_func (cairo_font_face_t *font_face)
{
    cairo_user_font_face_t *user_font_face;

    if (font_face->status)
  return NULL;

    if (! _cairo_font_face_is_user (font_face)) {
  if (_cairo_font_face_set_error (font_face, CAIRO_STATUS_FONT_TYPE_MISMATCH))
      return NULL;
    }

    user_font_face = (cairo_user_font_face_t *) font_face;
    return user_font_face->scaled_font_methods.unicode_to_glyph;
}

/**
 * cairo_user_scaled_font_get_foreground_marker:
 * @scaled_font: A user scaled font
 *
 * Gets the foreground pattern of the glyph currently being
 * rendered. A #cairo_user_scaled_font_render_glyph_func_t function
 * that has been set with
 * cairo_user_font_face_set_render_color_glyph_func() may call this
 * function to retrieve the current foreground pattern for the glyph
 * being rendered. The function should not be called outside of a
 * cairo_user_font_face_set_render_color_glyph_func() callback.
 *
 * The foreground marker pattern contains an internal marker to
 * indicate that it is to be substituted with the current source when
 * rendered to a surface. Querying the foreground marker will reveal a
 * solid black color, however this is not representative of the color
 * that will actually be used. Similarly, setting a solid black color
 * will render black, not the foreground pattern when the glyph is
 * painted to a surface. Using the foreground marker as the source
 * instead of cairo_user_scaled_font_get_foreground_source() in a
 * color render callback has the following benefits:
 *
 * 1. Cairo only needs to call the render callback once as it can
 * cache the recording. Cairo will substitute the actual foreground
 * color when rendering the recording.
 *
 * 2. On backends that have the concept of a foreground color in fonts such as
 * PDF, PostScript, and SVG, cairo can generate more optimal
 * output. The glyph can be included in an embedded font.
 *
 * The one drawback of the using foreground marker is the render
 * callback can not access the color components of the pattern as the
 * actual foreground pattern is not available at the time the render
 * callback is invoked. If the render callback needs to query the
 * foreground pattern, use
 * cairo_user_scaled_font_get_foreground_source().
 *
 * If the render callback simply wants to call cairo_set_source() with
 * the foreground pattern,
 * cairo_user_scaled_font_get_foreground_marker() is the preferred
 * function to use as it results in better performance than
 * cairo_user_scaled_font_get_foreground_source().
 *
 * Return value: the current foreground source marker pattern. This
 * object is owned by cairo. This object must not be modified or used
 * outside of a color render callback. To keep a reference to it,
 * you must call cairo_pattern_reference().
 *
 * Since: 1.18
 **/
cairo_pattern_t *
cairo_user_scaled_font_get_foreground_marker (cairo_scaled_font_t *scaled_font)
{
    cairo_user_scaled_font_t *user_scaled_font;

    if (scaled_font->backend != &_cairo_user_scaled_font_backend)
  return _cairo_pattern_create_in_error (CAIRO_STATUS_FONT_TYPE_MISMATCH);

    user_scaled_font = (cairo_user_scaled_font_t *)scaled_font;
    return user_scaled_font->foreground_marker;
}

/**
 * cairo_user_scaled_font_get_foreground_source:
 * @scaled_font: A user scaled font
 *
 * Gets the foreground pattern of the glyph currently being
 * rendered. A #cairo_user_scaled_font_render_glyph_func_t function
 * that has been set with
 * cairo_user_font_face_set_render_color_glyph_func() may call this
 * function to retrieve the current foreground pattern for the glyph
 * being rendered. The function should not be called outside of a
 * cairo_user_font_face_set_render_color_glyph_func() callback.
 *
 * This function returns the current source at the time the glyph is
 * rendered. Compared with
 * cairo_user_scaled_font_get_foreground_marker(), this function
 * returns the actual source pattern that will be used to render the
 * glyph.  The render callback is free to query the pattern and
 * extract color components or other pattern data. For example if the
 * render callback wants to create a gradient stop based on colors in
 * the foreground source pattern, it will need to use this function in
 * order to be able to query the colors in the foreground pattern.
 *
 * While this function does not have the restrictions on using the
 * pattern that cairo_user_scaled_font_get_foreground_marker() has, it
 * does incur a performance penalty. If a render callback calls this
 * function:
 *
 * 1. Cairo will call the render callback whenever the current pattern
 * of the context in which the glyph is rendered changes.
 *
 * 2. On backends that support font embedding (PDF, PostScript, and
 * SVG), cairo can not embed this glyph in a font. Instead the glyph
 * will be emitted as an image or sequence of drawing operations each
 * time it is used.
 *
 * Return value: the current foreground source pattern. This object is
 * owned by cairo. To keep a reference to it, you must call
 * cairo_pattern_reference().
 *
 * Since: 1.18
 **/
cairo_pattern_t *
cairo_user_scaled_font_get_foreground_source (cairo_scaled_font_t *scaled_font)
{
    cairo_user_scaled_font_t *user_scaled_font;

    if (scaled_font->backend != &_cairo_user_scaled_font_backend)
  return _cairo_pattern_create_in_error (CAIRO_STATUS_FONT_TYPE_MISMATCH);

    user_scaled_font = (cairo_user_scaled_font_t *)scaled_font;
    user_scaled_font->foreground_colors_used = TRUE;
    return user_scaled_font->foreground_pattern;
}

Coverage Report

Created: 2025-09-27 07:50