hb-fallback-shape.cc revision 13240:8c09472c3de2 
1/*
2 * Copyright �� 2011  Google, Inc.
3 *
4 *  This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 *
24 * Google Author(s): Behdad Esfahbod
25 */
26
27#define HB_SHAPER fallback
28#include "hb-shaper-impl-private.hh"
29
30
31/*
32 * shaper face data
33 */
34
35struct hb_fallback_shaper_face_data_t {};
36
37hb_fallback_shaper_face_data_t *
38_hb_fallback_shaper_face_data_create (hb_face_t *face HB_UNUSED)
39{
40  return (hb_fallback_shaper_face_data_t *) HB_SHAPER_DATA_SUCCEEDED;
41}
42
43void
44_hb_fallback_shaper_face_data_destroy (hb_fallback_shaper_face_data_t *data HB_UNUSED)
45{
46}
47
48
49/*
50 * shaper font data
51 */
52
53struct hb_fallback_shaper_font_data_t {};
54
55hb_fallback_shaper_font_data_t *
56_hb_fallback_shaper_font_data_create (hb_font_t *font HB_UNUSED)
57{
58  return (hb_fallback_shaper_font_data_t *) HB_SHAPER_DATA_SUCCEEDED;
59}
60
61void
62_hb_fallback_shaper_font_data_destroy (hb_fallback_shaper_font_data_t *data HB_UNUSED)
63{
64}
65
66
67/*
68 * shaper shape_plan data
69 */
70
71struct hb_fallback_shaper_shape_plan_data_t {};
72
73hb_fallback_shaper_shape_plan_data_t *
74_hb_fallback_shaper_shape_plan_data_create (hb_shape_plan_t    *shape_plan HB_UNUSED,
75                                            const hb_feature_t *user_features HB_UNUSED,
76                                            unsigned int        num_user_features HB_UNUSED)
77{
78  return (hb_fallback_shaper_shape_plan_data_t *) HB_SHAPER_DATA_SUCCEEDED;
79}
80
81void
82_hb_fallback_shaper_shape_plan_data_destroy (hb_fallback_shaper_shape_plan_data_t *data HB_UNUSED)
83{
84}
85
86
87/*
88 * shaper
89 */
90
91hb_bool_t
92_hb_fallback_shape (hb_shape_plan_t    *shape_plan HB_UNUSED,
93                    hb_font_t          *font,
94                    hb_buffer_t        *buffer,
95                    const hb_feature_t *features HB_UNUSED,
96                    unsigned int        num_features HB_UNUSED)
97{
98  /* TODO
99   *
100   * - Apply fallback kern.
101   * - Handle Variation Selectors?
102   * - Apply normalization?
103   *
104   * This will make the fallback shaper into a dumb "TrueType"
105   * shaper which many people unfortunately still request.
106   */
107
108  hb_codepoint_t space;
109  bool has_space = font->get_glyph (' ', 0, &space);
110
111  buffer->clear_positions ();
112
113  hb_direction_t direction = buffer->props.direction;
114  hb_unicode_funcs_t *unicode = buffer->unicode;
115  unsigned int count = buffer->len;
116  hb_glyph_info_t *info = buffer->info;
117  hb_glyph_position_t *pos = buffer->pos;
118  for (unsigned int i = 0; i < count; i++)
119  {
120    if (has_space && unicode->is_default_ignorable (info[i].codepoint)) {
121      info[i].codepoint = space;
122      pos[i].x_advance = 0;
123      pos[i].y_advance = 0;
124      continue;
125    }
126    font->get_glyph (info[i].codepoint, 0, &info[i].codepoint);
127    font->get_glyph_advance_for_direction (info[i].codepoint,
128                                           direction,
129                                           &pos[i].x_advance,
130                                           &pos[i].y_advance);
131    font->subtract_glyph_origin_for_direction (info[i].codepoint,
132                                               direction,
133                                               &pos[i].x_offset,
134                                               &pos[i].y_offset);
135  }
136
137  if (HB_DIRECTION_IS_BACKWARD (direction))
138    hb_buffer_reverse (buffer);
139
140  return true;
141}
142