1/*
2 * Copyright © 2011,2014  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, Roozbeh Pournader
25 */
26
27#include "hb-private.hh"
28
29#include "hb-ot.h"
30
31#include "hb-font-private.hh"
32
33#include "hb-ot-cmap-table.hh"
34#include "hb-ot-hhea-table.hh"
35#include "hb-ot-hmtx-table.hh"
36
37
38
39struct hb_ot_font_t
40{
41  unsigned int num_glyphs;
42  unsigned int num_hmetrics;
43  const OT::hmtx *hmtx;
44  hb_blob_t *hmtx_blob;
45
46  const OT::CmapSubtable *cmap;
47  const OT::CmapSubtable *cmap_uvs;
48  hb_blob_t *cmap_blob;
49};
50
51
52static hb_ot_font_t *
53_hb_ot_font_create (hb_font_t *font)
54{
55  hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));
56
57  if (unlikely (!ot_font))
58    return NULL;
59
60  ot_font->num_glyphs = font->face->get_num_glyphs ();
61
62  {
63    hb_blob_t *hhea_blob = OT::Sanitizer<OT::hhea>::sanitize (font->face->reference_table (HB_OT_TAG_hhea));
64    const OT::hhea *hhea = OT::Sanitizer<OT::hhea>::lock_instance (hhea_blob);
65    ot_font->num_hmetrics = hhea->numberOfHMetrics;
66    hb_blob_destroy (hhea_blob);
67  }
68  ot_font->hmtx_blob = OT::Sanitizer<OT::hmtx>::sanitize (font->face->reference_table (HB_OT_TAG_hmtx));
69  if (unlikely (!ot_font->num_hmetrics ||
70		2 * (ot_font->num_hmetrics + ot_font->num_glyphs) < hb_blob_get_length (ot_font->hmtx_blob)))
71  {
72    hb_blob_destroy (ot_font->hmtx_blob);
73    free (ot_font);
74    return NULL;
75  }
76  ot_font->hmtx = OT::Sanitizer<OT::hmtx>::lock_instance (ot_font->hmtx_blob);
77
78  ot_font->cmap_blob = OT::Sanitizer<OT::cmap>::sanitize (font->face->reference_table (HB_OT_TAG_cmap));
79  const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (ot_font->cmap_blob);
80  const OT::CmapSubtable *subtable = NULL;
81  const OT::CmapSubtable *subtable_uvs = NULL;
82
83  /* 32-bit subtables. */
84  if (!subtable) subtable = cmap->find_subtable (0, 6);
85  if (!subtable) subtable = cmap->find_subtable (0, 4);
86  if (!subtable) subtable = cmap->find_subtable (3, 10);
87  /* 16-bit subtables. */
88  if (!subtable) subtable = cmap->find_subtable (0, 3);
89  if (!subtable) subtable = cmap->find_subtable (3, 1);
90  /* Meh. */
91  if (!subtable) subtable = &OT::Null(OT::CmapSubtable);
92
93  /* UVS subtable. */
94  if (!subtable_uvs) subtable_uvs = cmap->find_subtable (0, 5);
95  /* Meh. */
96  if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtable);
97
98  ot_font->cmap = subtable;
99  ot_font->cmap_uvs = subtable_uvs;
100
101  return ot_font;
102}
103
104static void
105_hb_ot_font_destroy (hb_ot_font_t *ot_font)
106{
107  hb_blob_destroy (ot_font->cmap_blob);
108  hb_blob_destroy (ot_font->hmtx_blob);
109
110  free (ot_font);
111}
112
113
114static hb_bool_t
115hb_ot_get_glyph (hb_font_t *font HB_UNUSED,
116		 void *font_data,
117		 hb_codepoint_t unicode,
118		 hb_codepoint_t variation_selector,
119		 hb_codepoint_t *glyph,
120		 void *user_data HB_UNUSED)
121
122{
123  const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
124
125  if (unlikely (variation_selector))
126  {
127    switch (ot_font->cmap_uvs->get_glyph_variant (unicode,
128						  variation_selector,
129						  glyph))
130    {
131      case OT::GLYPH_VARIANT_NOT_FOUND:		return false;
132      case OT::GLYPH_VARIANT_FOUND:		return true;
133      case OT::GLYPH_VARIANT_USE_DEFAULT:	break;
134    }
135  }
136
137  return ot_font->cmap->get_glyph (unicode, glyph);
138}
139
140static hb_position_t
141hb_ot_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
142			   void *font_data,
143			   hb_codepoint_t glyph,
144			   void *user_data HB_UNUSED)
145{
146  const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
147
148  if (unlikely (glyph >= ot_font->num_glyphs))
149    return 0; /* Maybe better to return notdef's advance instead? */
150
151  if (glyph >= ot_font->num_hmetrics)
152    glyph = ot_font->num_hmetrics - 1;
153
154  return font->em_scale_x (ot_font->hmtx->longHorMetric[glyph].advanceWidth);
155}
156
157static hb_position_t
158hb_ot_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
159			   void *font_data,
160			   hb_codepoint_t glyph,
161			   void *user_data HB_UNUSED)
162{
163  /* TODO */
164  return 0;
165}
166
167static hb_bool_t
168hb_ot_get_glyph_h_origin (hb_font_t *font HB_UNUSED,
169			  void *font_data HB_UNUSED,
170			  hb_codepoint_t glyph HB_UNUSED,
171			  hb_position_t *x HB_UNUSED,
172			  hb_position_t *y HB_UNUSED,
173			  void *user_data HB_UNUSED)
174{
175  /* We always work in the horizontal coordinates. */
176  return true;
177}
178
179static hb_bool_t
180hb_ot_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
181			  void *font_data,
182			  hb_codepoint_t glyph,
183			  hb_position_t *x,
184			  hb_position_t *y,
185			  void *user_data HB_UNUSED)
186{
187  /* TODO */
188  return false;
189}
190
191static hb_position_t
192hb_ot_get_glyph_h_kerning (hb_font_t *font,
193			   void *font_data,
194			   hb_codepoint_t left_glyph,
195			   hb_codepoint_t right_glyph,
196			   void *user_data HB_UNUSED)
197{
198  /* TODO */
199  return 0;
200}
201
202static hb_position_t
203hb_ot_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,
204			   void *font_data HB_UNUSED,
205			   hb_codepoint_t top_glyph HB_UNUSED,
206			   hb_codepoint_t bottom_glyph HB_UNUSED,
207			   void *user_data HB_UNUSED)
208{
209  return 0;
210}
211
212static hb_bool_t
213hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
214			 void *font_data,
215			 hb_codepoint_t glyph,
216			 hb_glyph_extents_t *extents,
217			 void *user_data HB_UNUSED)
218{
219  /* TODO */
220  return false;
221}
222
223static hb_bool_t
224hb_ot_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
225			       void *font_data,
226			       hb_codepoint_t glyph,
227			       unsigned int point_index,
228			       hb_position_t *x,
229			       hb_position_t *y,
230			       void *user_data HB_UNUSED)
231{
232  /* TODO */
233  return false;
234}
235
236static hb_bool_t
237hb_ot_get_glyph_name (hb_font_t *font HB_UNUSED,
238		      void *font_data,
239		      hb_codepoint_t glyph,
240		      char *name, unsigned int size,
241		      void *user_data HB_UNUSED)
242{
243  /* TODO */
244  return false;
245}
246
247static hb_bool_t
248hb_ot_get_glyph_from_name (hb_font_t *font HB_UNUSED,
249			   void *font_data,
250			   const char *name, int len, /* -1 means nul-terminated */
251			   hb_codepoint_t *glyph,
252			   void *user_data HB_UNUSED)
253{
254  /* TODO */
255  return false;
256}
257
258
259static hb_font_funcs_t *
260_hb_ot_get_font_funcs (void)
261{
262  static const hb_font_funcs_t ot_ffuncs = {
263    HB_OBJECT_HEADER_STATIC,
264
265    true, /* immutable */
266
267    {
268#define HB_FONT_FUNC_IMPLEMENT(name) hb_ot_get_##name,
269      HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
270#undef HB_FONT_FUNC_IMPLEMENT
271    }
272  };
273
274  return const_cast<hb_font_funcs_t *> (&ot_ffuncs);
275}
276
277
278void
279hb_ot_font_set_funcs (hb_font_t *font)
280{
281  hb_ot_font_t *ot_font = _hb_ot_font_create (font);
282  if (unlikely (!ot_font))
283    return;
284
285  hb_font_set_funcs (font,
286		     _hb_ot_get_font_funcs (),
287		     ot_font,
288		     (hb_destroy_func_t) _hb_ot_font_destroy);
289}
290