1/*
2 * Copyright © 2011  Martin Hosken
3 * Copyright © 2011  SIL International
4 * Copyright © 2011,2012  Google, Inc.
5 *
6 *  This is part of HarfBuzz, a text shaping library.
7 *
8 * Permission is hereby granted, without written agreement and without
9 * license or royalty fees, to use, copy, modify, and distribute this
10 * software and its documentation for any purpose, provided that the
11 * above copyright notice and the following two paragraphs appear in
12 * all copies of this software.
13 *
14 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
15 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
16 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
17 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
18 * DAMAGE.
19 *
20 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
21 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
22 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
23 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
24 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
25 *
26 * Google Author(s): Behdad Esfahbod
27 */
28
29#define HB_SHAPER graphite2
30#define hb_graphite2_shaper_font_data_t gr_font
31#include "hb-shaper-impl-private.hh"
32
33#include <graphite2/Font.h>
34#include <graphite2/Segment.h>
35
36#include "hb-graphite2.h"
37
38#include "hb-ot-tag.h"
39
40
41HB_SHAPER_DATA_ENSURE_DECLARE(graphite2, face)
42HB_SHAPER_DATA_ENSURE_DECLARE(graphite2, font)
43
44
45/*
46 * shaper face data
47 */
48
49typedef struct hb_graphite2_tablelist_t {
50  struct hb_graphite2_tablelist_t *next;
51  hb_blob_t *blob;
52  unsigned int tag;
53} hb_graphite2_tablelist_t;
54
55struct hb_graphite2_shaper_face_data_t {
56  hb_face_t *face;
57  gr_face   *grface;
58  hb_graphite2_tablelist_t *tlist;
59};
60
61static const void *hb_graphite2_get_table (const void *data, unsigned int tag, size_t *len)
62{
63  hb_graphite2_shaper_face_data_t *face_data = (hb_graphite2_shaper_face_data_t *) data;
64  hb_graphite2_tablelist_t *tlist = face_data->tlist;
65
66  hb_blob_t *blob = NULL;
67
68  for (hb_graphite2_tablelist_t *p = tlist; p; p = p->next)
69    if (p->tag == tag) {
70      blob = p->blob;
71      break;
72    }
73
74  if (unlikely (!blob))
75  {
76    blob = face_data->face->reference_table (tag);
77
78    hb_graphite2_tablelist_t *p = (hb_graphite2_tablelist_t *) calloc (1, sizeof (hb_graphite2_tablelist_t));
79    if (unlikely (!p)) {
80      hb_blob_destroy (blob);
81      return NULL;
82    }
83    p->blob = blob;
84    p->tag = tag;
85
86    /* TODO Not thread-safe, but fairly harmless.
87     * We can do the double-chcked pointer cmpexch thing here. */
88    p->next = face_data->tlist;
89    face_data->tlist = p;
90  }
91
92  unsigned int tlen;
93  const char *d = hb_blob_get_data (blob, &tlen);
94  *len = tlen;
95  return d;
96}
97
98hb_graphite2_shaper_face_data_t *
99_hb_graphite2_shaper_face_data_create (hb_face_t *face)
100{
101  hb_blob_t *silf_blob = face->reference_table (HB_GRAPHITE2_TAG_SILF);
102  /* Umm, we just reference the table to check whether it exists.
103   * Maybe add better API for this? */
104  if (!hb_blob_get_length (silf_blob))
105  {
106    hb_blob_destroy (silf_blob);
107    return NULL;
108  }
109  hb_blob_destroy (silf_blob);
110
111  hb_graphite2_shaper_face_data_t *data = (hb_graphite2_shaper_face_data_t *) calloc (1, sizeof (hb_graphite2_shaper_face_data_t));
112  if (unlikely (!data))
113    hb_blob_destroy (silf_blob);
114
115  data->face = face;
116  data->grface = gr_make_face (data, &hb_graphite2_get_table, gr_face_preloadAll);
117
118  if (unlikely (!data->grface)) {
119    free (data);
120    return NULL;
121  }
122
123  return data;
124}
125
126void
127_hb_graphite2_shaper_face_data_destroy (hb_graphite2_shaper_face_data_t *data)
128{
129  hb_graphite2_tablelist_t *tlist = data->tlist;
130
131  while (tlist)
132  {
133    hb_graphite2_tablelist_t *old = tlist;
134    hb_blob_destroy (tlist->blob);
135    tlist = tlist->next;
136    free (old);
137  }
138
139  gr_face_destroy (data->grface);
140
141  free (data);
142}
143
144gr_face *
145hb_graphite2_face_get_gr_face (hb_face_t *face)
146{
147  if (unlikely (!hb_graphite2_shaper_face_data_ensure (face))) return NULL;
148  return HB_SHAPER_DATA_GET (face)->grface;
149}
150
151
152/*
153 * shaper font data
154 */
155
156static float hb_graphite2_get_advance (const void *hb_font, unsigned short gid)
157{
158  return ((hb_font_t *) hb_font)->get_glyph_h_advance (gid);
159}
160
161hb_graphite2_shaper_font_data_t *
162_hb_graphite2_shaper_font_data_create (hb_font_t *font)
163{
164  if (unlikely (!hb_graphite2_shaper_face_data_ensure (font->face))) return NULL;
165
166  hb_face_t *face = font->face;
167  hb_graphite2_shaper_face_data_t *face_data = HB_SHAPER_DATA_GET (face);
168
169  return gr_make_font_with_advance_fn (font->x_scale, font, &hb_graphite2_get_advance, face_data->grface);
170}
171
172void
173_hb_graphite2_shaper_font_data_destroy (hb_graphite2_shaper_font_data_t *data)
174{
175  gr_font_destroy (data);
176}
177
178gr_font *
179hb_graphite2_font_get_gr_font (hb_font_t *font)
180{
181  if (unlikely (!hb_graphite2_shaper_font_data_ensure (font))) return NULL;
182  return HB_SHAPER_DATA_GET (font);
183}
184
185
186/*
187 * shaper shape_plan data
188 */
189
190struct hb_graphite2_shaper_shape_plan_data_t {};
191
192hb_graphite2_shaper_shape_plan_data_t *
193_hb_graphite2_shaper_shape_plan_data_create (hb_shape_plan_t    *shape_plan HB_UNUSED,
194					     const hb_feature_t *user_features HB_UNUSED,
195					     unsigned int        num_user_features HB_UNUSED)
196{
197  return (hb_graphite2_shaper_shape_plan_data_t *) HB_SHAPER_DATA_SUCCEEDED;
198}
199
200void
201_hb_graphite2_shaper_shape_plan_data_destroy (hb_graphite2_shaper_shape_plan_data_t *data HB_UNUSED)
202{
203}
204
205
206/*
207 * shaper
208 */
209
210struct hb_graphite2_cluster_t {
211  unsigned int base_char;
212  unsigned int num_chars;
213  unsigned int base_glyph;
214  unsigned int num_glyphs;
215};
216
217hb_bool_t
218_hb_graphite2_shape (hb_shape_plan_t    *shape_plan,
219		     hb_font_t          *font,
220		     hb_buffer_t        *buffer,
221		     const hb_feature_t *features,
222		     unsigned int        num_features)
223{
224  hb_face_t *face = font->face;
225  gr_face *grface = HB_SHAPER_DATA_GET (face)->grface;
226  gr_font *grfont = HB_SHAPER_DATA_GET (font);
227
228  const char *lang = hb_language_to_string (hb_buffer_get_language (buffer));
229  const char *lang_end = strchr (lang, '-');
230  int lang_len = lang_end ? lang_end - lang : -1;
231  gr_feature_val *feats = gr_face_featureval_for_lang (grface, lang ? hb_tag_from_string (lang, lang_len) : 0);
232
233  while (num_features--)
234  {
235    const gr_feature_ref *fref = gr_face_find_fref (grface, features->tag);
236    if (fref)
237      gr_fref_set_feature_value (fref, features->value, feats);
238    features++;
239  }
240
241  gr_segment *seg = NULL;
242  const gr_slot *is;
243  unsigned int ci = 0, ic = 0;
244  float curradvx = 0., curradvy = 0.;
245
246  unsigned int scratch_size;
247  char *scratch = (char *) buffer->get_scratch_buffer (&scratch_size);
248
249#define ALLOCATE_ARRAY(Type, name, len) \
250  Type *name = (Type *) scratch; \
251  scratch += (len) * sizeof ((name)[0]); \
252  scratch_size -= (len) * sizeof ((name)[0]);
253
254  ALLOCATE_ARRAY (uint32_t, chars, buffer->len);
255
256  for (unsigned int i = 0; i < buffer->len; ++i)
257    chars[i] = buffer->info[i].codepoint;
258
259  hb_tag_t script_tag[2];
260  hb_ot_tags_from_script (hb_buffer_get_script (buffer), &script_tag[0], &script_tag[1]);
261
262  seg = gr_make_seg (grfont, grface,
263		     script_tag[1] == HB_TAG_NONE ? script_tag[0] : script_tag[1],
264		     feats,
265		     gr_utf32, chars, buffer->len,
266		     2 | (hb_buffer_get_direction (buffer) == HB_DIRECTION_RTL ? 1 : 0));
267
268  if (unlikely (!seg)) {
269    if (feats) gr_featureval_destroy (feats);
270    return false;
271  }
272
273  unsigned int glyph_count = gr_seg_n_slots (seg);
274  if (unlikely (!glyph_count)) {
275    if (feats) gr_featureval_destroy (feats);
276    gr_seg_destroy (seg);
277    return false;
278  }
279
280  scratch = (char *) buffer->get_scratch_buffer (&scratch_size);
281  while ((sizeof (hb_graphite2_cluster_t) * buffer->len +
282	  sizeof (hb_codepoint_t) * glyph_count) > scratch_size)
283  {
284    buffer->ensure (buffer->allocated * 2);
285    if (unlikely (buffer->in_error)) {
286      if (feats) gr_featureval_destroy (feats);
287      gr_seg_destroy (seg);
288      return false;
289    }
290    scratch = (char *) buffer->get_scratch_buffer (&scratch_size);
291  }
292
293  ALLOCATE_ARRAY (hb_graphite2_cluster_t, clusters, buffer->len);
294  ALLOCATE_ARRAY (hb_codepoint_t, gids, glyph_count);
295
296  memset (clusters, 0, sizeof (clusters[0]) * buffer->len);
297
298  hb_codepoint_t *pg = gids;
299  for (is = gr_seg_first_slot (seg), ic = 0; is; is = gr_slot_next_in_segment (is), ic++)
300  {
301    unsigned int before = gr_slot_before (is);
302    unsigned int after = gr_slot_after (is);
303    *pg = gr_slot_gid (is);
304    pg++;
305    while (clusters[ci].base_char > before && ci)
306    {
307      clusters[ci-1].num_chars += clusters[ci].num_chars;
308      clusters[ci-1].num_glyphs += clusters[ci].num_glyphs;
309      ci--;
310    }
311
312    if (gr_slot_can_insert_before (is) && clusters[ci].num_chars && before >= clusters[ci].base_char + clusters[ci].num_chars)
313    {
314      hb_graphite2_cluster_t *c = clusters + ci + 1;
315      c->base_char = clusters[ci].base_char + clusters[ci].num_chars;
316      c->num_chars = before - c->base_char;
317      c->base_glyph = ic;
318      c->num_glyphs = 0;
319      ci++;
320    }
321    clusters[ci].num_glyphs++;
322
323    if (clusters[ci].base_char + clusters[ci].num_chars < after + 1)
324	clusters[ci].num_chars = after + 1 - clusters[ci].base_char;
325  }
326  ci++;
327
328  //buffer->clear_output ();
329  for (unsigned int i = 0; i < ci; ++i)
330  {
331    for (unsigned int j = 0; j < clusters[i].num_glyphs; ++j)
332    {
333      hb_glyph_info_t *info = &buffer->info[clusters[i].base_glyph + j];
334      info->codepoint = gids[clusters[i].base_glyph + j];
335      info->cluster = gr_cinfo_base(gr_seg_cinfo(seg, clusters[i].base_char));
336    }
337  }
338  buffer->len = glyph_count;
339  //buffer->swap_buffers ();
340
341  if (HB_DIRECTION_IS_BACKWARD(buffer->props.direction))
342    curradvx = gr_seg_advance_X(seg);
343
344  hb_glyph_position_t *pPos;
345  for (pPos = hb_buffer_get_glyph_positions (buffer, NULL), is = gr_seg_first_slot (seg);
346       is; pPos++, is = gr_slot_next_in_segment (is))
347  {
348    pPos->x_offset = gr_slot_origin_X (is) - curradvx;
349    pPos->y_offset = gr_slot_origin_Y (is) - curradvy;
350    pPos->x_advance = gr_slot_advance_X (is, grface, grfont);
351    pPos->y_advance = gr_slot_advance_Y (is, grface, grfont);
352    if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
353      curradvx -= pPos->x_advance;
354    pPos->x_offset = gr_slot_origin_X (is) - curradvx;
355    if (!HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
356      curradvx += pPos->x_advance;
357    pPos->y_offset = gr_slot_origin_Y (is) - curradvy;
358    curradvy += pPos->y_advance;
359  }
360  if (!HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
361    pPos[-1].x_advance += gr_seg_advance_X(seg) - curradvx;
362
363  if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
364    hb_buffer_reverse_clusters (buffer);
365
366  if (feats) gr_featureval_destroy (feats);
367  gr_seg_destroy (seg);
368
369  return true;
370}
371