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      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 
     41 HB_SHAPER_DATA_ENSURE_DECLARE(graphite2, face)
     42 HB_SHAPER_DATA_ENSURE_DECLARE(graphite2, font)
     43 
     44 
     45 /*
     46  * shaper face data
     47  */
     48 
     49 typedef 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 
     55 struct hb_graphite2_shaper_face_data_t {
     56   hb_face_t *face;
     57   gr_face   *grface;
     58   hb_graphite2_tablelist_t *tlist;
     59 };
     60 
     61 static 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 
     98 hb_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 
    126 void
    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 
    144 gr_face *
    145 hb_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 
    156 static 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 
    161 hb_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 
    172 void
    173 _hb_graphite2_shaper_font_data_destroy (hb_graphite2_shaper_font_data_t *data)
    174 {
    175   gr_font_destroy (data);
    176 }
    177 
    178 gr_font *
    179 hb_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 
    190 struct hb_graphite2_shaper_shape_plan_data_t {};
    191 
    192 hb_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 
    200 void
    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 
    210 struct 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 
    217 hb_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