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      1 /*
      2  * Copyright  2010,2011,2012  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 #ifndef HB_OT_SHAPE_COMPLEX_PRIVATE_HH
     28 #define HB_OT_SHAPE_COMPLEX_PRIVATE_HH
     29 
     30 #include "hb-private.hh"
     31 
     32 #include "hb-ot-shape-private.hh"
     33 #include "hb-ot-shape-normalize-private.hh"
     34 
     35 
     36 
     37 /* buffer var allocations, used by complex shapers */
     38 #define complex_var_u8_0()	var2.u8[2]
     39 #define complex_var_u8_1()	var2.u8[3]
     40 
     41 
     42 enum hb_ot_shape_zero_width_marks_type_t {
     43   HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
     44 //  HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_EARLY,
     45   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE,
     46   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
     47   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
     48 
     49   HB_OT_SHAPE_ZERO_WIDTH_MARKS_DEFAULT = HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE
     50 };
     51 
     52 
     53 /* Master OT shaper list */
     54 #define HB_COMPLEX_SHAPERS_IMPLEMENT_SHAPERS \
     55   HB_COMPLEX_SHAPER_IMPLEMENT (default) /* should be first */ \
     56   HB_COMPLEX_SHAPER_IMPLEMENT (arabic) \
     57   HB_COMPLEX_SHAPER_IMPLEMENT (hangul) \
     58   HB_COMPLEX_SHAPER_IMPLEMENT (hebrew) \
     59   HB_COMPLEX_SHAPER_IMPLEMENT (indic) \
     60   HB_COMPLEX_SHAPER_IMPLEMENT (myanmar) \
     61   HB_COMPLEX_SHAPER_IMPLEMENT (sea) \
     62   HB_COMPLEX_SHAPER_IMPLEMENT (thai) \
     63   HB_COMPLEX_SHAPER_IMPLEMENT (tibetan) \
     64   /* ^--- Add new shapers here */
     65 
     66 
     67 struct hb_ot_complex_shaper_t
     68 {
     69   char name[8];
     70 
     71   /* collect_features()
     72    * Called during shape_plan().
     73    * Shapers should use plan->map to add their features and callbacks.
     74    * May be NULL.
     75    */
     76   void (*collect_features) (hb_ot_shape_planner_t *plan);
     77 
     78   /* override_features()
     79    * Called during shape_plan().
     80    * Shapers should use plan->map to override features and add callbacks after
     81    * common features are added.
     82    * May be NULL.
     83    */
     84   void (*override_features) (hb_ot_shape_planner_t *plan);
     85 
     86 
     87   /* data_create()
     88    * Called at the end of shape_plan().
     89    * Whatever shapers return will be accessible through plan->data later.
     90    * If NULL is returned, means a plan failure.
     91    */
     92   void *(*data_create) (const hb_ot_shape_plan_t *plan);
     93 
     94   /* data_destroy()
     95    * Called when the shape_plan is being destroyed.
     96    * plan->data is passed here for destruction.
     97    * If NULL is returned, means a plan failure.
     98    * May be NULL.
     99    */
    100   void (*data_destroy) (void *data);
    101 
    102 
    103   /* preprocess_text()
    104    * Called during shape().
    105    * Shapers can use to modify text before shaping starts.
    106    * May be NULL.
    107    */
    108   void (*preprocess_text) (const hb_ot_shape_plan_t *plan,
    109 			   hb_buffer_t              *buffer,
    110 			   hb_font_t                *font);
    111 
    112 
    113   hb_ot_shape_normalization_mode_t normalization_preference;
    114 
    115   /* decompose()
    116    * Called during shape()'s normalization.
    117    * May be NULL.
    118    */
    119   bool (*decompose) (const hb_ot_shape_normalize_context_t *c,
    120 		     hb_codepoint_t  ab,
    121 		     hb_codepoint_t *a,
    122 		     hb_codepoint_t *b);
    123 
    124   /* compose()
    125    * Called during shape()'s normalization.
    126    * May be NULL.
    127    */
    128   bool (*compose) (const hb_ot_shape_normalize_context_t *c,
    129 		   hb_codepoint_t  a,
    130 		   hb_codepoint_t  b,
    131 		   hb_codepoint_t *ab);
    132 
    133   /* setup_masks()
    134    * Called during shape().
    135    * Shapers should use map to get feature masks and set on buffer.
    136    * Shapers may NOT modify characters.
    137    * May be NULL.
    138    */
    139   void (*setup_masks) (const hb_ot_shape_plan_t *plan,
    140 		       hb_buffer_t              *buffer,
    141 		       hb_font_t                *font);
    142 
    143   hb_ot_shape_zero_width_marks_type_t zero_width_marks;
    144 
    145   bool fallback_position;
    146 };
    147 
    148 #define HB_COMPLEX_SHAPER_IMPLEMENT(name) extern HB_INTERNAL const hb_ot_complex_shaper_t _hb_ot_complex_shaper_##name;
    149 HB_COMPLEX_SHAPERS_IMPLEMENT_SHAPERS
    150 #undef HB_COMPLEX_SHAPER_IMPLEMENT
    151 
    152 
    153 static inline const hb_ot_complex_shaper_t *
    154 hb_ot_shape_complex_categorize (const hb_ot_shape_planner_t *planner)
    155 {
    156   switch ((hb_tag_t) planner->props.script)
    157   {
    158     default:
    159       return &_hb_ot_complex_shaper_default;
    160 
    161 
    162     /* Unicode-1.1 additions */
    163     case HB_SCRIPT_ARABIC:
    164 
    165     /* Unicode-3.0 additions */
    166     case HB_SCRIPT_MONGOLIAN:
    167     case HB_SCRIPT_SYRIAC:
    168 
    169     /* Unicode-5.0 additions */
    170     case HB_SCRIPT_NKO:
    171     case HB_SCRIPT_PHAGS_PA:
    172 
    173     /* Unicode-6.0 additions */
    174     case HB_SCRIPT_MANDAIC:
    175 
    176     /* Unicode-7.0 additions */
    177     case HB_SCRIPT_MANICHAEAN:
    178     case HB_SCRIPT_PSALTER_PAHLAVI:
    179 
    180       /* For Arabic script, use the Arabic shaper even if no OT script tag was found.
    181        * This is because we do fallback shaping for Arabic script (and not others). */
    182       if (planner->map.chosen_script[0] != HB_OT_TAG_DEFAULT_SCRIPT ||
    183 	  planner->props.script == HB_SCRIPT_ARABIC)
    184 	return &_hb_ot_complex_shaper_arabic;
    185       else
    186 	return &_hb_ot_complex_shaper_default;
    187 
    188 
    189     /* Unicode-1.1 additions */
    190     case HB_SCRIPT_THAI:
    191     case HB_SCRIPT_LAO:
    192 
    193       return &_hb_ot_complex_shaper_thai;
    194 
    195 
    196     /* Unicode-1.1 additions */
    197     case HB_SCRIPT_HANGUL:
    198 
    199       return &_hb_ot_complex_shaper_hangul;
    200 
    201 
    202     /* Unicode-2.0 additions */
    203     case HB_SCRIPT_TIBETAN:
    204 
    205       return &_hb_ot_complex_shaper_tibetan;
    206 
    207 
    208     /* Unicode-1.1 additions */
    209     case HB_SCRIPT_HEBREW:
    210 
    211       return &_hb_ot_complex_shaper_hebrew;
    212 
    213 
    214     /* ^--- Add new shapers here */
    215 
    216 
    217 #if 0
    218     /* Note:
    219      *
    220      * These disabled scripts are listed in ucd/IndicSyllabicCategory.txt, but according
    221      * to Martin Hosken and Jonathan Kew do not require complex shaping.
    222      *
    223      * TODO We should automate figuring out which scripts do not need complex shaping
    224      *
    225      * TODO We currently keep data for these scripts in our indic table.  Need to fix the
    226      * generator to not do that.
    227      */
    228 
    229 
    230     /* Simple? */
    231 
    232     /* Unicode-3.2 additions */
    233     case HB_SCRIPT_BUHID:
    234     case HB_SCRIPT_HANUNOO:
    235 
    236     /* Unicode-5.1 additions */
    237     case HB_SCRIPT_SAURASHTRA:
    238 
    239     /* Unicode-6.0 additions */
    240     case HB_SCRIPT_BATAK:
    241     case HB_SCRIPT_BRAHMI:
    242 
    243 
    244     /* Simple */
    245 
    246     /* Unicode-1.1 additions */
    247     /* These have their own shaper now. */
    248     case HB_SCRIPT_LAO:
    249     case HB_SCRIPT_THAI:
    250 
    251     /* Unicode-3.2 additions */
    252     case HB_SCRIPT_TAGALOG:
    253     case HB_SCRIPT_TAGBANWA:
    254 
    255     /* Unicode-4.0 additions */
    256     case HB_SCRIPT_LIMBU:
    257     case HB_SCRIPT_TAI_LE:
    258 
    259     /* Unicode-4.1 additions */
    260     case HB_SCRIPT_KHAROSHTHI:
    261     case HB_SCRIPT_SYLOTI_NAGRI:
    262 
    263     /* Unicode-5.1 additions */
    264     case HB_SCRIPT_KAYAH_LI:
    265 
    266     /* Unicode-5.2 additions */
    267     case HB_SCRIPT_TAI_VIET:
    268 
    269 
    270 #endif
    271 
    272     /* Unicode-1.1 additions */
    273     case HB_SCRIPT_BENGALI:
    274     case HB_SCRIPT_DEVANAGARI:
    275     case HB_SCRIPT_GUJARATI:
    276     case HB_SCRIPT_GURMUKHI:
    277     case HB_SCRIPT_KANNADA:
    278     case HB_SCRIPT_MALAYALAM:
    279     case HB_SCRIPT_ORIYA:
    280     case HB_SCRIPT_TAMIL:
    281     case HB_SCRIPT_TELUGU:
    282 
    283     /* Unicode-3.0 additions */
    284     case HB_SCRIPT_SINHALA:
    285 
    286     /* Unicode-5.0 additions */
    287     case HB_SCRIPT_BALINESE:
    288 
    289     /* Unicode-5.1 additions */
    290     case HB_SCRIPT_LEPCHA:
    291     case HB_SCRIPT_REJANG:
    292     case HB_SCRIPT_SUNDANESE:
    293 
    294     /* Unicode-5.2 additions */
    295     case HB_SCRIPT_JAVANESE:
    296     case HB_SCRIPT_KAITHI:
    297     case HB_SCRIPT_MEETEI_MAYEK:
    298 
    299     /* Unicode-6.0 additions */
    300 
    301     /* Unicode-6.1 additions */
    302     case HB_SCRIPT_CHAKMA:
    303     case HB_SCRIPT_SHARADA:
    304     case HB_SCRIPT_TAKRI:
    305 
    306       /* If the designer designed the font for the 'DFLT' script,
    307        * use the default shaper.  Otherwise, use the Indic shaper.
    308        * Note that for some simple scripts, there may not be *any*
    309        * GSUB/GPOS needed, so there may be no scripts found! */
    310       if (planner->map.chosen_script[0] == HB_TAG ('D','F','L','T'))
    311 	return &_hb_ot_complex_shaper_default;
    312       else
    313 	return &_hb_ot_complex_shaper_indic;
    314 
    315     case HB_SCRIPT_KHMER:
    316       /* A number of Khmer fonts in the wild don't have a 'pref' feature,
    317        * and as such won't shape properly via the Indic shaper;
    318        * however, they typically have 'liga' / 'clig' features that implement
    319        * the necessary "reordering" by means of ligature substitutions.
    320        * So we send such pref-less fonts through the generic shaper instead. */
    321       if (planner->map.found_script[0] &&
    322 	  hb_ot_layout_language_find_feature (planner->face, HB_OT_TAG_GSUB,
    323 					      planner->map.script_index[0],
    324 					      planner->map.language_index[0],
    325 					      HB_TAG ('p','r','e','f'),
    326 					      NULL))
    327 	return &_hb_ot_complex_shaper_indic;
    328       else
    329 	return &_hb_ot_complex_shaper_default;
    330 
    331     case HB_SCRIPT_MYANMAR:
    332       /* For Myanmar, we only want to use the Myanmar shaper if the "new" script
    333        * tag is found.  For "old" script tag we want to use the default shaper. */
    334       if (planner->map.chosen_script[0] == HB_TAG ('m','y','m','2'))
    335 	return &_hb_ot_complex_shaper_myanmar;
    336       else
    337 	return &_hb_ot_complex_shaper_default;
    338 
    339     /* Unicode-4.1 additions */
    340     case HB_SCRIPT_BUGINESE:
    341     case HB_SCRIPT_NEW_TAI_LUE:
    342 
    343     /* Unicode-5.1 additions */
    344     case HB_SCRIPT_CHAM:
    345 
    346     /* Unicode-5.2 additions */
    347     case HB_SCRIPT_TAI_THAM:
    348 
    349       /* If the designer designed the font for the 'DFLT' script,
    350        * use the default shaper.  Otherwise, use the Indic shaper.
    351        * Note that for some simple scripts, there may not be *any*
    352        * GSUB/GPOS needed, so there may be no scripts found! */
    353       if (planner->map.chosen_script[0] == HB_TAG ('D','F','L','T'))
    354 	return &_hb_ot_complex_shaper_default;
    355       else
    356 	return &_hb_ot_complex_shaper_sea;
    357   }
    358 }
    359 
    360 
    361 #endif /* HB_OT_SHAPE_COMPLEX_PRIVATE_HH */
    362