src/hb-ot-shape-complex-indic.cc

   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 #include "hb-ot-shape-complex-private.hh"
  28
  29 HB_BEGIN_DECLS
  30
  31
  32 /* buffer var allocations */
  33 #define indic_category() var2.u8[0] /* indic_category_t */
  34 #define indic_position() var2.u8[1] /* indic_matra_category_t */
  35
  36 #define INDIC_TABLE_ELEMENT_TYPE uint8_t
  37
  38 /* Cateories used in the OpenType spec:
  39  * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx
  40  */
  41 /* Note: This enum is duplicated in the -machine.rl source file.
  42  * Not sure how to avoid duplication. */
  43 enum indic_category_t {
  44   OT_X = 0,
  45   OT_C,
  46   OT_Ra, /* Not explicitly listed in the OT spec, but used in the grammar. */
  47   OT_V,
  48   OT_N,
  49   OT_H,
  50   OT_ZWNJ,
  51   OT_ZWJ,
  52   OT_M,
  53   OT_SM,
  54   OT_VD,
  55   OT_A,
  56   OT_NBSP
  57 };
  58
  59 /* Visual positions in a syllable from left to right. */
  60 enum indic_position_t {
  61   POS_PRE,
  62   POS_BASE,
  63   POS_ABOVE,
  64   POS_BELOW,
  65   POS_POST,
  66
  67   POS_INHERIT /* For Halant, Nukta, ZWJ, ZWNJ */
  68 };
  69
  70 /* Categories used in IndicSyllabicCategory.txt from UCD */
  71 /* The assignments are guesswork */
  72 enum indic_syllabic_category_t {
  73   INDIC_SYLLABIC_CATEGORY_OTHER                 = OT_X,
  74
  75   INDIC_SYLLABIC_CATEGORY_AVAGRAHA              = OT_X,
  76   INDIC_SYLLABIC_CATEGORY_BINDU                 = OT_SM,
  77   INDIC_SYLLABIC_CATEGORY_CONSONANT             = OT_C,
  78   INDIC_SYLLABIC_CATEGORY_CONSONANT_DEAD        = OT_C,
  79   INDIC_SYLLABIC_CATEGORY_CONSONANT_FINAL       = OT_C,
  80   INDIC_SYLLABIC_CATEGORY_CONSONANT_HEAD_LETTER = OT_C,
  81   INDIC_SYLLABIC_CATEGORY_CONSONANT_MEDIAL      = OT_C,
  82   INDIC_SYLLABIC_CATEGORY_CONSONANT_PLACEHOLDER = OT_NBSP,
  83   INDIC_SYLLABIC_CATEGORY_CONSONANT_SUBJOINED   = OT_C,
  84   INDIC_SYLLABIC_CATEGORY_CONSONANT_REPHA       = OT_C,
  85   INDIC_SYLLABIC_CATEGORY_MODIFYING_LETTER      = OT_X,
  86   INDIC_SYLLABIC_CATEGORY_NUKTA                 = OT_N,
  87   INDIC_SYLLABIC_CATEGORY_REGISTER_SHIFTER      = OT_X,
  88   INDIC_SYLLABIC_CATEGORY_TONE_LETTER           = OT_X,
  89   INDIC_SYLLABIC_CATEGORY_TONE_MARK             = OT_X,
  90   INDIC_SYLLABIC_CATEGORY_VIRAMA                = OT_H,
  91   INDIC_SYLLABIC_CATEGORY_VISARGA               = OT_SM,
  92   INDIC_SYLLABIC_CATEGORY_VOWEL                 = OT_V,
  93   INDIC_SYLLABIC_CATEGORY_VOWEL_DEPENDENT       = OT_M,
  94   INDIC_SYLLABIC_CATEGORY_VOWEL_INDEPENDENT     = OT_V
  95 };
  96
  97 /* Categories used in IndicSMatraCategory.txt from UCD */
  98 enum indic_matra_category_t {
  99   INDIC_MATRA_CATEGORY_NOT_APPLICABLE           = POS_BASE,
 100
 101   INDIC_MATRA_CATEGORY_LEFT                     = POS_PRE,
 102   INDIC_MATRA_CATEGORY_TOP                      = POS_ABOVE,
 103   INDIC_MATRA_CATEGORY_BOTTOM                   = POS_BELOW,
 104   INDIC_MATRA_CATEGORY_RIGHT                    = POS_POST,
 105
 106   /* We don't really care much about these since we decompose them
 107    * in the generic pre-shaping layer.  They will only be used if
 108    * the font does not cover the decomposition.  In which case, we
 109    * define these as aliases to the place we want the split-matra
 110    * glyph to show up.  Quite arbitrary. */
 111   INDIC_MATRA_CATEGORY_BOTTOM_AND_RIGHT         = INDIC_MATRA_CATEGORY_BOTTOM,
 112   INDIC_MATRA_CATEGORY_LEFT_AND_RIGHT           = INDIC_MATRA_CATEGORY_LEFT,
 113   INDIC_MATRA_CATEGORY_TOP_AND_BOTTOM           = INDIC_MATRA_CATEGORY_BOTTOM,
 114   INDIC_MATRA_CATEGORY_TOP_AND_BOTTOM_AND_RIGHT = INDIC_MATRA_CATEGORY_BOTTOM,
 115   INDIC_MATRA_CATEGORY_TOP_AND_LEFT             = INDIC_MATRA_CATEGORY_LEFT,
 116   INDIC_MATRA_CATEGORY_TOP_AND_LEFT_AND_RIGHT   = INDIC_MATRA_CATEGORY_LEFT,
 117   INDIC_MATRA_CATEGORY_TOP_AND_RIGHT            = INDIC_MATRA_CATEGORY_RIGHT,
 118
 119   INDIC_MATRA_CATEGORY_INVISIBLE                = INDIC_MATRA_CATEGORY_NOT_APPLICABLE,
 120   INDIC_MATRA_CATEGORY_OVERSTRUCK               = INDIC_MATRA_CATEGORY_NOT_APPLICABLE,
 121   INDIC_MATRA_CATEGORY_VISUAL_ORDER_LEFT        = INDIC_MATRA_CATEGORY_NOT_APPLICABLE
 122 };
 123
 124 /* Note: We use ASSERT_STATIC_EXPR_ZERO() instead of ASSERT_STATIC_EXPR() and the comma operation
 125  * because gcc fails to optimize the latter and fills the table in at runtime. */
 126 #define INDIC_COMBINE_CATEGORIES(S,M) \
 127   (ASSERT_STATIC_EXPR_ZERO (M == INDIC_MATRA_CATEGORY_NOT_APPLICABLE || (S == INDIC_SYLLABIC_CATEGORY_VIRAMA || S == INDIC_SYLLABIC_CATEGORY_VOWEL_DEPENDENT)) + \
 128    ASSERT_STATIC_EXPR_ZERO (S < 16 && M < 16) + \
 129    ((M << 4) | S))
 130
 131 #include "hb-ot-shape-complex-indic-table.hh"
 132
 133 /* XXX
 134  * This is a hack for now.  We should:
 135  * 1. Move this data into the main Indic table,
 136  * and/or
 137  * 2. Probe font lookups to determine consonant positions.
 138  */
 139 static const struct {
 140   hb_codepoint_t u;
 141   indic_position_t position;
 142 } consonant_positions[] = {
 143   {0x0930, POS_BELOW},
 144   {0x09AC, POS_BELOW},
 145   {0x09AF, POS_POST},
 146   {0x09B0, POS_BELOW},
 147   {0x09F0, POS_BELOW},
 148   {0x0A2F, POS_POST},
 149   {0x0A30, POS_BELOW},
 150   {0x0A35, POS_BELOW},
 151   {0x0A39, POS_BELOW},
 152   {0x0AB0, POS_BELOW},
 153   {0x0B24, POS_BELOW},
 154   {0x0B28, POS_BELOW},
 155   {0x0B2C, POS_BELOW},
 156   {0x0B2D, POS_BELOW},
 157   {0x0B2E, POS_BELOW},
 158   {0x0B2F, POS_POST},
 159   {0x0B30, POS_BELOW},
 160   {0x0B32, POS_BELOW},
 161   {0x0B33, POS_BELOW},
 162   {0x0B5F, POS_POST},
 163   {0x0B71, POS_BELOW},
 164   {0x0C15, POS_BELOW},
 165   {0x0C16, POS_BELOW},
 166   {0x0C17, POS_BELOW},
 167   {0x0C18, POS_BELOW},
 168   {0x0C19, POS_BELOW},
 169   {0x0C1A, POS_BELOW},
 170   {0x0C1B, POS_BELOW},
 171   {0x0C1C, POS_BELOW},
 172   {0x0C1D, POS_BELOW},
 173   {0x0C1E, POS_BELOW},
 174   {0x0C1F, POS_BELOW},
 175   {0x0C20, POS_BELOW},
 176   {0x0C21, POS_BELOW},
 177   {0x0C22, POS_BELOW},
 178   {0x0C23, POS_BELOW},
 179   {0x0C24, POS_BELOW},
 180   {0x0C25, POS_BELOW},
 181   {0x0C26, POS_BELOW},
 182   {0x0C27, POS_BELOW},
 183   {0x0C28, POS_BELOW},
 184   {0x0C2A, POS_BELOW},
 185   {0x0C2B, POS_BELOW},
 186   {0x0C2C, POS_BELOW},
 187   {0x0C2D, POS_BELOW},
 188   {0x0C2E, POS_BELOW},
 189   {0x0C2F, POS_BELOW},
 190   {0x0C30, POS_BELOW},
 191   {0x0C32, POS_BELOW},
 192   {0x0C33, POS_BELOW},
 193   {0x0C35, POS_BELOW},
 194   {0x0C36, POS_BELOW},
 195   {0x0C37, POS_BELOW},
 196   {0x0C38, POS_BELOW},
 197   {0x0C39, POS_BELOW},
 198   {0x0C95, POS_BELOW},
 199   {0x0C96, POS_BELOW},
 200   {0x0C97, POS_BELOW},
 201   {0x0C98, POS_BELOW},
 202   {0x0C99, POS_BELOW},
 203   {0x0C9A, POS_BELOW},
 204   {0x0C9B, POS_BELOW},
 205   {0x0C9C, POS_BELOW},
 206   {0x0C9D, POS_BELOW},
 207   {0x0C9E, POS_BELOW},
 208   {0x0C9F, POS_BELOW},
 209   {0x0CA0, POS_BELOW},
 210   {0x0CA1, POS_BELOW},
 211   {0x0CA2, POS_BELOW},
 212   {0x0CA3, POS_BELOW},
 213   {0x0CA4, POS_BELOW},
 214   {0x0CA5, POS_BELOW},
 215   {0x0CA6, POS_BELOW},
 216   {0x0CA7, POS_BELOW},
 217   {0x0CA8, POS_BELOW},
 218   {0x0CAA, POS_BELOW},
 219   {0x0CAB, POS_BELOW},
 220   {0x0CAC, POS_BELOW},
 221   {0x0CAD, POS_BELOW},
 222   {0x0CAE, POS_BELOW},
 223   {0x0CAF, POS_BELOW},
 224   {0x0CB0, POS_BELOW},
 225   {0x0CB2, POS_BELOW},
 226   {0x0CB3, POS_BELOW},
 227   {0x0CB5, POS_BELOW},
 228   {0x0CB6, POS_BELOW},
 229   {0x0CB7, POS_BELOW},
 230   {0x0CB8, POS_BELOW},
 231   {0x0CB9, POS_BELOW},
 232   {0x0CDE, POS_BELOW},
 233   {0x0D2F, POS_POST},
 234   {0x0D30, POS_POST},
 235   {0x0D32, POS_BELOW},
 236   {0x0D35, POS_POST},
 237 };
 238
 239
 240 static const struct {
 241   hb_tag_t tag;
 242   hb_bool_t is_global;
 243 } indic_basic_features[] =
 244 {
 245   {HB_TAG('n','u','k','t'), true},
 246   {HB_TAG('a','k','h','n'), false},
 247   {HB_TAG('r','p','h','f'), false},
 248   {HB_TAG('r','k','r','f'), false},
 249   {HB_TAG('p','r','e','f'), false},
 250   {HB_TAG('b','l','w','f'), false},
 251   {HB_TAG('h','a','l','f'), false},
 252   {HB_TAG('v','a','t','u'), true},
 253   {HB_TAG('p','s','t','f'), false},
 254   {HB_TAG('c','j','c','t'), true},
 255 };
 256
 257 /* Same order as the indic_basic_features array */
 258 enum {
 259   _NUKT,
 260   AKHN,
 261   RPHF,
 262   RKRF,
 263   PREF,
 264   BLWF,
 265   HALF,
 266   _VATU,
 267   PSTF,
 268   _CJCT,
 269 };
 270
 271 static const hb_tag_t indic_other_features[] =
 272 {
 273   HB_TAG('p','r','e','s'),
 274   HB_TAG('a','b','v','s'),
 275   HB_TAG('b','l','w','s'),
 276   HB_TAG('p','s','t','s'),
 277   HB_TAG('h','a','l','n'),
 278
 279   HB_TAG('d','i','s','t'),
 280   HB_TAG('a','b','v','m'),
 281   HB_TAG('b','l','w','m'),
 282 };
 283
 284 static void
 285 final_reordering (const hb_ot_map_t *map,
 286                   hb_face_t *face,
 287                   hb_buffer_t *buffer,
 288                   void *user_data HB_UNUSED)
 289 {
 290 }
 291
 292 void
 293 _hb_ot_shape_complex_collect_features_indic (hb_ot_map_builder_t *map, const hb_segment_properties_t  *props)
 294 {
 295   map->add_bool_feature (HB_TAG('l','o','c','l'));
 296   /* The Indic specs do not require ccmp, but we apply it here since if
 297    * there is a use of it, it's typically at the beginning. */
 298   map->add_bool_feature (HB_TAG('c','c','m','p'));
 299
 300   map->add_gsub_pause (NULL, NULL);
 301
 302   for (unsigned int i = 0; i < ARRAY_LENGTH (indic_basic_features); i++)
 303     map->add_bool_feature (indic_basic_features[i].tag, indic_basic_features[i].is_global);
 304
 305   map->add_gsub_pause (final_reordering, NULL);
 306
 307   for (unsigned int i = 0; i < ARRAY_LENGTH (indic_other_features); i++)
 308     map->add_bool_feature (indic_other_features[i], true);
 309 }
 310
 311
 312 static void
 313 found_syllable (hb_ot_map_t *map, hb_buffer_t *buffer,
 314                 unsigned int start, unsigned int end)
 315 {
 316   //fprintf (stderr, "%d %d\n", start, end);
 317 }
 318
 319 #include "hb-ot-shape-complex-indic-machine.hh"
 320
 321
 322 void
 323 _hb_ot_shape_complex_setup_masks_indic (hb_ot_map_t *map, hb_buffer_t *buffer)
 324 {
 325   unsigned int count = buffer->len;
 326
 327   for (unsigned int i = 0; i < count; i++)
 328   {
 329     unsigned int type = get_indic_categories (buffer->info[i].codepoint);
 330
 331     buffer->info[i].indic_category() = type & 0x0F;
 332     buffer->info[i].indic_position() = type >> 4;
 333   }
 334
 335   find_syllables (map, buffer);
 336
 337   hb_mask_t mask_array[ARRAY_LENGTH (indic_basic_features)] = {0};
 338   unsigned int num_masks = ARRAY_LENGTH (indic_basic_features);
 339   for (unsigned int i = 0; i < num_masks; i++)
 340     mask_array[i] = map->get_1_mask (indic_basic_features[i].tag);
 341 }
 342
 343
 344 HB_END_DECLS