src/hb-ot-layout.h

   1 /*
   2  * Copyright © 2007,2008,2009  Red Hat, 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  * Red Hat Author(s): Behdad Esfahbod
  25  */
  26
  27 #ifndef HB_OT_H_IN
  28 #error "Include <hb-ot.h> instead."
  29 #endif
  30
  31 #ifndef HB_OT_LAYOUT_H
  32 #define HB_OT_LAYOUT_H
  33
  34 #include "hb.h"
  35
  36 #include "hb-ot-name.h"
  37
  38 HB_BEGIN_DECLS
  39
  40
  41 #define HB_OT_TAG_BASE HB_TAG('B','A','S','E')
  42 #define HB_OT_TAG_GDEF HB_TAG('G','D','E','F')
  43 #define HB_OT_TAG_GSUB HB_TAG('G','S','U','B')
  44 #define HB_OT_TAG_GPOS HB_TAG('G','P','O','S')
  45 #define HB_OT_TAG_JSTF HB_TAG('J','S','T','F')
  46
  47
  48 /*
  49  * Script & Language tags.
  50  */
  51
  52 #define HB_OT_TAG_DEFAULT_SCRIPT        HB_TAG ('D', 'F', 'L', 'T')
  53 #define HB_OT_TAG_DEFAULT_LANGUAGE      HB_TAG ('d', 'f', 'l', 't')
  54
  55 /**
  56  * HB_OT_MAX_TAGS_PER_SCRIPT:
  57  *
  58  * Since: 2.0.0
  59  **/
  60 #define HB_OT_MAX_TAGS_PER_SCRIPT       3u
  61 /**
  62  * HB_OT_MAX_TAGS_PER_LANGUAGE:
  63  *
  64  * Since: 2.0.0
  65  **/
  66 #define HB_OT_MAX_TAGS_PER_LANGUAGE     3u
  67
  68 HB_EXTERN void
  69 hb_ot_tags_from_script_and_language (hb_script_t   script,
  70                                      hb_language_t language,
  71                                      unsigned int *script_count /* IN/OUT */,
  72                                      hb_tag_t     *script_tags /* OUT */,
  73                                      unsigned int *language_count /* IN/OUT */,
  74                                      hb_tag_t     *language_tags /* OUT */);
  75
  76 HB_EXTERN hb_script_t
  77 hb_ot_tag_to_script (hb_tag_t tag);
  78
  79 HB_EXTERN hb_language_t
  80 hb_ot_tag_to_language (hb_tag_t tag);
  81
  82 HB_EXTERN void
  83 hb_ot_tags_to_script_and_language (hb_tag_t       script_tag,
  84                                    hb_tag_t       language_tag,
  85                                    hb_script_t   *script /* OUT */,
  86                                    hb_language_t *language /* OUT */);
  87
  88
  89 /*
  90  * GDEF
  91  */
  92
  93 HB_EXTERN hb_bool_t
  94 hb_ot_layout_has_glyph_classes (hb_face_t *face);
  95
  96 /**
  97  * hb_ot_layout_glyph_class_t:
  98  * @HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED: Glyphs not matching the other classifications
  99  * @HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH: Spacing, single characters, capable of accepting marks
 100  * @HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE: Glyphs that represent ligation of multiple characters
 101  * @HB_OT_LAYOUT_GLYPH_CLASS_MARK: Non-spacing, combining glyphs that represent marks
 102  * @HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT: Spacing glyphs that represent part of a single character
 103  *
 104  * The GDEF classes defined for glyphs.
 105  *
 106  **/
 107 typedef enum {
 108   HB_OT_LAYOUT_GLYPH_CLASS_UNCLASSIFIED = 0,
 109   HB_OT_LAYOUT_GLYPH_CLASS_BASE_GLYPH   = 1,
 110   HB_OT_LAYOUT_GLYPH_CLASS_LIGATURE     = 2,
 111   HB_OT_LAYOUT_GLYPH_CLASS_MARK         = 3,
 112   HB_OT_LAYOUT_GLYPH_CLASS_COMPONENT    = 4
 113 } hb_ot_layout_glyph_class_t;
 114
 115 HB_EXTERN hb_ot_layout_glyph_class_t
 116 hb_ot_layout_get_glyph_class (hb_face_t      *face,
 117                               hb_codepoint_t  glyph);
 118
 119 HB_EXTERN void
 120 hb_ot_layout_get_glyphs_in_class (hb_face_t                  *face,
 121                                   hb_ot_layout_glyph_class_t  klass,
 122                                   hb_set_t                   *glyphs /* OUT */);
 123
 124
 125 /* Not that useful.  Provides list of attach points for a glyph that a
 126  * client may want to cache */
 127 HB_EXTERN unsigned int
 128 hb_ot_layout_get_attach_points (hb_face_t      *face,
 129                                 hb_codepoint_t  glyph,
 130                                 unsigned int    start_offset,
 131                                 unsigned int   *point_count /* IN/OUT */,
 132                                 unsigned int   *point_array /* OUT */);
 133
 134 /* Ligature caret positions */
 135 HB_EXTERN unsigned int
 136 hb_ot_layout_get_ligature_carets (hb_font_t      *font,
 137                                   hb_direction_t  direction,
 138                                   hb_codepoint_t  glyph,
 139                                   unsigned int    start_offset,
 140                                   unsigned int   *caret_count /* IN/OUT */,
 141                                   hb_position_t  *caret_array /* OUT */);
 142
 143
 144 /*
 145  * GSUB/GPOS feature query and enumeration interface
 146  */
 147
 148 #define HB_OT_LAYOUT_NO_SCRIPT_INDEX            0xFFFFu
 149 #define HB_OT_LAYOUT_NO_FEATURE_INDEX           0xFFFFu
 150 #define HB_OT_LAYOUT_DEFAULT_LANGUAGE_INDEX     0xFFFFu
 151 #define HB_OT_LAYOUT_NO_VARIATIONS_INDEX        0xFFFFFFFFu
 152
 153 HB_EXTERN unsigned int
 154 hb_ot_layout_table_get_script_tags (hb_face_t    *face,
 155                                     hb_tag_t      table_tag,
 156                                     unsigned int  start_offset,
 157                                     unsigned int *script_count /* IN/OUT */,
 158                                     hb_tag_t     *script_tags /* OUT */);
 159
 160 HB_EXTERN hb_bool_t
 161 hb_ot_layout_table_find_script (hb_face_t    *face,
 162                                 hb_tag_t      table_tag,
 163                                 hb_tag_t      script_tag,
 164                                 unsigned int *script_index);
 165
 166 HB_EXTERN hb_bool_t
 167 hb_ot_layout_table_select_script (hb_face_t      *face,
 168                                   hb_tag_t        table_tag,
 169                                   unsigned int    script_count,
 170                                   const hb_tag_t *script_tags,
 171                                   unsigned int   *script_index /* OUT */,
 172                                   hb_tag_t       *chosen_script /* OUT */);
 173
 174 HB_EXTERN unsigned int
 175 hb_ot_layout_table_get_feature_tags (hb_face_t    *face,
 176                                      hb_tag_t      table_tag,
 177                                      unsigned int  start_offset,
 178                                      unsigned int *feature_count /* IN/OUT */,
 179                                      hb_tag_t     *feature_tags /* OUT */);
 180
 181 HB_EXTERN unsigned int
 182 hb_ot_layout_script_get_language_tags (hb_face_t    *face,
 183                                        hb_tag_t      table_tag,
 184                                        unsigned int  script_index,
 185                                        unsigned int  start_offset,
 186                                        unsigned int *language_count /* IN/OUT */,
 187                                        hb_tag_t     *language_tags /* OUT */);
 188
 189 HB_EXTERN hb_bool_t
 190 hb_ot_layout_script_select_language (hb_face_t      *face,
 191                                      hb_tag_t        table_tag,
 192                                      unsigned int    script_index,
 193                                      unsigned int    language_count,
 194                                      const hb_tag_t *language_tags,
 195                                      unsigned int   *language_index /* OUT */);
 196
 197 HB_EXTERN hb_bool_t
 198 hb_ot_layout_language_get_required_feature_index (hb_face_t    *face,
 199                                                   hb_tag_t      table_tag,
 200                                                   unsigned int  script_index,
 201                                                   unsigned int  language_index,
 202                                                   unsigned int *feature_index);
 203
 204 HB_EXTERN hb_bool_t
 205 hb_ot_layout_language_get_required_feature (hb_face_t    *face,
 206                                             hb_tag_t      table_tag,
 207                                             unsigned int  script_index,
 208                                             unsigned int  language_index,
 209                                             unsigned int *feature_index,
 210                                             hb_tag_t     *feature_tag);
 211
 212 HB_EXTERN unsigned int
 213 hb_ot_layout_language_get_feature_indexes (hb_face_t    *face,
 214                                            hb_tag_t      table_tag,
 215                                            unsigned int  script_index,
 216                                            unsigned int  language_index,
 217                                            unsigned int  start_offset,
 218                                            unsigned int *feature_count /* IN/OUT */,
 219                                            unsigned int *feature_indexes /* OUT */);
 220
 221 HB_EXTERN unsigned int
 222 hb_ot_layout_language_get_feature_tags (hb_face_t    *face,
 223                                         hb_tag_t      table_tag,
 224                                         unsigned int  script_index,
 225                                         unsigned int  language_index,
 226                                         unsigned int  start_offset,
 227                                         unsigned int *feature_count /* IN/OUT */,
 228                                         hb_tag_t     *feature_tags /* OUT */);
 229
 230 HB_EXTERN hb_bool_t
 231 hb_ot_layout_language_find_feature (hb_face_t    *face,
 232                                     hb_tag_t      table_tag,
 233                                     unsigned int  script_index,
 234                                     unsigned int  language_index,
 235                                     hb_tag_t      feature_tag,
 236                                     unsigned int *feature_index);
 237
 238 HB_EXTERN unsigned int
 239 hb_ot_layout_feature_get_lookups (hb_face_t    *face,
 240                                   hb_tag_t      table_tag,
 241                                   unsigned int  feature_index,
 242                                   unsigned int  start_offset,
 243                                   unsigned int *lookup_count /* IN/OUT */,
 244                                   unsigned int *lookup_indexes /* OUT */);
 245
 246 HB_EXTERN unsigned int
 247 hb_ot_layout_table_get_lookup_count (hb_face_t    *face,
 248                                      hb_tag_t      table_tag);
 249
 250 HB_EXTERN void
 251 hb_ot_layout_collect_features (hb_face_t      *face,
 252                                hb_tag_t        table_tag,
 253                                const hb_tag_t *scripts,
 254                                const hb_tag_t *languages,
 255                                const hb_tag_t *features,
 256                                hb_set_t       *feature_indexes /* OUT */);
 257
 258 HB_EXTERN void
 259 hb_ot_layout_collect_lookups (hb_face_t      *face,
 260                               hb_tag_t        table_tag,
 261                               const hb_tag_t *scripts,
 262                               const hb_tag_t *languages,
 263                               const hb_tag_t *features,
 264                               hb_set_t       *lookup_indexes /* OUT */);
 265
 266 HB_EXTERN void
 267 hb_ot_layout_lookup_collect_glyphs (hb_face_t    *face,
 268                                     hb_tag_t      table_tag,
 269                                     unsigned int  lookup_index,
 270                                     hb_set_t     *glyphs_before, /* OUT.  May be NULL */
 271                                     hb_set_t     *glyphs_input,  /* OUT.  May be NULL */
 272                                     hb_set_t     *glyphs_after,  /* OUT.  May be NULL */
 273                                     hb_set_t     *glyphs_output  /* OUT.  May be NULL */);
 274
 275 #ifdef HB_NOT_IMPLEMENTED
 276 typedef struct
 277 {
 278   const hb_codepoint_t *before,
 279   unsigned int          before_length,
 280   const hb_codepoint_t *input,
 281   unsigned int          input_length,
 282   const hb_codepoint_t *after,
 283   unsigned int          after_length,
 284 } hb_ot_layout_glyph_sequence_t;
 285
 286 typedef hb_bool_t
 287 (*hb_ot_layout_glyph_sequence_func_t) (hb_font_t    *font,
 288                                        hb_tag_t      table_tag,
 289                                        unsigned int  lookup_index,
 290                                        const hb_ot_layout_glyph_sequence_t *sequence,
 291                                        void         *user_data);
 292
 293 HB_EXTERN void
 294 Xhb_ot_layout_lookup_enumerate_sequences (hb_face_t    *face,
 295                                          hb_tag_t      table_tag,
 296                                          unsigned int  lookup_index,
 297                                          hb_ot_layout_glyph_sequence_func_t callback,
 298                                          void         *user_data);
 299 #endif
 300
 301 /* Variations support */
 302
 303 HB_EXTERN hb_bool_t
 304 hb_ot_layout_table_find_feature_variations (hb_face_t    *face,
 305                                             hb_tag_t      table_tag,
 306                                             const int    *coords,
 307                                             unsigned int  num_coords,
 308                                             unsigned int *variations_index /* out */);
 309
 310 HB_EXTERN unsigned int
 311 hb_ot_layout_feature_with_variations_get_lookups (hb_face_t    *face,
 312                                                   hb_tag_t      table_tag,
 313                                                   unsigned int  feature_index,
 314                                                   unsigned int  variations_index,
 315                                                   unsigned int  start_offset,
 316                                                   unsigned int *lookup_count /* IN/OUT */,
 317                                                   unsigned int *lookup_indexes /* OUT */);
 318
 319
 320 /*
 321  * GSUB
 322  */
 323
 324 HB_EXTERN hb_bool_t
 325 hb_ot_layout_has_substitution (hb_face_t *face);
 326
 327 HB_EXTERN hb_bool_t
 328 hb_ot_layout_lookup_would_substitute (hb_face_t            *face,
 329                                       unsigned int          lookup_index,
 330                                       const hb_codepoint_t *glyphs,
 331                                       unsigned int          glyphs_length,
 332                                       hb_bool_t             zero_context);
 333
 334 HB_EXTERN void
 335 hb_ot_layout_lookup_substitute_closure (hb_face_t    *face,
 336                                         unsigned int  lookup_index,
 337                                         hb_set_t     *glyphs
 338                                         /*TODO , hb_bool_t  inclusive */);
 339
 340 HB_EXTERN void
 341 hb_ot_layout_lookups_substitute_closure (hb_face_t      *face,
 342                                          const hb_set_t *lookups,
 343                                          hb_set_t       *glyphs);
 344
 345
 346 #ifdef HB_NOT_IMPLEMENTED
 347 /* Note: You better have GDEF when using this API, or marks won't do much. */
 348 HB_EXTERN hb_bool_t
 349 Xhb_ot_layout_lookup_substitute (hb_font_t            *font,
 350                                 unsigned int          lookup_index,
 351                                 const hb_ot_layout_glyph_sequence_t *sequence,
 352                                 unsigned int          out_size,
 353                                 hb_codepoint_t       *glyphs_out,   /* OUT */
 354                                 unsigned int         *clusters_out, /* OUT */
 355                                 unsigned int         *out_length    /* OUT */);
 356 #endif
 357
 358
 359 /*
 360  * GPOS
 361  */
 362
 363 HB_EXTERN hb_bool_t
 364 hb_ot_layout_has_positioning (hb_face_t *face);
 365
 366 #ifdef HB_NOT_IMPLEMENTED
 367 /* Note: You better have GDEF when using this API, or marks won't do much. */
 368 HB_EXTERN hb_bool_t
 369 Xhb_ot_layout_lookup_position (hb_font_t            *font,
 370                               unsigned int          lookup_index,
 371                               const hb_ot_layout_glyph_sequence_t *sequence,
 372                               hb_glyph_position_t  *positions /* IN / OUT */);
 373 #endif
 374
 375 /* Optical 'size' feature info.  Returns true if found.
 376  * https://docs.microsoft.com/en-us/typography/opentype/spec/features_pt#size */
 377 HB_EXTERN hb_bool_t
 378 hb_ot_layout_get_size_params (hb_face_t       *face,
 379                               unsigned int    *design_size,       /* OUT.  May be NULL */
 380                               unsigned int    *subfamily_id,      /* OUT.  May be NULL */
 381                               hb_ot_name_id_t *subfamily_name_id, /* OUT.  May be NULL */
 382                               unsigned int    *range_start,       /* OUT.  May be NULL */
 383                               unsigned int    *range_end          /* OUT.  May be NULL */);
 384
 385
 386 HB_EXTERN hb_bool_t
 387 hb_ot_layout_feature_get_name_ids (hb_face_t       *face,
 388                                    hb_tag_t         table_tag,
 389                                    unsigned int     feature_index,
 390                                    hb_ot_name_id_t *label_id             /* OUT.  May be NULL */,
 391                                    hb_ot_name_id_t *tooltip_id           /* OUT.  May be NULL */,
 392                                    hb_ot_name_id_t *sample_id            /* OUT.  May be NULL */,
 393                                    unsigned int    *num_named_parameters /* OUT.  May be NULL */,
 394                                    hb_ot_name_id_t *first_param_id       /* OUT.  May be NULL */);
 395
 396
 397 HB_EXTERN unsigned int
 398 hb_ot_layout_feature_get_characters (hb_face_t      *face,
 399                                      hb_tag_t        table_tag,
 400                                      unsigned int    feature_index,
 401                                      unsigned int    start_offset,
 402                                      unsigned int   *char_count    /* IN/OUT.  May be NULL */,
 403                                      hb_codepoint_t *characters    /* OUT.     May be NULL */);
 404
 405 /*
 406  * BASE
 407  */
 408
 409 /**
 410  * hb_ot_layout_baseline_tag_t:
 411  * @HB_OT_LAYOUT_BASELINE_TAG_ROMAN: The baseline used by alphabetic scripts such as Latin, Cyrillic and Greek.
 412  * In vertical writing mode, the alphabetic baseline for characters rotated 90 degrees clockwise.
 413  * (This would not apply to alphabetic characters that remain upright in vertical writing mode, since these
 414  * characters are not rotated.)
 415  * @HB_OT_LAYOUT_BASELINE_TAG_HANGING: The hanging baseline. In horizontal direction, this is the horizontal
 416  * line from which syllables seem, to hang in Tibetan and other similar scripts. In vertical writing mode,
 417  * for Tibetan (or some other similar script) characters rotated 90 degrees clockwise.
 418  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT: Ideographic character face bottom or left edge,
 419  * if the direction is horizontal or vertical, respectively.
 420  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT: Ideographic character face top or right edge,
 421  * if the direction is horizontal or vertical, respectively.
 422  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT: Ideographic em-box bottom or left edge,
 423  * if the direction is horizontal or vertical, respectively.
 424  * @HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT: Ideographic em-box top or right edge baseline,
 425  * if the direction is horizontal or vertical, respectively.
 426  * @HB_OT_LAYOUT_BASELINE_TAG_MATH: The baseline about which mathematical characters are centered.
 427  * In vertical writing mode when mathematical characters rotated 90 degrees clockwise, are centered.
 428  *
 429  * Baseline tags from https://docs.microsoft.com/en-us/typography/opentype/spec/baselinetags
 430  *
 431  * Since: 2.6.0
 432  */
 433 typedef enum {
 434   HB_OT_LAYOUT_BASELINE_TAG_ROMAN                       = HB_TAG ('r','o','m','n'),
 435   HB_OT_LAYOUT_BASELINE_TAG_HANGING                     = HB_TAG ('h','a','n','g'),
 436   HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_BOTTOM_OR_LEFT    = HB_TAG ('i','c','f','b'),
 437   HB_OT_LAYOUT_BASELINE_TAG_IDEO_FACE_TOP_OR_RIGHT      = HB_TAG ('i','c','f','t'),
 438   HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT   = HB_TAG ('i','d','e','o'),
 439   HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_TOP_OR_RIGHT     = HB_TAG ('i','d','t','p'),
 440   HB_OT_LAYOUT_BASELINE_TAG_MATH                        = HB_TAG ('m','a','t','h'),
 441
 442   _HB_OT_LAYOUT_BASELINE_TAG_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
 443 } hb_ot_layout_baseline_tag_t;
 444
 445 HB_EXTERN hb_bool_t
 446 hb_ot_layout_get_baseline (hb_font_t                   *font,
 447                            hb_ot_layout_baseline_tag_t  baseline_tag,
 448                            hb_direction_t               direction,
 449                            hb_tag_t                     script_tag,
 450                            hb_tag_t                     language_tag,
 451                            hb_position_t               *coord        /* OUT.  May be NULL. */);
 452
 453
 454 HB_END_DECLS
 455
 456 #endif /* HB_OT_LAYOUT_H */