freetype1/lib/extend/ftxgpos.h

   1 /*******************************************************************
   2  *
   3  *  ftxgpos.h
   4  *
   5  *    TrueType Open GPOS table support
   6  *
   7  *  Copyright 1996-1999 by
   8  *  David Turner, Robert Wilhelm, and Werner Lemberg.
   9  *
  10  *  This file is part of the FreeType project, and may only be used
  11  *  modified and distributed under the terms of the FreeType project
  12  *  license, LICENSE.TXT.  By continuing to use, modify, or distribute
  13  *  this file you indicate that you have read the license and
  14  *  understand and accept it fully.
  15  *
  16  ******************************************************************/
  17
  18 #ifndef FTXOPEN_H
  19 #error "Don't include this file! Use ftxopen.h instead."
  20 #endif
  21
  22 #ifndef FTXGPOS_H
  23 #define FTXGPOS_H
  24
  25 #ifdef __cplusplus
  26 extern "C" {
  27 #endif
  28
  29 #define TTO_Err_Invalid_GPOS_SubTable_Format  0x1020
  30 #define TTO_Err_Invalid_GPOS_SubTable         0x1021
  31
  32
  33 /* Lookup types for glyph positioning */
  34
  35 #define GPOS_LOOKUP_SINGLE    1
  36 #define GPOS_LOOKUP_PAIR      2
  37 #define GPOS_LOOKUP_CURSIVE   3
  38 #define GPOS_LOOKUP_MARKBASE  4
  39 #define GPOS_LOOKUP_MARKLIG   5
  40 #define GPOS_LOOKUP_MARKMARK  6
  41 #define GPOS_LOOKUP_CONTEXT   7
  42 #define GPOS_LOOKUP_CHAIN     8
  43
  44
  45   struct  TTO_GPOSHeader_
  46   {
  47     TT_Bool          loaded;
  48     TT_ULong         offset;
  49
  50     TT_Fixed         Version;
  51
  52     TTO_ScriptList   ScriptList;
  53     TTO_FeatureList  FeatureList;
  54     TTO_LookupList   LookupList;
  55
  56     TTO_GDEFHeader*  gdef;
  57   };
  58
  59   typedef struct TTO_GPOSHeader_  TTO_GPOSHeader;
  60
  61
  62   /* shared tables */
  63
  64   struct  TTO_ValueRecord_
  65   {
  66     TT_Short    XPlacement;             /* horizontal adjustment for
  67                                            placement                      */
  68     TT_Short    YPlacement;             /* vertical adjustment for
  69                                            placement                      */
  70     TT_Short    XAdvance;               /* horizontal adjustment for
  71                                            advance                        */
  72     TT_Short    YAdvance;               /* vertical adjustment for
  73                                            advance                        */
  74     TTO_Device  XPlacementDevice;       /* device table for horizontal
  75                                            placement                      */
  76     TTO_Device  YPlacementDevice;       /* device table for vertical
  77                                            placement                      */
  78     TTO_Device  XAdvanceDevice;         /* device table for horizontal
  79                                            advance                        */
  80     TTO_Device  YAdvanceDevice;         /* device table for vertical
  81                                            advance                        */
  82     TT_UShort   XIdPlacement;           /* horizontal placement metric ID */
  83     TT_UShort   YIdPlacement;           /* vertical placement metric ID   */
  84     TT_UShort   XIdAdvance;             /* horizontal advance metric ID   */
  85     TT_UShort   YIdAdvance;             /* vertical advance metric ID     */
  86   };
  87
  88   typedef struct TTO_ValueRecord_  TTO_ValueRecord;
  89
  90
  91 /* Mask values to scan the value format of the ValueRecord structure.
  92    We always expand compressed ValueRecords of the font.              */
  93
  94 #define HAVE_X_PLACEMENT         0x0001
  95 #define HAVE_Y_PLACEMENT         0x0002
  96 #define HAVE_X_ADVANCE           0x0004
  97 #define HAVE_Y_ADVANCE           0x0008
  98 #define HAVE_X_PLACEMENT_DEVICE  0x0010
  99 #define HAVE_Y_PLACEMENT_DEVICE  0x0020
 100 #define HAVE_X_ADVANCE_DEVICE    0x0040
 101 #define HAVE_Y_ADVANCE_DEVICE    0x0080
 102 #define HAVE_X_ID_PLACEMENT      0x0100
 103 #define HAVE_Y_ID_PLACEMENT      0x0200
 104 #define HAVE_X_ID_ADVANCE        0x0400
 105 #define HAVE_Y_ID_ADVANCE        0x0800
 106
 107
 108   struct  TTO_AnchorFormat1_
 109   {
 110     TT_Short   XCoordinate;             /* horizontal value */
 111     TT_Short   YCoordinate;             /* vertical value   */
 112   };
 113
 114   typedef struct TTO_AnchorFormat1_  TTO_AnchorFormat1;
 115
 116
 117   struct  TTO_AnchorFormat2_
 118   {
 119     TT_Short   XCoordinate;             /* horizontal value             */
 120     TT_Short   YCoordinate;             /* vertical value               */
 121     TT_UShort  AnchorPoint;             /* index to glyph contour point */
 122   };
 123
 124   typedef struct TTO_AnchorFormat2_  TTO_AnchorFormat2;
 125
 126
 127   struct  TTO_AnchorFormat3_
 128   {
 129     TT_Short    XCoordinate;            /* horizontal value              */
 130     TT_Short    YCoordinate;            /* vertical value                */
 131     TTO_Device  XDeviceTable;           /* device table for X coordinate */
 132     TTO_Device  YDeviceTable;           /* device table for Y coordinate */
 133   };
 134
 135   typedef struct TTO_AnchorFormat3_  TTO_AnchorFormat3;
 136
 137
 138   struct  TTO_AnchorFormat4_
 139   {
 140     TT_UShort  XIdAnchor;               /* horizontal metric ID */
 141     TT_UShort  YIdAnchor;               /* vertical metric ID   */
 142   };
 143
 144   typedef struct TTO_AnchorFormat4_  TTO_AnchorFormat4;
 145
 146
 147   struct  TTO_Anchor_
 148   {
 149     TT_UShort  PosFormat;               /* 1, 2, 3, or 4 -- 0 indicates
 150                                            that there is no Anchor table */
 151
 152     union
 153     {
 154       TTO_AnchorFormat1  af1;
 155       TTO_AnchorFormat2  af2;
 156       TTO_AnchorFormat3  af3;
 157       TTO_AnchorFormat4  af4;
 158     } af;
 159   };
 160
 161   typedef struct TTO_Anchor_  TTO_Anchor;
 162
 163
 164   struct  TTO_MarkRecord_
 165   {
 166     TT_UShort   Class;                  /* mark class   */
 167     TTO_Anchor  MarkAnchor;             /* anchor table */
 168   };
 169
 170   typedef struct TTO_MarkRecord_  TTO_MarkRecord;
 171
 172
 173   struct  TTO_MarkArray_
 174   {
 175     TT_UShort        MarkCount;         /* number of MarkRecord tables */
 176     TTO_MarkRecord*  MarkRecord;        /* array of MarkRecord tables  */
 177   };
 178
 179   typedef struct TTO_MarkArray_  TTO_MarkArray;
 180
 181
 182   /* LookupType 1 */
 183
 184   struct  TTO_SinglePosFormat1_
 185   {
 186     TTO_ValueRecord  Value;             /* ValueRecord for all covered
 187                                            glyphs                      */
 188   };
 189
 190   typedef struct TTO_SinglePosFormat1_  TTO_SinglePosFormat1;
 191
 192
 193   struct  TTO_SinglePosFormat2_
 194   {
 195     TT_UShort         ValueCount;       /* number of ValueRecord tables */
 196     TTO_ValueRecord*  Value;            /* array of ValueRecord tables  */
 197   };
 198
 199   typedef struct TTO_SinglePosFormat2_  TTO_SinglePosFormat2;
 200
 201
 202   struct  TTO_SinglePos_
 203   {
 204     TT_UShort     PosFormat;            /* 1 or 2         */
 205     TTO_Coverage  Coverage;             /* Coverage table */
 206
 207     TT_UShort     ValueFormat;          /* format of ValueRecord table */
 208
 209     union
 210     {
 211       TTO_SinglePosFormat1  spf1;
 212       TTO_SinglePosFormat2  spf2;
 213     } spf;
 214   };
 215
 216   typedef struct TTO_SinglePos_  TTO_SinglePos;
 217
 218
 219   /* LookupType 2 */
 220
 221   struct  TTO_PairValueRecord_
 222   {
 223     TT_UShort        SecondGlyph;       /* glyph ID for second glyph  */
 224     TTO_ValueRecord  Value1;            /* pos. data for first glyph  */
 225     TTO_ValueRecord  Value2;            /* pos. data for second glyph */
 226   };
 227
 228   typedef struct TTO_PairValueRecord_  TTO_PairValueRecord;
 229
 230
 231   struct  TTO_PairSet_
 232   {
 233     TT_UShort             PairValueCount;
 234                                         /* number of PairValueRecord tables */
 235     TTO_PairValueRecord*  PairValueRecord;
 236                                         /* array of PairValueRecord tables  */
 237   };
 238
 239   typedef struct TTO_PairSet_  TTO_PairSet;
 240
 241
 242   struct  TTO_PairPosFormat1_
 243   {
 244     TT_UShort     PairSetCount;         /* number of PairSet tables    */
 245     TTO_PairSet*  PairSet;              /* array of PairSet tables     */
 246   };
 247
 248   typedef struct TTO_PairPosFormat1_  TTO_PairPosFormat1;
 249
 250
 251   struct  TTO_Class2Record_
 252   {
 253     TTO_ValueRecord  Value1;            /* pos. data for first glyph  */
 254     TTO_ValueRecord  Value2;            /* pos. data for second glyph */
 255   };
 256
 257   typedef struct TTO_Class2Record_  TTO_Class2Record;
 258
 259
 260   struct  TTO_Class1Record_
 261   {
 262     TTO_Class2Record*  Class2Record;    /* array of Class2Record tables */
 263   };
 264
 265   typedef struct TTO_Class1Record_  TTO_Class1Record;
 266
 267
 268   struct TTO_PairPosFormat2_
 269   {
 270     TTO_ClassDefinition  ClassDef1;     /* class def. for first glyph     */
 271     TTO_ClassDefinition  ClassDef2;     /* class def. for second glyph    */
 272     TT_UShort            Class1Count;   /* number of classes in ClassDef1
 273                                            table                          */
 274     TT_UShort            Class2Count;   /* number of classes in ClassDef2
 275                                            table                          */
 276     TTO_Class1Record*    Class1Record;  /* array of Class1Record tables   */
 277   };
 278
 279   typedef struct TTO_PairPosFormat2_  TTO_PairPosFormat2;
 280
 281
 282   struct  TTO_PairPos_
 283   {
 284     TT_UShort     PosFormat;            /* 1 or 2         */
 285     TTO_Coverage  Coverage;             /* Coverage table */
 286     TT_UShort     ValueFormat1;         /* format of ValueRecord table
 287                                            for first glyph             */
 288     TT_UShort     ValueFormat2;         /* format of ValueRecord table
 289                                            for second glyph            */
 290
 291     union
 292     {
 293       TTO_PairPosFormat1  ppf1;
 294       TTO_PairPosFormat2  ppf2;
 295     } ppf;
 296   };
 297
 298   typedef struct TTO_PairPos_  TTO_PairPos;
 299
 300
 301   /* LookupType 3 */
 302
 303   struct TTO_EntryExitRecord_
 304   {
 305     TTO_Anchor  EntryAnchor;            /* entry Anchor table */
 306     TTO_Anchor  ExitAnchor;             /* exit Anchor table  */
 307   };
 308
 309
 310   typedef struct TTO_EntryExitRecord_  TTO_EntryExitRecord;
 311
 312   struct  TTO_CursivePos_
 313   {
 314     TT_UShort             PosFormat;    /* always 1                         */
 315     TTO_Coverage          Coverage;     /* Coverage table                   */
 316     TT_UShort             EntryExitCount;
 317                                         /* number of EntryExitRecord tables */
 318     TTO_EntryExitRecord*  EntryExitRecord;
 319                                         /* array of EntryExitRecord tables  */
 320   };
 321
 322   typedef struct TTO_CursivePos_  TTO_CursivePos;
 323
 324
 325   /* LookupType 4 */
 326
 327   struct  TTO_BaseRecord_
 328   {
 329     TTO_Anchor*  BaseAnchor;            /* array of base glyph anchor
 330                                            tables                     */
 331   };
 332
 333   typedef struct TTO_BaseRecord_  TTO_BaseRecord;
 334
 335
 336   struct  TTO_BaseArray_
 337   {
 338     TT_UShort        BaseCount;         /* number of BaseRecord tables */
 339     TTO_BaseRecord*  BaseRecord;        /* array of BaseRecord tables  */
 340   };
 341
 342   typedef struct TTO_BaseArray_  TTO_BaseArray;
 343
 344
 345   struct  TTO_MarkBasePos_
 346   {
 347     TT_UShort      PosFormat;           /* always 1                  */
 348     TTO_Coverage   MarkCoverage;        /* mark glyph coverage table */
 349     TTO_Coverage   BaseCoverage;        /* base glyph coverage table */
 350     TT_UShort      ClassCount;          /* number of mark classes    */
 351     TTO_MarkArray  MarkArray;           /* mark array table          */
 352     TTO_BaseArray  BaseArray;           /* base array table          */
 353   };
 354
 355   typedef struct TTO_MarkBasePos_  TTO_MarkBasePos;
 356
 357
 358   /* LookupType 5 */
 359
 360   struct  TTO_ComponentRecord_
 361   {
 362     TTO_Anchor*  LigatureAnchor;        /* array of ligature glyph anchor
 363                                            tables                         */
 364   };
 365
 366   typedef struct TTO_ComponentRecord_  TTO_ComponentRecord;
 367
 368
 369   struct  TTO_LigatureAttach_
 370   {
 371     TT_UShort             ComponentCount;
 372                                         /* number of ComponentRecord tables */
 373     TTO_ComponentRecord*  ComponentRecord;
 374                                         /* array of ComponentRecord tables  */
 375   };
 376
 377   typedef struct TTO_LigatureAttach_  TTO_LigatureAttach;
 378
 379
 380   struct  TTO_LigatureArray_
 381   {
 382     TT_UShort            LigatureCount; /* number of LigatureAttach tables */
 383     TTO_LigatureAttach*  LigatureAttach;
 384                                         /* array of LigatureAttach tables  */
 385   };
 386
 387   typedef struct TTO_LigatureArray_  TTO_LigatureArray;
 388
 389
 390   struct  TTO_MarkLigPos_
 391   {
 392     TT_UShort          PosFormat;       /* always 1                      */
 393     TTO_Coverage       MarkCoverage;    /* mark glyph coverage table     */
 394     TTO_Coverage       LigatureCoverage;
 395                                         /* ligature glyph coverage table */
 396     TT_UShort          ClassCount;      /* number of mark classes        */
 397     TTO_MarkArray      MarkArray;       /* mark array table              */
 398     TTO_LigatureArray  LigatureArray;   /* ligature array table          */
 399   };
 400
 401   typedef struct TTO_MarkLigPos_  TTO_MarkLigPos;
 402
 403
 404   /* LookupType 6 */
 405
 406   struct TTO_Mark2Record_
 407   {
 408     TTO_Anchor*  Mark2Anchor;           /* array of mark glyph anchor
 409                                            tables                     */
 410   };
 411
 412   typedef struct TTO_Mark2Record_  TTO_Mark2Record;
 413
 414
 415   struct TTO_Mark2Array_
 416   {
 417     TT_UShort         Mark2Count;       /* number of Mark2Record tables */
 418     TTO_Mark2Record*  Mark2Record;      /* array of Mark2Record tables  */
 419   };
 420
 421   typedef struct TTO_Mark2Array_  TTO_Mark2Array;
 422
 423
 424   struct TTO_MarkMarkPos_
 425   {
 426     TT_UShort       PosFormat;          /* always 1                         */
 427     TTO_Coverage    Mark1Coverage;      /* first mark glyph coverage table  */
 428     TTO_Coverage    Mark2Coverage;      /* second mark glyph coverave table */
 429     TT_UShort       ClassCount;         /* number of combining mark classes */
 430     TTO_MarkArray   Mark1Array;         /* MarkArray table for first mark   */
 431     TTO_Mark2Array  Mark2Array;         /* MarkArray table for second mark  */
 432   };
 433
 434   typedef struct TTO_MarkMarkPos_  TTO_MarkMarkPos;
 435
 436
 437   /* needed by both lookup type 7 and 8 */
 438
 439   struct  TTO_PosLookupRecord_
 440   {
 441     TT_UShort  SequenceIndex;           /* index into current
 442                                            glyph sequence               */
 443     TT_UShort  LookupListIndex;         /* Lookup to apply to that pos. */
 444   };
 445
 446   typedef struct TTO_PosLookupRecord_  TTO_PosLookupRecord;
 447
 448
 449   /* LookupType 7 */
 450
 451   struct  TTO_PosRule_
 452   {
 453     TT_UShort             GlyphCount;   /* total number of input glyphs     */
 454     TT_UShort             PosCount;     /* number of PosLookupRecord tables */
 455     TT_UShort*            Input;        /* array of input glyph IDs         */
 456     TTO_PosLookupRecord*  PosLookupRecord;
 457                                         /* array of PosLookupRecord tables  */
 458   };
 459
 460   typedef struct TTO_PosRule_  TTO_PosRule;
 461
 462
 463   struct  TTO_PosRuleSet_
 464   {
 465     TT_UShort     PosRuleCount;         /* number of PosRule tables */
 466     TTO_PosRule*  PosRule;              /* array of PosRule tables  */
 467   };
 468
 469   typedef struct TTO_PosRuleSet_  TTO_PosRuleSet;
 470
 471
 472   struct  TTO_ContextPosFormat1_
 473   {
 474     TTO_Coverage     Coverage;          /* Coverage table              */
 475     TT_UShort        PosRuleSetCount;   /* number of PosRuleSet tables */
 476     TTO_PosRuleSet*  PosRuleSet;        /* array of PosRuleSet tables  */
 477   };
 478
 479   typedef struct TTO_ContextPosFormat1_  TTO_ContextPosFormat1;
 480
 481
 482   struct  TTO_PosClassRule_
 483   {
 484     TT_UShort             GlyphCount;   /* total number of context classes  */
 485     TT_UShort             PosCount;     /* number of PosLookupRecord tables */
 486     TT_UShort*            Class;        /* array of classes                 */
 487     TTO_PosLookupRecord*  PosLookupRecord;
 488                                         /* array of PosLookupRecord tables  */
 489   };
 490
 491   typedef struct TTO_PosClassRule_  TTO_PosClassRule;
 492
 493
 494   struct  TTO_PosClassSet_
 495   {
 496     TT_UShort          PosClassRuleCount;
 497                                         /* number of PosClassRule tables */
 498     TTO_PosClassRule*  PosClassRule;    /* array of PosClassRule tables  */
 499   };
 500
 501   typedef struct TTO_PosClassSet_  TTO_PosClassSet;
 502
 503
 504   /* The `MaxContextLength' field is not defined in the TTO specification
 505      but simplifies the implementation of this format.  It holds the
 506      maximal context length used in the context rules.                    */
 507
 508   struct  TTO_ContextPosFormat2_
 509   {
 510     TT_UShort            MaxContextLength;
 511                                         /* maximal context length       */
 512     TTO_Coverage         Coverage;      /* Coverage table               */
 513     TTO_ClassDefinition  ClassDef;      /* ClassDef table               */
 514     TT_UShort            PosClassSetCount;
 515                                         /* number of PosClassSet tables */
 516     TTO_PosClassSet*     PosClassSet;   /* array of PosClassSet tables  */
 517   };
 518
 519   typedef struct TTO_ContextPosFormat2_  TTO_ContextPosFormat2;
 520
 521
 522   struct  TTO_ContextPosFormat3_
 523   {
 524     TT_UShort             GlyphCount;   /* number of input glyphs           */
 525     TT_UShort             PosCount;     /* number of PosLookupRecord tables */
 526     TTO_Coverage*         Coverage;     /* array of Coverage tables         */
 527     TTO_PosLookupRecord*  PosLookupRecord;
 528                                         /* array of PosLookupRecord tables  */
 529   };
 530
 531   typedef struct TTO_ContextPosFormat3_  TTO_ContextPosFormat3;
 532
 533
 534   struct  TTO_ContextPos_
 535   {
 536     TT_UShort  PosFormat;               /* 1, 2, or 3     */
 537
 538     union
 539     {
 540       TTO_ContextPosFormat1  cpf1;
 541       TTO_ContextPosFormat2  cpf2;
 542       TTO_ContextPosFormat3  cpf3;
 543     } cpf;
 544   };
 545
 546   typedef struct TTO_ContextPos_  TTO_ContextPos;
 547
 548
 549   /* LookupType 8 */
 550
 551   struct  TTO_ChainPosRule_
 552   {
 553     TT_UShort             BacktrackGlyphCount;
 554                                         /* total number of backtrack glyphs */
 555     TT_UShort*            Backtrack;    /* array of backtrack glyph IDs     */
 556     TT_UShort             InputGlyphCount;
 557                                         /* total number of input glyphs     */
 558     TT_UShort*            Input;        /* array of input glyph IDs         */
 559     TT_UShort             LookaheadGlyphCount;
 560                                         /* total number of lookahead glyphs */
 561     TT_UShort*            Lookahead;    /* array of lookahead glyph IDs     */
 562     TT_UShort             PosCount;     /* number of PosLookupRecords       */
 563     TTO_PosLookupRecord*  PosLookupRecord;
 564                                         /* array of PosLookupRecords       */
 565   };
 566
 567   typedef struct TTO_ChainPosRule_  TTO_ChainPosRule;
 568
 569
 570   struct  TTO_ChainPosRuleSet_
 571   {
 572     TT_UShort          ChainPosRuleCount;
 573                                         /* number of ChainPosRule tables */
 574     TTO_ChainPosRule*  ChainPosRule;    /* array of ChainPosRule tables  */
 575   };
 576
 577   typedef struct TTO_ChainPosRuleSet_  TTO_ChainPosRuleSet;
 578
 579
 580   struct  TTO_ChainContextPosFormat1_
 581   {
 582     TTO_Coverage          Coverage;     /* Coverage table                   */
 583     TT_UShort             ChainPosRuleSetCount;
 584                                         /* number of ChainPosRuleSet tables */
 585     TTO_ChainPosRuleSet*  ChainPosRuleSet;
 586                                         /* array of ChainPosRuleSet tables  */
 587   };
 588
 589   typedef struct TTO_ChainContextPosFormat1_  TTO_ChainContextPosFormat1;
 590
 591
 592   struct  TTO_ChainPosClassRule_
 593   {
 594     TT_UShort             BacktrackGlyphCount;
 595                                         /* total number of backtrack
 596                                            classes                         */
 597     TT_UShort*            Backtrack;    /* array of backtrack classes      */
 598     TT_UShort             InputGlyphCount;
 599                                         /* total number of context classes */
 600     TT_UShort*            Input;        /* array of context classes        */
 601     TT_UShort             LookaheadGlyphCount;
 602                                         /* total number of lookahead
 603                                            classes                         */
 604     TT_UShort*            Lookahead;    /* array of lookahead classes      */
 605     TT_UShort             PosCount;     /* number of PosLookupRecords      */
 606     TTO_PosLookupRecord*  PosLookupRecord;
 607                                         /* array of substitution lookups   */
 608   };
 609
 610   typedef struct TTO_ChainPosClassRule_  TTO_ChainPosClassRule;
 611
 612
 613   struct  TTO_ChainPosClassSet_
 614   {
 615     TT_UShort               ChainPosClassRuleCount;
 616                                         /* number of ChainPosClassRule
 617                                            tables                      */
 618     TTO_ChainPosClassRule*  ChainPosClassRule;
 619                                         /* array of ChainPosClassRule
 620                                            tables                      */
 621   };
 622
 623   typedef struct TTO_ChainPosClassSet_  TTO_ChainPosClassSet;
 624
 625
 626   /* The `MaxXXXLength' fields are not defined in the TTO specification
 627      but simplifies the implementation of this format.  It holds the
 628      maximal context length used in the specific context rules.         */
 629
 630   struct  TTO_ChainContextPosFormat2_
 631   {
 632     TTO_Coverage           Coverage;    /* Coverage table             */
 633
 634     TT_UShort              MaxBacktrackLength;
 635                                         /* maximal backtrack length   */
 636     TTO_ClassDefinition    BacktrackClassDef;
 637                                         /* BacktrackClassDef table    */
 638     TT_UShort              MaxInputLength;
 639                                         /* maximal input length       */
 640     TTO_ClassDefinition    InputClassDef;
 641                                         /* InputClassDef table        */
 642     TT_UShort              MaxLookaheadLength;
 643                                         /* maximal lookahead length   */
 644     TTO_ClassDefinition    LookaheadClassDef;
 645                                         /* LookaheadClassDef table    */
 646
 647     TT_UShort              ChainPosClassSetCount;
 648                                         /* number of ChainPosClassSet
 649                                            tables                     */
 650     TTO_ChainPosClassSet*  ChainPosClassSet;
 651                                         /* array of ChainPosClassSet
 652                                            tables                     */
 653   };
 654
 655   typedef struct TTO_ChainContextPosFormat2_  TTO_ChainContextPosFormat2;
 656
 657
 658   struct  TTO_ChainContextPosFormat3_
 659   {
 660     TT_UShort             BacktrackGlyphCount;
 661                                         /* number of backtrack glyphs    */
 662     TTO_Coverage*         BacktrackCoverage;
 663                                         /* array of backtrack Coverage
 664                                            tables                        */
 665     TT_UShort             InputGlyphCount;
 666                                         /* number of input glyphs        */
 667     TTO_Coverage*         InputCoverage;
 668                                         /* array of input coverage
 669                                            tables                        */
 670     TT_UShort             LookaheadGlyphCount;
 671                                         /* number of lookahead glyphs    */
 672     TTO_Coverage*         LookaheadCoverage;
 673                                         /* array of lookahead coverage
 674                                            tables                        */
 675     TT_UShort             PosCount;     /* number of PosLookupRecords    */
 676     TTO_PosLookupRecord*  PosLookupRecord;
 677                                         /* array of substitution lookups */
 678   };
 679
 680   typedef struct TTO_ChainContextPosFormat3_  TTO_ChainContextPosFormat3;
 681
 682
 683   struct  TTO_ChainContextPos_
 684   {
 685     TT_UShort  PosFormat;             /* 1, 2, or 3 */
 686
 687     union
 688     {
 689       TTO_ChainContextPosFormat1  ccpf1;
 690       TTO_ChainContextPosFormat2  ccpf2;
 691       TTO_ChainContextPosFormat3  ccpf3;
 692     } ccpf;
 693   };
 694
 695   typedef struct TTO_ChainContextPos_  TTO_ChainContextPos;
 696
 697
 698   union  TTO_GPOS_SubTable_
 699   {
 700     TTO_SinglePos        single;
 701     TTO_PairPos          pair;
 702     TTO_CursivePos       cursive;
 703     TTO_MarkBasePos      markbase;
 704     TTO_MarkLigPos       marklig;
 705     TTO_MarkMarkPos      markmark;
 706     TTO_ContextPos       context;
 707     TTO_ChainContextPos  chain;
 708   };
 709
 710   typedef union TTO_GPOS_SubTable_  TTO_GPOS_SubTable;
 711
 712
 713   /* finally, the GPOS API */
 714
 715   EXPORT_DEF
 716   TT_Error  TT_Init_GPOS_Extension( TT_Engine  engine );
 717
 718   EXPORT_DEF
 719   TT_Error  TT_Load_GPOS_Table( TT_Face          face,
 720                                 TTO_GPOSHeader*  gpos,
 721                                 TTO_GDEFHeader*  gdef );
 722
 723   EXPORT_DEF
 724   TT_Error  TT_GPOS_Select_Script( TTO_GPOSHeader*  gpos,
 725                                    TT_ULong         script_tag,
 726                                    TT_UShort*       script_index );
 727   EXPORT_DEF
 728   TT_Error  TT_GPOS_Select_Language( TTO_GPOSHeader*  gpos,
 729                                      TT_ULong         language_tag,
 730                                      TT_UShort        script_index,
 731                                      TT_UShort*       language_index,
 732                                      TT_UShort*       req_feature_index );
 733   EXPORT_DEF
 734   TT_Error  TT_GPOS_Select_Feature( TTO_GPOSHeader*  gpos,
 735                                     TT_ULong         feature_tag,
 736                                     TT_UShort        script_index,
 737                                     TT_UShort        language_index,
 738                                     TT_UShort*       feature_index );
 739
 740   EXPORT_DEF
 741   TT_Error  TT_GPOS_Query_Scripts( TTO_GPOSHeader*  gpos,
 742                                    TT_ULong**       script_tag_list );
 743   EXPORT_DEF
 744   TT_Error  TT_GPOS_Query_Languages( TTO_GPOSHeader*  gpos,
 745                                      TT_UShort        script_index,
 746                                      TT_ULong**       language_tag_list );
 747   EXPORT_DEF
 748   TT_Error  TT_GPOS_Query_Features( TTO_GPOSHeader*  gpos,
 749                                     TT_UShort        script_index,
 750                                     TT_UShort        language_index,
 751                                     TT_ULong**       feature_tag_list );
 752
 753   EXPORT_DEF
 754   TT_Error  TT_GPOS_Add_Feature( TTO_GPOSHeader*  gpos,
 755                                  TT_UShort        feature_index,
 756                                  TT_UShort        property );
 757   EXPORT_DEF
 758   TT_Error  TT_GPOS_Clear_Features( TTO_GPOSHeader*  gpos );
 759
 760 #ifdef __cplusplus
 761 }
 762 #endif
 763
 764 #endif /* FTXGPOS_H */
 765
 766
 767 /* END */