/******************************************************************* * *  ftxkern.h                                                   1.0 * *    High-Level API Kerning extension * *  Copyright 1996-2001 by *  David Turner, Robert Wilhelm, and Werner Lemberg. * *  This file is part of the FreeType project, and may only be used *  modified and distributed under the terms of the FreeType project *  license, LICENSE.TXT.  By continuing to use, modify, or distribute *  this file you indicate that you have read the license and *  understand and accept it fully. * * *  The kerning support is currently part of the engine extensions. * *  This file should _not_ depend on engine internal types. * ******************************************************************/#ifndef FTXKERN_H#define FTXKERN_H#include "freetype.h"#ifdef __cplusplusextern "C" {#endif  /* The kerning support in FreeType is minimal.  This means that  */  /* we do not try to interpret the kerning data in any way to     */  /* `cook' it for a user application.  This API lets you access   */  /* directly the kerning tables found in the TrueType file; it's  */  /* up to the client application to apply its own processing on   */  /* these.                                                        */  /* The reason for this is that we generally do not encourage     */  /* feature-bloat of the core engine.  Moreover, not all          */  /* libraries or font servers really need kerning data, or all    */  /* formats of this data.                                         */  /************** kerning error codes *****************************/  /* we choose the class 0x0A for our errors, this should not      */  /* match with any error code class used in any other extension   */#define TT_Err_Invalid_Kerning_Table_Format  0x0A00#define TT_Err_Invalid_Kerning_Table         0x0A01  /********** structures definitions ******************************/  /* Remember that all types and function are accessible by client */  /* applications in this section, and thus should have the `TT_'  */  /* prefix.                                                       */  /* format 0 kerning pair */  struct  TT_Kern_0_Pair_  {    TT_UShort  left;   /* index of left  glyph in pair */    TT_UShort  right;  /* index of right glyph in pair */    TT_FWord   value;  /* kerning value                */  };  typedef struct TT_Kern_0_Pair_  TT_Kern_0_Pair;  /* format 0 kerning subtable */  struct  TT_Kern_0_  {    TT_UShort  nPairs;          /* number of kerning pairs */    TT_UShort  searchRange;     /* these values are defined by the TT spec */    TT_UShort  entrySelector;   /* for table searchs.                      */    TT_UShort  rangeShift;    TT_Kern_0_Pair*  pairs;     /* a table of nPairs `pairs' */  };  typedef struct TT_Kern_0_  TT_Kern_0;  /* format 2 kerning glyph class */  struct  TT_Kern_2_Class_  {    TT_UShort   firstGlyph;   /* first glyph in range                    */    TT_UShort   nGlyphs;      /* number of glyphs in range               */    TT_UShort*  classes;      /* a table giving for each ranged glyph    */                              /* its class offset in the subtable pairs  */                              /* two-dimensional array                   */  };  typedef struct TT_Kern_2_Class_  TT_Kern_2_Class;  /* format 2 kerning subtable */  struct TT_Kern_2_  {    TT_UShort        rowWidth;   /* length of one row in bytes         */    TT_Kern_2_Class  leftClass;  /* left class table                   */    TT_Kern_2_Class  rightClass; /* right class table                  */    TT_FWord*        array;      /* 2-dimensional kerning values array */  };  typedef struct TT_Kern_2_  TT_Kern_2;  /* kerning subtable */  struct  TT_Kern_Subtable_  {    TT_Bool    loaded;   /* boolean; indicates whether the table is   */                         /* loaded                                    */    TT_UShort  version;  /* table version number                      */    TT_Long    offset;   /* file offset of table                      */    TT_UShort  length;   /* length of table, _excluding_ header       */    TT_Byte    coverage; /* lower 8 bit of the coverage table entry   */    TT_Byte    format;   /* the subtable format, as found in the      */                         /* higher 8 bits of the coverage table entry */    union    {      TT_Kern_0  kern0;      TT_Kern_2  kern2;    } t;  };  typedef struct TT_Kern_Subtable_  TT_Kern_Subtable;  struct  TT_Kerning_  {    TT_UShort          version;  /* kern table version number. starts at 0 */    TT_UShort          nTables;  /* number of tables                       */    TT_Kern_Subtable*  tables;   /* the kerning sub-tables                 */  };  typedef struct TT_Kerning_  TT_Kerning;  /***************** high-level API extension **************************/  /* Initialize Kerning extension, must be called after                 */  /* TT_Init_FreeType(). There is no need for a finalizer               */  FT_EXPORT_DEF( TT_Error )  TT_Init_Kerning_Extension( TT_Engine  engine );  /* Note on the implemented mechanism:                                 */  /* The kerning table directory is loaded with the face through the    */  /* extension constructor.  However, the tables will only be loaded    */  /* on demand, as they may represent a lot of data, unnecessary to     */  /* most applications.                                                 */  /* Queries a pointer to the kerning directory for the face object     */  FT_EXPORT_DEF( TT_Error )  TT_Get_Kerning_Directory( TT_Face      face,                            TT_Kerning*  directory );  /* Load the kerning table number `kern_index' in the kerning          */  /* directory.  The table will stay in memory until the `face'         */  /* face is destroyed.                                                 */  FT_EXPORT_DEF( TT_Error )  TT_Load_Kerning_Table( TT_Face    face,                         TT_UShort  kern_index );#ifdef __cplusplus}#endif#endif /* FTXKERN_H *//* END */