thirdparty/freetype-2.3.12/src/truetype/ttinterp.h

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ttinterp.h                                                             */
   4 /*                                                                         */
   5 /*    TrueType bytecode interpreter (specification).                       */
   6 /*                                                                         */
   7 /*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007 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
  19 #ifndef __TTINTERP_H__
  20 #define __TTINTERP_H__
  21
  22 #include <ft2build.h>
  23 #include "ttobjs.h"
  24
  25
  26 FT_BEGIN_HEADER
  27
  28
  29 #ifndef TT_CONFIG_OPTION_STATIC_INTERPRETER /* indirect implementation */
  30
  31 #define EXEC_OP_   TT_ExecContext  exc,
  32 #define EXEC_OP    TT_ExecContext  exc
  33 #define EXEC_ARG_  exc,
  34 #define EXEC_ARG   exc
  35
  36 #else                                       /* static implementation */
  37
  38 #define EXEC_OP_   /* void */
  39 #define EXEC_OP    /* void */
  40 #define EXEC_ARG_  /* void */
  41 #define EXEC_ARG   /* void */
  42
  43 #endif /* TT_CONFIG_OPTION_STATIC_INTERPRETER */
  44
  45
  46   /*************************************************************************/
  47   /*                                                                       */
  48   /* Rounding mode constants.                                              */
  49   /*                                                                       */
  50 #define TT_Round_Off             5
  51 #define TT_Round_To_Half_Grid    0
  52 #define TT_Round_To_Grid         1
  53 #define TT_Round_To_Double_Grid  2
  54 #define TT_Round_Up_To_Grid      4
  55 #define TT_Round_Down_To_Grid    3
  56 #define TT_Round_Super           6
  57 #define TT_Round_Super_45        7
  58
  59
  60   /*************************************************************************/
  61   /*                                                                       */
  62   /* Function types used by the interpreter, depending on various modes    */
  63   /* (e.g. the rounding mode, whether to render a vertical or horizontal   */
  64   /* line etc).                                                            */
  65   /*                                                                       */
  66   /*************************************************************************/
  67
  68   /* Rounding function */
  69   typedef FT_F26Dot6
  70   (*TT_Round_Func)( EXEC_OP_ FT_F26Dot6  distance,
  71                              FT_F26Dot6  compensation );
  72
  73   /* Point displacement along the freedom vector routine */
  74   typedef void
  75   (*TT_Move_Func)( EXEC_OP_ TT_GlyphZone  zone,
  76                             FT_UShort     point,
  77                             FT_F26Dot6    distance );
  78
  79   /* Distance projection along one of the projection vectors */
  80   typedef FT_F26Dot6
  81   (*TT_Project_Func)( EXEC_OP_ FT_Pos   dx,
  82                                FT_Pos   dy );
  83
  84   /* reading a cvt value.  Take care of non-square pixels if necessary */
  85   typedef FT_F26Dot6
  86   (*TT_Get_CVT_Func)( EXEC_OP_ FT_ULong  idx );
  87
  88   /* setting or moving a cvt value.  Take care of non-square pixels  */
  89   /* if necessary                                                    */
  90   typedef void
  91   (*TT_Set_CVT_Func)( EXEC_OP_ FT_ULong    idx,
  92                                FT_F26Dot6  value );
  93
  94
  95   /*************************************************************************/
  96   /*                                                                       */
  97   /* This structure defines a call record, used to manage function calls.  */
  98   /*                                                                       */
  99   typedef struct  TT_CallRec_
 100   {
 101     FT_Int   Caller_Range;
 102     FT_Long  Caller_IP;
 103     FT_Long  Cur_Count;
 104     FT_Long  Cur_Restart;
 105
 106   } TT_CallRec, *TT_CallStack;
 107
 108
 109   /*************************************************************************/
 110   /*                                                                       */
 111   /* The main structure for the interpreter which collects all necessary   */
 112   /* variables and states.                                                 */
 113   /*                                                                       */
 114   typedef struct  TT_ExecContextRec_
 115   {
 116     TT_Face            face;
 117     TT_Size            size;
 118     FT_Memory          memory;
 119
 120     /* instructions state */
 121
 122     FT_Error           error;      /* last execution error */
 123
 124     FT_Long            top;        /* top of exec. stack   */
 125
 126     FT_UInt            stackSize;  /* size of exec. stack  */
 127     FT_Long*           stack;      /* current exec. stack  */
 128
 129     FT_Long            args;
 130     FT_UInt            new_top;    /* new top after exec.  */
 131
 132     TT_GlyphZoneRec    zp0,        /* zone records */
 133                        zp1,
 134                        zp2,
 135                        pts,
 136                        twilight;
 137
 138     FT_Size_Metrics    metrics;
 139     TT_Size_Metrics    tt_metrics; /* size metrics */
 140
 141     TT_GraphicsState   GS;         /* current graphics state */
 142
 143     FT_Int             curRange;  /* current code range number   */
 144     FT_Byte*           code;      /* current code range          */
 145     FT_Long            IP;        /* current instruction pointer */
 146     FT_Long            codeSize;  /* size of current range       */
 147
 148     FT_Byte            opcode;    /* current opcode              */
 149     FT_Int             length;    /* length of current opcode    */
 150
 151     FT_Bool            step_ins;  /* true if the interpreter must */
 152                                   /* increment IP after ins. exec */
 153     FT_Long            cvtSize;
 154     FT_Long*           cvt;
 155
 156     FT_UInt            glyphSize; /* glyph instructions buffer size */
 157     FT_Byte*           glyphIns;  /* glyph instructions buffer */
 158
 159     FT_UInt            numFDefs;  /* number of function defs         */
 160     FT_UInt            maxFDefs;  /* maximum number of function defs */
 161     TT_DefArray        FDefs;     /* table of FDefs entries          */
 162
 163     FT_UInt            numIDefs;  /* number of instruction defs */
 164     FT_UInt            maxIDefs;  /* maximum number of ins defs */
 165     TT_DefArray        IDefs;     /* table of IDefs entries     */
 166
 167     FT_UInt            maxFunc;   /* maximum function index     */
 168     FT_UInt            maxIns;    /* maximum instruction index  */
 169
 170     FT_Int             callTop,    /* top of call stack during execution */
 171                        callSize;   /* size of call stack */
 172     TT_CallStack       callStack;  /* call stack */
 173
 174     FT_UShort          maxPoints;    /* capacity of this context's `pts' */
 175     FT_Short           maxContours;  /* record, expressed in points and  */
 176                                      /* contours.                        */
 177
 178     TT_CodeRangeTable  codeRangeTable;  /* table of valid code ranges */
 179                                         /* useful for the debugger   */
 180
 181     FT_UShort          storeSize;  /* size of current storage */
 182     FT_Long*           storage;    /* storage area            */
 183
 184     FT_F26Dot6         period;     /* values used for the */
 185     FT_F26Dot6         phase;      /* `SuperRounding'     */
 186     FT_F26Dot6         threshold;
 187
 188 #if 0
 189     /* this seems to be unused */
 190     FT_Int             cur_ppem;   /* ppem along the current proj vector */
 191 #endif
 192
 193     FT_Bool            instruction_trap; /* If `True', the interpreter will */
 194                                          /* exit after each instruction     */
 195
 196     TT_GraphicsState   default_GS;       /* graphics state resulting from   */
 197                                          /* the prep program                */
 198     FT_Bool            is_composite;     /* true if the glyph is composite  */
 199     FT_Bool            pedantic_hinting; /* true if pedantic interpretation */
 200
 201     /* latest interpreter additions */
 202
 203     FT_Long            F_dot_P;    /* dot product of freedom and projection */
 204                                    /* vectors                               */
 205     TT_Round_Func      func_round; /* current rounding function             */
 206
 207     TT_Project_Func    func_project,   /* current projection function */
 208                        func_dualproj,  /* current dual proj. function */
 209                        func_freeProj;  /* current freedom proj. func  */
 210
 211     TT_Move_Func       func_move;      /* current point move function */
 212     TT_Move_Func       func_move_orig; /* move original position function */
 213
 214     TT_Get_CVT_Func    func_read_cvt;  /* read a cvt entry              */
 215     TT_Set_CVT_Func    func_write_cvt; /* write a cvt entry (in pixels) */
 216     TT_Set_CVT_Func    func_move_cvt;  /* incr a cvt entry (in pixels)  */
 217
 218     FT_Bool            grayscale;      /* are we hinting for grayscale? */
 219
 220   } TT_ExecContextRec;
 221
 222
 223   extern const TT_GraphicsState  tt_default_graphics_state;
 224
 225
 226   FT_LOCAL( FT_Error )
 227   TT_Goto_CodeRange( TT_ExecContext  exec,
 228                      FT_Int          range,
 229                      FT_Long         IP );
 230
 231   FT_LOCAL( FT_Error )
 232   TT_Set_CodeRange( TT_ExecContext  exec,
 233                     FT_Int          range,
 234                     void*           base,
 235                     FT_Long         length );
 236
 237   FT_LOCAL( FT_Error )
 238   TT_Clear_CodeRange( TT_ExecContext  exec,
 239                       FT_Int          range );
 240
 241
 242   /*************************************************************************/
 243   /*                                                                       */
 244   /* <Function>                                                            */
 245   /*    TT_New_Context                                                     */
 246   /*                                                                       */
 247   /* <Description>                                                         */
 248   /*    Queries the face context for a given font.  Note that there is     */
 249   /*    now a _single_ execution context in the TrueType driver which is   */
 250   /*    shared among faces.                                                */
 251   /*                                                                       */
 252   /* <Input>                                                               */
 253   /*    face :: A handle to the source face object.                        */
 254   /*                                                                       */
 255   /* <Return>                                                              */
 256   /*    A handle to the execution context.  Initialized for `face'.        */
 257   /*                                                                       */
 258   /* <Note>                                                                */
 259   /*    Only the glyph loader and debugger should call this function.      */
 260   /*                                                                       */
 261   FT_EXPORT( TT_ExecContext )
 262   TT_New_Context( TT_Driver  driver );
 263
 264   FT_LOCAL( FT_Error )
 265   TT_Done_Context( TT_ExecContext  exec );
 266
 267   FT_LOCAL( FT_Error )
 268   TT_Load_Context( TT_ExecContext  exec,
 269                    TT_Face         face,
 270                    TT_Size         size );
 271
 272   FT_LOCAL( FT_Error )
 273   TT_Save_Context( TT_ExecContext  exec,
 274                    TT_Size         ins );
 275
 276   FT_LOCAL( FT_Error )
 277   TT_Run_Context( TT_ExecContext  exec,
 278                   FT_Bool         debug );
 279
 280
 281   /*************************************************************************/
 282   /*                                                                       */
 283   /* <Function>                                                            */
 284   /*    TT_RunIns                                                          */
 285   /*                                                                       */
 286   /* <Description>                                                         */
 287   /*    Executes one or more instruction in the execution context.  This   */
 288   /*    is the main function of the TrueType opcode interpreter.           */
 289   /*                                                                       */
 290   /* <Input>                                                               */
 291   /*    exec :: A handle to the target execution context.                  */
 292   /*                                                                       */
 293   /* <Return>                                                              */
 294   /*    FreeType error code.  0 means success.                             */
 295   /*                                                                       */
 296   /* <Note>                                                                */
 297   /*    Only the object manager and debugger should call this function.    */
 298   /*                                                                       */
 299   /*    This function is publicly exported because it is directly          */
 300   /*    invoked by the TrueType debugger.                                  */
 301   /*                                                                       */
 302   FT_EXPORT( FT_Error )
 303   TT_RunIns( TT_ExecContext  exec );
 304
 305
 306 FT_END_HEADER
 307
 308 #endif /* __TTINTERP_H__ */
 309
 310
 311 /* END */