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, 2010 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     FT_Long  Cur_End;
 106
 107   } TT_CallRec, *TT_CallStack;
 108
 109
 110   /*************************************************************************/
 111   /*                                                                       */
 112   /* The main structure for the interpreter which collects all necessary   */
 113   /* variables and states.                                                 */
 114   /*                                                                       */
 115   typedef struct  TT_ExecContextRec_
 116   {
 117     TT_Face            face;
 118     TT_Size            size;
 119     FT_Memory          memory;
 120
 121     /* instructions state */
 122
 123     FT_Error           error;      /* last execution error */
 124
 125     FT_Long            top;        /* top of exec. stack   */
 126
 127     FT_UInt            stackSize;  /* size of exec. stack  */
 128     FT_Long*           stack;      /* current exec. stack  */
 129
 130     FT_Long            args;
 131     FT_UInt            new_top;    /* new top after exec.  */
 132
 133     TT_GlyphZoneRec    zp0,        /* zone records */
 134                        zp1,
 135                        zp2,
 136                        pts,
 137                        twilight;
 138
 139     FT_Size_Metrics    metrics;
 140     TT_Size_Metrics    tt_metrics; /* size metrics */
 141
 142     TT_GraphicsState   GS;         /* current graphics state */
 143
 144     FT_Int             curRange;  /* current code range number   */
 145     FT_Byte*           code;      /* current code range          */
 146     FT_Long            IP;        /* current instruction pointer */
 147     FT_Long            codeSize;  /* size of current range       */
 148
 149     FT_Byte            opcode;    /* current opcode              */
 150     FT_Int             length;    /* length of current opcode    */
 151
 152     FT_Bool            step_ins;  /* true if the interpreter must */
 153                                   /* increment IP after ins. exec */
 154     FT_ULong           cvtSize;
 155     FT_Long*           cvt;
 156
 157     FT_UInt            glyphSize; /* glyph instructions buffer size */
 158     FT_Byte*           glyphIns;  /* glyph instructions buffer */
 159
 160     FT_UInt            numFDefs;  /* number of function defs         */
 161     FT_UInt            maxFDefs;  /* maximum number of function defs */
 162     TT_DefArray        FDefs;     /* table of FDefs entries          */
 163
 164     FT_UInt            numIDefs;  /* number of instruction defs */
 165     FT_UInt            maxIDefs;  /* maximum number of ins defs */
 166     TT_DefArray        IDefs;     /* table of IDefs entries     */
 167
 168     FT_UInt            maxFunc;   /* maximum function index     */
 169     FT_UInt            maxIns;    /* maximum instruction index  */
 170
 171     FT_Int             callTop,    /* top of call stack during execution */
 172                        callSize;   /* size of call stack */
 173     TT_CallStack       callStack;  /* call stack */
 174
 175     FT_UShort          maxPoints;    /* capacity of this context's `pts' */
 176     FT_Short           maxContours;  /* record, expressed in points and  */
 177                                      /* contours.                        */
 178
 179     TT_CodeRangeTable  codeRangeTable;  /* table of valid code ranges */
 180                                         /* useful for the debugger   */
 181
 182     FT_UShort          storeSize;  /* size of current storage */
 183     FT_Long*           storage;    /* storage area            */
 184
 185     FT_F26Dot6         period;     /* values used for the */
 186     FT_F26Dot6         phase;      /* `SuperRounding'     */
 187     FT_F26Dot6         threshold;
 188
 189 #if 0
 190     /* this seems to be unused */
 191     FT_Int             cur_ppem;   /* ppem along the current proj vector */
 192 #endif
 193
 194     FT_Bool            instruction_trap; /* If `True', the interpreter will */
 195                                          /* exit after each instruction     */
 196
 197     TT_GraphicsState   default_GS;       /* graphics state resulting from   */
 198                                          /* the prep program                */
 199     FT_Bool            is_composite;     /* true if the glyph is composite  */
 200     FT_Bool            pedantic_hinting; /* true if pedantic interpretation */
 201
 202     /* latest interpreter additions */
 203
 204     FT_Long            F_dot_P;    /* dot product of freedom and projection */
 205                                    /* vectors                               */
 206     TT_Round_Func      func_round; /* current rounding function             */
 207
 208     TT_Project_Func    func_project,   /* current projection function */
 209                        func_dualproj,  /* current dual proj. function */
 210                        func_freeProj;  /* current freedom proj. func  */
 211
 212     TT_Move_Func       func_move;      /* current point move function */
 213     TT_Move_Func       func_move_orig; /* move original position function */
 214
 215     TT_Get_CVT_Func    func_read_cvt;  /* read a cvt entry              */
 216     TT_Set_CVT_Func    func_write_cvt; /* write a cvt entry (in pixels) */
 217     TT_Set_CVT_Func    func_move_cvt;  /* incr a cvt entry (in pixels)  */
 218
 219     FT_Bool            grayscale;      /* are we hinting for grayscale? */
 220
 221   } TT_ExecContextRec;
 222
 223
 224   extern const TT_GraphicsState  tt_default_graphics_state;
 225
 226
 227   FT_LOCAL( FT_Error )
 228   TT_Goto_CodeRange( TT_ExecContext  exec,
 229                      FT_Int          range,
 230                      FT_Long         IP );
 231
 232   FT_LOCAL( FT_Error )
 233   TT_Set_CodeRange( TT_ExecContext  exec,
 234                     FT_Int          range,
 235                     void*           base,
 236                     FT_Long         length );
 237
 238   FT_LOCAL( FT_Error )
 239   TT_Clear_CodeRange( TT_ExecContext  exec,
 240                       FT_Int          range );
 241
 242
 243   FT_LOCAL( FT_Error )
 244   Update_Max( FT_Memory  memory,
 245               FT_ULong*  size,
 246               FT_Long    multiplier,
 247               void*      _pbuff,
 248               FT_ULong   new_max );
 249
 250
 251   /*************************************************************************/
 252   /*                                                                       */
 253   /* <Function>                                                            */
 254   /*    TT_New_Context                                                     */
 255   /*                                                                       */
 256   /* <Description>                                                         */
 257   /*    Queries the face context for a given font.  Note that there is     */
 258   /*    now a _single_ execution context in the TrueType driver which is   */
 259   /*    shared among faces.                                                */
 260   /*                                                                       */
 261   /* <Input>                                                               */
 262   /*    face :: A handle to the source face object.                        */
 263   /*                                                                       */
 264   /* <Return>                                                              */
 265   /*    A handle to the execution context.  Initialized for `face'.        */
 266   /*                                                                       */
 267   /* <Note>                                                                */
 268   /*    Only the glyph loader and debugger should call this function.      */
 269   /*                                                                       */
 270   FT_EXPORT( TT_ExecContext )
 271   TT_New_Context( TT_Driver  driver );
 272
 273   FT_LOCAL( FT_Error )
 274   TT_Done_Context( TT_ExecContext  exec );
 275
 276   FT_LOCAL( FT_Error )
 277   TT_Load_Context( TT_ExecContext  exec,
 278                    TT_Face         face,
 279                    TT_Size         size );
 280
 281   FT_LOCAL( FT_Error )
 282   TT_Save_Context( TT_ExecContext  exec,
 283                    TT_Size         ins );
 284
 285   FT_LOCAL( FT_Error )
 286   TT_Run_Context( TT_ExecContext  exec,
 287                   FT_Bool         debug );
 288
 289
 290   /*************************************************************************/
 291   /*                                                                       */
 292   /* <Function>                                                            */
 293   /*    TT_RunIns                                                          */
 294   /*                                                                       */
 295   /* <Description>                                                         */
 296   /*    Executes one or more instruction in the execution context.  This   */
 297   /*    is the main function of the TrueType opcode interpreter.           */
 298   /*                                                                       */
 299   /* <Input>                                                               */
 300   /*    exec :: A handle to the target execution context.                  */
 301   /*                                                                       */
 302   /* <Return>                                                              */
 303   /*    FreeType error code.  0 means success.                             */
 304   /*                                                                       */
 305   /* <Note>                                                                */
 306   /*    Only the object manager and debugger should call this function.    */
 307   /*                                                                       */
 308   /*    This function is publicly exported because it is directly          */
 309   /*    invoked by the TrueType debugger.                                  */
 310   /*                                                                       */
 311   FT_EXPORT( FT_Error )
 312   TT_RunIns( TT_ExecContext  exec );
 313
 314
 315 FT_END_HEADER
 316
 317 #endif /* __TTINTERP_H__ */
 318
 319
 320 /* END */