src/truetype/ttinterp.h

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ttinterp.h                                                             */
   4 /*                                                                         */
   5 /*    TrueType bytecode interpreter (specification).                       */
   6 /*                                                                         */
   7 /*  Copyright 1996-2007, 2010, 2012-2014 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   /* getting current ppem.  Take care of non-square pixels if necessary */
  85   typedef FT_Long
  86   (*TT_Cur_Ppem_Func)( EXEC_OP );
  87
  88   /* reading a cvt value.  Take care of non-square pixels if necessary */
  89   typedef FT_F26Dot6
  90   (*TT_Get_CVT_Func)( EXEC_OP_ FT_ULong  idx );
  91
  92   /* setting or moving a cvt value.  Take care of non-square pixels  */
  93   /* if necessary                                                    */
  94   typedef void
  95   (*TT_Set_CVT_Func)( EXEC_OP_ FT_ULong    idx,
  96                                FT_F26Dot6  value );
  97
  98
  99   /*************************************************************************/
 100   /*                                                                       */
 101   /* This structure defines a call record, used to manage function calls.  */
 102   /*                                                                       */
 103   typedef struct  TT_CallRec_
 104   {
 105     FT_Int   Caller_Range;
 106     FT_Long  Caller_IP;
 107     FT_Long  Cur_Count;
 108
 109     TT_DefRecord  *Def; /* either FDEF or IDEF */
 110
 111   } TT_CallRec, *TT_CallStack;
 112
 113
 114 #ifdef TT_CONFIG_OPTION_SUBPIXEL_HINTING
 115
 116   /*************************************************************************/
 117   /*                                                                       */
 118   /* These structures define rules used to tweak subpixel hinting for      */
 119   /* various fonts.  "", 0, "", NULL value indicates to match any value.   */
 120   /*                                                                       */
 121
 122 #define SPH_MAX_NAME_SIZE      32
 123 #define SPH_MAX_CLASS_MEMBERS  100
 124
 125   typedef struct  SPH_TweakRule_
 126   {
 127     const char      family[SPH_MAX_NAME_SIZE];
 128     const FT_UInt   ppem;
 129     const char      style[SPH_MAX_NAME_SIZE];
 130     const FT_ULong  glyph;
 131
 132   } SPH_TweakRule;
 133
 134
 135   typedef struct  SPH_ScaleRule_
 136   {
 137     const char      family[SPH_MAX_NAME_SIZE];
 138     const FT_UInt   ppem;
 139     const char      style[SPH_MAX_NAME_SIZE];
 140     const FT_ULong  glyph;
 141     const FT_ULong  scale;
 142
 143   } SPH_ScaleRule;
 144
 145
 146   typedef struct  SPH_Font_Class_
 147   {
 148     const char  name[SPH_MAX_NAME_SIZE];
 149     const char  member[SPH_MAX_CLASS_MEMBERS][SPH_MAX_NAME_SIZE];
 150
 151   } SPH_Font_Class;
 152
 153 #endif /* TT_CONFIG_OPTION_SUBPIXEL_HINTING */
 154
 155
 156   /*************************************************************************/
 157   /*                                                                       */
 158   /* The main structure for the interpreter which collects all necessary   */
 159   /* variables and states.                                                 */
 160   /*                                                                       */
 161   typedef struct  TT_ExecContextRec_
 162   {
 163     TT_Face            face;
 164     TT_Size            size;
 165     FT_Memory          memory;
 166
 167     /* instructions state */
 168
 169     FT_Error           error;      /* last execution error */
 170
 171     FT_Long            top;        /* top of exec. stack   */
 172
 173     FT_UInt            stackSize;  /* size of exec. stack  */
 174     FT_Long*           stack;      /* current exec. stack  */
 175
 176     FT_Long            args;
 177     FT_UInt            new_top;    /* new top after exec.  */
 178
 179     TT_GlyphZoneRec    zp0,        /* zone records */
 180                        zp1,
 181                        zp2,
 182                        pts,
 183                        twilight;
 184
 185     FT_Size_Metrics    metrics;
 186     TT_Size_Metrics    tt_metrics; /* size metrics */
 187
 188     TT_GraphicsState   GS;         /* current graphics state */
 189
 190     FT_Int             curRange;  /* current code range number   */
 191     FT_Byte*           code;      /* current code range          */
 192     FT_Long            IP;        /* current instruction pointer */
 193     FT_Long            codeSize;  /* size of current range       */
 194
 195     FT_Byte            opcode;    /* current opcode              */
 196     FT_Int             length;    /* length of current opcode    */
 197
 198     FT_Bool            step_ins;  /* true if the interpreter must */
 199                                   /* increment IP after ins. exec */
 200     FT_ULong           cvtSize;
 201     FT_Long*           cvt;
 202
 203     FT_UInt            glyphSize; /* glyph instructions buffer size */
 204     FT_Byte*           glyphIns;  /* glyph instructions buffer */
 205
 206     FT_UInt            numFDefs;  /* number of function defs         */
 207     FT_UInt            maxFDefs;  /* maximum number of function defs */
 208     TT_DefArray        FDefs;     /* table of FDefs entries          */
 209
 210     FT_UInt            numIDefs;  /* number of instruction defs */
 211     FT_UInt            maxIDefs;  /* maximum number of ins defs */
 212     TT_DefArray        IDefs;     /* table of IDefs entries     */
 213
 214     FT_UInt            maxFunc;   /* maximum function index     */
 215     FT_UInt            maxIns;    /* maximum instruction index  */
 216
 217     FT_Int             callTop,    /* top of call stack during execution */
 218                        callSize;   /* size of call stack */
 219     TT_CallStack       callStack;  /* call stack */
 220
 221     FT_UShort          maxPoints;    /* capacity of this context's `pts' */
 222     FT_Short           maxContours;  /* record, expressed in points and  */
 223                                      /* contours.                        */
 224
 225     TT_CodeRangeTable  codeRangeTable;  /* table of valid code ranges */
 226                                         /* useful for the debugger   */
 227
 228     FT_UShort          storeSize;  /* size of current storage */
 229     FT_Long*           storage;    /* storage area            */
 230
 231     FT_F26Dot6         period;     /* values used for the */
 232     FT_F26Dot6         phase;      /* `SuperRounding'     */
 233     FT_F26Dot6         threshold;
 234
 235     FT_Bool            instruction_trap; /* If `True', the interpreter will */
 236                                          /* exit after each instruction     */
 237
 238     TT_GraphicsState   default_GS;       /* graphics state resulting from   */
 239                                          /* the prep program                */
 240     FT_Bool            is_composite;     /* true if the glyph is composite  */
 241     FT_Bool            pedantic_hinting; /* true if pedantic interpretation */
 242
 243     /* latest interpreter additions */
 244
 245     FT_Long            F_dot_P;    /* dot product of freedom and projection */
 246                                    /* vectors                               */
 247     TT_Round_Func      func_round; /* current rounding function             */
 248
 249     TT_Project_Func    func_project,   /* current projection function */
 250                        func_dualproj,  /* current dual proj. function */
 251                        func_freeProj;  /* current freedom proj. func  */
 252
 253     TT_Move_Func       func_move;      /* current point move function */
 254     TT_Move_Func       func_move_orig; /* move original position function */
 255
 256     TT_Cur_Ppem_Func   func_cur_ppem;  /* get current proj. ppem value  */
 257
 258     TT_Get_CVT_Func    func_read_cvt;  /* read a cvt entry              */
 259     TT_Set_CVT_Func    func_write_cvt; /* write a cvt entry (in pixels) */
 260     TT_Set_CVT_Func    func_move_cvt;  /* incr a cvt entry (in pixels)  */
 261
 262     FT_Bool            grayscale;      /* are we hinting for grayscale? */
 263
 264 #ifdef TT_CONFIG_OPTION_SUBPIXEL_HINTING
 265     TT_Round_Func      func_round_sphn;   /* subpixel rounding function */
 266
 267     FT_Bool            subpixel;          /* Using subpixel hinting?       */
 268     FT_Bool            ignore_x_mode;     /* Standard rendering mode for   */
 269                                           /* subpixel hinting.  On if gray */
 270                                           /* or subpixel hinting is on.    */
 271
 272     /* The following 4 aren't fully implemented but here for MS rasterizer */
 273     /* compatibility.                                                      */
 274     FT_Bool            compatible_widths;     /* compatible widths?        */
 275     FT_Bool            symmetrical_smoothing; /* symmetrical_smoothing?    */
 276     FT_Bool            bgr;                   /* bgr instead of rgb?       */
 277     FT_Bool            subpixel_positioned;   /* subpixel positioned       */
 278                                               /* (DirectWrite ClearType)?  */
 279
 280     FT_Int             rasterizer_version;    /* MS rasterizer version     */
 281
 282     FT_Bool            iup_called;            /* IUP called for glyph?     */
 283
 284     FT_ULong           sph_tweak_flags;       /* flags to control          */
 285                                               /* hint tweaks               */
 286
 287     FT_ULong           sph_in_func_flags;     /* flags to indicate if in   */
 288                                               /* special functions         */
 289
 290 #endif /* TT_CONFIG_OPTION_SUBPIXEL_HINTING */
 291
 292   } TT_ExecContextRec;
 293
 294
 295   extern const TT_GraphicsState  tt_default_graphics_state;
 296
 297
 298 #ifdef TT_USE_BYTECODE_INTERPRETER
 299   FT_LOCAL( void )
 300   TT_Goto_CodeRange( TT_ExecContext  exec,
 301                      FT_Int          range,
 302                      FT_Long         IP );
 303
 304   FT_LOCAL( void )
 305   TT_Set_CodeRange( TT_ExecContext  exec,
 306                     FT_Int          range,
 307                     void*           base,
 308                     FT_Long         length );
 309
 310   FT_LOCAL( void )
 311   TT_Clear_CodeRange( TT_ExecContext  exec,
 312                       FT_Int          range );
 313
 314
 315   FT_LOCAL( FT_Error )
 316   Update_Max( FT_Memory  memory,
 317               FT_ULong*  size,
 318               FT_Long    multiplier,
 319               void*      _pbuff,
 320               FT_ULong   new_max );
 321 #endif /* TT_USE_BYTECODE_INTERPRETER */
 322
 323
 324   /*************************************************************************/
 325   /*                                                                       */
 326   /* <Function>                                                            */
 327   /*    TT_New_Context                                                     */
 328   /*                                                                       */
 329   /* <Description>                                                         */
 330   /*    Queries the face context for a given font.  Note that there is     */
 331   /*    now a _single_ execution context in the TrueType driver which is   */
 332   /*    shared among faces.                                                */
 333   /*                                                                       */
 334   /* <Input>                                                               */
 335   /*    face :: A handle to the source face object.                        */
 336   /*                                                                       */
 337   /* <Return>                                                              */
 338   /*    A handle to the execution context.  Initialized for `face'.        */
 339   /*                                                                       */
 340   /* <Note>                                                                */
 341   /*    Only the glyph loader and debugger should call this function.      */
 342   /*                                                                       */
 343   FT_EXPORT( TT_ExecContext )
 344   TT_New_Context( TT_Driver  driver );
 345
 346
 347 #ifdef TT_USE_BYTECODE_INTERPRETER
 348   FT_LOCAL( void )
 349   TT_Done_Context( TT_ExecContext  exec );
 350
 351   FT_LOCAL( FT_Error )
 352   TT_Load_Context( TT_ExecContext  exec,
 353                    TT_Face         face,
 354                    TT_Size         size );
 355
 356   FT_LOCAL( void )
 357   TT_Save_Context( TT_ExecContext  exec,
 358                    TT_Size         ins );
 359
 360   FT_LOCAL( FT_Error )
 361   TT_Run_Context( TT_ExecContext  exec,
 362                   FT_Bool         debug );
 363 #endif /* TT_USE_BYTECODE_INTERPRETER */
 364
 365
 366   /*************************************************************************/
 367   /*                                                                       */
 368   /* <Function>                                                            */
 369   /*    TT_RunIns                                                          */
 370   /*                                                                       */
 371   /* <Description>                                                         */
 372   /*    Executes one or more instruction in the execution context.  This   */
 373   /*    is the main function of the TrueType opcode interpreter.           */
 374   /*                                                                       */
 375   /* <Input>                                                               */
 376   /*    exec :: A handle to the target execution context.                  */
 377   /*                                                                       */
 378   /* <Return>                                                              */
 379   /*    FreeType error code.  0 means success.                             */
 380   /*                                                                       */
 381   /* <Note>                                                                */
 382   /*    Only the object manager and debugger should call this function.    */
 383   /*                                                                       */
 384   /*    This function is publicly exported because it is directly          */
 385   /*    invoked by the TrueType debugger.                                  */
 386   /*                                                                       */
 387   FT_EXPORT( FT_Error )
 388   TT_RunIns( TT_ExecContext  exec );
 389
 390
 391 FT_END_HEADER
 392
 393 #endif /* __TTINTERP_H__ */
 394
 395
 396 /* END */