1 /***************************************************************************/ 2 /* */ 3 /* ttinterp.h */ 4 /* */ 5 /* TrueType bytecode interpreter (specification). */ 6 /* */ 7 /* Copyright 1996-2001, 2002 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 23 #include <ft2build.h> 24 #include "ttobjs.h" 25 26 27 FT_BEGIN_HEADER 28 29 30 #ifndef TT_CONFIG_OPTION_STATIC_INTEPRETER /* indirect implementation */ 31 32 #define EXEC_OP_ TT_ExecContext exc, 33 #define EXEC_OP TT_ExecContext exc 34 #define EXEC_ARG_ exc, 35 #define EXEC_ARG exc 36 37 #else /* static implementation */ 38 39 #define EXEC_OP_ /* void */ 40 #define EXEC_OP /* void */ 41 #define EXEC_ARG_ /* void */ 42 #define EXEC_ARG /* void */ 43 44 #endif /* TT_CONFIG_OPTION_STATIC_INTERPRETER */ 45 46 47 /*************************************************************************/ 48 /* */ 49 /* Rounding mode constants. */ 50 /* */ 51 #define TT_Round_Off 5 52 #define TT_Round_To_Half_Grid 0 53 #define TT_Round_To_Grid 1 54 #define TT_Round_To_Double_Grid 2 55 #define TT_Round_Up_To_Grid 4 56 #define TT_Round_Down_To_Grid 3 57 #define TT_Round_Super 6 58 #define TT_Round_Super_45 7 59 60 61 /*************************************************************************/ 62 /* */ 63 /* Function types used by the interpreter, depending on various modes */ 64 /* (e.g. the rounding mode, whether to render a vertical or horizontal */ 65 /* line etc). */ 66 /* */ 67 /*************************************************************************/ 68 69 /* Rounding function */ 70 typedef FT_F26Dot6 71 (*TT_Round_Func)( EXEC_OP_ FT_F26Dot6 distance, 72 FT_F26Dot6 compensation ); 73 74 /* Point displacement along the freedom vector routine */ 75 typedef void 76 (*TT_Move_Func)( EXEC_OP_ TT_GlyphZone zone, 77 FT_UShort point, 78 FT_F26Dot6 distance ); 79 80 /* Distance projection along one of the projection vectors */ 81 typedef FT_F26Dot6 82 (*TT_Project_Func)( EXEC_OP_ FT_Vector* v1, 83 FT_Vector* v2 ); 84 85 /* reading a cvt value. Take care of non-square pixels if necessary */ 86 typedef FT_F26Dot6 87 (*TT_Get_CVT_Func)( EXEC_OP_ FT_ULong idx ); 88 89 /* setting or moving a cvt value. Take care of non-square pixels */ 90 /* if necessary */ 91 typedef void 92 (*TT_Set_CVT_Func)( EXEC_OP_ FT_ULong idx, 93 FT_F26Dot6 value ); 94 95 96 /*************************************************************************/ 97 /* */ 98 /* This structure defines a call record, used to manage function calls. */ 99 /* */ 100 typedef struct TT_CallRec_ 101 { 102 FT_Int Caller_Range; 103 FT_Long Caller_IP; 104 FT_Long Cur_Count; 105 FT_Long Cur_Restart; 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_Long 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 */ 213 214 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_ULong loadSize; 219 TT_SubGlyph_Stack loadStack; /* loading subglyph stack */ 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 /*************************************************************************/ 244 /* */ 245 /* <Function> */ 246 /* TT_New_Context */ 247 /* */ 248 /* <Description> */ 249 /* Queries the face context for a given font. Note that there is */ 250 /* now a _single_ execution context in the TrueType driver which is */ 251 /* shared among faces. */ 252 /* */ 253 /* <Input> */ 254 /* face :: A handle to the source face object. */ 255 /* */ 256 /* <Return> */ 257 /* A handle to the execution context. Initialized for `face'. */ 258 /* */ 259 /* <Note> */ 260 /* Only the glyph loader and debugger should call this function. */ 261 /* */ 262 FT_EXPORT( TT_ExecContext ) 263 TT_New_Context( TT_Face face ); 264 265 266 FT_LOCAL( FT_Error ) 267 TT_Done_Context( TT_ExecContext exec ); 268 269 FT_LOCAL( FT_Error ) 270 TT_Destroy_Context( TT_ExecContext exec, 271 FT_Memory memory ); 272 273 FT_LOCAL( FT_Error ) 274 TT_Load_Context( TT_ExecContext exec, 275 TT_Face face, 276 TT_Size size ); 277 278 FT_LOCAL( FT_Error ) 279 TT_Save_Context( TT_ExecContext exec, 280 TT_Size ins ); 281 282 FT_LOCAL( FT_Error ) 283 TT_Run_Context( TT_ExecContext exec, 284 FT_Bool debug ); 285 286 287 /*************************************************************************/ 288 /* */ 289 /* <Function> */ 290 /* TT_RunIns */ 291 /* */ 292 /* <Description> */ 293 /* Executes one or more instruction in the execution context. This */ 294 /* is the main function of the TrueType opcode interpreter. */ 295 /* */ 296 /* <Input> */ 297 /* exec :: A handle to the target execution context. */ 298 /* */ 299 /* <Return> */ 300 /* FreeType error code. 0 means success. */ 301 /* */ 302 /* <Note> */ 303 /* Only the object manager and debugger should call this function. */ 304 /* */ 305 /* This function is publicly exported because it is directly */ 306 /* invoked by the TrueType debugger. */ 307 /* */ 308 FT_EXPORT( FT_Error ) 309 TT_RunIns( TT_ExecContext exec ); 310 311 312 FT_END_HEADER 313 314 #endif /* __TTINTERP_H__ */ 315 316 317 /* END */ 318