1 /***************************************************************************/
2 /* */
3 /* ttinterp.h */
4 /* */
5 /* TrueType bytecode interpreter (specification). */
6 /* */
7 /* Copyright 1996-2001 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 /***************************************************************************/
19 #ifndef __TTINTERP_H__
20 #define __TTINTERP_H__
23 #include <ft2build.h>
24 #include "ttobjs.h"
27 FT_BEGIN_HEADER
30 #ifndef TT_CONFIG_OPTION_STATIC_INTEPRETER /* indirect implementation */
32 #define EXEC_OP_ TT_ExecContext exc,
33 #define EXEC_OP TT_ExecContext exc
34 #define EXEC_ARG_ exc,
35 #define EXEC_ARG exc
37 #else /* static implementation */
39 #define EXEC_OP_ /* void */
40 #define EXEC_OP /* void */
41 #define EXEC_ARG_ /* void */
42 #define EXEC_ARG /* void */
44 #endif /* TT_CONFIG_OPTION_STATIC_INTERPRETER */
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
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 /*************************************************************************/
69 /* Rounding function */
70 typedef FT_F26Dot6
71 (*TT_Round_Func)( EXEC_OP_ FT_F26Dot6 distance,
72 FT_F26Dot6 compensation );
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 );
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 );
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 index );
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 index,
93 FT_F26Dot6 value );
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;
107 } TT_CallRec, *TT_CallStack;
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;
121 /* instructions state */
123 FT_Error error; /* last execution error */
125 FT_Long top; /* top of exec. stack */
127 FT_UInt stackSize; /* size of exec. stack */
128 FT_Long* stack; /* current exec. stack */
130 FT_Long args;
131 FT_UInt new_top; /* new top after exec. */
133 TT_GlyphZone zp0, /* zone records */
134 zp1,
135 zp2,
136 pts,
137 twilight;
139 FT_Size_Metrics metrics;
140 TT_Size_Metrics tt_metrics; /* size metrics */
142 TT_GraphicsState GS; /* current graphics state */
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 */
149 FT_Byte opcode; /* current opcode */
150 FT_Int length; /* length of current opcode */
152 FT_Bool step_ins; /* true if the interpreter must */
153 /* increment IP after ins. exec */
154 FT_Long cvtSize;
155 FT_Long* cvt;
157 FT_UInt glyphSize; /* glyph instructions buffer size */
158 FT_Byte* glyphIns; /* glyph instructions buffer */
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 */
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 */
168 FT_UInt maxFunc; /* maximum function index */
169 FT_UInt maxIns; /* maximum instruction index */
171 FT_Int callTop, /* top of call stack during execution */
172 callSize; /* size of call stack */
173 TT_CallStack callStack; /* call stack */
175 FT_UShort maxPoints; /* capacity of this context's `pts' */
176 FT_Short maxContours; /* record, expressed in points and */
177 /* contours. */
179 TT_CodeRangeTable codeRangeTable; /* table of valid code ranges */
180 /* useful for the debugger */
182 FT_UShort storeSize; /* size of current storage */
183 FT_Long* storage; /* storage area */
185 FT_F26Dot6 period; /* values used for the */
186 FT_F26Dot6 phase; /* `SuperRounding' */
187 FT_F26Dot6 threshold;
189 #if 0
190 /* this seems to be unused */
191 FT_Int cur_ppem; /* ppem along the current proj vector */
192 #endif
194 FT_Bool instruction_trap; /* If `True', the interpreter will */
195 /* exit after each instruction */
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 for pedantic interpretation */
202 /* latest interpreter additions */
204 FT_Long F_dot_P; /* dot product of freedom and projection */
205 /* vectors */
206 TT_Round_Func func_round; /* current rounding function */
208 TT_Project_Func func_project, /* current projection function */
209 func_dualproj, /* current dual proj. function */
210 func_freeProj; /* current freedom proj. func */
212 TT_Move_Func func_move; /* current point move function */
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) */
218 FT_ULong loadSize;
219 TT_SubGlyph_Stack loadStack; /* loading subglyph stack */
221 } TT_ExecContextRec;
224 extern const TT_GraphicsState tt_default_graphics_state;
227 FT_LOCAL FT_Error
228 TT_Goto_CodeRange( TT_ExecContext exec,
229 FT_Int range,
230 FT_Long IP );
232 FT_LOCAL FT_Error
233 TT_Set_CodeRange( TT_ExecContext exec,
234 FT_Int range,
235 void* base,
236 FT_Long length );
238 FT_LOCAL FT_Error
239 TT_Clear_CodeRange( TT_ExecContext exec,
240 FT_Int range );
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 );
266 FT_LOCAL FT_Error
267 TT_Done_Context( TT_ExecContext exec );
269 FT_LOCAL FT_Error
270 TT_Destroy_Context( TT_ExecContext exec,
271 FT_Memory memory );
273 FT_LOCAL FT_Error
274 TT_Load_Context( TT_ExecContext exec,
275 TT_Face face,
276 TT_Size size );
278 FT_LOCAL FT_Error
279 TT_Save_Context( TT_ExecContext exec,
280 TT_Size ins );
282 FT_LOCAL FT_Error
283 TT_Run_Context( TT_ExecContext exec,
284 FT_Bool debug );
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 );
312 FT_END_HEADER
314 #endif /* __TTINTERP_H__ */
317 /* END */