1 /***************************************************************************/
5 /* TrueType bytecode interpreter (specification). */
7 /* Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2010 by */
8 /* David Turner, Robert Wilhelm, and Werner Lemberg. */
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. */
16 /***************************************************************************/
19 #ifndef __TTINTERP_H__
20 #define __TTINTERP_H__
29 #ifndef TT_CONFIG_OPTION_STATIC_INTERPRETER /* indirect implementation */
31 #define EXEC_OP_ TT_ExecContext exc,
32 #define EXEC_OP TT_ExecContext exc
33 #define EXEC_ARG_ exc,
36 #else /* static implementation */
38 #define EXEC_OP_ /* void */
39 #define EXEC_OP /* void */
40 #define EXEC_ARG_ /* void */
41 #define EXEC_ARG /* void */
43 #endif /* TT_CONFIG_OPTION_STATIC_INTERPRETER */
46 /*************************************************************************/
48 /* Rounding mode constants. */
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
60 /*************************************************************************/
62 /* Function types used by the interpreter, depending on various modes */
63 /* (e.g. the rounding mode, whether to render a vertical or horizontal */
66 /*************************************************************************/
68 /* Rounding function */
70 (*TT_Round_Func)( EXEC_OP_ FT_F26Dot6 distance,
71 FT_F26Dot6 compensation );
73 /* Point displacement along the freedom vector routine */
75 (*TT_Move_Func)( EXEC_OP_ TT_GlyphZone zone,
77 FT_F26Dot6 distance );
79 /* Distance projection along one of the projection vectors */
81 (*TT_Project_Func)( EXEC_OP_ FT_Pos dx,
84 /* reading a cvt value. Take care of non-square pixels if necessary */
86 (*TT_Get_CVT_Func)( EXEC_OP_ FT_ULong idx );
88 /* setting or moving a cvt value. Take care of non-square pixels */
91 (*TT_Set_CVT_Func)( EXEC_OP_ FT_ULong idx,
95 /*************************************************************************/
97 /* This structure defines a call record, used to manage function calls. */
99 typedef struct TT_CallRec_
107 } TT_CallRec, *TT_CallStack;
110 /*************************************************************************/
112 /* The main structure for the interpreter which collects all necessary */
113 /* variables and states. */
115 typedef struct TT_ExecContextRec_
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 */
131 FT_UInt new_top; /* new top after exec. */
133 TT_GlyphZoneRec zp0, /* zone records */
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 */
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 */
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;
190 /* this seems to be unused */
191 FT_Int cur_ppem; /* ppem along the current proj vector */
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 if pedantic interpretation */
202 /* latest interpreter additions */
204 FT_Long F_dot_P; /* dot product of freedom and projection */
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 */
213 TT_Move_Func func_move_orig; /* move original position function */
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) */
219 FT_Bool grayscale; /* are we hinting for grayscale? */
224 extern const TT_GraphicsState tt_default_graphics_state;
228 TT_Goto_CodeRange( TT_ExecContext exec,
233 TT_Set_CodeRange( TT_ExecContext exec,
239 TT_Clear_CodeRange( TT_ExecContext exec,
244 Update_Max( FT_Memory memory,
251 /*************************************************************************/
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. */
262 /* face :: A handle to the source face object. */
265 /* A handle to the execution context. Initialized for `face'. */
268 /* Only the glyph loader and debugger should call this function. */
270 FT_EXPORT( TT_ExecContext )
271 TT_New_Context( TT_Driver driver );
274 TT_Done_Context( TT_ExecContext exec );
277 TT_Load_Context( TT_ExecContext exec,
282 TT_Save_Context( TT_ExecContext exec,
286 TT_Run_Context( TT_ExecContext exec,
290 /*************************************************************************/
296 /* Executes one or more instruction in the execution context. This */
297 /* is the main function of the TrueType opcode interpreter. */
300 /* exec :: A handle to the target execution context. */
303 /* FreeType error code. 0 means success. */
306 /* Only the object manager and debugger should call this function. */
308 /* This function is publicly exported because it is directly */
309 /* invoked by the TrueType debugger. */
311 FT_EXPORT( FT_Error )
312 TT_RunIns( TT_ExecContext exec );
317 #endif /* __TTINTERP_H__ */