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ttinterp.h

Last change on this file was 2, checked in by jglee, 11 years ago
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1	/***************************************************************************/
2	/* */
3	/* ttinterp.h */
4	/* */
5	/* TrueType bytecode interpreter (specification). */
6	/* */
7	/* Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007 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
106	} TT_CallRec, *TT_CallStack;
107
108
109	/*************************************************************************/
110	/* */
111	/* The main structure for the interpreter which collects all necessary */
112	/* variables and states. */
113	/* */
114	typedef struct TT_ExecContextRec_
115	{
116	TT_Face face;
117	TT_Size size;
118	FT_Memory memory;
119
120	/* instructions state */
121
122	FT_Error error; /* last execution error */
123
124	FT_Long top; /* top of exec. stack */
125
126	FT_UInt stackSize; /* size of exec. stack */
127	FT_Long* stack; /* current exec. stack */
128
129	FT_Long args;
130	FT_UInt new_top; /* new top after exec. */
131
132	TT_GlyphZoneRec zp0, /* zone records */
133	zp1,
134	zp2,
135	pts,
136	twilight;
137
138	FT_Size_Metrics metrics;
139	TT_Size_Metrics tt_metrics; /* size metrics */
140
141	TT_GraphicsState GS; /* current graphics state */
142
143	FT_Int curRange; /* current code range number */
144	FT_Byte* code; /* current code range */
145	FT_Long IP; /* current instruction pointer */
146	FT_Long codeSize; /* size of current range */
147
148	FT_Byte opcode; /* current opcode */
149	FT_Int length; /* length of current opcode */
150
151	FT_Bool step_ins; /* true if the interpreter must */
152	/* increment IP after ins. exec */
153	FT_Long cvtSize;
154	FT_Long* cvt;
155
156	FT_UInt glyphSize; /* glyph instructions buffer size */
157	FT_Byte* glyphIns; /* glyph instructions buffer */
158
159	FT_UInt numFDefs; /* number of function defs */
160	FT_UInt maxFDefs; /* maximum number of function defs */
161	TT_DefArray FDefs; /* table of FDefs entries */
162
163	FT_UInt numIDefs; /* number of instruction defs */
164	FT_UInt maxIDefs; /* maximum number of ins defs */
165	TT_DefArray IDefs; /* table of IDefs entries */
166
167	FT_UInt maxFunc; /* maximum function index */
168	FT_UInt maxIns; /* maximum instruction index */
169
170	FT_Int callTop, /* top of call stack during execution */
171	callSize; /* size of call stack */
172	TT_CallStack callStack; /* call stack */
173
174	FT_UShort maxPoints; /* capacity of this context's `pts' */
175	FT_Short maxContours; /* record, expressed in points and */
176	/* contours. */
177
178	TT_CodeRangeTable codeRangeTable; /* table of valid code ranges */
179	/* useful for the debugger */
180
181	FT_UShort storeSize; /* size of current storage */
182	FT_Long* storage; /* storage area */
183
184	FT_F26Dot6 period; /* values used for the */
185	FT_F26Dot6 phase; /* `SuperRounding' */
186	FT_F26Dot6 threshold;
187
188	#if 0
189	/* this seems to be unused */
190	FT_Int cur_ppem; /* ppem along the current proj vector */
191	#endif
192
193	FT_Bool instruction_trap; /* If `True', the interpreter will */
194	/* exit after each instruction */
195
196	TT_GraphicsState default_GS; /* graphics state resulting from */
197	/* the prep program */
198	FT_Bool is_composite; /* true if the glyph is composite */
199	FT_Bool pedantic_hinting; /* true if pedantic interpretation */
200
201	/* latest interpreter additions */
202
203	FT_Long F_dot_P; /* dot product of freedom and projection */
204	/* vectors */
205	TT_Round_Func func_round; /* current rounding function */
206
207	TT_Project_Func func_project, /* current projection function */
208	func_dualproj, /* current dual proj. function */
209	func_freeProj; /* current freedom proj. func */
210
211	TT_Move_Func func_move; /* current point move function */
212	TT_Move_Func func_move_orig; /* move original position 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_Bool grayscale; /* are we hinting for grayscale? */
219
220	} TT_ExecContextRec;
221
222
223	extern const TT_GraphicsState tt_default_graphics_state;
224
225
226	FT_LOCAL( FT_Error )
227	TT_Goto_CodeRange( TT_ExecContext exec,
228	FT_Int range,
229	FT_Long IP );
230
231	FT_LOCAL( FT_Error )
232	TT_Set_CodeRange( TT_ExecContext exec,
233	FT_Int range,
234	void* base,
235	FT_Long length );
236
237	FT_LOCAL( FT_Error )
238	TT_Clear_CodeRange( TT_ExecContext exec,
239	FT_Int range );
240
241
242	/*************************************************************************/
243	/* */
244	/* <Function> */
245	/* TT_New_Context */
246	/* */
247	/* <Description> */
248	/* Queries the face context for a given font. Note that there is */
249	/* now a _single_ execution context in the TrueType driver which is */
250	/* shared among faces. */
251	/* */
252	/* <Input> */
253	/* face :: A handle to the source face object. */
254	/* */
255	/* <Return> */
256	/* A handle to the execution context. Initialized for `face'. */
257	/* */
258	/* <Note> */
259	/* Only the glyph loader and debugger should call this function. */
260	/* */
261	FT_EXPORT( TT_ExecContext )
262	TT_New_Context( TT_Driver driver );
263
264	FT_LOCAL( FT_Error )
265	TT_Done_Context( TT_ExecContext exec );
266
267	FT_LOCAL( FT_Error )
268	TT_Load_Context( TT_ExecContext exec,
269	TT_Face face,
270	TT_Size size );
271
272	FT_LOCAL( FT_Error )
273	TT_Save_Context( TT_ExecContext exec,
274	TT_Size ins );
275
276	FT_LOCAL( FT_Error )
277	TT_Run_Context( TT_ExecContext exec,
278	FT_Bool debug );
279
280
281	/*************************************************************************/
282	/* */
283	/* <Function> */
284	/* TT_RunIns */
285	/* */
286	/* <Description> */
287	/* Executes one or more instruction in the execution context. This */
288	/* is the main function of the TrueType opcode interpreter. */
289	/* */
290	/* <Input> */
291	/* exec :: A handle to the target execution context. */
292	/* */
293	/* <Return> */
294	/* FreeType error code. 0 means success. */
295	/* */
296	/* <Note> */
297	/* Only the object manager and debugger should call this function. */
298	/* */
299	/* This function is publicly exported because it is directly */
300	/* invoked by the TrueType debugger. */
301	/* */
302	FT_EXPORT( FT_Error )
303	TT_RunIns( TT_ExecContext exec );
304
305
306	FT_END_HEADER
307
308	#endif /* __TTINTERP_H__ */
309
310
311	/* END */

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source: svn/trunk/zasc/freetype-2.3.9/ttinterp.h

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