ttinterp.h
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上传日期:2020-08-09
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- /***************************************************************************/
- /* */
- /* ttinterp.h */
- /* */
- /* TrueType bytecode interpreter (specification). */
- /* */
- /* Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007 by */
- /* David Turner, Robert Wilhelm, and Werner Lemberg. */
- /* */
- /* This file is part of the FreeType project, and may only be used, */
- /* modified, and distributed under the terms of the FreeType project */
- /* license, LICENSE.TXT. By continuing to use, modify, or distribute */
- /* this file you indicate that you have read the license and */
- /* understand and accept it fully. */
- /* */
- /***************************************************************************/
- #ifndef __TTINTERP_H__
- #define __TTINTERP_H__
- #include <ft2build.h>
- #include "ttobjs.h"
- FT_BEGIN_HEADER
- #ifndef TT_CONFIG_OPTION_STATIC_INTERPRETER /* indirect implementation */
- #define EXEC_OP_ TT_ExecContext exc,
- #define EXEC_OP TT_ExecContext exc
- #define EXEC_ARG_ exc,
- #define EXEC_ARG exc
- #else /* static implementation */
- #define EXEC_OP_ /* void */
- #define EXEC_OP /* void */
- #define EXEC_ARG_ /* void */
- #define EXEC_ARG /* void */
- #endif /* TT_CONFIG_OPTION_STATIC_INTERPRETER */
- /*************************************************************************/
- /* */
- /* Rounding mode constants. */
- /* */
- #define TT_Round_Off 5
- #define TT_Round_To_Half_Grid 0
- #define TT_Round_To_Grid 1
- #define TT_Round_To_Double_Grid 2
- #define TT_Round_Up_To_Grid 4
- #define TT_Round_Down_To_Grid 3
- #define TT_Round_Super 6
- #define TT_Round_Super_45 7
- /*************************************************************************/
- /* */
- /* Function types used by the interpreter, depending on various modes */
- /* (e.g. the rounding mode, whether to render a vertical or horizontal */
- /* line etc). */
- /* */
- /*************************************************************************/
- /* Rounding function */
- typedef FT_F26Dot6
- (*TT_Round_Func)( EXEC_OP_ FT_F26Dot6 distance,
- FT_F26Dot6 compensation );
- /* Point displacement along the freedom vector routine */
- typedef void
- (*TT_Move_Func)( EXEC_OP_ TT_GlyphZone zone,
- FT_UShort point,
- FT_F26Dot6 distance );
- /* Distance projection along one of the projection vectors */
- typedef FT_F26Dot6
- (*TT_Project_Func)( EXEC_OP_ FT_Pos dx,
- FT_Pos dy );
- /* reading a cvt value. Take care of non-square pixels if necessary */
- typedef FT_F26Dot6
- (*TT_Get_CVT_Func)( EXEC_OP_ FT_ULong idx );
- /* setting or moving a cvt value. Take care of non-square pixels */
- /* if necessary */
- typedef void
- (*TT_Set_CVT_Func)( EXEC_OP_ FT_ULong idx,
- FT_F26Dot6 value );
- /*************************************************************************/
- /* */
- /* This structure defines a call record, used to manage function calls. */
- /* */
- typedef struct TT_CallRec_
- {
- FT_Int Caller_Range;
- FT_Long Caller_IP;
- FT_Long Cur_Count;
- FT_Long Cur_Restart;
- } TT_CallRec, *TT_CallStack;
- /*************************************************************************/
- /* */
- /* The main structure for the interpreter which collects all necessary */
- /* variables and states. */
- /* */
- typedef struct TT_ExecContextRec_
- {
- TT_Face face;
- TT_Size size;
- FT_Memory memory;
- /* instructions state */
- FT_Error error; /* last execution error */
- FT_Long top; /* top of exec. stack */
- FT_UInt stackSize; /* size of exec. stack */
- FT_Long* stack; /* current exec. stack */
- FT_Long args;
- FT_UInt new_top; /* new top after exec. */
- TT_GlyphZoneRec zp0, /* zone records */
- zp1,
- zp2,
- pts,
- twilight;
- FT_Size_Metrics metrics;
- TT_Size_Metrics tt_metrics; /* size metrics */
- TT_GraphicsState GS; /* current graphics state */
- FT_Int curRange; /* current code range number */
- FT_Byte* code; /* current code range */
- FT_Long IP; /* current instruction pointer */
- FT_Long codeSize; /* size of current range */
- FT_Byte opcode; /* current opcode */
- FT_Int length; /* length of current opcode */
- FT_Bool step_ins; /* true if the interpreter must */
- /* increment IP after ins. exec */
- FT_Long cvtSize;
- FT_Long* cvt;
- FT_UInt glyphSize; /* glyph instructions buffer size */
- FT_Byte* glyphIns; /* glyph instructions buffer */
- FT_UInt numFDefs; /* number of function defs */
- FT_UInt maxFDefs; /* maximum number of function defs */
- TT_DefArray FDefs; /* table of FDefs entries */
- FT_UInt numIDefs; /* number of instruction defs */
- FT_UInt maxIDefs; /* maximum number of ins defs */
- TT_DefArray IDefs; /* table of IDefs entries */
- FT_UInt maxFunc; /* maximum function index */
- FT_UInt maxIns; /* maximum instruction index */
- FT_Int callTop, /* top of call stack during execution */
- callSize; /* size of call stack */
- TT_CallStack callStack; /* call stack */
- FT_UShort maxPoints; /* capacity of this context's `pts' */
- FT_Short maxContours; /* record, expressed in points and */
- /* contours. */
- TT_CodeRangeTable codeRangeTable; /* table of valid code ranges */
- /* useful for the debugger */
- FT_UShort storeSize; /* size of current storage */
- FT_Long* storage; /* storage area */
- FT_F26Dot6 period; /* values used for the */
- FT_F26Dot6 phase; /* `SuperRounding' */
- FT_F26Dot6 threshold;
- #if 0
- /* this seems to be unused */
- FT_Int cur_ppem; /* ppem along the current proj vector */
- #endif
- FT_Bool instruction_trap; /* If `True', the interpreter will */
- /* exit after each instruction */
- TT_GraphicsState default_GS; /* graphics state resulting from */
- /* the prep program */
- FT_Bool is_composite; /* true if the glyph is composite */
- FT_Bool pedantic_hinting; /* true if pedantic interpretation */
- /* latest interpreter additions */
- FT_Long F_dot_P; /* dot product of freedom and projection */
- /* vectors */
- TT_Round_Func func_round; /* current rounding function */
- TT_Project_Func func_project, /* current projection function */
- func_dualproj, /* current dual proj. function */
- func_freeProj; /* current freedom proj. func */
- TT_Move_Func func_move; /* current point move function */
- TT_Move_Func func_move_orig; /* move original position function */
- TT_Get_CVT_Func func_read_cvt; /* read a cvt entry */
- TT_Set_CVT_Func func_write_cvt; /* write a cvt entry (in pixels) */
- TT_Set_CVT_Func func_move_cvt; /* incr a cvt entry (in pixels) */
- FT_Bool grayscale; /* are we hinting for grayscale? */
- } TT_ExecContextRec;
- extern const TT_GraphicsState tt_default_graphics_state;
- FT_LOCAL( FT_Error )
- TT_Goto_CodeRange( TT_ExecContext exec,
- FT_Int range,
- FT_Long IP );
- FT_LOCAL( FT_Error )
- TT_Set_CodeRange( TT_ExecContext exec,
- FT_Int range,
- void* base,
- FT_Long length );
- FT_LOCAL( FT_Error )
- TT_Clear_CodeRange( TT_ExecContext exec,
- FT_Int range );
- /*************************************************************************/
- /* */
- /* <Function> */
- /* TT_New_Context */
- /* */
- /* <Description> */
- /* Queries the face context for a given font. Note that there is */
- /* now a _single_ execution context in the TrueType driver which is */
- /* shared among faces. */
- /* */
- /* <Input> */
- /* face :: A handle to the source face object. */
- /* */
- /* <Return> */
- /* A handle to the execution context. Initialized for `face'. */
- /* */
- /* <Note> */
- /* Only the glyph loader and debugger should call this function. */
- /* */
- FT_EXPORT( TT_ExecContext )
- TT_New_Context( TT_Driver driver );
- FT_LOCAL( FT_Error )
- TT_Done_Context( TT_ExecContext exec );
- FT_LOCAL( FT_Error )
- TT_Load_Context( TT_ExecContext exec,
- TT_Face face,
- TT_Size size );
- FT_LOCAL( FT_Error )
- TT_Save_Context( TT_ExecContext exec,
- TT_Size ins );
- FT_LOCAL( FT_Error )
- TT_Run_Context( TT_ExecContext exec,
- FT_Bool debug );
- /*************************************************************************/
- /* */
- /* <Function> */
- /* TT_RunIns */
- /* */
- /* <Description> */
- /* Executes one or more instruction in the execution context. This */
- /* is the main function of the TrueType opcode interpreter. */
- /* */
- /* <Input> */
- /* exec :: A handle to the target execution context. */
- /* */
- /* <Return> */
- /* FreeType error code. 0 means success. */
- /* */
- /* <Note> */
- /* Only the object manager and debugger should call this function. */
- /* */
- /* This function is publicly exported because it is directly */
- /* invoked by the TrueType debugger. */
- /* */
- FT_EXPORT( FT_Error )
- TT_RunIns( TT_ExecContext exec );
- FT_END_HEADER
- #endif /* __TTINTERP_H__ */
- /* END */