ref: c30aea9846efff38b7eefb15c1f361d93dff65ea
dir: /src/truetype/ttinterp.h/
/***************************************************************************/
/* */
/* ttinterp.h */
/* */
/* TrueType bytecode intepreter (specification). */
/* */
/* Copyright 1996-1999 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 <ttobjs.h>
#ifdef __cplusplus
extern "C" {
#endif
#ifndef TT_STATIC_INTEPRETER /* 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_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 TT_F26Dot6 (*TT_Round_Func)( EXEC_OP_ TT_F26Dot6 distance,
TT_F26Dot6 compensation );
/* Point displacement along the freedom vector routine */
typedef void (*TT_Move_Func)( EXEC_OP_ FT_GlyphZone* zone,
TT_UInt point,
TT_F26Dot6 distance );
/* Distance projection along one of the projection vectors */
typedef TT_F26Dot6 (*TT_Project_Func)( EXEC_OP_ TT_Vector* v1,
TT_Vector* v2 );
/* reading a cvt value. Take care of non-square pixels if necessary */
typedef TT_F26Dot6 (*TT_Get_CVT_Func)( EXEC_OP_ TT_ULong index );
/* setting or moving a cvt value. Take care of non-square pixels */
/* if necessary */
typedef void (*TT_Set_CVT_Func)( EXEC_OP_ TT_ULong index,
TT_F26Dot6 value );
/*************************************************************************/
/* */
/* This structure defines a call record, used to manage function calls. */
/* */
typedef struct TT_CallRec_
{
TT_Int Caller_Range;
TT_Long Caller_IP;
TT_Long Cur_Count;
TT_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 */
TT_Error error; /* last execution error */
TT_Long top; /* top of exec. stack */
TT_UInt stackSize; /* size of exec. stack */
TT_Long* stack; /* current exec. stack */
TT_Long args;
TT_UInt new_top; /* new top after exec. */
FT_GlyphZone zp0, /* zone records */
zp1,
zp2,
pts,
twilight;
FT_Size_Metrics metrics;
TT_Size_Metrics tt_metrics; /* size metrics */
TT_GraphicsState GS; /* current graphics state */
TT_Int curRange; /* current code range number */
TT_Byte* code; /* current code range */
TT_Long IP; /* current instruction pointer */
TT_Long codeSize; /* size of current range */
TT_Byte opcode; /* current opcode */
TT_Int length; /* length of current opcode */
TT_Bool step_ins; /* true if the interpreter must */
/* increment IP after ins. exec */
TT_Long cvtSize;
TT_Long* cvt;
TT_UInt glyphSize; /* glyph instructions buffer size */
TT_Byte* glyphIns; /* glyph instructions buffer */
TT_UInt numFDefs; /* number of function defs */
TT_UInt maxFDefs; /* maximum number of function defs */
TT_DefArray FDefs; /* table of FDefs entries */
TT_UInt numIDefs; /* number of instruction defs */
TT_UInt maxIDefs; /* maximum number of ins defs */
TT_DefArray IDefs; /* table of IDefs entries */
TT_UInt maxFunc; /* maximum function index */
TT_UInt maxIns; /* maximum instruction index */
TT_Int callTop, /* top of call stack during execution */
callSize; /* size of call stack */
TT_CallStack callStack; /* call stack */
TT_UShort maxPoints; /* capacity of this context's `pts' */
TT_Short maxContours; /* record, expressed in points and */
/* contours. */
TT_CodeRangeTable codeRangeTable; /* table of valid code ranges */
/* useful for the debugger */
TT_UShort storeSize; /* size of current storage */
TT_Long* storage; /* storage area */
TT_F26Dot6 period; /* values used for the */
TT_F26Dot6 phase; /* `SuperRounding' */
TT_F26Dot6 threshold;
/* this seems to be unused */
#if 0
TT_Int cur_ppem; /* ppem along the current proj vector */
#endif
TT_Bool instruction_trap; /* If `True', the interpreter will */
/* exit after each instruction */
TT_GraphicsState default_GS; /* graphics state resulting from */
/* the prep program */
TT_Bool is_composite; /* true if the glyph is composite */
TT_Bool pedantic_hinting; /* true for pedantic interpretation */
/* latest interpreter additions */
TT_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_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) */
TT_ULong loadSize;
TT_SubGlyph_Stack loadStack; /* loading subglyph stack */
} TT_ExecContextRec;
LOCAL_DEF
const TT_GraphicsState tt_default_graphics_state;
/*************************************************************************/
/* */
/* <Function> */
/* TT_Goto_CodeRange */
/* */
/* <Description> */
/* Switches to a new code range (updates the code related elements in */
/* `exec', and `IP'). */
/* */
/* <Input> */
/* range :: The new execution code range. */
/* IP :: The new IP in the new code range. */
/* */
/* <InOut> */
/* exec :: The target execution context. */
/* */
/* <Return> */
/* TrueType error code. 0 means success. */
/* */
LOCAL_DEF
TT_Error TT_Goto_CodeRange( TT_ExecContext exec,
TT_Int range,
TT_Long IP );
/*************************************************************************/
/* */
/* <Function> */
/* TT_Set_CodeRange */
/* */
/* <Description> */
/* Sets a code range. */
/* */
/* <Input> */
/* range :: The code range index. */
/* base :: The new code base. */
/* length :: The range size in bytes. */
/* */
/* <InOut> */
/* exec :: The target execution context. */
/* */
/* <Return> */
/* TrueType error code. 0 means success. */
/* */
LOCAL_DEF
TT_Error TT_Set_CodeRange( TT_ExecContext exec,
TT_Int range,
void* base,
TT_Long length );
/*************************************************************************/
/* */
/* <Function> */
/* TT_Clear_CodeRange */
/* */
/* <Description> */
/* Clears a code range. */
/* */
/* <Input> */
/* range :: The code range index. */
/* */
/* <InOut> */
/* exec :: The target execution context. */
/* */
/* <Return> */
/* TrueType error code. 0 means success. */
/* */
/* <Note> */
/* Does not set the Error variable. */
/* */
LOCAL_DEF
TT_Error TT_Clear_CodeRange( TT_ExecContext exec,
TT_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. */
/* */
/* This function is publicly exported because it is directly */
/* invoked by the TrueType debugger.. */
/* */
EXPORT_DEF(TT_ExecContext) TT_New_Context( TT_Face face );
/*************************************************************************/
/* */
/* <Function> */
/* TT_Done_Context */
/* */
/* <Description> */
/* Discards an execution context. */
/* */
/* <Input> */
/* exec :: A handle to the target execution context. */
/* */
/* <Return> */
/* TrueType error code. 0 means success. */
/* */
/* <Note> */
/* Only the glyph loader and debugger should call this function. */
/* */
LOCAL_DEF
TT_Error TT_Done_Context( TT_ExecContext exec );
/*************************************************************************/
/* */
/* <Function> */
/* TT_Destroy_Context */
/* */
/* <Description> */
/* Destroys a given context. */
/* */
/* <Input> */
/* exec :: A handle to the target execution context. */
/* memory :: A handle to the parent memory object. */
/* */
/* <Return> */
/* TrueType error code. 0 means success. */
/* */
/* <Note> */
/* Only the glyph loader and debugger should call this function. */
/* */
LOCAL_DEF
TT_Error TT_Destroy_Context( TT_ExecContext exec,
FT_Memory memory );
/*************************************************************************/
/* */
/* <Function> */
/* TT_Load_Context */
/* */
/* <Description> */
/* Prepare an execution context for glyph hinting. */
/* */
/* <Input> */
/* exec :: A handle to the target execution context. */
/* face :: A handle to the source face object. */
/* size :: A handle to the source size object. */
/* */
/* <Return> */
/* TrueType error code. 0 means success. */
/* */
/* <Note> */
/* Only the glyph loader and debugger should call this function. */
/* */
LOCAL_DEF
TT_Error TT_Load_Context( TT_ExecContext exec,
TT_Face face,
TT_Size size );
/*************************************************************************/
/* */
/* <Function> */
/* TT_Save_Context */
/* */
/* <Description> */
/* Saves the code ranges in a `size' object. */
/* */
/* <Input> */
/* exec :: A handle to the source execution context. */
/* */
/* <Output> */
/* ins :: A handle to the target size object. */
/* */
/* <Return> */
/* TrueType error code. 0 means success. */
/* */
/* <Note> */
/* Only the glyph loader and debugger should call this function. */
/* */
LOCAL_DEF
TT_Error TT_Save_Context( TT_ExecContext exec,
TT_Size ins );
/*************************************************************************/
/* */
/* <Function> */
/* TT_Run_Context */
/* */
/* <Description> */
/* Executes one or more instructions in the execution context. */
/* */
/* <Input> */
/* exec :: A handle to the target execution context. */
/* */
/* debug :: A Boolean flag. If set, the function sets some internal */
/* variables and returns immediately, otherwise TT_RunIns() */
/* is called. */
/* */
/* <Return> */
/* TrueTyoe error code. 0 means success. */
/* */
/* <Note> */
/* Only the glyph loader and debugger should call this function. */
/* */
LOCAL_DEF
TT_Error TT_Run_Context( TT_ExecContext exec,
TT_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> */
/* TrueType error code. 0 means success. */
/* */
/* <Note> */
/* Only object manager and debugger should call this function. */
/* */
/* This function is publicly exported because it is directly */
/* invoked by the TrueType debugger.. */
/* */
EXPORT_DEF(TT_Error) TT_RunIns( TT_ExecContext exec );
#ifdef __cplusplus
}
#endif
#endif /* TTINTERP_H */
/* END */