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/***************************************************************************/ |
/* */ |
/* ftcalc.h */ |
/* */ |
/* Arithmetic computations (specification). */ |
/* */ |
/* Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2008, 2009 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. */ |
/* */ |
/***************************************************************************/ |
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#ifndef __FTCALC_H__ |
#define __FTCALC_H__ |
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#include <ft2build.h> |
#include FT_FREETYPE_H |
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FT_BEGIN_HEADER |
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/*************************************************************************/ |
/* */ |
/* <Function> */ |
/* FT_FixedSqrt */ |
/* */ |
/* <Description> */ |
/* Computes the square root of a 16.16 fixed point value. */ |
/* */ |
/* <Input> */ |
/* x :: The value to compute the root for. */ |
/* */ |
/* <Return> */ |
/* The result of `sqrt(x)'. */ |
/* */ |
/* <Note> */ |
/* This function is not very fast. */ |
/* */ |
FT_BASE( FT_Int32 ) |
FT_SqrtFixed( FT_Int32 x ); |
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#ifdef FT_CONFIG_OPTION_OLD_INTERNALS |
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/*************************************************************************/ |
/* */ |
/* <Function> */ |
/* FT_Sqrt32 */ |
/* */ |
/* <Description> */ |
/* Computes the square root of an Int32 integer (which will be */ |
/* handled as an unsigned long value). */ |
/* */ |
/* <Input> */ |
/* x :: The value to compute the root for. */ |
/* */ |
/* <Return> */ |
/* The result of `sqrt(x)'. */ |
/* */ |
FT_EXPORT( FT_Int32 ) |
FT_Sqrt32( FT_Int32 x ); |
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#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */ |
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/*************************************************************************/ |
/* */ |
/* FT_MulDiv() and FT_MulFix() are declared in freetype.h. */ |
/* */ |
/*************************************************************************/ |
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#ifdef TT_USE_BYTECODE_INTERPRETER |
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/*************************************************************************/ |
/* */ |
/* <Function> */ |
/* FT_MulDiv_No_Round */ |
/* */ |
/* <Description> */ |
/* A very simple function used to perform the computation `(a*b)/c' */ |
/* (without rounding) with maximal accuracy (it uses a 64-bit */ |
/* intermediate integer whenever necessary). */ |
/* */ |
/* This function isn't necessarily as fast as some processor specific */ |
/* operations, but is at least completely portable. */ |
/* */ |
/* <Input> */ |
/* a :: The first multiplier. */ |
/* b :: The second multiplier. */ |
/* c :: The divisor. */ |
/* */ |
/* <Return> */ |
/* The result of `(a*b)/c'. This function never traps when trying to */ |
/* divide by zero; it simply returns `MaxInt' or `MinInt' depending */ |
/* on the signs of `a' and `b'. */ |
/* */ |
FT_BASE( FT_Long ) |
FT_MulDiv_No_Round( FT_Long a, |
FT_Long b, |
FT_Long c ); |
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#endif /* TT_USE_BYTECODE_INTERPRETER */ |
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/* |
* A variant of FT_Matrix_Multiply which scales its result afterwards. |
* The idea is that both `a' and `b' are scaled by factors of 10 so that |
* the values are as precise as possible to get a correct result during |
* the 64bit multiplication. Let `sa' and `sb' be the scaling factors of |
* `a' and `b', respectively, then the scaling factor of the result is |
* `sa*sb'. |
*/ |
FT_BASE( void ) |
FT_Matrix_Multiply_Scaled( const FT_Matrix* a, |
FT_Matrix *b, |
FT_Long scaling ); |
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/* |
* A variant of FT_Vector_Transform. See comments for |
* FT_Matrix_Multiply_Scaled. |
*/ |
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FT_BASE( void ) |
FT_Vector_Transform_Scaled( FT_Vector* vector, |
const FT_Matrix* matrix, |
FT_Long scaling ); |
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/* |
* Return -1, 0, or +1, depending on the orientation of a given corner. |
* We use the Cartesian coordinate system, with positive vertical values |
* going upwards. The function returns +1 if the corner turns to the |
* left, -1 to the right, and 0 for undecidable cases. |
*/ |
FT_BASE( FT_Int ) |
ft_corner_orientation( FT_Pos in_x, |
FT_Pos in_y, |
FT_Pos out_x, |
FT_Pos out_y ); |
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/* |
* Return TRUE if a corner is flat or nearly flat. This is equivalent to |
* saying that the angle difference between the `in' and `out' vectors is |
* very small. |
*/ |
FT_BASE( FT_Int ) |
ft_corner_is_flat( FT_Pos in_x, |
FT_Pos in_y, |
FT_Pos out_x, |
FT_Pos out_y ); |
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#define INT_TO_F26DOT6( x ) ( (FT_Long)(x) << 6 ) |
#define INT_TO_F2DOT14( x ) ( (FT_Long)(x) << 14 ) |
#define INT_TO_FIXED( x ) ( (FT_Long)(x) << 16 ) |
#define F2DOT14_TO_FIXED( x ) ( (FT_Long)(x) << 2 ) |
#define FLOAT_TO_FIXED( x ) ( (FT_Long)( x * 65536.0 ) ) |
#define FIXED_TO_INT( x ) ( FT_RoundFix( x ) >> 16 ) |
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#define ROUND_F26DOT6( x ) ( x >= 0 ? ( ( (x) + 32 ) & -64 ) \ |
: ( -( ( 32 - (x) ) & -64 ) ) ) |
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FT_END_HEADER |
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#endif /* __FTCALC_H__ */ |
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/* END */ |