/***************************************************************************/
/* */
/* 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. */
/* */
/***************************************************************************/
#ifndef __FTCALC_H__
#define __FTCALC_H__
#include <ft2build.h>
#include FT_FREETYPE_H
FT_BEGIN_HEADER
/*************************************************************************/
/* */
/* <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 );
#ifdef FT_CONFIG_OPTION_OLD_INTERNALS
/*************************************************************************/
/* */
/* <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 );
#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */
/*************************************************************************/
/* */
/* FT_MulDiv() and FT_MulFix() are declared in freetype.h. */
/* */
/*************************************************************************/
#ifdef TT_USE_BYTECODE_INTERPRETER
/*************************************************************************/
/* */
/* <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 );
#endif /* TT_USE_BYTECODE_INTERPRETER */
/*
* 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 );
/*
* A variant of FT_Vector_Transform. See comments for
* FT_Matrix_Multiply_Scaled.
*/
FT_BASE( void )
FT_Vector_Transform_Scaled( FT_Vector* vector,
const FT_Matrix* matrix,
FT_Long scaling );
/*
* 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 );
/*
* 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 );
#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 )
#define ROUND_F26DOT6( x ) ( x >= 0 ? ( ( (x) + 32 ) & -64 ) \
: ( -( ( 32 - (x) ) & -64 ) ) )
FT_END_HEADER
#endif /* __FTCALC_H__ */
/* END */
Submit an article or tip