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- /***************************************************************************/
- /* */
- /* ftcalc.h */
- /* */
- /* Arithmetic computations (specification). */
- /* */
- /* Copyright 1996-2006, 2008, 2009, 2012-2013 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
- #if 0
- /*************************************************************************/
- /* */
- /* <Function> */
- /* FT_SqrtFixed */
- /* */
- /* <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 );
- #endif /* 0 */
- /*************************************************************************/
- /* */
- /* FT_MulDiv() and FT_MulFix() are declared in freetype.h. */
- /* */
- /*************************************************************************/
- /*************************************************************************/
- /* */
- /* <Function> */
- /* FT_MulDiv_No_Round */
- /* */
- /* <Description> */
- /* A very simple function used to perform the computation `(a*b)/c' */
- /* (without rounding) with maximum 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 );
- /*
- * 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 );
- /*
- * Return the most significant bit index.
- */
- FT_BASE( FT_Int )
- FT_MSB( FT_UInt32 z );
- /*
- * Return sqrt(x*x+y*y), which is the same as `FT_Vector_Length' but uses
- * two fixed-point arguments instead.
- */
- FT_BASE( FT_Fixed )
- FT_Hypot( FT_Fixed x,
- FT_Fixed 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 */
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