ref: 476a76650b8670d63048a925134e93e46becfaf2
dir: /include/internal/ftcalc.h/
/***************************************************************************/ /* */ /* 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 */