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Diffstat (limited to 'include/internal/ftcalc.h')
| -rw-r--r-- | include/internal/ftcalc.h | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/include/internal/ftcalc.h b/include/internal/ftcalc.h new file mode 100644 index 0000000..03bd68e --- /dev/null +++ b/include/internal/ftcalc.h @@ -0,0 +1,171 @@ +/***************************************************************************/ +/* */ +/* 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 */ |