| /***************************************************************************/ |
| /* */ |
| /* 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 "../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 ); |
| |
| |
| /*************************************************************************/ |
| /* */ |
| /* 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 */ |