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| 4680 | right-hear | 1 | /***************************************************************************/ |
| 2 | /* */ |
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| 3 | /* ftcalc.h */ |
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| 4 | /* */ |
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| 5 | /* Arithmetic computations (specification). */ |
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| 6 | /* */ |
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| 7 | /* Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2008, 2009 by */ |
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| 8 | /* David Turner, Robert Wilhelm, and Werner Lemberg. */ |
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| 9 | /* */ |
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| 10 | /* This file is part of the FreeType project, and may only be used, */ |
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| 11 | /* modified, and distributed under the terms of the FreeType project */ |
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| 12 | /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ |
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| 13 | /* this file you indicate that you have read the license and */ |
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| 14 | /* understand and accept it fully. */ |
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| 15 | /* */ |
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| 16 | /***************************************************************************/ |
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| 17 | |||
| 18 | |||
| 19 | #ifndef __FTCALC_H__ |
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| 20 | #define __FTCALC_H__ |
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| 21 | |||
| 22 | |||
| 23 | #include |
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| 24 | #include FT_FREETYPE_H |
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| 25 | |||
| 26 | |||
| 27 | FT_BEGIN_HEADER |
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| 28 | |||
| 29 | |||
| 30 | /*************************************************************************/ |
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| 31 | /* */ |
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| 32 | /* |
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| 33 | /* FT_FixedSqrt */ |
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| 34 | /* */ |
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| 35 | /* |
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| 36 | /* Computes the square root of a 16.16 fixed point value. */ |
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| 37 | /* */ |
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| 38 | /* */ |
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| 39 | /* x :: The value to compute the root for. */ |
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| 40 | /* */ |
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| 41 | /* |
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| 42 | /* The result of `sqrt(x)'. */ |
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| 43 | /* */ |
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| 44 | /* |
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| 45 | /* This function is not very fast. */ |
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| 46 | /* */ |
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| 47 | FT_BASE( FT_Int32 ) |
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| 48 | FT_SqrtFixed( FT_Int32 x ); |
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| 49 | |||
| 50 | |||
| 51 | #ifdef FT_CONFIG_OPTION_OLD_INTERNALS |
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| 52 | |||
| 53 | /*************************************************************************/ |
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| 54 | /* */ |
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| 55 | /* |
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| 56 | /* FT_Sqrt32 */ |
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| 57 | /* */ |
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| 58 | /* |
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| 59 | /* Computes the square root of an Int32 integer (which will be */ |
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| 60 | /* handled as an unsigned long value). */ |
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| 61 | /* */ |
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| 62 | /* */ |
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| 63 | /* x :: The value to compute the root for. */ |
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| 64 | /* */ |
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| 65 | /* |
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| 66 | /* The result of `sqrt(x)'. */ |
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| 67 | /* */ |
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| 68 | FT_EXPORT( FT_Int32 ) |
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| 69 | FT_Sqrt32( FT_Int32 x ); |
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| 70 | |||
| 71 | #endif /* FT_CONFIG_OPTION_OLD_INTERNALS */ |
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| 72 | |||
| 73 | |||
| 74 | /*************************************************************************/ |
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| 75 | /* */ |
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| 76 | /* FT_MulDiv() and FT_MulFix() are declared in freetype.h. */ |
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| 77 | /* */ |
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| 78 | /*************************************************************************/ |
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| 79 | |||
| 80 | |||
| 81 | #ifdef TT_USE_BYTECODE_INTERPRETER |
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| 82 | |||
| 83 | /*************************************************************************/ |
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| 84 | /* */ |
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| 85 | /* |
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| 86 | /* FT_MulDiv_No_Round */ |
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| 87 | /* */ |
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| 88 | /* |
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| 89 | /* A very simple function used to perform the computation `(a*b)/c' */ |
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| 90 | /* (without rounding) with maximal accuracy (it uses a 64-bit */ |
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| 91 | /* intermediate integer whenever necessary). */ |
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| 92 | /* */ |
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| 93 | /* This function isn't necessarily as fast as some processor specific */ |
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| 94 | /* operations, but is at least completely portable. */ |
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| 95 | /* */ |
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| 96 | /* */ |
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| 97 | /* a :: The first multiplier. */ |
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| 98 | /* b :: The second multiplier. */ |
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| 99 | /* c :: The divisor. */ |
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| 100 | /* */ |
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| 101 | /* |
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| 102 | /* The result of `(a*b)/c'. This function never traps when trying to */ |
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| 103 | /* divide by zero; it simply returns `MaxInt' or `MinInt' depending */ |
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| 104 | /* on the signs of `a' and `b'. */ |
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| 105 | /* */ |
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| 106 | FT_BASE( FT_Long ) |
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| 107 | FT_MulDiv_No_Round( FT_Long a, |
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| 108 | FT_Long b, |
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| 109 | FT_Long c ); |
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| 110 | |||
| 111 | #endif /* TT_USE_BYTECODE_INTERPRETER */ |
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| 112 | |||
| 113 | |||
| 114 | /* |
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| 115 | * A variant of FT_Matrix_Multiply which scales its result afterwards. |
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| 116 | * The idea is that both `a' and `b' are scaled by factors of 10 so that |
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| 117 | * the values are as precise as possible to get a correct result during |
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| 118 | * the 64bit multiplication. Let `sa' and `sb' be the scaling factors of |
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| 119 | * `a' and `b', respectively, then the scaling factor of the result is |
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| 120 | * `sa*sb'. |
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| 121 | */ |
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| 122 | FT_BASE( void ) |
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| 123 | FT_Matrix_Multiply_Scaled( const FT_Matrix* a, |
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| 124 | FT_Matrix *b, |
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| 125 | FT_Long scaling ); |
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| 126 | |||
| 127 | |||
| 128 | /* |
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| 129 | * A variant of FT_Vector_Transform. See comments for |
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| 130 | * FT_Matrix_Multiply_Scaled. |
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| 131 | */ |
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| 132 | |||
| 133 | FT_BASE( void ) |
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| 134 | FT_Vector_Transform_Scaled( FT_Vector* vector, |
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| 135 | const FT_Matrix* matrix, |
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| 136 | FT_Long scaling ); |
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| 137 | |||
| 138 | |||
| 139 | /* |
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| 140 | * Return -1, 0, or +1, depending on the orientation of a given corner. |
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| 141 | * We use the Cartesian coordinate system, with positive vertical values |
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| 142 | * going upwards. The function returns +1 if the corner turns to the |
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| 143 | * left, -1 to the right, and 0 for undecidable cases. |
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| 144 | */ |
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| 145 | FT_BASE( FT_Int ) |
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| 146 | ft_corner_orientation( FT_Pos in_x, |
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| 147 | FT_Pos in_y, |
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| 148 | FT_Pos out_x, |
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| 149 | FT_Pos out_y ); |
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| 150 | |||
| 151 | /* |
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| 152 | * Return TRUE if a corner is flat or nearly flat. This is equivalent to |
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| 153 | * saying that the angle difference between the `in' and `out' vectors is |
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| 154 | * very small. |
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| 155 | */ |
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| 156 | FT_BASE( FT_Int ) |
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| 157 | ft_corner_is_flat( FT_Pos in_x, |
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| 158 | FT_Pos in_y, |
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| 159 | FT_Pos out_x, |
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| 160 | FT_Pos out_y ); |
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| 161 | |||
| 162 | |||
| 163 | #define INT_TO_F26DOT6( x ) ( (FT_Long)(x) << 6 ) |
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| 164 | #define INT_TO_F2DOT14( x ) ( (FT_Long)(x) << 14 ) |
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| 165 | #define INT_TO_FIXED( x ) ( (FT_Long)(x) << 16 ) |
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| 166 | #define F2DOT14_TO_FIXED( x ) ( (FT_Long)(x) << 2 ) |
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| 167 | #define FLOAT_TO_FIXED( x ) ( (FT_Long)( x * 65536.0 ) ) |
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| 168 | #define FIXED_TO_INT( x ) ( FT_RoundFix( x ) >> 16 ) |
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| 169 | |||
| 170 | #define ROUND_F26DOT6( x ) ( x >= 0 ? ( ( (x) + 32 ) & -64 ) \ |
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| 171 | : ( -( ( 32 - (x) ) & -64 ) ) ) |
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| 172 | |||
| 173 | |||
| 174 | FT_END_HEADER |
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| 175 | |||
| 176 | #endif /* __FTCALC_H__ */ |
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| 177 | |||
| 178 | |||
| 179 | /* END */ |