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1 /***************************************************************************/ |
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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 |
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18 |
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19 #ifndef __FTCALC_H__ |
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20 #define __FTCALC_H__ |
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21 |
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22 |
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23 #include <ft2build.h> |
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24 #include FT_FREETYPE_H |
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25 |
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26 |
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27 FT_BEGIN_HEADER |
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28 |
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29 |
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30 /*************************************************************************/ |
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31 /* */ |
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32 /* <Function> */ |
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33 /* FT_FixedSqrt */ |
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34 /* */ |
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35 /* <Description> */ |
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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 /* <Input> */ |
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39 /* x :: The value to compute the root for. */ |
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40 /* */ |
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41 /* <Return> */ |
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42 /* The result of `sqrt(x)'. */ |
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43 /* */ |
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44 /* <Note> */ |
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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 |
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50 |
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51 #ifdef FT_CONFIG_OPTION_OLD_INTERNALS |
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52 |
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53 /*************************************************************************/ |
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54 /* */ |
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55 /* <Function> */ |
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56 /* FT_Sqrt32 */ |
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57 /* */ |
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58 /* <Description> */ |
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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 /* <Input> */ |
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63 /* x :: The value to compute the root for. */ |
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64 /* */ |
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65 /* <Return> */ |
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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 |
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71 #endif /* FT_CONFIG_OPTION_OLD_INTERNALS */ |
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72 |
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73 |
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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 |
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80 |
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81 #ifdef TT_USE_BYTECODE_INTERPRETER |
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82 |
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83 /*************************************************************************/ |
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84 /* */ |
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85 /* <Function> */ |
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86 /* FT_MulDiv_No_Round */ |
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87 /* */ |
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88 /* <Description> */ |
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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 /* <Input> */ |
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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 /* <Return> */ |
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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 |
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111 #endif /* TT_USE_BYTECODE_INTERPRETER */ |
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112 |
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113 |
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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 |
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127 |
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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 |
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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 |
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138 |
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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 |
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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 |
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162 |
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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 |
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170 #define ROUND_F26DOT6( x ) ( x >= 0 ? ( ( (x) + 32 ) & -64 ) \ |
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171 : ( -( ( 32 - (x) ) & -64 ) ) ) |
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172 |
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173 |
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174 FT_END_HEADER |
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175 |
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176 #endif /* __FTCALC_H__ */ |
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177 |
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178 |
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179 /* END */ |