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1 /***************************************************************************/ |
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2 /* */ |
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3 /* fttrigon.h */ |
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4 /* */ |
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5 /* FreeType trigonometric functions (specification). */ |
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6 /* */ |
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7 /* Copyright 2001, 2003, 2005, 2007 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 __FTTRIGON_H__ |
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20 #define __FTTRIGON_H__ |
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21 |
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22 #include FT_FREETYPE_H |
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23 |
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24 #ifdef FREETYPE_H |
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25 #error "freetype.h of FreeType 1 has been loaded!" |
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26 #error "Please fix the directory search order for header files" |
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27 #error "so that freetype.h of FreeType 2 is found first." |
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28 #endif |
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29 |
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30 |
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31 FT_BEGIN_HEADER |
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32 |
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33 |
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34 /*************************************************************************/ |
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35 /* */ |
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36 /* <Section> */ |
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37 /* computations */ |
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38 /* */ |
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39 /*************************************************************************/ |
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40 |
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41 |
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42 /************************************************************************* |
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43 * |
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44 * @type: |
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45 * FT_Angle |
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46 * |
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47 * @description: |
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48 * This type is used to model angle values in FreeType. Note that the |
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49 * angle is a 16.16 fixed float value expressed in degrees. |
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50 * |
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51 */ |
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52 typedef FT_Fixed FT_Angle; |
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53 |
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54 |
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55 /************************************************************************* |
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56 * |
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57 * @macro: |
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58 * FT_ANGLE_PI |
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59 * |
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60 * @description: |
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61 * The angle pi expressed in @FT_Angle units. |
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62 * |
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63 */ |
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64 #define FT_ANGLE_PI ( 180L << 16 ) |
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65 |
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66 |
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67 /************************************************************************* |
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68 * |
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69 * @macro: |
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70 * FT_ANGLE_2PI |
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71 * |
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72 * @description: |
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73 * The angle 2*pi expressed in @FT_Angle units. |
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74 * |
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75 */ |
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76 #define FT_ANGLE_2PI ( FT_ANGLE_PI * 2 ) |
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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 * @macro: |
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82 * FT_ANGLE_PI2 |
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83 * |
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84 * @description: |
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85 * The angle pi/2 expressed in @FT_Angle units. |
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86 * |
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87 */ |
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88 #define FT_ANGLE_PI2 ( FT_ANGLE_PI / 2 ) |
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89 |
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90 |
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91 /************************************************************************* |
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92 * |
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93 * @macro: |
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94 * FT_ANGLE_PI4 |
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95 * |
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96 * @description: |
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97 * The angle pi/4 expressed in @FT_Angle units. |
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98 * |
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99 */ |
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100 #define FT_ANGLE_PI4 ( FT_ANGLE_PI / 4 ) |
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101 |
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102 |
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103 /************************************************************************* |
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104 * |
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105 * @function: |
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106 * FT_Sin |
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107 * |
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108 * @description: |
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109 * Return the sinus of a given angle in fixed point format. |
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110 * |
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111 * @input: |
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112 * angle :: |
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113 * The input angle. |
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114 * |
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115 * @return: |
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116 * The sinus value. |
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117 * |
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118 * @note: |
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119 * If you need both the sinus and cosinus for a given angle, use the |
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120 * function @FT_Vector_Unit. |
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121 * |
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122 */ |
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123 FT_EXPORT( FT_Fixed ) |
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124 FT_Sin( FT_Angle angle ); |
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125 |
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126 |
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127 /************************************************************************* |
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128 * |
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129 * @function: |
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130 * FT_Cos |
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131 * |
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132 * @description: |
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133 * Return the cosinus of a given angle in fixed point format. |
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134 * |
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135 * @input: |
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136 * angle :: |
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137 * The input angle. |
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138 * |
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139 * @return: |
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140 * The cosinus value. |
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141 * |
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142 * @note: |
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143 * If you need both the sinus and cosinus for a given angle, use the |
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144 * function @FT_Vector_Unit. |
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145 * |
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146 */ |
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147 FT_EXPORT( FT_Fixed ) |
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148 FT_Cos( FT_Angle angle ); |
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149 |
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150 |
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151 /************************************************************************* |
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152 * |
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153 * @function: |
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154 * FT_Tan |
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155 * |
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156 * @description: |
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157 * Return the tangent of a given angle in fixed point format. |
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158 * |
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159 * @input: |
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160 * angle :: |
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161 * The input angle. |
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162 * |
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163 * @return: |
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164 * The tangent value. |
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165 * |
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166 */ |
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167 FT_EXPORT( FT_Fixed ) |
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168 FT_Tan( FT_Angle angle ); |
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169 |
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170 |
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171 /************************************************************************* |
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172 * |
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173 * @function: |
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174 * FT_Atan2 |
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175 * |
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176 * @description: |
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177 * Return the arc-tangent corresponding to a given vector (x,y) in |
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178 * the 2d plane. |
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179 * |
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180 * @input: |
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181 * x :: |
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182 * The horizontal vector coordinate. |
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183 * |
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184 * y :: |
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185 * The vertical vector coordinate. |
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186 * |
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187 * @return: |
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188 * The arc-tangent value (i.e. angle). |
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189 * |
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190 */ |
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191 FT_EXPORT( FT_Angle ) |
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192 FT_Atan2( FT_Fixed x, |
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193 FT_Fixed y ); |
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194 |
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195 |
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196 /************************************************************************* |
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197 * |
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198 * @function: |
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199 * FT_Angle_Diff |
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200 * |
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201 * @description: |
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202 * Return the difference between two angles. The result is always |
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203 * constrained to the ]-PI..PI] interval. |
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204 * |
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205 * @input: |
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206 * angle1 :: |
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207 * First angle. |
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208 * |
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209 * angle2 :: |
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210 * Second angle. |
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211 * |
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212 * @return: |
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213 * Constrained value of `value2-value1'. |
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214 * |
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215 */ |
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216 FT_EXPORT( FT_Angle ) |
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217 FT_Angle_Diff( FT_Angle angle1, |
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218 FT_Angle angle2 ); |
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219 |
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220 |
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221 /************************************************************************* |
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222 * |
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223 * @function: |
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224 * FT_Vector_Unit |
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225 * |
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226 * @description: |
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227 * Return the unit vector corresponding to a given angle. After the |
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228 * call, the value of `vec.x' will be `sin(angle)', and the value of |
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229 * `vec.y' will be `cos(angle)'. |
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230 * |
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231 * This function is useful to retrieve both the sinus and cosinus of a |
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232 * given angle quickly. |
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233 * |
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234 * @output: |
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235 * vec :: |
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236 * The address of target vector. |
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237 * |
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238 * @input: |
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239 * angle :: |
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240 * The address of angle. |
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241 * |
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242 */ |
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243 FT_EXPORT( void ) |
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244 FT_Vector_Unit( FT_Vector* vec, |
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245 FT_Angle angle ); |
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246 |
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247 |
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248 /************************************************************************* |
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249 * |
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250 * @function: |
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251 * FT_Vector_Rotate |
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252 * |
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253 * @description: |
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254 * Rotate a vector by a given angle. |
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255 * |
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256 * @inout: |
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257 * vec :: |
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258 * The address of target vector. |
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259 * |
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260 * @input: |
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261 * angle :: |
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262 * The address of angle. |
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263 * |
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264 */ |
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265 FT_EXPORT( void ) |
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266 FT_Vector_Rotate( FT_Vector* vec, |
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267 FT_Angle angle ); |
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268 |
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269 |
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270 /************************************************************************* |
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271 * |
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272 * @function: |
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273 * FT_Vector_Length |
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274 * |
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275 * @description: |
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276 * Return the length of a given vector. |
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277 * |
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278 * @input: |
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279 * vec :: |
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280 * The address of target vector. |
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281 * |
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282 * @return: |
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283 * The vector length, expressed in the same units that the original |
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284 * vector coordinates. |
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285 * |
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286 */ |
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287 FT_EXPORT( FT_Fixed ) |
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288 FT_Vector_Length( FT_Vector* vec ); |
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289 |
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290 |
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291 /************************************************************************* |
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292 * |
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293 * @function: |
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294 * FT_Vector_Polarize |
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295 * |
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296 * @description: |
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297 * Compute both the length and angle of a given vector. |
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298 * |
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299 * @input: |
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300 * vec :: |
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301 * The address of source vector. |
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302 * |
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303 * @output: |
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304 * length :: |
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305 * The vector length. |
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306 * |
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307 * angle :: |
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308 * The vector angle. |
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309 * |
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310 */ |
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311 FT_EXPORT( void ) |
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312 FT_Vector_Polarize( FT_Vector* vec, |
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313 FT_Fixed *length, |
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314 FT_Angle *angle ); |
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315 |
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316 |
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317 /************************************************************************* |
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318 * |
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319 * @function: |
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320 * FT_Vector_From_Polar |
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321 * |
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322 * @description: |
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323 * Compute vector coordinates from a length and angle. |
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324 * |
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325 * @output: |
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326 * vec :: |
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327 * The address of source vector. |
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328 * |
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329 * @input: |
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330 * length :: |
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331 * The vector length. |
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332 * |
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333 * angle :: |
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334 * The vector angle. |
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335 * |
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336 */ |
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337 FT_EXPORT( void ) |
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338 FT_Vector_From_Polar( FT_Vector* vec, |
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339 FT_Fixed length, |
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340 FT_Angle angle ); |
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341 |
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342 /* */ |
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343 |
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344 |
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345 FT_END_HEADER |
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346 |
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347 #endif /* __FTTRIGON_H__ */ |
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348 |
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349 |
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350 /* END */ |