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4349 | Serge | 1 | /***************************************************************************/ |
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, 2013 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 __FTTRIGON_H__ |
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20 | #define __FTTRIGON_H__ |
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21 | |||
22 | #include FT_FREETYPE_H |
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23 | |||
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 | |||
30 | |||
31 | FT_BEGIN_HEADER |
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32 | |||
33 | |||
34 | /*************************************************************************/ |
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35 | /* */ |
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36 | /* |
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37 | /* computations */ |
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38 | /* */ |
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39 | /*************************************************************************/ |
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40 | |||
41 | |||
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-point 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 | |||
54 | |||
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 | |||
66 | |||
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 | |||
78 | |||
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 | |||
90 | |||
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 | |||
102 | |||
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 | |||
126 | |||
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 | |||
150 | |||
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 | |||
170 | |||
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 | |||
195 | |||
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 | |||
220 | |||
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 | |||
247 | |||
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 | |||
269 | |||
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 | |||
290 | |||
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 | |||
316 | |||
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 | |||
342 | /* */ |
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343 | |||
344 | |||
345 | FT_END_HEADER |
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346 | |||
347 | #endif /* __FTTRIGON_H__ */ |
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348 | |||
349 | |||
350 | /* END */><> |