1 | /* epicycle --- The motion of a body with epicycles, as in the pre-Copernican |
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2 | * cosmologies. |
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3 | * |
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4 | * Copyright (c) 1998 James Youngman <jay@gnu.org> |
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5 | * |
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6 | * Permission to use, copy, modify, distribute, and sell this software and its |
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7 | * documentation for any purpose is hereby granted without fee, provided that |
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8 | * the above copyright notice appear in all copies and that both that |
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9 | * copyright notice and this permission notice appear in supporting |
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10 | * documentation. No representations are made about the suitability of this |
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11 | * software for any purpose. It is provided "as is" without express or |
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12 | * implied warranty. |
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13 | */ |
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14 | |
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15 | /* Standard C headers; screenhack.h assumes that these have already |
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16 | * been included if required -- for example, it defines M_PI if not |
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17 | * already defined. |
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18 | */ |
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19 | #include <float.h> |
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20 | #include <math.h> |
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21 | |
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22 | |
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23 | #include "screenhack.h" |
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24 | #include "erase.h" |
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25 | |
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26 | /* MIT-SHM headers omitted; this screenhack doesn't use it */ |
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27 | |
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28 | |
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29 | |
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30 | /*********************************************************/ |
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31 | /******************** MAGIC CONSTANTS ********************/ |
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32 | /*********************************************************/ |
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33 | #define MIN_RADIUS (5) /* smallest allowable circle radius */ |
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34 | #define FILL_PROPORTION (0.9) /* proportion of screen to fill by scaling. */ |
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35 | /*********************************************************/ |
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36 | /***************** END OF MAGIC CONSTANTS ****************/ |
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37 | /*********************************************************/ |
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38 | |
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39 | |
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40 | |
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41 | #define FULLCIRCLE (2.0 * M_PI) /* radians in a circle. */ |
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42 | |
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43 | |
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44 | /* Name of the Screensaver hack */ |
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45 | char *progclass="Epicycle"; |
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46 | |
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47 | /* Some of these resource values here are hand-tuned to give a |
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48 | * pleasing variety of interesting shapes. These are not the only |
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49 | * good settings, but you may find you need to change some as a group |
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50 | * to get pleasing figures. |
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51 | */ |
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52 | char *defaults [] = { |
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53 | ".background: black", |
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54 | ".foreground: white", |
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55 | "*colors: 100", |
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56 | "*color0: red", |
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57 | "*delay: 1000", |
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58 | "*holdtime: 2", |
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59 | "*lineWidth: 4", |
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60 | "*minCircles: 2", |
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61 | "*maxCircles: 10", |
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62 | "*minSpeed: 0.003", |
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63 | "*maxSpeed: 0.005", |
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64 | "*harmonics: 8", |
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65 | "*timestep: 1.0", |
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66 | "*timestepCoarseFactor: 1.0", /* no option for this resource. */ |
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67 | "*divisorPoisson: 0.4", |
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68 | "*sizeFactorMin: 1.05", |
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69 | "*sizeFactorMax: 2.05", |
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70 | 0 |
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71 | }; |
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72 | |
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73 | /* options passed to this program */ |
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74 | XrmOptionDescRec options [] = { |
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75 | { "-color0", ".color0", XrmoptionSepArg, 0 }, |
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76 | { "-colors", ".colors", XrmoptionSepArg, 0 }, |
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77 | { "-colours", ".colors", XrmoptionSepArg, 0 }, |
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78 | { "-foreground", ".foreground", XrmoptionSepArg, 0 }, |
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79 | { "-delay", ".delay", XrmoptionSepArg, 0 }, |
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80 | { "-holdtime", ".holdtime", XrmoptionSepArg, 0 }, |
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81 | { "-linewidth", ".lineWidth", XrmoptionSepArg, 0 }, |
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82 | { "-min_circles", ".minCircles", XrmoptionSepArg, 0 }, |
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83 | { "-max_circles", ".maxCircles", XrmoptionSepArg, 0 }, |
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84 | { "-min_speed", ".minSpeed", XrmoptionSepArg, 0 }, |
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85 | { "-max_speed", ".maxSpeed", XrmoptionSepArg, 0 }, |
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86 | { "-harmonics", ".harmonics", XrmoptionSepArg, 0 }, |
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87 | { "-timestep", ".timestep", XrmoptionSepArg, 0 }, |
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88 | { "-divisor_poisson",".divisorPoisson",XrmoptionSepArg, 0 }, |
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89 | { "-size_factor_min", ".sizeFactorMin", XrmoptionSepArg, 0 }, |
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90 | { "-size_factor_max", ".sizeFactorMax", XrmoptionSepArg, 0 }, |
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91 | { 0, 0, 0, 0 } |
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92 | }; |
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93 | |
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94 | |
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95 | static Display *dpy; |
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96 | static Window window; |
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97 | static GC color0; |
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98 | static int width, height; |
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99 | static int x_offset, y_offset; |
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100 | static int unit_pixels; |
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101 | static unsigned long bg; |
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102 | static Colormap cmap; |
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103 | static int restart = 0; |
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104 | static int stop = 0; |
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105 | static double wdot_max; |
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106 | static XColor *colors = NULL; |
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107 | static int ncolors = 2; |
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108 | static int color_shift_pos=0; /* how far we are towards that. */ |
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109 | static double colour_cycle_rate = 1.0; |
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110 | static int harmonics = 8; |
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111 | static double divisorPoisson = 0.4; |
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112 | static double sizeFactorMin = 1.05; |
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113 | static double sizeFactorMax = 2.05; |
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114 | static int minCircles; |
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115 | static int maxCircles; |
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116 | |
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117 | /* Each circle is centred on a point on the rim of another circle. |
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118 | */ |
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119 | struct tagCircle |
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120 | { |
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121 | long radius; /* in pixels */ |
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122 | double w; /* position (radians ccw from x-axis) */ |
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123 | double initial_w; /* starting position */ |
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124 | double wdot; /* rotation rate (change in w per iteration) */ |
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125 | int divisor; |
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126 | |
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127 | struct tagCircle *pchild; |
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128 | }; |
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129 | typedef struct tagCircle Circle; |
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130 | |
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131 | |
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132 | struct tagBody /* a body that moves on a system of circles. */ |
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133 | { |
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134 | int x_origin, y_origin; |
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135 | int x, y; |
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136 | int old_x, old_y; |
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137 | int current_color; /* pixel index into colors[] */ |
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138 | Circle *epicycles; /* system of circles on which it moves. */ |
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139 | struct tagBody *next; /* next in list. */ |
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140 | }; |
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141 | typedef struct tagBody Body; |
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142 | |
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143 | |
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144 | /* Determine the GCD of two numbers using Euclid's method. The other |
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145 | * possible algorighm is Stein's method, but it's probably only going |
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146 | * to be much faster on machines with no divide instruction, like the |
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147 | * ARM and the Z80. The former is very fast anyway and the latter |
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148 | * probably won't run X clients; in any case, this calculation is not |
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149 | * the bulk of the computational expense of the program. I originally |
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150 | * tried using Stein's method, but I wanted to remove the gotos. Not |
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151 | * wanting to introduce possible bugs, I plumped for Euclid's method |
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152 | * instead. Lastly, Euclid's algorithm is preferred to the |
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153 | * generalisation for N inputs. |
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154 | * |
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155 | * See Knuth, section 4.5.2. |
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156 | */ |
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157 | static int |
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158 | gcd(int u, int v) /* Euclid's Method */ |
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159 | { |
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160 | /* If either operand of % is negative, the sign of the result is |
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161 | * implementation-defined. See section 6.3.5 "Multiplicative |
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162 | * Operators" of the ANSI C Standard (page 46 [LEFT HAND PAGE!] of |
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163 | * "Annotated C Standard", Osborne, ISBN 0-07-881952-0). |
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164 | */ |
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165 | if (u < 0) u = -u; |
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166 | if (v < 0) v = -v; |
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167 | |
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168 | while (0 != v) |
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169 | { |
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170 | int r; |
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171 | r = u % v; |
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172 | u = v; |
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173 | v = r; |
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174 | } |
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175 | return u; |
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176 | } |
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177 | |
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178 | /* Determine the Lowest Common Multiple of two integers, using |
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179 | * Euclid's Proposition 34, as explained in Knuth's The Art of |
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180 | * Computer Programming, Vol 2, section 4.5.2. |
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181 | */ |
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182 | static int |
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183 | lcm(int u, int v) |
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184 | { |
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185 | return u / gcd(u,v) * v; |
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186 | } |
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187 | |
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188 | static long |
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189 | random_radius(double scale) |
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190 | { |
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191 | long r; |
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192 | |
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193 | r = frand(scale) * unit_pixels/2; /* for frand() see utils/yarandom.h */ |
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194 | if (r < MIN_RADIUS) |
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195 | r = MIN_RADIUS; |
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196 | return r; |
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197 | } |
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198 | |
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199 | |
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200 | static long |
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201 | random_divisor(void) |
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202 | { |
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203 | int divisor = 1; |
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204 | int sign; |
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205 | |
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206 | while (frand(1.0) < divisorPoisson && divisor <= harmonics) |
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207 | { |
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208 | ++divisor; |
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209 | } |
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210 | sign = (frand(1.0) < 0.5) ? +1 : -1; |
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211 | return sign * divisor; |
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212 | } |
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213 | |
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214 | |
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215 | static void |
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216 | oom(void) |
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217 | { |
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218 | fprintf(stderr, "Failed to allocate memory!\n"); |
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219 | exit(-1); |
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220 | } |
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221 | |
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222 | |
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223 | /* Construct a circle or die. |
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224 | */ |
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225 | Circle * |
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226 | new_circle(double scale) |
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227 | { |
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228 | Circle *p = malloc(sizeof(Circle)); |
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229 | |
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230 | p->radius = random_radius(scale); |
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231 | p->w = p->initial_w = 0.0; |
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232 | p->divisor = random_divisor(); |
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233 | p->wdot = wdot_max / p->divisor; |
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234 | p->pchild = NULL; |
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235 | |
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236 | return p; |
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237 | } |
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238 | |
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239 | static void delete_circle(Circle *p) |
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240 | { |
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241 | free(p); |
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242 | } |
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243 | |
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244 | static void |
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245 | delete_circle_chain(Circle *p) |
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246 | { |
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247 | while (p) |
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248 | { |
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249 | Circle *q = p->pchild; |
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250 | delete_circle(p); |
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251 | p = q; |
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252 | } |
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253 | } |
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254 | |
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255 | Circle * |
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256 | new_circle_chain(void) |
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257 | { |
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258 | Circle *head; |
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259 | double scale = 1.0, factor; |
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260 | int n; |
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261 | |
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262 | /* Parent circles are larger than their children by a factor of at |
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263 | * least FACTOR_MIN and at most FACTOR_MAX. |
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264 | */ |
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265 | factor = sizeFactorMin + frand(sizeFactorMax - sizeFactorMin); |
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266 | |
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267 | /* There are between minCircles and maxCircles in each figure. |
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268 | */ |
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269 | if (maxCircles == minCircles) |
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270 | n = minCircles; /* Avoid division by zero. */ |
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271 | else |
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272 | n = minCircles + random() % (maxCircles - minCircles); |
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273 | |
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274 | head = NULL; |
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275 | while (n--) |
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276 | { |
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277 | Circle *p = new_circle(scale); |
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278 | p->pchild = head; |
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279 | head = p; |
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280 | |
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281 | scale /= factor; |
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282 | } |
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283 | return head; |
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284 | } |
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285 | |
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286 | static void |
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287 | assign_random_common_w(Circle *p) |
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288 | { |
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289 | double w_common = frand(FULLCIRCLE); /* anywhere on the circle */ |
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290 | while (p) |
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291 | { |
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292 | p->initial_w = w_common; |
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293 | p = p->pchild; |
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294 | } |
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295 | } |
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296 | |
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297 | static Body * |
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298 | new_body(void) |
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299 | { |
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300 | Body *p = malloc(sizeof(Body)); |
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301 | if (NULL == p) |
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302 | oom(); |
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303 | p->epicycles = new_circle_chain(); |
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304 | p->current_color = 0; /* ?? start them all on different colors? */ |
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305 | p->next = NULL; |
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306 | p->x = p->y = 0; |
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307 | p->old_x = p->old_y = 0; |
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308 | p->x_origin = p->y_origin = 0; |
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309 | |
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310 | /* Start all the epicycles at the same w value to make it easier to |
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311 | * figure out at what T value the cycle is closed. We don't just fix |
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312 | * the initial W value because that makes all the patterns tend to |
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313 | * be symmetrical about the X axis. |
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314 | */ |
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315 | assign_random_common_w(p->epicycles); |
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316 | return p; |
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317 | } |
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318 | |
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319 | static void |
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320 | delete_body(Body *p) |
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321 | { |
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322 | delete_circle_chain(p->epicycles); |
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323 | free(p); |
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324 | } |
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325 | |
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326 | |
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327 | static void |
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328 | draw_body(Body *pb, GC gc) |
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329 | { |
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330 | XDrawLine(dpy, window, gc, pb->old_x, pb->old_y, pb->x, pb->y); |
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331 | } |
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332 | |
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333 | static long |
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334 | compute_divisor_lcm(Circle *p) |
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335 | { |
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336 | long l = 1; |
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337 | |
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338 | while (p) |
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339 | { |
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340 | l = lcm(l, p->divisor); |
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341 | p = p->pchild; |
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342 | } |
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343 | return l; |
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344 | } |
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345 | |
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346 | |
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347 | /* move_body() |
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348 | * |
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349 | * Calculate the position for the body at time T. We work in double |
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350 | * rather than int to avoid the cumulative errors that would be caused |
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351 | * by the rounding implicit in an assignment to int. |
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352 | */ |
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353 | static void |
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354 | move_body(Body *pb, double t) |
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355 | { |
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356 | Circle *p; |
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357 | double x, y; |
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358 | |
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359 | pb->old_x = pb->x; |
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360 | pb->old_y = pb->y; |
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361 | |
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362 | x = pb->x_origin; |
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363 | y = pb->y_origin; |
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364 | |
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365 | for (p=pb->epicycles; NULL != p; p=p->pchild) |
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366 | { |
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367 | /* angular pos = initial_pos + time * angular speed */ |
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368 | /* but this is an angular position, so modulo FULLCIRCLE. */ |
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369 | p->w = fmod(p->initial_w + (t * p->wdot), FULLCIRCLE); |
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370 | |
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371 | x += (p->radius * cos(p->w)); |
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372 | y += (p->radius * sin(p->w)); |
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373 | } |
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374 | |
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375 | pb->x = (int)x; |
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376 | pb->y = (int)y; |
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377 | } |
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378 | |
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379 | static int |
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380 | colour_init(XWindowAttributes *pxgwa) |
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381 | { |
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382 | XGCValues gcv; |
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383 | |
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384 | #if 0 |
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385 | int H = random() % 360; /* colour choice from attraction.c. */ |
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386 | double S1 = 0.25; |
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387 | double S2 = 1.00; |
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388 | double V = frand(0.25) + 0.75; |
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389 | int line_width = 0; |
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390 | #endif |
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391 | |
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392 | int retval = 1; |
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393 | unsigned long valuemask = 0L; |
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394 | unsigned long fg; |
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395 | |
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396 | /* Free any already allocated colors... |
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397 | */ |
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398 | if (colors) |
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399 | { |
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400 | free_colors(dpy, cmap, colors, ncolors); |
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401 | colors = 0; |
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402 | ncolors = 0; |
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403 | } |
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404 | |
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405 | ncolors = get_integer_resource ("colors", "Colors"); |
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406 | if (0 == ncolors) /* English spelling? */ |
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407 | ncolors = get_integer_resource ("colours", "Colors"); |
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408 | |
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409 | if (ncolors < 2) |
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410 | ncolors = 2; |
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411 | if (ncolors <= 2) |
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412 | mono_p = True; |
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413 | colors = 0; |
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414 | |
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415 | if (!mono_p) |
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416 | { |
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417 | colors = (XColor *) malloc(sizeof(*colors) * (ncolors+1)); |
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418 | if (!colors) |
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419 | oom(); |
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420 | |
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421 | make_smooth_colormap (dpy, pxgwa->visual, cmap, colors, &ncolors, |
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422 | True, /* allocate */ |
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423 | False, /* not writable */ |
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424 | True); /* verbose (complain about failure) */ |
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425 | if (ncolors <= 2) |
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426 | { |
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427 | if (colors) |
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428 | free (colors); |
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429 | colors = 0; |
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430 | mono_p = True; |
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431 | } |
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432 | } |
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433 | |
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434 | |
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435 | bg = get_pixel_resource ("background", "Background", dpy, cmap); |
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436 | |
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437 | /* Set the line width |
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438 | */ |
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439 | gcv.line_width = get_integer_resource ("lineWidth", "Integer"); |
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440 | if (gcv.line_width) |
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441 | { |
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442 | valuemask |= GCLineWidth; |
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443 | |
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444 | gcv.join_style = JoinRound; |
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445 | gcv.cap_style = CapRound; |
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446 | |
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447 | valuemask |= (GCCapStyle | GCJoinStyle); |
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448 | } |
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449 | |
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450 | |
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451 | /* Set the drawing function. |
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452 | */ |
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453 | gcv.function = GXcopy; |
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454 | valuemask |= GCFunction; |
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455 | |
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456 | /* Set the foreground. |
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457 | */ |
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458 | if (mono_p) |
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459 | fg = get_pixel_resource ("foreground", "Foreground", dpy, cmap); |
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460 | else |
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461 | fg = bg ^ get_pixel_resource (("color0"), "Foreground", dpy, cmap); |
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462 | gcv.foreground = fg; |
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463 | valuemask |= GCForeground; |
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464 | |
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465 | /* Actually create the GC. |
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466 | */ |
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467 | color0 = XCreateGC (dpy, window, valuemask, &gcv); |
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468 | |
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469 | return retval; |
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470 | } |
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471 | |
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472 | |
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473 | /* check_events(); originally from XScreensaver: hacks/maze.c, |
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474 | * but now quite heavily modified. |
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475 | * |
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476 | * Reaction to events:- |
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477 | * |
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478 | * Mouse 1 -- new figure } |
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479 | * 2 -- new figure }-- ignored when running on root window. |
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480 | * 3 -- exit } |
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481 | * |
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482 | * Window resized or exposed -- new figure. |
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483 | * Window iconised -- wait until it's re-mapped, then start a new figure. |
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484 | */ |
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485 | static int |
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486 | check_events (void) /* X event handler [ rhess ] */ |
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487 | { |
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488 | XEvent e; |
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489 | int unmapped = 0; |
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490 | |
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491 | while (unmapped || XPending(dpy)) |
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492 | { |
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493 | XNextEvent(dpy, &e); |
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494 | |
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495 | switch (e.type) |
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496 | { |
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497 | case ButtonPress: |
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498 | switch (e.xbutton.button) |
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499 | { |
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500 | case 3: |
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501 | exit (0); |
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502 | break; |
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503 | |
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504 | case 2: |
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505 | case 1: |
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506 | default: |
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507 | restart = 1 ; |
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508 | stop = 0 ; |
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509 | break; |
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510 | } |
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511 | break; |
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512 | |
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513 | case ConfigureNotify: |
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514 | restart = 1; |
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515 | break; |
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516 | |
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517 | case UnmapNotify: |
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518 | printf("unmapped!\n"); |
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519 | unmapped = 1; |
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520 | restart = 1; /* restart with new fig. when re-mapped. */ |
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521 | break; |
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522 | |
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523 | case Expose: |
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524 | if (0 == e.xexpose.count) |
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525 | { |
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526 | /* We can get several expose events in the queue. |
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527 | * Only the last one has a zero count. We eat |
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528 | * events in this function so as to avoid restarting |
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529 | * the screensaver many times in quick succession. |
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530 | */ |
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531 | restart = 1; |
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532 | } |
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533 | /* If we had been unmapped and are now waiting to be re-mapped, |
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534 | * indicate that we condition we are waiting for is now met. |
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535 | */ |
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536 | if (unmapped) |
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537 | printf("re-mapped!\n"); |
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538 | unmapped = 0; |
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539 | break; |
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540 | |
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541 | default: |
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542 | screenhack_handle_event(dpy, &e); |
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543 | break; |
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544 | } |
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545 | |
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546 | /* If we're unmapped, don't return to the caller. This |
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547 | * prevents us wasting CPU, calculating new positions for |
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548 | * things that will never be plotted. This is a real CPU |
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549 | * saver. |
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550 | */ |
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551 | if (!unmapped) |
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552 | return 1; |
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553 | } |
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554 | return 0; |
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555 | } |
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556 | |
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557 | |
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558 | static void |
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559 | setup(void) |
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560 | { |
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561 | XWindowAttributes xgwa; |
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562 | int root; |
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563 | |
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564 | XGetWindowAttributes (dpy, window, &xgwa); |
---|
565 | cmap = xgwa.colormap; |
---|
566 | |
---|
567 | width = xgwa.width; |
---|
568 | height = xgwa.height; |
---|
569 | x_offset = width / 2; |
---|
570 | y_offset = height / 2; |
---|
571 | unit_pixels = width < height ? width : height; |
---|
572 | |
---|
573 | { |
---|
574 | static Bool done = False; |
---|
575 | if (!done) |
---|
576 | { |
---|
577 | colour_init(&xgwa); |
---|
578 | done = True; |
---|
579 | } |
---|
580 | } |
---|
581 | |
---|
582 | root = get_boolean_resource("root", "Boolean"); |
---|
583 | |
---|
584 | if (root) |
---|
585 | { |
---|
586 | XSelectInput(dpy, window, ExposureMask); |
---|
587 | } |
---|
588 | else |
---|
589 | { |
---|
590 | XGetWindowAttributes (dpy, window, &xgwa); |
---|
591 | XSelectInput (dpy, window, |
---|
592 | xgwa.your_event_mask | ExposureMask | |
---|
593 | ButtonPressMask |StructureNotifyMask); |
---|
594 | } |
---|
595 | |
---|
596 | } |
---|
597 | static void |
---|
598 | color_step(Body *pb, double frac) |
---|
599 | { |
---|
600 | if (!mono_p) |
---|
601 | { |
---|
602 | int newshift = ncolors * fmod(frac * colour_cycle_rate, 1.0); |
---|
603 | if (newshift != color_shift_pos) |
---|
604 | { |
---|
605 | pb->current_color = newshift; |
---|
606 | XSetForeground (dpy, color0, colors[pb->current_color].pixel); |
---|
607 | color_shift_pos = newshift; |
---|
608 | } |
---|
609 | } |
---|
610 | } |
---|
611 | |
---|
612 | |
---|
613 | long |
---|
614 | distance(long x1, long y1, long x2, long y2) |
---|
615 | { |
---|
616 | long dx, dy; |
---|
617 | |
---|
618 | dx = x2 - x1; |
---|
619 | dy = y2 - y1; |
---|
620 | return dx*dx + dy*dy; |
---|
621 | } |
---|
622 | |
---|
623 | #if 0 |
---|
624 | static int poisson_irand(double p) |
---|
625 | { |
---|
626 | int r = 1; |
---|
627 | while (fabs(frand(1.0)) < p) |
---|
628 | ++r; |
---|
629 | return r < 1 ? 1 : r; |
---|
630 | } |
---|
631 | #endif |
---|
632 | |
---|
633 | static void |
---|
634 | precalculate_figure(Body *pb, |
---|
635 | double xtime, double step, |
---|
636 | int *x_max, int *y_max, |
---|
637 | int *x_min, int *y_min) |
---|
638 | { |
---|
639 | double t; |
---|
640 | |
---|
641 | move_body(pb, 0.0); /* move once to avoid initial line from origin */ |
---|
642 | *x_min = *x_max = pb->x; |
---|
643 | *y_min = *y_max = pb->y; |
---|
644 | |
---|
645 | for (t=0.0; t<xtime; t += step) |
---|
646 | { |
---|
647 | move_body(pb, t); /* move once to avoid initial line from origin */ |
---|
648 | if (pb->x > *x_max) |
---|
649 | *x_max = pb->x; |
---|
650 | if (pb->x < *x_min) |
---|
651 | *x_min = pb->x; |
---|
652 | if (pb->y > *y_max) |
---|
653 | *y_max = pb->y; |
---|
654 | if (pb->y < *y_min) |
---|
655 | *y_min = pb->y; |
---|
656 | } |
---|
657 | } |
---|
658 | |
---|
659 | static int i_max(int a, int b) |
---|
660 | { |
---|
661 | return (a>b) ? a : b; |
---|
662 | } |
---|
663 | |
---|
664 | static void rescale_circles(Body *pb, |
---|
665 | int x_max, int y_max, |
---|
666 | int x_min, int y_min) |
---|
667 | { |
---|
668 | double xscale, yscale, scale; |
---|
669 | double xm, ym; |
---|
670 | |
---|
671 | x_max -= x_offset; |
---|
672 | x_min -= x_offset; |
---|
673 | y_max -= y_offset; |
---|
674 | y_min -= y_offset; |
---|
675 | |
---|
676 | x_max = i_max(x_max, -x_min); |
---|
677 | y_max = i_max(y_max, -y_min); |
---|
678 | |
---|
679 | |
---|
680 | xm = width / 2.0; |
---|
681 | ym = height / 2.0; |
---|
682 | if (x_max > xm) |
---|
683 | xscale = xm / x_max; |
---|
684 | else |
---|
685 | xscale = 1.0; |
---|
686 | if (y_max > ym) |
---|
687 | yscale = ym / y_max; |
---|
688 | else |
---|
689 | yscale = 1.0; |
---|
690 | |
---|
691 | if (xscale < yscale) /* wider than tall */ |
---|
692 | scale = xscale; /* ensure width fits onscreen */ |
---|
693 | else |
---|
694 | scale = yscale; /* ensure height fits onscreen */ |
---|
695 | |
---|
696 | |
---|
697 | scale *= FILL_PROPORTION; /* only fill FILL_PROPORTION of screen */ |
---|
698 | if (scale < 1.0) /* only reduce, don't enlarge. */ |
---|
699 | { |
---|
700 | Circle *p; |
---|
701 | for (p=pb->epicycles; p; p=p->pchild) |
---|
702 | { |
---|
703 | p->radius *= scale; |
---|
704 | } |
---|
705 | } |
---|
706 | else |
---|
707 | { |
---|
708 | printf("enlarge by x%.2f skipped...\n", scale); |
---|
709 | } |
---|
710 | } |
---|
711 | |
---|
712 | |
---|
713 | /* angular speeds of the circles are harmonics of a fundamental |
---|
714 | * value. That should please the Pythagoreans among you... :-) |
---|
715 | */ |
---|
716 | static double |
---|
717 | random_wdot_max(void) |
---|
718 | { |
---|
719 | /* Maximum and minimum values for the choice of wdot_max. Possible |
---|
720 | * epicycle speeds vary from wdot_max to (wdot_max * harmonics). |
---|
721 | */ |
---|
722 | double minspeed, maxspeed; |
---|
723 | minspeed = get_float_resource("minSpeed", "Double"); |
---|
724 | maxspeed = get_float_resource("maxSpeed", "Double"); |
---|
725 | return harmonics * (minspeed + FULLCIRCLE * frand(maxspeed-minspeed)); |
---|
726 | } |
---|
727 | |
---|
728 | /* this is the function called for your screensaver */ |
---|
729 | /*GLOBAL*/ void |
---|
730 | screenhack(Display *disp, Window win) |
---|
731 | { |
---|
732 | Body *pb = NULL; |
---|
733 | long l; |
---|
734 | double t, timestep, circle, xtime, timestep_coarse; |
---|
735 | int delay; |
---|
736 | int uncleared = 1; |
---|
737 | int xmax, xmin, ymax, ymin; |
---|
738 | int holdtime = get_integer_resource ("holdtime", "Integer"); |
---|
739 | |
---|
740 | dpy = disp; |
---|
741 | window = win; |
---|
742 | |
---|
743 | circle = FULLCIRCLE; |
---|
744 | |
---|
745 | XClearWindow(dpy, window); |
---|
746 | uncleared = 0; |
---|
747 | |
---|
748 | delay = get_integer_resource ("delay", "Integer"); |
---|
749 | harmonics = get_integer_resource("harmonics", "Integer"); |
---|
750 | divisorPoisson = get_float_resource("divisorPoisson", "Double"); |
---|
751 | |
---|
752 | timestep = get_float_resource("timestep", "Double"); |
---|
753 | timestep_coarse = timestep * |
---|
754 | get_float_resource("timestepCoarseFactor", "Double"); |
---|
755 | |
---|
756 | sizeFactorMin = get_float_resource("sizeFactorMin", "Double"); |
---|
757 | sizeFactorMax = get_float_resource("sizeFactorMax", "Double"); |
---|
758 | |
---|
759 | minCircles = get_integer_resource ("minCircles", "Integer"); |
---|
760 | maxCircles = get_integer_resource ("maxCircles", "Integer"); |
---|
761 | |
---|
762 | xtime = 0; /* is this right? */ |
---|
763 | while (0 == stop) |
---|
764 | { |
---|
765 | setup(); /* do this inside the loop to cope with any window resizing */ |
---|
766 | restart = 0; |
---|
767 | |
---|
768 | /* Flush any outstanding events; this has the side effect of |
---|
769 | * reducing the number of "false restarts"; resdtarts caused by |
---|
770 | * one event (e.g. ConfigureNotify) followed by another |
---|
771 | * (e.g. Expose). |
---|
772 | */ |
---|
773 | XSync(dpy, True); |
---|
774 | |
---|
775 | wdot_max = random_wdot_max(); |
---|
776 | |
---|
777 | if (pb) |
---|
778 | { |
---|
779 | delete_body(pb); |
---|
780 | pb = NULL; |
---|
781 | } |
---|
782 | pb = new_body(); |
---|
783 | pb->x_origin = pb->x = x_offset; |
---|
784 | pb->y_origin = pb->y = y_offset; |
---|
785 | |
---|
786 | |
---|
787 | if (uncleared) |
---|
788 | { |
---|
789 | erase_full_window(dpy, window); |
---|
790 | uncleared = 0; |
---|
791 | } |
---|
792 | |
---|
793 | fflush(stdout); |
---|
794 | precalculate_figure(pb, xtime, timestep_coarse, |
---|
795 | &xmax, &ymax, &xmin, &ymin); |
---|
796 | |
---|
797 | rescale_circles(pb, xmax, ymax, xmin, ymin); |
---|
798 | |
---|
799 | move_body(pb, 0.0); /* move once to avoid initial line from origin */ |
---|
800 | move_body(pb, 0.0); /* move once to avoid initial line from origin */ |
---|
801 | |
---|
802 | |
---|
803 | t = 0.0; /* start at time zero. */ |
---|
804 | |
---|
805 | l = compute_divisor_lcm(pb->epicycles); |
---|
806 | |
---|
807 | colour_cycle_rate = fabs(l); |
---|
808 | |
---|
809 | xtime = fabs(l * circle / wdot_max); |
---|
810 | |
---|
811 | if (colors) /* (colors==NULL) if mono_p */ |
---|
812 | XSetForeground (dpy, color0, colors[pb->current_color].pixel); |
---|
813 | |
---|
814 | while (0 == restart) |
---|
815 | { |
---|
816 | color_step(pb, t/xtime ); |
---|
817 | draw_body(pb, color0); |
---|
818 | uncleared = 1; |
---|
819 | |
---|
820 | |
---|
821 | /* Check if the figure is complete...*/ |
---|
822 | if (t > xtime) |
---|
823 | { |
---|
824 | XSync (dpy, False); |
---|
825 | |
---|
826 | check_events(); |
---|
827 | if (holdtime) |
---|
828 | sleep(holdtime); /* show complete figure for a bit. */ |
---|
829 | |
---|
830 | restart = 1; /* begin new figure. */ |
---|
831 | } |
---|
832 | |
---|
833 | |
---|
834 | check_events(); |
---|
835 | if (delay) |
---|
836 | usleep (delay); |
---|
837 | |
---|
838 | t += timestep; |
---|
839 | move_body(pb, t); |
---|
840 | check_events(); |
---|
841 | } |
---|
842 | } |
---|
843 | } |
---|
844 | |
---|