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1 perry 1 XScreenSaver
2 !!!XScreenSaver
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 OPTIONS
7 ENVIRONMENT
8 SEE ALSO
9 COPYRIGHT
10 AUTHOR
11 ----
12 !!NAME
13
14
15 attraction - interactions of opposing forces
16 !!SYNOPSIS
17
18
19 __attraction__ [[-display ''host:display.screen'']
20 [[-foreground ''color''] [[-background ''color'']
21 [[-window] [[-root] [[-mono] [[-install] [[-visual ''visual'']
22 [[-points ''int''] [[-threshold ''int''] [[-mode balls |
23 lines | polygons | splines | filled-splines | tails ] [[-size
24 ''int''] [[-segments ''int''] [[-delay ''usecs'']
25 [[-color-shift ''int''] [[-radius ''int''] [[-vx
26 ''int''] [[-vy ''int''] [[-glow] [[-noglow] [[-orbit]
27 [[-viscosity ''float''] [[-mouse] [[-no-mouse] [[-mouse-size]
28 [[-walls] [[-nowalls] [[-maxspeed] [[-nomaxspeed]
29 [[-correct-bounce] [[-fast-bounce]
30 !!DESCRIPTION
31
32
33 The ''attraction'' program has several visually different
34 modes of operation, all of which are based on the
35 interactions of a set of control points which attract each
36 other up to a certain distance, and then begin to repel each
37 other. The attraction/repulsion is proportional to the
38 distance between any two particles.
39 !!OPTIONS
40
41
42 ''attraction'' accepts the following
43 options:
44
45
46 __-window__
47
48
49 Draw on a newly-created window. This is the
50 default.
51
52
53 __-root__
54
55
56 Draw on the root window.
57
58
59 __-mono__
60
61
62 If on a color display, pretend we're on a monochrome
63 display.
64
65
66 __-install__
67
68
69 Install a private colormap for the window.
70
71
72 __-visual__ ''visual''
73
74
75 Specify which visual to use. Legal values are the name of a
76 visual class, or the id number (decimal or hex) of a
77 specific visual.
78
79
80 __-points integer__
81
82
83 How many control points should be used, or 0 to select the
84 number randomly. Default 0. Between 3 and 15 works
85 best.
86
87
88 __-threshold integer__
89
90
91 The distance (in pixels) from each particle at which the
92 attractive force becomes repulsive. Default
93 100.
94
95
96 __-mode balls | lines | polygons | tails | splines |
97 filled-splines__
98
99
100 In ''balls'' mode (the default) the control points are
101 drawn as filled circles. The larger the circle, the more
102 massive the particle.
103
104
105 In ''lines'' mode, the control points are connected by
106 straight lines; the effect is something like
107 ''qix''.
108
109
110 In ''polygons'' mode, the control points are connected by
111 straight lines, and filled in. This is most interesting in
112 color.
113
114
115 In ''splines'' mode, a closed spline is interpolated from
116 the control points.
117
118
119 In ''filled-splines'' mode, the splines are filled in
120 instead of being outlines. This is most interesting in
121 color.
122
123
124 In ''tails'' mode, the path which each particle follows
125 is indicated by a worm-like trail, whose length is
126 controlled by the ''segments'' parameter.
127
128
129 __-size integer__
130
131
132 The size of the balls in pixels, or 0, meaning to select the
133 sizes randomly (the default.) If this is specified, then all
134 balls will be the same size. This option has an effect in
135 all modes, since the ``size'' of the balls controls their
136 mass.
137
138
139 __-segments integer__
140
141
142 If in ''lines'' or ''polygons'' mode, how many sets of
143 line segments or polygons should be drawn. Default 100. This
144 has no effect in ''balls'' mode. If ''segments'' is 0,
145 then no segments will ever be erased (this is only useful in
146 color.)
147
148
149 __-delay microseconds__
150
151
152 How much of a delay should be introduced between steps of
153 the animation. Default 10000, or about 0.01
154 seconds.
155
156
157 __-color-shift int__
158
159
160 If on a color display, the color of the line segments or
161 polygons will cycle through the color map. This specifies
162 how many lines will be drawn before a new color is chosen.
163 (When a small number of colors are available, increasing
164 this value will yield smoother transitions.) Default 3. This
165 has no effect in ''balls'' mode.
166
167
168 __-radius__
169
170
171 The size in pixels of the circle on which the points are
172 initially positioned. The default is slightly smaller than
173 the size of the window.
174
175
176 __-glow__
177
178
179 This is consulted only in ''balls'' mode. If this is
180 specified, then the saturation of the colors of the points
181 will vary according to their current acceleration. This has
182 the effect that the balls flare brighter when they are
183 reacting to each other most strongly.
184
185
186 In ''glow'' mode, all of the balls will be drawn the same
187 (random) color, modulo the saturation shifts. In non-glow
188 mode, the balls will each be drawn in a random color that
189 doesn't change.
190
191
192 __-noglow__
193
194
195 Don't do ``glowing.'' This is the default.
196
197
198 __-vx pixels__
199
200
201 __-vy pixels__
202
203
204 Initial velocity of the balls. This has no effect in
205 __-orbit__ mode.
206
207
208 __-orbit__
209
210
211 Make the initial force on each ball be tangential to the
212 circle on which they are initially placed, with the right
213 velocity to hold them in orbit about each other. After a
214 while, roundoff errors will cause the orbit to
215 decay.
216
217
218 __-vmult float__
219
220
221 In orbit mode, the initial velocity of the balls is
222 multiplied by this; a number less than 1 will make the balls
223 pull closer together, and a larger number will make them
224 move apart. The default is 0.9, meaning a slight inward
225 pull.
226
227
228 __-viscosity float__
229
230
231 This sets the viscosity of the hypothetical fluid through
232 which the control points move; the default is 1, meaning no
233 resistance. Values higher than 1 aren't interesting; lower
234 values cause less motion.
235
236
237 One interesting thing to try is
238
239
240 attraction -viscosity 0.8 -points 75 \
241 -mouse -geometry =500x500
242 Give it a few seconds to settle down into a stable clump, and then move the mouse through it to make
243
244
245 __-mouse__
246
247
248 This will cause the mouse to be considered a control point;
249 it will not be drawn, but it will influence the other
250 points, so you can wave the mouse and influence the images
251 being created.
252
253
254 __-no-mouse__
255
256
257 Turns off __-mouse__.
258
259
260 __-mouse-size integer__
261
262
263 In __-mouse__ mode, this sets the mass of the mouse
264 (analagously to the __-size__ parameter.)
265
266
267 __-nowalls__
268
269
270 This will cause the balls to continue on past the edge of
271 the screen or window. They will still be kept track of and
272 can come back.
273
274
275 __-walls__
276
277
278 This will cause the balls to bounce when they get to the
279 edge of the screen or window. This is the default
280 behavior.
281
282
283 __-maxspeed__
284
285
286 Imposes a maximum speed (default). If a ball ends up going
287 faster than this, it will be treated as though there were .9
288 viscosity until it is under the limit. This stops the balls
289 from continually accelerating (which they have a tendancy to
290 do), but also causes balls moving very fast to tend to clump
291 in the lower right corner.
292
293
294 __-nomaxspeed__
295
296
297 If this is specified, no maximum speed is set for the
298 balls.
299
300
301 __-fast-bounce__
302
303
304 Uses the old, simple bouncing algorithm (default). This
305 simply moves any ball that is out of bounds back to a wall
306 and reverses its velocity. This works fine for most cases,
307 but under some circumstances, the simplification can lead to
308 annoying effects.
309
310
311 __-correct-bounce__
312
313
314 Uses a more intelligent bouncing algorithm. This method
315 actually reflects the balls off the walls until they are
316 within bounds. This can be slow if balls are bouncing a
317 whole lot, perhaps because of -nomaxspeed.
318
319
320 __-graphmode none | x | y | both | speed__
321
322
323 For
324 !!ENVIRONMENT
325
326
327 __DISPLAY__ to get the default host and display
328 number.
329
330
331 __XENVIRONMENT__
332
333
334 to get the name of a resource file that overrides the global
335 resources stored in the RESOURCE_MANAGER
336 property.
337 !!SEE ALSO
338
339
4 perry 340 X(1), xscreensaver(1)
1 perry 341 !!COPYRIGHT
342
343
344 Copyright 1992, 1993, 1997 by Jamie Zawinski. Permission to
345 use, copy, modify, distribute, and sell this software and
346 its documentation for any purpose is hereby granted without
347 fee, provided that the above copyright notice appear in all
348 copies and that both that copyright notice and this
349 permission notice appear in supporting documentation. No
350 representations are made about the suitability of this
351 software for any purpose. It is provided
352 !!AUTHOR
353
354
355 Jamie Zawinski
356
357
358 Viscosity and mouse support by Philip Edward Cutone,
359 III.
360
361
362 Walls, speed limit options, new bouncing, graphs, and tail
363 mode fix by Matthew Strait. 31 March 2001
364 ----
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