14 .TH XScreenSaver 1 "14-Jun-97" "X Version 11"
16 attraction - interactions of opposing forces
19 [\-display \fIhost:display.screen\fP] [\-foreground \fIcolor\fP]
20 [\-background \fIcolor\fP] [\-window] [\-root] [\-mono] [\-install]
21 [\-visual \fIvisual\fP] [\-points \fIint\fP] [\-threshold \fIint\fP]
22 [\-mode balls | lines | polygons | splines | filled-splines | tails ]
23 [\-size \fIint\fP] [\-segments \fIint\fP] [\-delay \fIusecs\fP]
24 [\-color-shift \fIint\fP] [\-radius \fIint\fP]
25 [\-vx \fIint\fP] [\-vy \fIint\fP] [\-glow] [\-noglow]
26 [\-orbit] [\-viscosity \fIfloat\fP] [\-mouse] [\-no-mouse] [\-mouse-size]
27 [\-walls] [\-nowalls] [\-maxspeed] [\-nomaxspeed]
28 [\-correct-bounce] [\-fast-bounce]
30 The \fIattraction\fP program has several visually different modes of
31 operation, all of which are based on the interactions of a set of control
32 points which attract each other up to a certain distance, and then begin
33 to repel each other. The attraction/repulsion is proportional to the
34 distance between any two particles.
37 accepts the following options:
40 Draw on a newly-created window. This is the default.
43 Draw on the root window.
46 If on a color display, pretend we're on a monochrome display.
49 Install a private colormap for the window.
51 .B \-visual \fIvisual\fP
52 Specify which visual to use. Legal values are the name of a visual class,
53 or the id number (decimal or hex) of a specific visual.
56 How many control points should be used, or 0 to select the number randomly.
57 Default 0. Between 3 and 15 works best.
59 .B \-threshold integer
60 The distance (in pixels) from each particle at which the attractive force
61 becomes repulsive. Default 100.
63 .B \-mode "balls | lines | polygons | tails | splines | filled-splines"
64 In \fIballs\fP mode (the default) the control points are drawn as filled
65 circles. The larger the circle, the more massive the particle.
67 In \fIlines\fP mode, the control points are connected by straight lines;
68 the effect is something like \fIqix\fP.
70 In \fIpolygons\fP mode, the control points are connected by straight
71 lines, and filled in. This is most interesting in color.
73 In \fIsplines\fP mode, a closed spline is interpolated from the control
76 In \fIfilled-splines\fP mode, the splines are filled in instead of being
77 outlines. This is most interesting in color.
79 In \fItails\fP mode, the path which each particle follows is indicated
80 by a worm-like trail, whose length is controlled by the \fIsegments\fP
84 The size of the balls in pixels, or 0, meaning to select the sizes
85 randomly (the default.) If this is specified, then all balls will be
86 the same size. This option has an effect in all modes, since the ``size''
87 of the balls controls their mass.
90 If in \fIlines\fP or \fIpolygons\fP mode, how many sets of line segments
91 or polygons should be drawn. Default 100. This has no effect in \fIballs\fP
92 mode. If \fIsegments\fP is 0, then no segments will ever be erased (this
93 is only useful in color.)
95 .B \-delay microseconds
96 How much of a delay should be introduced between steps of the animation.
97 Default 10000, or about 0.01 seconds.
100 If on a color display, the color of the line segments or polygons will
101 cycle through the color map. This specifies how many lines will be drawn
102 before a new color is chosen. (When a small number of colors are available,
103 increasing this value will yield smoother transitions.) Default 3.
104 This has no effect in \fIballs\fP mode.
107 The size in pixels of the circle on which the points are initially positioned.
108 The default is slightly smaller than the size of the window.
111 This is consulted only in \fIballs\fP mode. If this is specified, then
112 the saturation of the colors of the points will vary according to their
113 current acceleration. This has the effect that the balls flare brighter
114 when they are reacting to each other most strongly.
116 In \fIglow\fP mode, all of the balls will be drawn the same (random)
117 color, modulo the saturation shifts. In non-glow mode, the balls will
118 each be drawn in a random color that doesn't change.
121 Don't do ``glowing.'' This is the default.
126 Initial velocity of the balls. This has no effect in \fB\-orbit\fP mode.
129 Make the initial force on each ball be tangential to the circle on which
130 they are initially placed, with the right velocity to hold them in orbit
131 about each other. After a while, roundoff errors will cause the orbit
135 In orbit mode, the initial velocity of the balls is multiplied by this;
136 a number less than 1 will make the balls pull closer together, and a larger
137 number will make them move apart. The default is 0.9, meaning a slight
141 This sets the viscosity of the hypothetical fluid through which the control
142 points move; the default is 1, meaning no resistance. Values higher than 1
143 aren't interesting; lower values cause less motion.
145 One interesting thing to try is
147 attraction -viscosity 0.8 -points 75 \\
148 -mouse -geometry =500x500
150 Give it a few seconds to settle down into a stable clump, and then move
151 the mouse through it to make "waves".
154 This will cause the mouse to be considered a control point; it will not be
155 drawn, but it will influence the other points, so you can wave the mouse
156 and influence the images being created.
159 Turns off \fB\-mouse\fP.
161 .B \-mouse-size integer
162 In \fB\-mouse\fP mode, this sets the mass of the mouse (analagously to the
163 \fB\-size\fP parameter.)
166 This will cause the balls to continue on past the edge of the
167 screen or window. They will still be kept track of and can come back.
170 This will cause the balls to bounce when they get
171 to the edge of the screen or window. This is the default behavior.
174 Imposes a maximum speed (default). If a ball ends up going faster than
175 this, it will be treated as though there were .9 viscosity until it is
176 under the limit. This stops the balls from continually accelerating (which
177 they have a tendancy to do), but also causes balls moving very fast to
178 tend to clump in the lower right corner.
181 If this is specified, no maximum speed is set for the balls.
184 Uses the old, simple bouncing algorithm (default). This simply moves any
185 ball that is out of bounds back to a wall and reverses its velocity.
186 This works fine for most cases, but under some circumstances, the
187 simplification can lead to annoying effects.
190 Uses a more intelligent bouncing algorithm. This method actually reflects
191 the balls off the walls until they are within bounds. This can be slow
192 if balls are bouncing a whole lot, perhaps because of -nomaxspeed.
194 .B \-graphmode none | x | y | both | speed
195 For "x", "y", and "both", displays the given velocities of each ball as a
196 bar graph in the same window as the balls. For "speed", displays the total
197 speed of each ball. Default is "none".
201 to get the default host and display number.
204 to get the name of a resource file that overrides the global resources
205 stored in the RESOURCE_MANAGER property.
210 Copyright \(co 1992, 1993, 1997 by Jamie Zawinski. Permission to use, copy,
211 modify, distribute, and sell this software and its documentation for any
212 purpose is hereby granted without fee, provided that the above copyright
213 notice appear in all copies and that both that copyright notice and this
214 permission notice appear in supporting documentation. No representations are
215 made about the suitability of this software for any purpose. It is provided
216 "as is" without express or implied warranty.
218 Jamie Zawinski <jwz@jwz.org>, 13-aug-92.
220 Viscosity and mouse support by Philip Edward Cutone, III.
222 Walls, speed limit options, new bouncing, graphs, and tail mode fix by
223 Matthew Strait. 31 March 2001
projects / xscreensaver / blob