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-.TH XScreenSaver 1 "14-Jun-97" "X Version 11"
-.SH NAME
-attraction - interactions of opposing forces
-.SH SYNOPSIS
-.B attraction
-[\-display \fIhost:display.screen\fP] [\-foreground \fIcolor\fP] [\-background \fIcolor\fP] [\-window] [\-root] [\-mono] [\-install] [\-visual \fIvisual\fP] [\-points \fIint\fP] [\-threshold \fIint\fP] [\-mode balls | lines | polygons | splines | filled-splines | tails ] [\-size \fIint\fP] [\-segments \fIint\fP] [\-delay \fIusecs\fP] [\-color-shift \fIint\fP] [\-radius \fIint\fP] [\-vx \fIint\fP] [\-vy \fIint\fP] [\-glow] [\-noglow] [\-orbit] [\-viscosity \fIfloat\fP] [\-mouse] [\-no-mouse] [\-mouse-size]
-.SH DESCRIPTION
-The \fIattraction\fP program has several visually different modes of
-operation, all of which are based on the interactions of a set of control
-points which attract each other up to a certain distance, and then begin
-to repel each other. The attraction/repulsion is proportional to the
-distance between any two particles.
-.SH OPTIONS
-.I attraction
-accepts the following options:
-.TP 8
-.B \-window
-Draw on a newly-created window. This is the default.
-.TP 8
-.B \-root
-Draw on the root window.
-.TP 8
-.B \-mono
-If on a color display, pretend we're on a monochrome display.
-.TP 8
-.B \-install
-Install a private colormap for the window.
-.TP 8
-.B \-visual \fIvisual\fP
-Specify which visual to use. Legal values are the name of a visual class,
-or the id number (decimal or hex) of a specific visual.
-.TP 8
-.B \-points integer
-How many control points should be used, or 0 to select the number randomly.
-Default 0. Between 3 and 15 works best.
-.TP 8
-.B \-threshold integer
-The distance (in pixels) from each particle at which the attractive force
-becomes repulsive. Default 100.
-.TP 8
-.B \-mode "balls | lines | polygons | tails | splines | filled-splines"
-In \fIballs\fP mode (the default) the control points are drawn as filled
-circles. The larger the circle, the more massive the particle.
-
-In \fIlines\fP mode, the control points are connected by straight lines;
-the effect is something like \fIqix\fP.
-
-In \fIpolygons\fP mode, the control points are connected by straight
-lines, and filled in. This is most interesting in color.
-
-In \fIsplines\fP mode, a closed spline is interpolated from the control
-points.
-
-In \fIfilled-splines\fP mode, the splines are filled in instead of being
-outlines. This is most interesting in color.
-
-In \fItails\fP mode, the path which each particle follows is indicated
-by a worm-like trail, whose length is controlled by the \fIsegments\fP
-parameter.
-.TP 8
-.B \-size integer
-The size of the balls in pixels, or 0, meaning to select the sizes
-randomly (the default.) If this is specified, then all balls will be
-the same size. This option has an effect in all modes, since the ``size''
-of the balls controls their mass.
-.TP 8
-.B \-segments integer
-If in \fIlines\fP or \fIpolygons\fP mode, how many sets of line segments
-or polygons should be drawn. Default 100. This has no effect in \fIballs\fP
-mode. If \fIsegments\fP is 0, then no segments will ever be erased (this
-is only useful in color.)
-.TP 8
-.B \-delay microseconds
-How much of a delay should be introduced between steps of the animation.
-Default 10000, or about 0.01 seconds.
-.TP 8
-.B \-color-shift int
-If on a color display, the color of the line segments or polygons will
-cycle through the color map. This specifies how many lines will be drawn
-before a new color is chosen. (When a small number of colors are available,
-increasing this value will yield smoother transitions.) Default 3.
-This has no effect in \fIballs\fP mode.
-.TP 8
-.B \-radius
-The size in pixels of the circle on which the points are initially positioned.
-The default is slightly smaller than the size of the window.
-.TP 8
-.B \-glow
-This is consulted only in \fIballs\fP mode. If this is specified, then
-the saturation of the colors of the points will vary according to their
-current acceleration. This has the effect that the balls flare brighter
-when they are reacting to each other most strongly.
-
-In \fIglow\fP mode, all of the balls will be drawn the same (random)
-color, modulo the saturation shifts. In non-glow mode, the balls will
-each be drawn in a random color that doesn't change.
-.TP 8
-.B \-noglow
-Don't do ``glowing.'' This is the default.
-.TP 8
-.B \-vx pixels
-.TP 8
-.B \-vy pixels
-Initial velocity of the balls. This has no effect in \fB\-orbit\fP mode.
-.TP 8
-.B \-orbit
-Make the initial force on each ball be tangential to the circle on which
-they are initially placed, with the right velocity to hold them in orbit
-about each other. After a while, roundoff errors will cause the orbit
-to decay.
-.TP 8
-.B \-vmult float
-In orbit mode, the initial velocity of the balls is multiplied by this;
-a number less than 1 will make the balls pull closer together, and a larger
-number will make them move apart. The default is 0.9, meaning a slight
-inward pull.
-.TP 8
-.B \-viscosity float
-This sets the viscosity of the hypothetical fluid through which the control
-points move; the default is 1, meaning no resistance. Values higher than 1
-aren't interesting; lower values cause less motion.
-
-One interesting thing to try is
-.EX
-attraction -viscosity 0.8 -points 75 \\
- -mouse -geometry =500x500
-.EE
-Give it a few seconds to settle down into a stable clump, and then move
-the mouse through it to make "waves".
-.TP 8
-.B \-mouse
-This will cause the mouse to be considered a control point; it will not be
-drawn, but it will influence the other points, so you can wave the mouse
-and influence the images being created.
-.TP 8
-.B \-no-mouse
-Turns off \fB\-mouse\fP.
-.TP 8
-.B \-mouse-size integer
-In \fB\-mouse\fP mode, this sets the mass of the mouse (analagously to the
-\fB\-size\fP parameter.)
-.SH ENVIRONMENT
-.PP
-.TP 8
-.B DISPLAY
-to get the default host and display number.
-.TP 8
-.B XENVIRONMENT
-to get the name of a resource file that overrides the global resources
-stored in the RESOURCE_MANAGER property.
-.SH SEE ALSO
-.BR X (1),
-.BR xscreensaver (1)
-.SH COPYRIGHT
-Copyright \(co 1992, 1993, 1997 by Jamie Zawinski. Permission to use, copy,
-modify, distribute, and sell this software and its documentation for any
-purpose is hereby granted without fee, provided that the above copyright
-notice appear in all copies and that both that copyright notice and this
-permission notice appear in supporting documentation. No representations are
-made about the suitability of this software for any purpose. It is provided
-"as is" without express or implied warranty.
-.SH AUTHOR
-Jamie Zawinski <jwz@netscape.com>, 13-aug-92.
-
-Viscosity and mouse support by Philip Edward Cutone, III.
projects / xscreensaver / blobdiff