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]
+[\-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]
+[\-walls] [\-nowalls] [\-maxspeed] [\-nomaxspeed]
+[\-correct-bounce] [\-fast-bounce]
.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
.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 \-nowalls
+This will cause the balls to continue on past the edge of the
+screen or window. They will still be kept track of and can come back.
+.TP 8
+.B \-walls
+This will cause the balls to bounce when they get
+to the edge of the screen or window. This is the default behavior.
+.TP 8
+.B \-maxspeed
+Imposes a maximum speed (default). If a ball ends up going faster than
+this, it will be treated as though there were .9 viscosity until it is
+under the limit. This stops the balls from continually accelerating (which
+they have a tendancy to do), but also causes balls moving very fast to
+tend to clump in the lower right corner.
+.TP 8
+.B \-nomaxspeed
+If this is specified, no maximum speed is set for the balls.
+.TP 8
+.B \-fast-bounce
+Uses the old, simple bouncing algorithm (default). This simply moves any
+ball that is out of bounds back to a wall and reverses its velocity.
+This works fine for most cases, but under some circumstances, the
+simplification can lead to annoying effects.
+.TP 8
+.B \-correct-bounce
+Uses a more intelligent bouncing algorithm. This method actually reflects
+the balls off the walls until they are within bounds. This can be slow
+if balls are bouncing a whole lot, perhaps because of -nomaxspeed.
+.TP 8
+.B \-graphmode none | x | y | both | speed
+For "x", "y", and "both", displays the given velocities of each ball as a
+bar graph in the same window as the balls. For "speed", displays the total
+speed of each ball. Default is "none".
+.BR
+.SH ENVIRONMENT
.B DISPLAY
to get the default host and display number.
.TP 8
Jamie Zawinski <jwz@jwz.org>, 13-aug-92.
Viscosity and mouse support by Philip Edward Cutone, III.
+
+Walls, speed limit options, new bouncing, graphs, and tail mode fix by
+Matthew Strait. 31 March 2001