+++ /dev/null
-.de EX \"Begin example
-.ne 5
-.if n .sp 1
-.if t .sp .5
-.nf
-.in +.5i
-..
-.de EE
-.fi
-.in -.5i
-.if n .sp 1
-.if t .sp .5
-..
-.TH XScreenSaver 1 "27-Apr-97" "X Version 11"
-.SH NAME
-epicycle - draws a point moving around a circle which moves around a cicle which...
-.SH SYNOPSIS
-.B epicycle
-[\-display \fIhost:display.screen\fP] [\-root] [\-window] [\-mono] [\-install] [\-noinstall] [\-visual \fIviz\fP] [\-colors \fIN\fP] [\-foreground \fIname\fP] [\-color\-shift \fIN\fP] [\-delay \fImicroseconds\fP] [\-holdtime \fIseconds\fP] [\-linewidth \fIN\fP] [\-min_circles \fIN\fP] [\-max_circles \fIN\fP] [\-min_speed \fInumber\fP] [\-max_speed \fInumber\fP] [\-harmonics \fIN\fP] [\-timestep \fInumber\fP] [\-divisor_poisson \fIprobability\fP] [\-size_factor_min \fInumber\fP] [\-size_factor_max \fInumber\fP]
-.SH DESCRIPTION
-The epicycle program draws the path traced out by a point on the edge
-of a circle. That circle rotates around a point on the rim of another
-circle, and so on, several times. The random curves produced can be
-simple or complex, convex or concave, but they are always closed
-curves (they never go in indefinitely).
-
-You can configure both the way the curves are drawn and the way in
-which the random sequence of circles is generated, either with
-command-line options or X resources.
-.SH OPTIONS
-.TP 8
-.B \-display \fIhost:display.screen\fP
-Specifies which X display we should use (see the section DISPLAY NAMES in
-.BR X (1)
-for more information about this option).
-.TP 8
-.B \-root
-Draw on the root window.
-.TP 8
-.B \-window
-Draw on a newly-created window. This is the default.
-.TP 8
-.B \-mono
-If on a color display, pretend we're on a monochrome display.
-If we're on a mono display, we have no choice.
-.TP 8
-.B \-install
-Install a private colormap for the window.
-.TP 8
-.B \-noinstall
-Don't install a private colormap for the window.
-.TP 8
-.B \-visual \fIviz\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.
-Possible choices include
-
-.RS
-default, best, mono, monochrome, gray, grey, color, staticgray, staticcolor,
-truecolor, grayscale, greyscale, pseudocolor, directcolor, \fInumber\fP
-
-If a decimal or hexadecimal number is used,
-.BR XGetVisualInfo (3X)
-is consulted to obtain the required visual.
-.RE
-.TP 8
-.B \-colors \fIN\fP
-How many colors should be used (if possible). The colors are chosen
-randomly.
-.TP 8
-.B \-foreground \fIname\fP
-With
-.BR \-mono ,
-this option selects the foreground colour.
-.TP 8
-.B \-delay \fImicroseconds\fP
-Specifies the delay between drawing successive line segments of the
-path. If you do not specify
-.BR -sync ,
-some X servers may batch up several drawing operations together,
-producing a less smooth effect. This is more likely to happen
-in monochrome mode (on monochrome servers or when
-.B \-mono
-is specified).
-.TP 8
-.B \-holdtime \fIseconds\fP
-When the figure is complete,
-.I epicycle
-pauses this number of seconds.
-.TP 8
-.B \-linewidth \fIN\fP
-Width in pixels of the body's track. Specifying values greater than
-one may cause slower drawing. The fastest value is usually zero,
-meaning one pixel.
-.TP 8
-.B \-min_circles \fIN\fP
-Smallest number of epicycles in the figure.
-.TP 8
-.B \-max_circles \fIN\fP
-Largest number of epicycles in the figure.
-.TP 8
-.B \-min_speed \fInumber\fP
-Smallest possible value for the base speed of revolution of the
-epicycles. The actual speeds of the epicycles vary from this down
-to
-.IB "min_speed / harmonics" .
-.TP 8
-.B \-max_speed \fInumber\fP
-Smallest possible value for the base speed of revolution of the
-epicycles.
-.TP 8
-.B \-harmonics \fIN\fP
-Number of possible harmonics; the larger this value is, the greater
-the possible variety of possible speeds of epicycle.
-.TP 8
-.B \-timestep \fInumber\fP
-Decreasing this value will reduce the distance the body moves for
-each line segment, possibly producing a smoother figure. Increasing
-it may produce faster results.
-.TP 8
-.B \-divisor_poisson \fIprobability\fP
-Each epicycle rotates at a rate which is a factor of the base speed.
-The speed of each epicycle is the base speed divided by some integer
-between 1 and the value of the
-.B \-harmonics
-option. This integer is decided by starting at 1 and tossing
-a biased coin. For each consecutive head, the value is incremented by
-one. The integer will not be incremented above the value of the
-.B \-harmonics
-option. The argument of this option decides the bias of the coin; it
-is the probability that that coin will produce a head at any given toss.
-.TP 8
-.B \-size_factor_min \fInumber\fP
-Epicycles are always at least this factor smaller than their
-parents.
-.TP 8
-.B \-size_factor_max \fInumber\fP
-Epicycles are never more than this factor smaller than their parents.
-.SH RESOURCES
-.EX
-Option Resource Default Value
------- -------- -------------
--colors .colors 100
--delay .delay 1000
--holdtime .holdtime 2
--linewidth .lineWidth 4
--min_circles .minCircles 2
--max_circles .maxCircles 10
--min_speed .minSpeed 0.003
--max_speed .maxSpeed 0.005
--harmonics .harmonics 8
--timestep .timestep 1.0
--divisor_poisson .divisorPoisson 0.4
--size_factor_min .sizeFactorMin 1.05
--size_factor_max .sizeFactorMax 2.05
- .timestepCoarseFactor 1.0
-.EE
-Before the drawing of the figure is begun, a preliminary calculation
-of the path is done in order to scale the radii of the epicycles so
-as to fit the figure on the screen or window. For the sake of speed,
-This calculation is done with a larger timestep than the actual
-drawing. The time-step used is the value of the
-.B \-timestep
-option multiplied by the timestepCoarseFactor resource. The default
-value of 1 will almost always work fast enough and so this resource
-is not available as a command-line option.
-.SH USER INTERFACE
-The program runs mostly without user interaction. When running on the
-root window, no input is accepted. When running in its own window,
-the program will exit if mouse button 3 is pressed. If any other
-mouse button is pressed, the current figure will be abandoned and
-another will be started.
-.SH HISTORY
-The geometry of epicycles was perfected by Hipparchus of Rhodes at
-some time around 125 B.C., 185 years after the birth of Aristarchus of
-Samos, the inventor of the heliocentric universe model. Hipparchus
-applied epicycles to the Sun and the Moon. Ptolemy of Alexandria went
-on to apply them to what was then the known universe, at around 150
-A.D. Copernicus went on to apply them to the heliocentric model at
-the beginning of the sixteenth century. Johannes Kepler discovered
-that the planets actually move in elliptical orbits in about 1602.
-The inverse-square law of gravity was suggested by Boulliau in 1645.
-Isaac Newton's
-.I Principia Mathematica
-was published in 1687, and proved that Kepler's laws derived from
-Newtonian gravitation.
-.SH BUGS
-The colour selection is re-done for every figure. This may
-generate too much network traffic for this program to work well
-over slow or long links.
-.SH COPYRIGHT
-Copyright \(co 1998, James Youngman. 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
-James Youngman <jay@gnu.org>, April 1998.
projects / xscreensaver / blobdiff