Section: XScreenSaver manual (6)
Updated: 5.40 (12-Aug-2018)
petri - simulates mold growing in a petri dish
] [-foreground color
] [-background color
] [-window] [-root] [-mono] [-install] [-visual visual
] [-delay microseconds
] [-size integer
] [-mem-throttle amount
] [-count integer
] [-originalcolors] [-diaglim real
] [-anychan real
] [-minorchan real
] [-instantdeathchan real
] [-minlifespeed real
] [-maxlifespeed real
] [-mindeathspeed real
] [-maxdeathspeed real
] [-minlifespan integer
] [-maxlifespan integer
simulates mold growing in a petri dish via a state-heavy grid
of automata (vaguely like Conway's Life, only with much more state per
accepts the following options:
Draw on a newly-created window. This is the default.
Draw on the root window.
If on a color display, pretend we're on a monochrome display.
Install a private colormap for the window.
- -visual visual
Which visual to use. Legal values are the name of a visual class,
or the id number (decimal or hex) of a specific visual.
- -delay microseconds
The interframe delay, in microseconds. Defaults to 10000, resource
- -size integer
The size of a cell in pixels. Defaults to 4, resource size.
- -mem-throttle amount
The maximum amount of memory to consume, specified either in megabytes
(suffix "M"), kilobytes (suffix "K"), or bytes (sans suffix). In order
to meet the memory requirement, the cell size may be increased.
Defaults to 22M, resource memThrottle.
- -count integer
How many different varieties of mold to grow (including Black Death).
Defaults to 8, resource count.
If specified, indicates that the colors used should be the artist's
original choices (a fixed set of primary and secondary colors). In this
case, count must be 8 or less. Defaults to not specified (i.e., false),
- -diaglim real
The age limit for diagonal growth as a multiplier of
orthogonal growth (range 1..2). 1 means square growth, 1.414
(i.e., sqrt(2)) means approximately circular growth, 2 means
diamond growth. Defaults to 1.414, resource diaglim.
- -anychan real
The chance (range 0..1) that at each iteration, one or more
new cells will be born. Defaults to 0.0015, resource anychan.
- -minorchan real
The chance (range 0..1) that, given that new cells will be born, that only
two will be added (hence being a minor cell birth event).
Defaults to 0.5, resource minorchan.
- -instantdeathchan real
The chance (range 0..1) that, given that death and destruction will happen,
that instead of using Black Death cells, death will come instantaneously.
Defaults to 0.2, resource instantdeathchan.
- -minlifespeed real
The minimum speed for living cells as a fraction of the maximum possible
speed (range 0..1). Defaults to 0.04, resource minlifespeed.
- -maxlifespeed real
The maximum speed for living cells as a fraction of the maximum possible
speed (range 0..1). Defaults to 0.13, resource maxlifespeed.
- -mindeathspeed real
The minimum speed for Black Death cells as a fraction of the maximum possible
speed (range 0..1). Defaults to 0.42, resource mindeathspeed.
- -maxdeathspeed real
The maximum speed for Black Death cells as a fraction of the maximum possible
speed (range 0..1). Defaults to 0.46, resource maxdeathspeed.
- -minlifespan integer
The minimum lifespan for a colony, in iterations, before Black Death
comes. Defaults to 500, resource minlifespan.
- -maxlifespan integer
The maximum lifespan for a colony, in iterations, before Black Death
comes. Defaults to 1500, resource maxlifespan.
Display the current frame rate and CPU load.
to get the default host and display number.
to get the name of a resource file that overrides the global resources
stored in the RESOURCE_MANAGER property.
There are resource equivalents for each option, noted above.
There are no known bugs in
as of this writing.
Copyright © 1992-2000 by Dan Bornstein.
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
Dan Bornstein <email@example.com