petri(6) XScreenSaver manual petri(6)

petri - simulates mold growing in a petri dish

petri [-display host:display.screen] [-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] [-fps]

petri 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 cell).

petri 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.
Which visual to use. Legal values are the name of a visual class, or the id number (decimal or hex) of a specific visual.
The interframe delay, in microseconds. Defaults to 10000, resource delay.
The size of a cell in pixels. Defaults to 4, resource size.
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.
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), resource originalcolors.
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.
The chance (range 0..1) that at each iteration, one or more new cells will be born. Defaults to 0.0015, resource anychan.
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.
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.
The minimum speed for living cells as a fraction of the maximum possible speed (range 0..1). Defaults to 0.04, resource minlifespeed.
The maximum speed for living cells as a fraction of the maximum possible speed (range 0..1). Defaults to 0.13, resource maxlifespeed.
The minimum speed for Black Death cells as a fraction of the maximum possible speed (range 0..1). Defaults to 0.42, resource mindeathspeed.
The maximum speed for Black Death cells as a fraction of the maximum possible speed (range 0..1). Defaults to 0.46, resource maxdeathspeed.
The minimum lifespan for a colony, in iterations, before Black Death comes. Defaults to 500, resource minlifespan.
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 petri as of this writing.

xscreensaver(1)

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 implied warranty.

Dan Bornstein <danfuzz@milk.com>, 06-Jul-2000.

6.02 (11-Oct-2021) X Version 11