glitchpeg(6) XScreenSaver manual glitchpeg(6)

NAME

glitchpeg - glitched image screen saver.

SYNOPSIS

glitchpeg [--display host:display.screen] [--visual visual]
[--window] [--root] [--window-id number] [--delay number] [--duration
number] [--count number]

DESCRIPTION

Loads an image, corrupts it, and then displays the corrupted version,
several times a second. After a while, finds a new image to corrupt.

It glitches the image by altering random bytes in the compressed
image file before de-compressing it. This creates interesting visual
effects on JPEG files, but doesn't work well on PNG files, since PNG
contains checksums that detect simple corruption.

OPTIONS

--visual visual
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.

--window
Draw on a newly-created window. This is the default.

--root Draw on the root window.

--window-id number
Draw on the specified window.

--delay number
Per-frame delay, in microseconds. Default: 30000 (0.03
seconds).

--duration number
How many seconds before loading a new image. Default: 120.

--count number
Number of glitches to introduce per iteration. Default: 400.

ENVIRONMENT

DISPLAY to get the default host and display number.

XENVIRONMENT
to get the name of a resource file that overrides the global
resources stored in the RESOURCE_MANAGER property.

XSCREENSAVER_WINDOW
The window ID to use with --root.

SECURITY

Because this program is feeding intentionally-invalid data into your
operating system's image-decoding libraries, it is possible that it
may crash as a result of that corrupted data.

That should not be possible -- but it might be.

Please note that if this happens, that indicates a serious security
bug in your system's image libraries! It likely means that your
libraries are susceptible to buffer overflow attacks or similar,
which can lead to remote code execution. You should report that bug
to the maintainers of those image libraries.

In the context of xscreensaver, when configured to load only local
image files, this should not be a direct security concern: this
screen saver crashing will not affect the xscreensaver daemon and
will not unlock your screen.

SEE ALSO

X(1), xscreensaver(1)

COPYRIGHT

Copyright (C) 2018 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.

AUTHOR

Jamie Zawinski.

X Version 11 6.09 (07-Jun-2024) glitchpeg(6)