NAME

       glitchpeg - glitched image screen saver.

SYNOPSIS

       glitchpeg  [-display  host:display.screen]  [-visual  visual]  [-window]  [-root]  [-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.

       -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: 100.

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.

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 © 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.