Provided by: xscreensaver_5.36-1ubuntu1_amd64 
NAME
xscreensaver-demo - interactively control the background xscreensaver daemon
SYNOPSIS
xscreensaver-demo [-display host:display.screen] [-prefs] [--debug]
DESCRIPTION
The xscreensaver-demo program is a graphical front-end for setting the parameters used by the background
xscreensaver(1) daemon. It is essentially two things: a tool for editing the ~/.xscreensaver file; and a
tool for demoing the various graphics hacks that the xscreensaver daemon will launch.
The main window consists of a menu bar and two tabbed pages. The first page is for editing the list of
demos, and the second is for editing various other parameters of the screensaver.
MENU COMMANDS
All of these commands are on either the File or Help menus:
Blank Screen Now
Activates the background xscreensaver daemon, which will then run a demo at random. This is the same
as running xscreensaver-command(1) with the -activate option.
Lock Screen Now
Just like Blank Screen Now, except the screen will be locked as well (even if it is not configured to
lock all the time.) This is the same as running xscreensaver-command(1) with the -lock option.
Kill Daemon
If the xscreensaver daemon is running on this screen, kill it. This is the same as running
xscreensaver-command(1) with the -exit option.
Restart Daemon
If the xscreensaver daemon is running on this screen, kill it. Then launch it again. This is the
same as doing ``xscreensaver-command -exit'' followed by ``xscreensaver''.
Note that it is not the same as doing ``xscreensaver-command -restart''.
Exit
Exits the xscreensaver-demo program (this program) without affecting the background xscreensaver
daemon, if any.
About...
Displays the version number of this program, xscreensaver-demo.
Documentation...
Opens up a web browser looking at the XScreenSaver web page, where you can find online copies of the
xscreensaver(1), xscreensaver-demo(1), and xscreensaver-command(1) manuals.
DISPLAY MODES TAB
This page contains a list of the names of the various display modes, a preview area, and some fields that
let you configure screen saver behavior.
Mode
This option menu controls the activation behavior of the screen saver. The options are:
Disable Screen Saver
Don't ever blank the screen, and don't ever allow the monitor to power down.
Blank Screen Only
When blanking the screen, just go black: don't run any graphics.
Only One Screen Saver
When blanking the screen, only ever use one particular display mode (the one selected in the
list.)
Random Screen Saver
When blanking the screen, select a random display mode from among those that are enabled and
applicable. If there are multiple monitors connected, run a different display mode on each one.
This is the default.
Random Same Saver
This is just like Random Screen Saver, except that the same randomly-chosen display mode will be
run on all monitors, instead of different ones on each.
Demo List
Double-clicking in the list on the left will let you try out the indicated demo. The screen will go
black, and the program will run in full-screen mode, just as it would if the xscreensaver daemon had
launched it. Clicking the mouse again will stop the demo and un-blank the screen.
Single-clicking in the list will run it in the small preview pane on the right. (But beware: many of
the display modes behave somewhat differently when running in full-screen mode, so the scaled-down
view might not give an accurate impression.)
When Mode is set to Random Screen Saver, each name in the list has a checkbox next to it: this
controls whether this display mode is enabled. If it is unchecked, then that mode will not be
chosen. (Though you can still run it explicitly by double-clicking on its name.)
Arrow Buttons
Beneath the list are a pair of up and down arrows. Clicking on the down arrow will select the next
item in the list, and then run it in full-screen mode, just as if you had double-clicked on it. The
up arrow goes the other way. This is just a shortcut for trying out all of the display modes in
turn.
Blank After
After the user has been idle this long, the xscreensaver daemon will blank the screen.
Cycle After
After the screensaver has been running for this long, the currently running graphics demo will be
killed, and a new one started. If this is 0, then the graphics demo will never be changed: only one
demo will run until the screensaver is deactivated by user activity.
The running saver will be restarted every this-many minutes even in Only One Screen Saver mode, since
some savers tend to converge on a steady state.
Lock Screen
When this is checked, the screen will be locked when it activates.
Lock Screen After
This controls the length of the ``grace period'' between when the screensaver activates, and when the
screen becomes locked. For example, if this is 5 minutes, and Blank After is 10 minutes, then after
10 minutes, the screen would blank. If there was user activity at 12 minutes, no password would be
required to un-blank the screen. But, if there was user activity at 15 minutes or later (that is,
Lock Screen After minutes after activation) then a password would be required. The default is 0,
meaning that if locking is enabled, then a password will be required as soon as the screen blanks.
Preview
This button, below the small preview window, runs the demo in full-screen mode so that you can try it
out. This is the same thing that happens when you double-click an element in the list. Click the
mouse to dismiss the full-screen preview.
Settings
This button will pop up a dialog where you can configure settings specific to the display mode
selected in the list.
SETTINGS DIALOG
When you click on the Settings button on the Display Modes tab, a configuration dialog will pop up that
lets you customize settings of the selected display mode. Each display mode has its own custom
configuration controls on the left side.
On the right side is a paragraph or two describing the display mode. Below that is a Documentation
button that will display the display mode's manual page, if it has one, in a new window (since each of
the display modes is actually a separate program, they each have their own manual.)
The Advanced button reconfigures the dialog box so that you can edit the display mode's command line
directly, instead of using the graphical controls.
ADVANCED TAB
This tab lets you change various settings used by the xscreensaver daemon itself, as well as some global
options shared by all of the display modes.
Image Manipulation
Some of the graphics hacks manipulate images. These settings control where those source images come
from. (All of these options work by invoking the xscreensaver-getimage(1) program, which is what
actually does the work.)
Grab Desktop Images
If this option is selected, then they are allowed to manipulate the desktop image, that is, a
display mode might draw a picture of your desktop melting, or being distorted in some way. The
security-paranoid might want to disable this option, because if it is set, it means that the
windows on your desktop will occasionally be visible while your screen is locked. Others will
not be able to do anything, but they may be able to see whatever you left on your screen.
Grab Video Frames
If your system has a video capture card, selecting this option will allow the image-manipulating
modes to capture a frame of video to operate on.
Choose Random Image
If this option is set, then the image-manipulating modes will select a random image file to
operate on, from the specified source. That source may be a local directory, which will be
recursively searched for images. Or, it may be the URL of an RSS or Atom feed (e.g., a Flickr
gallery), in which case a random image from that feed will be selected instead. The contents of
the feed will be cached locally and refreshed periodically as needed.
If more than one of the above image-related options are selected, then one will be chosen at random.
If none of them are selected, then an image of video colorbars will be used instead.
Text Manipulation
Some of the display modes display and manipulate text. The following options control how that text is
generated. (These parameters control the behavior of the xscreensaver-text(1) program, which is what
actually does the work.)
Host Name and Time
If this checkbox is selected, then the text used by the screen savers will be the local host
name, OS version, date, time, and system load.
Text
If this checkbox is selected, then the literal text typed in the field to its right will be used.
If it contains % escape sequences, they will be expanded as per strftime(2).
Text File
If this checkbox is selected, then the contents of the corresponding file will be displayed.
Program
If this checkbox is selected, then the given program will be run, repeatedly, and its output will
be displayed.
URL If this checkbox is selected, then the given HTTP URL will be downloaded and displayed
repeatedly. If the document contains HTML, RSS, or Atom, it will be converted to plain-text
first.
Note: this re-downloads the document every time the screen saver runs out of text, so it will
probably be hitting that web server multiple times a minute. Be careful that the owner of that
server doesn't consider that to be abusive.
Power Management Settings
These settings control whether, and when, your monitor powers down.
Power Management Enabled
Whether the monitor should be powered down after a period of inactivity.
If this option is grayed out, it means your X server does not support the XDPMS extension, and so
control over the monitor's power state is not available.
If you're using a laptop, don't be surprised if this has no effect: many laptops have monitor
power-saving behavior built in at a very low level that is invisible to Unix and X. On such
systems, you can typically only adjust the power-saving delays by changing settings in the BIOS
in some hardware-specific way.
Standby After
If Power Management Enabled is selected, the monitor will go black after this much idle time.
(Graphics demos will stop running, also.)
Suspend After
If Power Management Enabled is selected, the monitor will go into power-saving mode after this
much idle time. This duration should be greater than or equal to Standby.
Off After
If Power Management Enabled is selected, the monitor will fully power down after this much idle
time. This duration should be greater than or equal to Suspend.
Quick Power-off in Blank Only Mode
If the display mode is set to Blank Screen Only and this is checked, then the monitor will be
powered off immediately upon blanking, regardless of the other power-management settings. In
this way, the power management idle-timers can be completely disabled, but the screen will be
powered off when black. (This might be preferable on laptops.)
Fading and Colormaps
These options control how the screen fades to or from black when a screen saver begins or ends.
Fade To Black When Blanking
If selected, then when the screensaver activates, the current contents of the screen will fade to
black instead of simply winking out. (Note: this doesn't work with all X servers.) A fade will
also be done when switching graphics hacks (when the Cycle After expires.)
Unfade From Black When Unblanking
The complement to Fade Colormap: if selected, then when the screensaver deactivates, the original
contents of the screen will fade in from black instead of appearing immediately. This is only
done if Fade Colormap is also selected.
Fade Duration
When fading or unfading are selected, this controls how long the fade will take.
Install Colormap
On 8-bit screens, whether to install a private colormap while the screensaver is active, so that
the graphics hacks can get as many colors as possible. This does nothing if you are running in
16-bit or better.
There are more settings than these available, but these are the most commonly used ones; see the manual
for xscreensaver(1) for other parameters that can be set by editing the ~/.xscreensaver file, or the X
resource database.
COMMAND-LINE OPTIONS
xscreensaver-demo accepts the following command line options.
-display host:display.screen
The X display to use. The xscreensaver-demo program will open its window on that display, and
also control the xscreensaver daemon that is managing that same display.
-prefs Start up with the Advanced tab selected by default instead of the Display Modes tab.
-debug Causes lots of diagnostics to be printed on stderr.
It is important that the xscreensaver and xscreensaver-demo processes be running on the same machine, or
at least, on two machines that share a file system. When xscreensaver-demo writes a new version of the
~/.xscreensaver file, it's important that the xscreensaver see that same file. If the two processes are
seeing different ~/.xscreensaver files, things will malfunction.
ENVIRONMENT
DISPLAY to get the default host and display number.
PATH to find the sub-programs to run. However, note that the sub-programs are actually launched by
the xscreensaver daemon, not by xscreensaver-demo itself. So, what matters is what $PATH that
the xscreensaver program sees.
HOME for the directory in which to read and write the .xscreensaver file.
XENVIRONMENT
to get the name of a resource file that overrides the global resources stored in the
RESOURCE_MANAGER property.
HTTP_PROXY or http_proxy
to get the default HTTP proxy host and port.
UPGRADES
The latest version of xscreensaver, an online version of this manual, and a FAQ can always be found at
https://www.jwz.org/xscreensaver/
SEE ALSO
X(1), xscreensaver(1), xscreensaver-command(1), xscreensaver-getimage(1), xscreensaver-text(1)
COPYRIGHT
Copyright © 1992-2015 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 <jwz@jwz.org>, 13-aug-92.
Please let me know if you find any bugs or make any improvements.