Provided by: xscreensaver_5.34-2ubuntu1_amd64 
NAME
xscreensaver - extensible screen saver and screen locking framework
SYNOPSIS
xscreensaver [-display host:display.screen] [-verbose] [-no-splash] [-no-capture-stderr]
[-log filename]
DESCRIPTION
The xscreensaver program waits until the keyboard and mouse have been idle for a period,
and then runs a graphics demo chosen at random. It turns off as soon as there is any
mouse or keyboard activity.
This program can lock your terminal in order to prevent others from using it, though its
default mode of operation is merely to display pretty pictures on your screen when it is
not in use.
It also provides configuration and control of your monitor's power-saving features.
GETTING STARTED
For the impatient, try this:
xscreensaver &
xscreensaver-demo
The xscreensaver-demo(1) program pops up a dialog box that lets you configure the screen
saver, and experiment with the various display modes.
Note that xscreensaver has a client-server model: the xscreensaver program is a daemon
that runs in the background; it is controlled by the foreground xscreensaver-demo(1) and
xscreensaver-command(1) programs.
CONFIGURATION
The easiest way to configure xscreensaver is to simply run the xscreensaver-demo(1)
program, and change the settings through the GUI. The rest of this manual page describes
lower level ways of changing settings.
I'll repeat that because it's important:
The easy way to configure xscreensaver is to run the xscreensaver-demo(1) program.
You shouldn't need to know any of the stuff described in this manual unless you are
trying to do something tricky, like customize xscreensaver for site-wide use or
something.
Options to xscreensaver are stored in one of two places: in a .xscreensaver file in your
home directory; or in the X resource database. If the .xscreensaver file exists, it
overrides any settings in the resource database.
The syntax of the .xscreensaver file is similar to that of the .Xdefaults file; for
example, to set the timeout parameter in the .xscreensaver file, you would write the
following:
timeout: 5
whereas, in the .Xdefaults file, you would write
xscreensaver.timeout: 5
If you change a setting in the .xscreensaver file while xscreensaver is already running,
it will notice this, and reload the file. (The file will be reloaded the next time the
screen saver needs to take some action, such as blanking or unblanking the screen, or
picking a new graphics mode.)
If you change a setting in your X resource database, or if you want xscreensaver to notice
your changes immediately instead of the next time it wakes up, then you will need to
reload your .Xdefaults file, and then tell the running xscreensaver process to restart
itself, like so:
xrdb < ~/.Xdefaults
xscreensaver-command -restart
If you want to set the system-wide defaults, then make your edits to the xscreensaver app-
defaults file, which should have been installed when xscreensaver itself was installed.
The app-defaults file will usually be named /usr/lib/X11/app-defaults/XScreenSaver, but
different systems might keep it in a different place (for example, /usr/openwin/lib/app-
defaults/XScreenSaver on Solaris.)
When settings are changed in the Preferences dialog box (see above) the current settings
will be written to the .xscreensaver file. (The .Xdefaults file and the app-defaults file
will never be written by xscreensaver itself.)
COMMAND-LINE OPTIONS
xscreensaver also accepts a few command-line options, mostly for use when debugging: for
normal operation, you should configure things via the ~/.xscreensaver file.
-display host:display.screen
The X display to use. For displays with multiple screens, XScreenSaver will
manage all screens on the display simultaniously.
-verbose
Same as setting the verbose resource to true: print diagnostics on stderr and on
the xscreensaver window.
-no-capture-stderr
Do not redirect the stdout and stderr streams to the xscreensaver window itself.
If xscreensaver is crashing, you might need to do this in order to see the error
message.
-log filename
This is exactly the same as redirecting stdout and stderr to the given file (for
append). This is useful when reporting bugs.
HOW IT WORKS
When it is time to activate the screensaver, a full-screen black window is created on each
screen of the display. Each window is created in such a way that, to any subsequently-
created programs, it will appear to be a "virtual root" window. Because of this, any
program which draws on the root window (and which understands virtual roots) can be used
as a screensaver. The various graphics demos are, in fact, just standalone programs that
know how to draw on the provided window.
When the user becomes active again, the screensaver windows are unmapped, and the running
subprocesses are killed by sending them SIGTERM. This is also how the subprocesses are
killed when the screensaver decides that it's time to run a different demo: the old one is
killed and a new one is launched.
You can control a running screensaver process by using the xscreensaver-command(1) program
(which see.)
POWER MANAGEMENT
Modern X servers contain support to power down the monitor after an idle period. If the
monitor has powered down, then xscreensaver will notice this (after a few minutes), and
will not waste CPU by drawing graphics demos on a black screen. An attempt will also be
made to explicitly power the monitor back up as soon as user activity is detected.
The ~/.xscreensaver file controls the configuration of your display's power management
settings: if you have used xset(1) to change your power management settings, then
xscreensaver will override those changes with the values specified in ~/.xscreensaver (or
with its built-in defaults, if there is no ~/.xscreensaver file yet.)
To change your power management settings, run xscreensaver-demo(1) and change the various
timeouts through the user interface. Alternately, you can edit the ~/.xscreensaver file
directly.
If the power management section is grayed out in the xscreensaver-demo(1) window, then
that means that 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 changing the DPMS settings 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 adjust the power-saving
delays only by changing settings in the BIOS in some hardware-specific way.
If DPMS seems not to be working with XFree86, make sure the "DPMS" option is set in your
/etc/X11/XF86Config file. See the XF86Config(5) manual for details.
USING GNOME OR UNITY
For the better part of a decade, GNOME shipped xscreensaver as-is, and everything just
worked out of the box. In 2005, however, they decided to re-invent the wheel and ship
their own replacement for the xscreensaver daemon called "gnome-screensaver", rather than
improving xscreensaver and contributing their changes back. As a result, the "gnome-
screensaver" program is insecure, bug-ridden, and missing many features of xscreensaver.
You shouldn't use it.
To replace gnome-screensaver with xscreensaver:
1: Fully uninstall the gnome-screensaver package.
sudo apt-get remove gnome-screensaver
2: Launch xscreensaver at login.
Select "Startup Applications" from the menu (or manually launch "gnome-session-
properties") and add "xscreensaver".
3: Make GNOME's "Lock Screen" use xscreensaver.
sudo ln -sf /usr/bin/xscreensaver-command \
/usr/bin/gnome-screensaver-command
That doesn't work under Unity, though. Apparently it has its own built-in screen
locker which is not gnome-screensaver, and cannot be removed, and yet still manages
to be bug-addled and insecure. Keep reinventing that wheel, guys! (If you have
figured out how to replace Unity's locking "feature" with xscreensaver, let me
know.)
4: Turn off Unity's built-in blanking.
Open "System Settings / Brightness & Lock";
Un-check "Start Automatically";
Set "Turn screen off when inactive for" to "Never."
USING KDE
Like GNOME, KDE also decided to invent their own screen saver framework from scratch
instead of simply using xscreensaver. To replace the KDE screen saver with xscreensaver,
do the following:
1: Turn off KDE's screen saver.
Open the "Control Center" and select the "Appearance & Themes / Screensaver" page.
Un-check "Start Automatically".
2: Find your Autostart directory.
Open the "System Administration / Paths" page, and see what your "Autostart path"
is set to: it will probably be ~/.kde/Autostart/ or something similar.
3: Make xscreensaver be an Autostart program.
Create a .desktop file in your autostart directory called xscreensaver.desktop that
contains the following five lines:
[Desktop Entry]
Exec=xscreensaver
Name=XScreenSaver
Type=Application
X-KDE-StartupNotify=false
4: Make the various "lock session" buttons call xscreensaver.
The file you want to replace next has moved around over the years. It might be
called /usr/libexec/kde4/kscreenlocker, or it might be called "kdesktop_lock" or
"krunner_lock" or "kscreenlocker_greet", and it might be in /usr/lib/kde4/libexec/
or in /usr/kde/3.5/bin/ or even in /usr/bin/, depending on the distro and phase of
the moon. Replace the contents of that file with these two lines:
#!/bin/sh
xscreensaver-command -lock
Make sure the file is executable (chmod a+x).
Now use xscreensaver normally, controlling it via the usual xscreensaver-demo(1) and
xscreensaver-command(1) mechanisms.
USING SYSTEMD
If the above didn't do it, and your system has systemd(1), then give this a try:
1: Create a service.
Create the file ~/.config/systemd/user/xscreensaver.service containing:
[Unit]
Description=XScreenSaver
[Service]
ExecStart=xscreensaver
[Install]
WantedBy=default.target
2. Enable it.
systemctl --user enable xscreensaver
Then restart X11.
USING UPSTART
Still not working, but on your distro, that newfangled systemd(1) nonsense has already
fallen out of favor? Then maybe this will work: launch the Startup Applications applet,
click "Add", and enter these lines, then restart X11:
Name: XScreenSaver
Command: xscreensaver
Comment: xscreensaver
USING GDM
You can run xscreensaver from your gdm(1) session, so that the screensaver will run even
when nobody is logged in on the console. To do this, run gdmconfig(1) and on the
Background page, type the command "xscreensaver -nosplash" into the Background Program
field. That will cause gdm to run xscreensaver while nobody is logged in, and kill it as
soon as someone does log in. (The user will then be responsible for starting xscreensaver
on their own, if they want.)
Another way to accomplish the same thing is to edit the file /etc/X11/gdm/gdm.conf to
include:
BackgroundProgram=xscreensaver -nosplash
RunBackgroundProgramAlways=true
In this situation, the xscreensaver process will probably be running as user gdm instead
of root. You can configure the settings for this nobody-logged-in state (timeouts, DPMS,
etc.) by editing the ~gdm/.xscreensaver file.
To get gdm to run the BackgroundProgram, you may need to switch it from the "Graphical
Greeter" to the "Standard Greeter".
It is safe to run xscreensaver as root (as xdm or gdm may do.) If run as root,
xscreensaver changes its effective user and group ids to something safe (like "nobody")
before connecting to the X server or launching user-specified programs.
An unfortunate side effect of this (important) security precaution is that it may conflict
with cookie-based authentication.
If you get "connection refused" errors when running xscreensaver from gdm, then this
probably means that you have xauth(1) or some other security mechanism turned on. For
information on the X server's access control mechanisms, see the man pages for X(1),
Xsecurity(1), xauth(1), and xhost(1).
BUGS
Bugs? There are no bugs. Ok, well, maybe. If you find one, please let me know.
http://www.jwz.org/xscreensaver/bugs.html explains how to construct the most useful bug
reports.
Locking and root logins
In order for it to be safe for xscreensaver to be launched by xdm, certain precautions
had to be taken, among them that xscreensaver never runs as root. In particular, if
it is launched as root (as xdm is likely to do), xscreensaver will disavow its
privileges, and switch itself to a safe user id (such as nobody.)
An implication of this is that if you log in as root on the console, xscreensaver will
refuse to lock the screen (because it can't tell the difference between root being
logged in on the console, and a normal user being logged in on the console but
xscreensaver having been launched by the xdm(1) Xsetup file.)
The solution to this is simple: you shouldn't be logging in on the console as root in
the first place! (What, are you crazy or something?)
Proper Unix hygiene dictates that you should log in as yourself, and su(1) to root as
necessary. People who spend their day logged in as root are just begging for
disaster.
XAUTH and XDM
For xscreensaver to work when launched by xdm(1) or gdm(1), programs running on the
local machine as user "nobody" must be able to connect to the X server. This means
that if you want to run xscreensaver on the console while nobody is logged in, you may
need to disable cookie-based access control (and allow all users who can log in to the
local machine to connect to the display.)
You should be sure that this is an acceptable thing to do in your environment before
doing it. See the "Using GDM" section, above, for more details.
Passwords
If you get an error message at startup like "couldn't get password of user" then this
probably means that you're on a system in which the getpwent(3) library routine can
only be effectively used by root. If this is the case, then xscreensaver must be
installed as setuid to root in order for locking to work. Care has been taken to make
this a safe thing to do.
It also may mean that your system uses shadow passwords instead of the standard
getpwent(3) interface; in that case, you may need to change some options with
configure and recompile.
If you change your password after xscreensaver has been launched, it will continue
using your old password to unlock the screen until xscreensaver is restarted. On some
systems, it may accept both your old and new passwords. So, after you change your
password, you'll have to do
xscreensaver-command -restart
to make xscreensaver notice.
PAM Passwords
If your system uses PAM (Pluggable Authentication Modules), then in order for
xscreensaver to use PAM properly, PAM must be told about xscreensaver. The
xscreensaver installation process should update the PAM data (on Linux, by creating
the file /etc/pam.d/xscreensaver for you, and on Solaris, by telling you what lines to
add to the /etc/pam.conf file.)
If the PAM configuration files do not know about xscreensaver, then you might be in a
situation where xscreensaver will refuse to ever unlock the screen.
This is a design flaw in PAM (there is no way for a client to tell the difference
between PAM responding "I have never heard of your module", and responding, "you typed
the wrong password".) As far as I can tell, there is no way for xscreensaver to
automatically work around this, or detect the problem in advance, so if you have PAM,
make sure it is configured correctly!
Machine Load
Although this program "nices" the subprocesses that it starts, graphics-intensive
subprograms can still overload the machine by causing the X server process itself
(which is not "niced") to consume many cycles. Care has been taken in all the modules
shipped with xscreensaver to sleep periodically, and not run full tilt, so as not to
cause appreciable load.
However, if you are running the OpenGL-based screen savers on a machine that does not
have a video card with 3D acceleration, they will make your machine slow, despite
nice(1).
Your options are: don't use the OpenGL display modes; or, collect the spare change
hidden under the cushions of your couch, and use it to buy a video card manufactured
after 1998. (It doesn't even need to be fast 3D hardware: the problem will be fixed
if there is any 3D hardware at all.)
XFree86's Magic Keystrokes
The XFree86 X server traps certain magic keystrokes before client programs ever see
them. Two that are of note are Ctrl+Alt+Backspace, which causes the X server to exit;
and Ctrl+Alt+Fn, which switches virtual consoles. The X server will respond to these
keystrokes even if xscreensaver has the screen locked. Depending on your setup, you
might consider this a problem.
Unfortunately, there is no way for xscreensaver itself to override the interpretation
of these keys. If you want to disable Ctrl+Alt+Backspace globally, you need to set
the DontZap flag in your /etc/X11/XF86Config file. To globally disable VT switching,
you can set the DontVTSwitch flag. See the XF86Config(5) manual for details.
X RESOURCES
These are the X resources use by the xscreensaver program. You probably won't need to
change these manually (that's what the xscreensaver-demo(1) program is for).
timeout (class Time)
The screensaver will activate (blank the screen) after the keyboard and mouse have
been idle for this many minutes. Default 10 minutes.
cycle (class Time)
After the screensaver has been running for this many minutes, the currently
running graphics-hack sub-process will be killed (with SIGTERM), and a new one
started. If this is 0, then the graphics hack will never be changed: only one
demo will run until the screensaver is deactivated by user activity. Default 10
minutes.
The running saver will be restarted every cycle minutes even when mode is one,
since some savers tend to converge on a steady state.
lock (class Boolean)
Enable locking: before the screensaver will turn off, it will require you to type
the password of the logged-in user (really, the person who ran xscreensaver), or
the root password. (Note: this doesn't work if the screensaver is launched by
xdm(1) because it can't know the user-id of the logged-in user. See the "Using
XDM(1)" section, below.
lockTimeout (class Time)
If locking is enabled, 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, and -timeout is 10, 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-timeout 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.
passwdTimeout (class Time)
If the screen is locked, then this is how many seconds the password dialog box
should be left on the screen before giving up (default 30 seconds.) This should
not be too large: the X server is grabbed for the duration that the password
dialog box is up (for security purposes) and leaving the server grabbed for too
long can cause problems.
dpmsEnabled (class Boolean)
Whether power management is enabled.
dpmsStandby (class Time)
If power management is enabled, how long until the monitor goes solid black.
dpmsSuspend (class Time)
If power management is enabled, how long until the monitor goes into power-saving
mode.
dpmsOff (class Time)
If power management is enabled, how long until the monitor powers down completely.
Note that these settings will have no effect unless both the X server and the
display hardware support power management; not all do. See the Power Management
section, below, for more information.
dpmsQuickOff (class Boolean)
If mode is blank and this is true, then the screen will be powered down
immediately upon blanking, regardless of other power-management settings.
visualID (class VisualID)
Specify which X visual to use by default. (Note carefully that this resource is
called visualID, not merely visual; if you set the visual resource instead, things
will malfunction in obscure ways for obscure reasons.)
Legal values for the VisualID resource are:
default Use the screen's default visual (the visual of the root window.) This is
the default.
best Use the visual which supports the most colors. Note, however, that the
visual with the most colors might be a TrueColor visual, which does not
support colormap animation. Some programs have more interesting behavior
when run on PseudoColor visuals than on TrueColor.
mono Use a monochrome visual, if there is one.
gray Use a grayscale or staticgray visual, if there is one and it has more than
one plane (that is, it's not monochrome.)
color Use the best of the color visuals, if there are any.
GL Use the visual that is best for OpenGL programs. (OpenGL programs have
somewhat different requirements than other X programs.)
class where class is one of StaticGray, StaticColor, TrueColor, GrayScale,
PseudoColor, or DirectColor. Selects the deepest visual of the given
class.
number where number (decimal or hex) is interpreted as a visual id number, as
reported by the xdpyinfo(1) program; in this way you can have finer
control over exactly which visual gets used, for example, to select a
shallower one than would otherwise have been chosen.
Note that this option specifies only the default visual that will be used: the
visual used may be overridden on a program-by-program basis. See the description
of the programs resource, below.
installColormap (class Boolean)
On PseudoColor (8-bit) displays, install a private colormap while the screensaver
is active, so that the graphics hacks can get as many colors as possible. This is
the default. (This only applies when the screen's default visual is being used,
since non-default visuals get their own colormaps automatically.) This can also
be overridden on a per-hack basis: see the discussion of the default-n name in the
section about the programs resource.
This does nothing if you have a TrueColor (16-bit or deeper) display.
verbose (class Boolean)
Whether to print diagnostics. Default false.
timestamp (class Boolean)
Whether to print the time of day along with any other diagnostic messages.
Default true.
splash (class Boolean)
Whether to display a splash screen at startup. Default true.
splashDuration (class Time)
How long the splash screen should remain visible; default 5 seconds.
helpURL (class URL)
The splash screen has a Help button on it. When you press it, it will display the
web page indicated here in your web browser.
loadURL (class LoadURL)
This is the shell command used to load a URL into your web browser. The default
setting will load it into Mozilla/Netscape if it is already running, otherwise,
will launch a new browser looking at the helpURL.
demoCommand (class DemoCommand)
This is the shell command run when the Demo button on the splash window is
pressed. It defaults to xscreensaver-demo(1).
prefsCommand (class PrefsCommand)
This is the shell command run when the Prefs button on the splash window is
pressed. It defaults to xscreensaver-demo -prefs.
newLoginCommand (class NewLoginCommand)
If set, this is the shell command that is run when the "New Login" button is
pressed on the unlock dialog box, in order to create a new desktop session without
logging out the user who has locked the screen. Typically this will be some
variant of gdmflexiserver(1) or kdmctl(1).
nice (class Nice)
The sub-processes created by xscreensaver will be "niced" to this level, so that
they are given lower priority than other processes on the system, and don't
increase the load unnecessarily. The default is 10. (Higher numbers mean lower
priority; see nice(1) for details.)
fade (class Boolean)
If this is true, then when the screensaver activates, the current contents of the
screen will fade to black instead of simply winking out. This only works on
certain systems. A fade will also be done when switching graphics hacks (when the
cycle timer expires.) Default: true.
unfade (class Boolean)
If this is true, then when the screensaver deactivates, the original contents of
the screen will fade in from black instead of appearing immediately. This only
works on certain systems, and if fade is true as well. Default false.
fadeSeconds (class Time)
If fade is true, this is how long the fade will be in seconds (default 3 seconds.)
fadeTicks (class Integer)
If fade is true, this is how many times a second the colormap will be changed to
effect a fade. Higher numbers yield smoother fades, but may make the fades take
longer than the specified fadeSeconds if your server isn't fast enough to keep up.
Default 20.
captureStderr (class Boolean)
Whether xscreensaver should redirect its stdout and stderr streams to the window
itself. Since its nature is to take over the screen, you would not normally see
error messages generated by xscreensaver or the sub-programs it runs; this
resource will cause the output of all relevant programs to be drawn on the
screensaver window itself, as well as being written to the controlling terminal of
the screensaver driver process. Default true.
ignoreUninstalledPrograms (class Boolean)
There may be programs in the list that are not installed on the system, yet are
marked as "enabled." If this preference is true, then such programs will simply
be ignored. If false, then a warning will be printed if an attempt is made to run
the nonexistent program. Also, the xscreensaver-demo(1) program will suppress the
non-existent programs from the list if this is true. Default: false.
authWarningSlack (class Integer)
If all failed unlock attempts (incorrect password entered) were made within this
period of time, the usual dialog that warns about such attempts after a successful
login will be suppressed. The assumption is that incorrect passwords entered
within a few seconds of a correct one are user error, rather than hostile action.
Default 20 seconds.
GetViewPortIsFullOfLies (class Boolean)
Set this to true if the xscreensaver window doesn't cover the whole screen. This
works around a longstanding XFree86 bug #421. See the xscreensaver FAQ for
details.
font (class Font)
The font used for the stdout/stderr text, if captureStderr is true. Default
*-medium-r-*-140-*-m-* (a 14 point fixed-width font.)
mode (class Mode)
Controls the behavior of xscreensaver. Legal values are:
random When blanking the screen, select a random display mode from among those
that are enabled and applicable. This is the default.
random-same
Like random, but if there are multiple screens, each screen will run the
same random display mode, instead of each screen running a different one.
one When blanking the screen, only ever use one particular display mode (the
one indicated by the selected setting.)
blank When blanking the screen, just go black: don't run any graphics hacks.
off Don't ever blank the screen, and don't ever allow the monitor to power
down.
selected (class Integer)
When mode is set to one, this is the one, indicated by its index in the programs
list. You're crazy if you count them and set this number by hand: let
xscreensaver-demo(1) do it for you!
programs (class Programs)
The graphics hacks which xscreensaver runs when the user is idle. The value of
this resource is a multi-line string, one sh-syntax command per line. Each line
must contain exactly one command: no semicolons, no ampersands.
When the screensaver starts up, one of these is selected (according to the mode
setting), and run. After the cycle period expires, it is killed, and another is
selected and run.
If a line begins with a dash (-) then that particular program is disabled: it
won't be selected at random (though you can still select it explicitly using the
xscreensaver-demo(1) program.)
If all programs are disabled, then the screen will just be made blank, as when
mode is set to blank.
To disable a program, you must mark it as disabled with a dash instead of removing
it from the list. This is because the system-wide (app-defaults) and per-user
(.xscreensaver) settings are merged together, and if a user just deletes an entry
from their programs list, but that entry still exists in the system-wide list,
then it will come back. However, if the user disables it, then their setting
takes precedence.
If the display has multiple screens, then a different program will be run for each
screen. (All screens are blanked and unblanked simultaneously.)
Note that you must escape the newlines; here is an example of how you might set
this in your ~/.xscreensaver file:
programs: \
qix -root \n\
ico -r -faces -sleep 1 -obj ico \n\
xdaliclock -builtin2 -root \n\
xv -root -rmode 5 image.gif -quit \n
Make sure your $PATH environment variable is set up correctly before xscreensaver
is launched, or it won't be able to find the programs listed in the programs
resource.
To use a program as a screensaver, two things are required: that that program draw
on the root window (or be able to be configured to draw on the root window); and
that that program understand "virtual root" windows, as used by virtual window
managers such as tvtwm(1). (Generally, this is accomplished by just including the
"vroot.h" header file in the program's source.)
Visuals:
Because xscreensaver was created back when dinosaurs roamed the earth, it still
contains support for some things you've probably never seen, such as 1-bit
monochrome monitors, grayscale monitors, and monitors capable of displaying only
8-bit colormapped images.
If there are some programs that you want to run only when using a color display,
and others that you want to run only when using a monochrome display, you can
specify that like this:
mono: mono-program -root \n\
color: color-program -root \n\
More generally, you can specify the kind of visual that should be used for the
window on which the program will be drawing. For example, if one program works
best if it has a colormap, but another works best if it has a 24-bit visual, both
can be accommodated:
PseudoColor: cmap-program -root \n\
TrueColor: 24bit-program -root \n\
In addition to the symbolic visual names described above (in the discussion of the
visualID resource) one other visual name is supported in the programs list:
default-n
This is like default, but also requests the use of the default colormap,
instead of a private colormap. (That is, it behaves as if the -no-install
command-line option was specified, but only for this particular hack.) This
is provided because some third-party programs that draw on the root window
(notably: xv(1), and xearth(1)) make assumptions about the visual and
colormap of the root window: assumptions which xscreensaver can violate.
If you specify a particular visual for a program, and that visual does not exist
on the screen, then that program will not be chosen to run. This means that on
displays with multiple screens of different depths, you can arrange for
appropriate hacks to be run on each. For example, if one screen is color and the
other is monochrome, hacks that look good in mono can be run on one, and hacks
that only look good in color will show up on the other.
You shouldn't ever need to change the following resources:
pointerPollTime (class Time)
When server extensions are not in use, this controls how frequently xscreensaver
checks to see if the mouse position or buttons have changed. Default 5 seconds.
pointerHysteresis (class Integer)
If the mouse moves less than this-many pixels in a second, ignore it (do not
consider that to be "activity.") This is so that the screen doesn't un-blank (or
fail to blank) just because you bumped the desk. Default: 10 pixels.
windowCreationTimeout (class Time)
When server extensions are not in use, this controls the delay between when
windows are created and when xscreensaver selects events on them. Default 30
seconds.
initialDelay (class Time)
When server extensions are not in use, xscreensaver will wait this many seconds
before selecting events on existing windows, under the assumption that
xscreensaver is started during your login procedure, and the window state may be
in flux. Default 0. (This used to default to 30, but that was back in the days
when slow machines and X terminals were more common...)
procInterrupts (class Boolean)
This resource controls whether the /proc/interrupts file should be consulted to
decide whether the user is idle. This is the default if xscreensaver has been
compiled on a system which supports this mechanism (i.e., Linux systems.)
The benefit to doing this is that xscreensaver can note that the user is active
even when the X console is not the active one: if the user is typing in another
virtual console, xscreensaver will notice that and will fail to activate. For
example, if you're playing Quake in VGA-mode, xscreensaver won't wake up in the
middle of your game and start competing for CPU.
The drawback to doing this is that perhaps you really do want idleness on the X
console to cause the X display to lock, even if there is activity on other virtual
consoles. If you want that, then set this option to False. (Or just lock the X
console manually.)
The default value for this resource is True, on systems where it works.
overlayStderr (class Boolean)
If captureStderr is True, and your server supports "overlay" visuals, then the
text will be written into one of the higher layers instead of into the same layer
as the running screenhack. Set this to False to disable that (though you
shouldn't need to.)
overlayTextForeground (class Foreground)
The foreground color used for the stdout/stderr text, if captureStderr is true.
Default: Yellow.
overlayTextBackground (class Background)
The background color used for the stdout/stderr text, if captureStderr is true.
Default: Black.
bourneShell (class BourneShell)
The pathname of the shell that xscreensaver uses to start subprocesses. This must
be whatever your local variant of /bin/sh is: in particular, it must not be csh.
ENVIRONMENT
DISPLAY to get the default host and display number, and to inform the sub-programs of the
screen on which to draw.
XSCREENSAVER_WINDOW
Passed to sub-programs to indicate the ID of the window on which they should draw.
This is necessary on Xinerama/RANDR systems where multiple physical monitors share
a single X11 "Screen".
PATH to find the sub-programs to run.
HOME for the directory in which to read the .xscreensaver file.
XENVIRONMENT
to get the name of a resource file that overrides the global resources stored in
the RESOURCE_MANAGER property.
UPGRADES
The latest version of xscreensaver, an online version of this manual, and a FAQ can always
be found at http://www.jwz.org/xscreensaver/
SEE ALSO
X(1), Xsecurity(1), xauth(1), xdm(1), gdm(1), xhost(1), xscreensaver-demo(1),
xscreensaver-command(1), xscreensaver-gl-helper(1), xscreensaver-getimage(1),
xscreensaver-text(1).
COPYRIGHT
Copyright © 1991-2015 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>. Written in late 1991; version 1.0 posted to comp.sources.x
on 17-Aug-1992.
Please let me know if you find any bugs or make any improvements.
And a huge thank you to the hundreds of people who have contributed, in large ways and
small, to the xscreensaver collection over the past two decades!