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.

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.

Mode

This option menu controls the 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 hacks.

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. This is the default.

Random Same Saver

This option only appears if you have multiple monitors. This is just like Random Screen Saver, except that the same randomly-chosen display mode will be run on all monitors, instead of a different one being run 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, making the dialog box visible again.

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.

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.

Grab Desktop Images

Some of the graphics hacks manipulate 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 from disk, from the directory you specify in the text entry field. That directory will be recursively searched for files, and it is assumed that all the files under that directory are images.

If more than one of these 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.

(All three of these options work by invoking the xscreensaver-getimage(1) program, which is what actually does the work.)

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, 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, 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! It might be considered abusive for you to point this at a web server that you do not control, as it will probably be hitting that server multiple times a minute.

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.

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.

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 may 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. It also lets you configure the X visual type that this mode will require. If you specify one (other than Any) then the program will only be run on that kind of visual. For example, you can specify that a particular program should only be run if color is available, and another should only be run in monochrome. See the discussion of the programs parameter in the Configuration section of the xscreensaver(1) manual. (OpenGL programs should always have their visual set to "GL".)

-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.

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 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.

Please let me know if you find any bugs or make any improvements.