Chapter 6 Setting Screensavers

This chapter describes how to set preferences for the screensaver. This chapter also provides information about how to modify the displays that are available for the screensaver.

Introduction to Screensavers

A screensaver is an application that replaces the image on a screen when the screen is not in use. The screensaver application for the Java Desktop System is XScreenSaver. The following sections describe how to set preferences for the XScreenSaver application, and how to modify the displays that are available for the screensaver.

Setting Screensaver Preferences

The default screensaver preferences are stored in a file called XScreenSaver. This file is stored in different locations, depending on your operating system, as shown in the following table:

To modify screensaver application preferences, users can use the Screensaver preference tool. When a user modifies the screensaver preferences, the preferences are stored in the home directory of the user, in the $HOME/.xscreensaver file. For information about screensaver preferences, see the latest version of the Java Desktop System Release 3 User Guide.

Users can also run a command to start the Screensaver preference tool. The command that you use depends on your operating system, as shown in the following table:

To set default screensaver preferences for all users, modify the XScreenSaver file. You can also use the XScreenSaver dialog to create a $HOME/.xscreensaver file, then copy the file to the location of the XScreenSaver file.

To restore the default settings for a user, delete the $HOME/.xscreensaver file from the home directory of the user. If no $HOME/.xscreensaver file is present, the system uses the default preferences in the XScreenSaver file.

The default display behavior of XScreenSaver is to display a blank screen. The blank screen might confuse users. You might want to change this default display behavior.

To activate changes to the screensaver preferences, use the following command to reload the screensaver preferences:

# xscreensaver-command -restart

The xset application does not work with XScreenSaver at the time of publication of this guide. To modify screensaver preferences, modify the XScreenSaver file or the $HOME/.xscreensaver file.

Modifying Screensaver Displays

The screensaver application allows users to choose one or more screensaver displays. A screensaver display is an application that displays images on the screen when the screen is not in use. The screensaver displays are listed in the XScreenSaver file and in the $HOME/.xscreensaver file.

To Add a Screensaver Display

Perform the following steps:

1. Copy the executable file for the display to the appropriate directory. The directory depends on your operating system, as shown in the following table:

   Operating System	Directory
   Linux	/usr/lib/xscreensaver
   Solaris	/usr/openwin/lib/xscreensaver/hacks

2. Add the command for the screensaver display to the XScreenSaver file or the $HOME/.xscreensaver file. Include any arguments that are required to run the screensaver display on the whole screen, rather than in a window. For example, you might want to include the -root option to display the screensaver display on the whole screen.

To Disable a Screensaver Display on Linux Systems

To disable a screensaver display, add a minus sign (-) at the start of the command for the screensaver display in the preferences file. The following excerpt from a $HOME/.xscreensaver file shows a disabled Qix (solid) screensaver display:

-		 "Qix (solid)" 	qix -root -solid -segments 100

To Disable a Screensaver Display on Solaris Systems

To disable screensaver displays for all users on a Sun Ray^TM client, rename the /usr/openwin/lib/xscreensaver/hacks directory to any name other than hacks.

OpenGL screensaver displays are provided with the GNOME Desktop. By default, all OpenGL screensaver displays are disabled, because many users do not have the OpenGL library installed. Users who have the OpenGL library installed can use the XScreenSaver dialog to enable OpenGL screensaver displays.

Some screensaver displays show the contents of the screen of the user. To avoid security violations, screensaver displays that show the contents of the screen are not included in the Java Desktop System.

The Pluggable Authentication Modules (PAM) service name for the XScreenSaver application is dtsession. This name is used for compatibility with previous applications.