14 .TH XScreenSaver 1 "15-Mar-99 (3.08)" "X Version 11"
16 xscreensaver - graphics hack and screen locker, launched when the user is idle
19 [\-display \fIhost:display.screen\fP] \
20 [\-timeout \fIint\fP] \
24 [\-lock\-timeout \fIint\fP] \
25 [\-visual \fIvisual\fP] \
32 [\-no\-capture\-stderr] \
37 [\-no\-mit\-extension] \
39 [\-no\-sgi\-extension] \
40 [\-xidle\-extension] \
41 [\-no\-xidle\-extension] \
42 [\-proc\-interrupts] \
43 [\-no\-proc\-interrupts] \
44 [\-xrm \fIresources\fP]
46 The \fIxscreensaver\fP program waits until the keyboard and mouse have been
47 idle for a period, and then runs a graphics demo chosen at random. It
48 turns off as soon as there is any mouse or keyboard activity.
50 This program can lock your terminal in order to prevent others from using it,
51 though its default mode of operation is merely to display pretty pictures on
52 your screen when it is not in use.
54 The benefit that this program has over the combination of the
58 programs is the ease with which new graphics hacks can be installed. You
59 don't need to recompile (or even re-run) this program to add a new display
62 For the impatient, try this:
68 .BR xscreensaver-demo (1)
69 program should pop up a dialog box that lets you experiment with the
70 xscreensaver settings and graphics modes.
75 xscreensaver has a client-server model: the \fIxscreensaver\fP program is a
76 daemon that runs in the background; it is controlled by the foreground
77 .BR xscreensaver-demo (1)
79 .BR xscreensaver-command (1)
82 Options to \fIxscreensaver\fP are specified in one of two places: in
83 a \fI.xscreensaver\fP file in your home directory; or in the X resource
84 database. If the \fI.xscreensaver\fP file exists, it overrides any settings
85 in the resource database.
87 The syntax of the \fI.xscreensaver\fP file is similar to that of
88 the \fI.Xdefaults\fP file; for example, to set the \fItimeout\fP paramter
89 in the \fI.xscreensaver\fP file, you would write the following:
93 whereas, in the \fI.Xdefaults\fP file, you would write
95 xscreensaver.timeout: 5
97 If you change a setting in the \fI.xscreensaver\fP file while xscreensaver
98 is already running, it will notice this, and reload the file. (The file will
99 be reloaded the next time the screen saver needs to take some action, such as
100 blanking or unblanking the screen, or picking a new graphics mode.)
102 If you change a setting in your X resource database, or if you want
103 xscreensaver to notice your changes immediately instead of the next time
104 it wakes up, then you will need to tell the running xscreensaver process
105 to re-initialize itself, like so:
107 xscreensaver-command -restart
109 Note that if you changed the \fI.Xdefaults\fP file, you might also need to run
114 If you want to set the system-wide defaults, then make your edits to
115 the xscreensaver app-defaults file, which should have been installed
116 when xscreensaver itself was installed. The app-defaults file will
117 usually be named /usr/lib/X11/app-defaults/XScreenSaver, but different
118 systems might keep it in a different place (for example,
119 /usr/openwin/lib/app-defaults/XScreenSaver on Solaris.)
121 When settings are changed in the Preferences dialog box (see above)
122 the current settings will be written to the \fI.xscreensaver\fP file.
123 (The \fI.Xdefaults\fP file and the app-defaults file will never be
124 written by xscreensaver itself.)
127 .B timeout\fP (class \fBTime\fP)
128 The screensaver will activate (blank the screen) after the keyboard and
129 mouse have been idle for this many minutes. Default 10 minutes.
131 .B cycle\fP (class \fBTime\fP)
132 After the screensaver has been running for this many minutes, the currently
133 running graphics-hack sub-process will be killed (with \fBSIGTERM\fP), and a
134 new one started. If this is 0, then the graphics hack will never be changed:
135 only one demo will run until the screensaver is deactivated by user activity.
138 .B lock\fP (class \fBBoolean\fP)
139 Enable locking: before the screensaver will turn off, it will require you
140 to type the password of the logged-in user (really, the person who ran
141 xscreensaver), or the root password. (\fBNote:\fP this doesn't work if the
142 screensaver is launched by
144 because it can't know the user-id of the logged-in user. See
145 the ``\fIUsing XDM(1)\fP'' section, below.
147 .B lockTimeout\fP (class \fBTime\fP)
148 If locking is enabled, this controls the length of the ``grace period''
149 between when the screensaver activates, and when the screen becomes locked.
150 For example, if this is 5, and \fI\-timeout\fP is 10, then after 10 minutes,
151 the screen would blank. If there was user activity at 12 minutes, no password
152 would be required to un-blank the screen. But, if there was user activity
153 at 15 minutes or later (that is, \fI\-lock\-timeout\fP minutes after
154 activation) then a password would be required. The default is 0, meaning
155 that if locking is enabled, then a password will be required as soon as the
158 .B passwdTimeout\fP (class \fBTime\fP)
159 If the screen is locked, then this is how many seconds the password dialog box
160 should be left on the screen before giving up (default 30 seconds.) This
161 should not be too large: the X server is grabbed for the duration that the
162 password dialog box is up (for security purposes) and leaving the server
163 grabbed for too long can cause problems.
165 .B visualID\fP (class \fBVisualID\fP)
166 Specify which X visual to use by default. (Note carefully that this resource
167 is called \fBvisualID\fP, not merely \fBvisual\fP; if you set the \fBvisual\fP
168 resource instead, things will malfunction in obscure ways for obscure reasons.)
170 Legal values for the \fBVisualID\fP resource are:
174 Use the screen's default visual (the visual of the root window.)
178 Use the visual which supports the most colors. Note, however, that the
179 visual with the most colors might be a TrueColor visual, which does not
180 support colormap animation. Some programs have more interesting behavior
181 when run on PseudoColor visuals than on TrueColor.
184 Use a monochrome visual, if there is one.
187 Use a grayscale or staticgray visual, if there is one and it has more than
188 one plane (that is, it's not monochrome.)
191 Use the best of the color visuals, if there are any.
194 where \fIclass\fP is one of \fBStaticGray\fP, \fBStaticColor\fP,
195 \fBTrueColor\fP, \fBGrayScale\fP, \fBPseudoColor\fP, or \fBDirectColor\fP.
196 Selects the deepest visual of the given class.
199 where \fInumber\fP (decimal or hex) is interpreted as a visual id number,
202 program; in this way you can have finer control over exactly which visual
203 gets used, for example, to select a shallower one than would otherwise
208 Note that this option specifies only the \fIdefault\fP visual that will
209 be used: the visual used may be overridden on a program-by-program basis.
210 See the description of the \fBprograms\fP resource, below.
213 .B installColormap\fP (class \fBBoolean\fP)
214 Install a private colormap while the screensaver is active, so that the
215 graphics hacks can get as many colors as possible. This is the
216 default. (This only applies when the screen's default visual is being
217 used, since non-default visuals get their own colormaps automatically.)
218 This can also be overridden on a per-hack basis: see the discussion of
219 the \fBdefault\-n\fP name in the section about the \fBprograms\fP resource.
221 .B verbose\fP (class \fBBoolean\fP)
222 Whether to print diagnostics. Default false.
224 .B timestamp\fP (class \fBBoolean\fP)
225 Whether to print the time of day along with any other diagnostic messages.
228 .B splash\fP (class \fBBoolean\fP)
229 Whether to display a splash screen at startup. Default true.
231 .B splashDuration\fP (class \fBTime\fP)
232 How long the splash screen should remain visible; default 5 seconds.
234 .B helpURL\fP (class \fBURL\fP)
235 The splash screen has a \fIHelp\fP button on it. When you press it, it will
236 display the web page indicated here in your web browser.
238 .B loadURL\fP (class \fBLoadURL\fP)
239 This is the shell command used to load a URL into your web browser.
240 The default setting will load it into Netscape if it is already running,
241 otherwise, will launch a new Netscape looking at the \fIhelpURL\fP.
243 .B demoCommand\fP (class \fBDemoCommand\fP)
244 This is the shell command run when the \fIDemo\fP button on the splash window
245 is pressed. It defaults to \fIxscreensaver\-demo\fP.
247 .B prefsCommand\fP (class \fBPrefsCommand\fP)
248 This is the shell command run when the \fIPrefs\fP button on the splash window
249 is pressed. It defaults to \fIxscreensaver\-demo\ \-prefs\fP.
251 .B nice\fP (class \fBNice\fP)
252 The sub-processes created by \fIxscreensaver\fP will be ``niced'' to this
253 level, so that they are given lower priority than other processes on the
254 system, and don't increase the load unnecessarily. The default is 10.
256 (Higher numbers mean lower priority; see
260 .B fade\fP (class \fBBoolean\fP)
261 If this is true, then when the screensaver activates, the current contents
262 of the screen will fade to black instead of simply winking out. This only
263 works on displays with writable colormaps, that is, if the screen's default
264 visual is a PseudoColor visual. A fade will also be done when
265 switching graphics hacks (when the \fIcycle\fP timer expires.)
268 .B unfade\fP (class \fBBoolean\fP)
269 If this is true, then when the screensaver deactivates, the original contents
270 of the screen will fade in from black instead of appearing immediately. This
271 only works on displays with writable colormaps, and if \fIfade\fP is true
272 as well. Default false.
274 .B fadeSeconds\fP (class \fBTime\fP)
275 If \fIfade\fP is true, this is how long the fade will be in
276 seconds (default 3 seconds.)
278 .B fadeTicks\fP (class \fBInteger\fP)
279 If \fIfade\fP is true, this is how many times a second the colormap will
280 be changed to effect a fade. Higher numbers yield smoother fades, but
281 may make the fades take longer than the specified \fIfadeSeconds\fP if
282 your server isn't fast enough to keep up. Default 20.
284 .B captureStderr\fP (class \fBBoolean\fP)
285 Whether \fIxscreensaver\fP should redirect its stdout and stderr streams to
286 the window itself. Since its nature is to take over the screen, you would not
287 normally see error messages generated by xscreensaver or the sub-programs it
288 runs; this resource will cause the output of all relevant programs to be
289 drawn on the screensaver window itself, as well as being written to the
290 controlling terminal of the screensaver driver process. Default true.
292 .B font\fP (class \fBFont\fP)
293 The font used for the stdout/stderr text, if \fBcaptureStderr\fP is true.
294 Default \fB*\-medium\-r\-*\-140\-*\-m\-*\fP (a 14 point fixed-width font.)
296 .B programs\fP (class \fBPrograms\fP)
297 The graphics hacks which \fIxscreensaver\fP runs when the user is idle.
298 The value of this resource is a string, one \fIsh\fP-syntax command per line.
299 Each line must contain exactly one command: no semicolons, no ampersands.
301 When the screensaver starts up, one of these is selected at random, and
302 run. After the \fIcycle\fP period expires, it is killed, and another
305 If the value of this resource is empty, then no programs will be run; the
306 screen will simply be made black.
308 If the display has multiple screens, then a different program will be run
309 for each screen. (All screens are blanked and unblanked simultaniously.)
311 Note that you must escape the newlines; here is an example of how you
312 might set this in your \fI~/.xscreensaver\fP file:
318 ico -r -faces -sleep 1 -obj ico \\n\\
319 xdaliclock -builtin2 -root \\n\\
320 xv -root -rmode 5 image.gif -quit \\n
324 Make sure your \fB$PATH\fP environment variable is set up correctly
325 \fIbefore\fP xscreensaver is launched, or it won't be able to find the
326 programs listed in the \fIprograms\fP resource.
328 To use a program as a screensaver, two things are required: that that
329 program draw on the root window (or be able to be configured to draw on
330 the root window); and that that program understand ``virtual root''
331 windows, as used by virtual window managers such as
333 (Generally, this is accomplished by just including the \fI"vroot.h"\fP
334 header file in the program's source.)
336 If there are some programs that you want to run only when using a color
337 display, and others that you want to run only when using a monochrome
338 display, you can specify that like this:
340 mono: mono-program -root \\n\\
341 color: color-program -root \\n\\
345 More generally, you can specify the kind of visual that should be used for
346 the window on which the program will be drawing. For example, if one
347 program works best if it has a colormap, but another works best if it has
348 a 24-bit visual, both can be accommodated:
350 PseudoColor: cmap-program -root \\n\\
351 TrueColor: 24bit-program -root \\n\\
355 In addition to the symbolic visual names described above (in the discussion
356 of the \fIvisualID\fP resource) one other visual name is supported in
357 the \fIprograms\fP list:
361 This is like \fBdefault\fP, but also requests the use of the default colormap,
362 instead of a private colormap. (That is, it behaves as if
363 the \fI\-no\-install\fP command-line option was specified, but only for
364 this particular hack.) This is provided because some third-party programs
365 that draw on the root window (notably:
369 make assumptions about the visual and colormap of the root window:
370 assumptions which xscreensaver can violate.
373 If you specify a particular visual for a program, and that visual does not
374 exist on the screen, then that program will not be chosen to run. This
375 means that on displays with multiple screens of different depths, you can
376 arrange for appropriate hacks to be run on each. For example, if one screen
377 is color and the other is monochrome, hacks that look good in mono can be
378 run on one, and hacks that only look good in color will show up on the other.
382 Normally you won't need to change the following resources:
385 .B pointerPollTime\fP (class \fBTime\fP)
386 When server extensions are not in use, this controls how
387 frequently \fIxscreensaver\fP checks to see if the mouse position or buttons
388 have changed. Default 5 seconds.
390 .B windowCreationTimeout\fP (class \fBTime\fP)
391 When server extensions are not in use, this controls the delay between when
392 windows are created and when \fIxscreensaver\fP selects events on them.
395 .B initialDelay\fP (class \fBTime\fP)
396 When server extensions are not in use, \fIxscreensaver\fP will wait this many
397 seconds before selecting events on existing windows, under the assumption that
398 \fIxscreensaver\fP is started during your login procedure, and the window
399 state may be in flux. Default 0. (This used to default to 30, but that was
400 back in the days when slow machines and X terminals were more common...)
402 .B sgiSaverExtension\fP (class \fBBoolean\fP)
403 There are a number of different X server extensions which can make
404 xscreensaver's job easier. The next few resources specify whether these
405 extensions should be utilized if they are available.
407 This resource controls whether the SGI \fBSCREEN_SAVER\fP server extension
408 will be used to decide whether the user is idle. This is the default
409 if \fIxscreensaver\fP has been compiled with support for this
410 extension (which is the default on SGI systems.). If it is available,
411 the \fBSCREEN_SAVER\fP method is faster and more reliable than what will
412 be done otherwise, so use it if you can. (This extension is only available
413 on Silicon Graphics systems, unfortunately.)
415 .B mitSaverExtension\fP (class \fBBoolean\fP)
416 This resource controls whether the \fBMIT\-SCREEN\-SAVER\fP server extension
417 will be used to decide whether the user is idle. However, the default for
418 this resource is \fIfalse\fP, because even if this extension is available,
419 it is flaky (and it also makes the \fBfade\fP option not work properly.)
420 Use of this extension is not recommended.
422 .B xidleExtension\fP (class \fBBoolean\fP)
423 This resource controls whether the \fBXIDLE\fP server extension will be
424 used to decide whether the user is idle. This is the default
425 if \fIxscreensaver\fP has been compiled with support for this extension.
426 (This extension is only available for X11R4 and X11R5 systems, unfortunately.)
428 .B procInterrupts\fP (class \fBBoolean\fP)
429 This resource controls whether the \fB/proc/interrupts\fP file should be
430 consulted to decide whether the user is idle. This is the default
431 if \fIxscreensaver\fP has been compiled on a system which supports this
432 mechanism (i.e., Linux systems.)
434 The benefit to doing this is that \fIxscreensaver\fP can note that the user
435 is active even when the X console is not the active one: if the user is
436 typing in another virtual console, xscreensaver will notice that and will
437 fail to activate. For example, if you're playing Quake in VGA-mode,
438 xscreensaver won't wake up in the middle of your game and start competing
441 The drawback to doing this is that perhaps you \fIreally do\fP want idleness
442 on the X console to cause the X display to lock, even if there is activity
443 on other virtual consoles. If you want that, then set this option to False.
444 (Or just lock the X console manually.)
446 .B overlayStderr\fP (class \fBBoolean\fP)
447 If \fBcaptureStderr\fP is True, and your server supports ``overlay'' visuals,
448 then the text will be written into one of the higher layers instead of into
449 the same layer as the running screenhack. Set this to False to disable
450 that (though you shouldn't need to.)
452 .B overlayTextForeground\fP (class \fBForeground\fP)
453 The foreground color used for the stdout/stderr text, if \fBcaptureStderr\fP
454 is true. Default: Yellow.
456 .B overlayTextBackground\fP (class \fBBackground\fP)
457 The background color used for the stdout/stderr text, if \fBcaptureStderr\fP
458 is true. Default: Black.
460 .B bourneShell\fP (class \fBBourneShell\fP)
461 The pathname of the shell that \fIxscreensaver\fP uses to start subprocesses.
462 This must be whatever your local variant of \fB/bin/sh\fP is: in particular,
463 it must not be \fBcsh\fP.
464 .SH COMMAND-LINE OPTIONS
466 also accepts the following command line options. Except for
467 the \fI\-display\fP option, these command-line options are all
468 simply shorthand for the X resources described in
469 the \fIConfiguration\fP section, above.
471 .B \-display \fIhost:display.screen\fP
472 The X display to use. For displays with multiple screens, XScreenSaver
473 will manage all screens on the display simultaniously; the \fIscreen\fP
474 argument (the ``default'' screen) says which screen should be used for
475 dialog boxes (the password window, \fIDemo Mode\fP, etc.)
477 .B \-timeout \fIminutes\fP
478 Same as the \fItimeout\fP resource.
480 .B \-cycle \fIminutes\fP
481 Same as the \fIcycle\fP resource.
484 Same as setting the \fIlock\fP resource to \fItrue\fP.
487 Same as setting the \fIlock\fP resource to \fIfalse\fP.
489 .B \-lock\-timeout \fIminutes\fP
490 Same as the \fIlockTimeout\fP resource.
492 .B \-visual \fIvisual\fP
493 Same as the \fIvisualID\fP resource.
496 Same as setting the \fIinstallColormap\fP resource to \fItrue\fP.
499 Same as setting the \fIinstallColormap\fP resource to \fIfalse\fP.
502 Same as setting the \fIverbose\fP resource to \fItrue\fP.
505 Same as setting the \fIverbose\fP resource to \fIfalse\fP.
508 Same as setting the \fItimestamp\fP resource to \fItrue\fP.
511 Same as setting the \fIcaptureStderr\fP resource to \fItrue\fP.
513 .B \-no\-capture\-stderr
514 Same as setting the \fIcaptureStderr\fP resource to \fIfalse\fP.
517 Same as setting the \fIsplash\fP resource to \fItrue\fP.
520 Same as setting the \fIsplash\fP resource to \fIfalse\fP.
522 .B \-nice \fIinteger\fP
523 Same as the \fInice\fP resource.
526 Same as setting the \fIsgiSaverExtension\fP resource to \fItrue\fP.
528 .B \-no\-sgi\-extension
529 Same as setting the \fIsgiSaverExtension\fP resource to \fIfalse\fP.
532 Same as setting the \fImitSaverExtension\fP resource to \fItrue\fP.
534 .B \-no\-mit\-extension
535 Same as setting the \fImitSaverExtension\fP resource to \fIfalse\fP.
537 .B \-xidle\-extension
538 Same as setting the \fIxidleExtension\fP resource to \fItrue\fP.
540 .B \-no\-xidle\-extension
541 Same as setting the \fIxidleExtension\fP resource to \fIfalse\fP.
543 .B \-proc\-interrupts
544 Same as setting the \fIprocInterrupts\fP resource to \fItrue\fP.
546 .B \-no\-proc\-interrupts
547 Same as setting the \fIprocInterrupts\fP resource to \fIfalse\fP.
549 .B \-xrm \fIresource-specification\fP
550 As with all other Xt programs, you can specify X resources on the command-line
551 using the \fI\-xrm\fP argument. Most of the interesting resources have
552 command-line equivalents, however.
554 When it is time to activate the screensaver, a full-screen black window is
555 created on each screen of the display. Each window is created in such a way
556 that, to any subsequently-created programs, it will appear to be a ``virtual
557 root'' window. Because of this, any program which draws on the root
558 window (and which understands virtual roots) can be used as a screensaver.
560 When the user becomes active again, the screensaver windows are unmapped, and
561 the running subprocesses are killed by sending them \fBSIGTERM\fP. This is
562 also how the subprocesses are killed when the screensaver decides that it's
563 time to run a different demo: the old one is killed and a new one is launched.
565 Before launching a subprocess, \fIxscreensaver\fP stores an appropriate value
566 for \fB$DISPLAY\fP in the environment that the child will recieve. (This is
567 so that if you start \fIxscreensaver\fP with a \fI-display\fP argument, the
568 programs which \fIxscreensaver\fP launches will draw on the same display;
569 and so that the child will end up drawing on the appropriate screen of a
570 multi-headed display.)
572 When the screensaver turns off, or is killed, care is taken to restore
573 the ``real'' virtual root window if there is one. Because of this, it is
574 important that you not kill the screensaver process with \fIkill -9\fP if
575 you are running a virtual-root window manager. If you kill it with \-9,
576 you may need to restart your window manager to repair the damage. This
577 isn't an issue if you aren't running a virtual-root window manager.
579 For all the gory details, see the commentary at the top of xscreensaver.c.
581 You can control a running screensaver process by using the
582 .BR xscreensaver\-command (1)
585 Modern X servers contain support to power down the monitor after an idle
586 period. If the monitor has powered down, then \fIxscreensaver\fP will
587 notice this, and will not waste CPU by drawing graphics demos on a black
588 screen. An attempt will also be made to explicitly power the monitor
589 back up as soon as user activity is detected.
591 If your X server supports power management, then
593 will accept a \fBdpms\fP option. So, if you wanted \fIxscreensaver\fP
594 to activate after 5 minutes, but you wanted your monitor to power down
595 after one hour (3600 seconds) you would do this:
599 See the man page for the
601 program for details. (Note that power management requires both software
602 support in the X server, and hardware support in the monitor itself.)
604 You can run \fIxscreensaver\fP from your
606 session, so that the screensaver will run even when nobody is logged
609 The trick to using xscreensaver with \fIxdm\fP is this: keep in mind the
610 two very different states in which xscreensaver will be running:
613 .B 1: Nobody logged in.
615 If you're thinking of running xscreensaver from XDM at all, then it's
616 probably because you want graphics demos to be running on the console
617 when nobody is logged in there. In this case, xscreensaver will function
618 only as a screen saver, not a screen locker: it doesn't make sense
619 for xscreensaver to lock the screen, since nobody is logged in yet!
620 The only thing on the screen is the XDM login prompt.
622 .B 2: Somebody logged in.
624 Once someone has logged in through the XDM login window, the situation is
625 very different. For example: now it makes sense to lock the screen (and
626 prompt for the logged in user's password); and now xscreensaver should
627 consult that user's \fI~/.xscreensaver\fP file; and so on.
630 The difference between these two states comes down to a question of,
631 which user is the \fIxscreensaver\fP process running as? For the first
632 state, it doesn't matter. If you start \fIxscreensaver\fP in the usual
633 XDM way, then xscreensaver will probably end up running as root, which
634 is fine for the first case (the ``nobody logged in'' case.)
636 However, once someone is logged in, running as root is no longer fine:
637 because xscreensaver will be consulting root's \fI.xscreensaver\fP file
638 instead of that of the logged in user, and won't be prompting for the
639 logged in user's password, and so on. (This is not a security problem,
640 it's just not what you want.)
642 So, once someone has logged in, you want xscreensaver to be running as that
643 user. The way to accomplish this is to kill the old xscreensaver process
644 and start a new one (as the new user.)
646 The simplest way to accomplish all of this is as follows:
649 .B 1: Launch xscreensaver before anyone logs in.
651 To the file \fI/usr/lib/X11/xdm/Xsetup\fP, add the lines
653 xscreensaver-command -exit
656 This will run xscreensaver as root, over the XDM login window.
657 Moving the mouse will cause the screen to un-blank, and allow the user
658 to type their password at XDM to log in.
660 .B 2: Restart xscreensaver when someone logs in.
662 Near the top of the file \fI/usr/lib/X11/xdm/Xsession\fP, add those same lines:
664 xscreensaver-command -exit
667 When someone logs in, this will kill off the existing (root) xscreensaver
668 process, and start a new one, running as the user who has just logged in.
669 If the user's .xscreensaver file requests locking, they'll get it. They
670 will also get their own choice of timeouts, and graphics demos, and so on.
672 Alternately, each user could just put those lines in their
673 personal \fI~/.xsession\fP files.
676 Make sure you have \fB$PATH\fP set up correctly in the \fIXsetup\fP
677 and \fIXsession\fP scripts, or \fIxdm\fP won't be able to
678 find \fIxscreensaver\fP, and/or \fIxscreensaver\fP won't be able to
679 find its graphics demos.
681 (If your system does not seem to be executing the \fIXsetup\fP file, you
682 may need to configure it to do so: the traditional way to do this is
683 to make that file the value of the \fIDisplayManager*setup\fP resource
684 in the \fI/usr/lib/X11/xdm/xdm-config\fP file. See the man page for
688 It is safe to run \fIxscreensaver\fP as root (as \fIxdm\fP is likely to do.)
689 If run as root, \fIxscreensaver\fP changes its effective user and group ids
690 to something safe (like \fI"nobody"\fP) before connecting to the X server
691 or launching user-specified programs.
693 An unfortunate side effect of this (important) security precaution is that
694 it may conflict with cookie-based authentication.
696 If you get "connection refused" errors when running \fIxscreensaver\fP
697 from \fIxdm\fP, then this probably means that you have
699 or some other security mechanism turned on. One way around this is to
700 add \fB"xhost\ +localhost"\fP to \fIXsetup\fP, just before \fIxscreensaver\fP
703 Note that this will give access to the X server to anyone capable of logging
704 in to the local machine, so in some environments, this might not be
705 appropriate. If turning off file-system-based access control is not
706 acceptable, then running \fIxscreensaver\fP from the \fIXsetup\fP file
707 might not be possible, and xscreensaver will only work when running as
708 a normal, unprivileged user.
710 For more information on the X server's access control mechanisms, see the
717 .SH USING CDE (COMMON DESKTOP ENVIRONMENT)
718 The easiest way to use \fIxscreensaver\fP on a system with CDE is to simply
719 switch off the built-in CDE screensaver, and use \fIxscreensaver\fP instead;
720 and second, to tell the front panel to run
721 .BR xscreensaver\-command (1)
722 with the \fI\-lock\fP option when the \fILock\fP icon is clicked.
724 To accomplish this involves five steps:
727 \fB1: Switch off CDE's locker\fP
728 Do this by turning off ``\fIScreen Saver and Screen Lock\fP'' in the
729 Screen section of the Style Manager.
731 \fB2: Edit sessionetc\fP
732 Edit the file \fI~/.dt/sessions/sessionetc\fP and add to it the line
736 This will cause \fIxscreensaver\fP to be launched when you log in.
737 (As always, make sure that xscreensaver and the graphics demos are on
738 your \fB$PATH\fP; the path needs to be set in \fI.cshrc\fP
739 and/or \fI.dtprofile\fP, not \fI.login\fP.)
741 \fB3: Create XScreenSaver.dt\fP
742 Create a file called \fI~/.dt/types/XScreenSaver.dt\fP with the following
749 EXEC_STRING xscreensaver-command -lock
754 This defines a ``lock'' command for the CDE front panel, that knows how
755 to talk to \fIxscreensaver\fP.
757 \fB4: Create Lock.fp\fP
758 Create a file called \fI~/.dt/types/Lock.fp\fP with the following
764 CONTAINER_NAME Switch
765 CONTAINER_TYPE SWITCH
769 PUSH_ACTION XScreenSaver
770 HELP_TOPIC FPOnItemLock
774 This associates the CDE front panel ``Lock'' icon with the lock command
775 we just defined in step 3.
778 Select ``\fIRestart Workspace Manager\fP'' from the popup menu to make
779 your changes take effect. If things seem not to be working, check the
780 file \fI~/.dt/errorlog\fP for error messages.
782 .SH USING HP VUE (VISUAL USER ENVIRONMENT)
783 Since CDE is a descendant of VUE, the instructions for using xscreensaver
784 under VUE are similar to the above:
787 \fB1: Switch off VUE's locker\fP
788 Open the ``\fIStyle Manager\fP'' and select ``\fIScreen\fP.''
789 Turn off ``\fIScreen Saver and Screen Lock\fP'' option.
791 \fB2: Make sure you have a Session\fP
792 Next, go to the Style Manager's, ``\fIStartup\fP'' page.
793 Click on ``\fISet Home Session\fP'' to create a session, then
794 on ``\fIReturn to Home Session\fP'' to select this session each
797 \fB3: Edit vue.session\fP
798 Edit the file \fI~/.vue/sessions/home/vue.session\fP and add to it
801 vuesmcmd -screen 0 -cmd "xscreensaver"
803 This will cause \fIxscreensaver\fP to be launched when you log in.
804 (As always, make sure that xscreensaver and the graphics demos are on
805 your \fB$PATH\fP; the path needs to be set in \fI.cshrc\fP
806 and/or \fI.profile\fP, not \fI.login\fP.)
808 \fB3: Edit vuewmrc\fP
809 Edit the file \fI~/.vue/vuewmrc\fP and add (or change) the Lock control:
815 PUSH_ACTION f.exec "xscreensaver-command -lock"
819 This associates the VUE front panel ``Lock'' icon with the xscreensaver
825 .BR xscreensaver-command (1)
826 program is a perfect candidate for something to add to your window manager's
827 popup menus. If you use
831 or (probably) any of \fItwm\fP's many descendants, you can do it like this:
834 \fB1. Create ~/.mwmrc (or ~/.twmrc or ...)\fP
835 If you don't have a \fI~/.mwmrc\fP file (or, on SGIs, a \fI~/.4Dwmrc\fP file;
836 or, with twm, a \fI~/.twmrc\fP file) then create one by making a copy of
837 the \fI/usr/lib/X11/system.mwmrc\fP
838 file (or \fI/usr/lib/X11/twm/system.twmrc\fP, and so on.)
840 \fB2. Add a menu definition.\fP
845 "Blank Screen Now" !"sleep 3; xscreensaver-command -activate"
846 "Lock Screen Now" !"sleep 3; xscreensaver-command -lock"
847 "Screen Saver Demo" !"xscreensaver-demo"
848 "Screen Saver Preferences" !"xscreensaver-demo -prefs"
849 "Reinitialize Screen Saver" !"xscreensaver-command -restart"
850 "Kill Screen Saver" !"xscreensaver-command -exit"
851 "Launch Screen Saver" !"xscreensaver &"
855 \fB3. Add the menu\fP
860 find the section of the file that says \fIMenu DefaultRootMenu\fP.
863 it will probably be \fImenu "defops"\fP. If you add a line somewhere
864 in that menu definition that reads
866 "XScreenSaver" f.menu XScreenSaver
868 then this will add an XScreenSaver sub-menu to your default root-window
869 popup menu. Alternately, you could just put the xscreensaver menu items
870 directly into the root menu.
873 Other window managers are guaranteed to do things gratuitously differently.
875 Bugs? There are no bugs. Ok, well, maybe. If you find one, please let
876 me know. http://www.jwz.org/xscreensaver/bugs.html explains how to
877 construct the most useful bug reports.
880 If xscreensaver has been launched from
882 before anyone has logged in, you will need to kill and then restart the
883 xscreensaver daemon after you have logged in, or you will be confused by
884 the results. (For example, locking won't work, and your \fI~/.xscreensaver\fP
885 file will be ignored.)
887 When you are logged in, you want the \fIxscreensaver\fP daemon to be
888 running under \fIyour\fP user id, not as root or some other user.
890 If it has already been started by \fIxdm\fP, you can kill it by sending
891 it the \fBexit\fP command, and then re-launching it as you, by putting
892 something like the following in your personal X startup script:
894 xscreensaver-command -exit
897 The ``\fIUsing XDM(1)\fP'' section, above, goes into more detail, and explains
898 how to configure the system to do this for all users automatically.
900 .B Locking and root logins
901 In order for it to be safe for xscreensaver to be launched by \fIxdm\fP,
902 certain precautions had to be taken, among them that xscreensaver never
903 runs as \fIroot\fP. In particular, if it is launched as root (as \fIxdm\fP
904 is likely to do), xscreensaver will disavow its privileges, and switch
905 itself to a safe user id (such as \fInobody\fP.)
907 An implication of this is that if you log in as \fIroot\fP on the console,
908 xscreensaver will refuse to lock the screen (because it can't tell
909 the difference between \fIroot\fP being logged in on the console, and a
910 normal user being logged in on the console but xscreensaver having been
916 The solution to this is simple: you shouldn't be logging in on the console
917 as \fIroot\fP in the first place! (What, are you crazy or something?)
919 Proper Unix hygiene dictates that you should log in as yourself, and
921 to \fIroot\fP as necessary. People who spend their day logged in
922 as \fIroot\fP are just begging for disaster.
925 For xscreensaver to work when launched by
927 programs running on the local machine as user \fI"nobody"\fP must be
928 able to connect to the X server. This means that if you want to run
929 xscreensaver on the console while nobody is logged in, you may need
930 to disable cookie-based access control (and allow all users who can log
931 in to the local machine to connect to the display.)
933 You should be sure that this is an acceptable thing to do in your
934 environment before doing it. See the ``\fIUsing XDM(1)\fP'' section,
935 above, for more details.
937 If anyone has suggestions on how xscreensaver could be made to work with
939 without first turning off \fI.Xauthority\fP-based access control, please
943 If you get an error message at startup like ``couldn't get password
944 of \fIuser\fP'' then this probably means that you're on a system in which
947 library routine can only be effectively used by root. If this is the case,
948 then \fIxscreensaver\fP must be installed as setuid to root in order for
949 locking to work. Care has been taken to make this a safe thing to do.
951 It also may mean that your system uses shadow passwords instead of the standard
953 interface; in that case, you may need to change some options
954 with \fIconfigure\fP and recompile.
956 If you change your password after xscreensaver has been launched, it will
957 continue using your old password to unlock the screen until xscreensaver
958 is restarted. So, after you change your password, you'll have to do
960 xscreensaver-command -restart
962 to make \fIxscreensaver\fP notice.
965 If your system uses PAM (Pluggable Authentication Modules), then in order
966 for xscreensaver to use PAM properly, PAM must be told about xscreensaver.
967 The xscreensaver installation process should update the PAM data (on Linux,
968 by creating the file \fI/etc/pam.d/xscreensaver\fP for you, and on Solaris,
969 by telling you what lines to add to the \fI/etc/pam.conf\fP file.)
971 If the PAM configuration files do not know about xscreensaver, then
972 you \fImight\fP be in a situation where xscreensaver will refuse to ever
975 This is a design flaw in PAM (there is no way for a client to tell the
976 difference between PAM responding ``I have never heard of your module,''
977 and responding, ``you typed the wrong password.'') As far as I can tell,
978 there is no way for xscreensaver to automatically work around this, or
979 detect the problem in advance, so if you have PAM, make sure it is
980 configured correctly!
982 .B Colormap lossage: TWM
983 The \fBinstallColormap\fP option doesn't work very well with the
985 window manager and its descendants.
987 There is a race condition between the screensaver and this window manager,
988 which can result in the screensaver's colormap not getting installed
989 properly, meaning the graphics hacks will appear in essentially random
990 colors. (If the screen goes white instead of black, this is probably why.)
996 window managers don't have this problem. The race condition exists
997 because X (really, ICCCM) does not provide a way for an OverrideRedirect
998 window to have its own colormap, short of grabbing the server (which is
999 neither a good idea, nor really possible with the current design.) What
1000 happens is that, as soon as xscreensaver installs its colormap, \fBtwm\fP
1001 responds to the resultant \fBColormapNotify\fP event by re-instaling the
1002 default colormap. Apparently, \fBtwm\fP doesn't \fIalways\fP do this; it
1003 seems to do it regularly if the screensaver is activated from a menu item,
1004 but seems to not do it if the screensaver comes on of its own volition, or
1005 is activated from another console.
1008 .B Attention, window manager authors!
1009 You should only call
1010 .BR XInstallColormap (3)
1011 in response to user events. That is, it is appropriate to install a colormap
1012 in response to \fBFocusIn\fP, \fBFocusOut\fP, \fBEnterNotify\fP,
1013 and \fBLeaveNotify\fP events; but it is not appropriate to call it in
1014 response to \fBColormapNotify\fP events. If you install colormaps in
1015 response to \fIapplication\fP actions as well as in response to \fIuser\fP
1016 actions, then you create the situation where it is impossible for
1017 override-redirect applications (such as xscreensaver) to display their
1018 windows in the proper colors.
1021 .B Colormap lossage: XV, XAnim, XEarth
1022 Some programs don't operate properly on visuals other than the default one,
1023 or with colormaps other than the default one. See the discussion of the
1024 magic "default-n" visual name in the description of the \fBprograms\fP
1025 resource in the \fIConfiguration\fP section. When programs only work with
1026 the default colormap, you need to use a syntax like this:
1028 default-n: xv -root image-1.gif -quit \\n\\
1029 default-n: xearth -nostars -wait 0 \\n\\
1031 It would also work to turn off the \fBinstallColormap\fP option altogether,
1032 but that would deny extra colors to those programs that \fIcan\fP take
1036 Although this program ``nices'' the subprocesses that it starts,
1037 graphics-intensive subprograms can still overload the machine by causing
1038 the X server process itself (which is not ``niced'') to suck a lot of
1039 cycles. Care should be taken to slow down programs intended for use as
1040 screensavers by inserting strategic calls to
1044 (or making liberal use of any \fI\-delay\fP options which the programs
1047 Note that the OpenGL-based graphics demos are real pigs on machines that
1048 don't have texture hardware.
1050 Also, an active screensaver will cause your X server to be pretty much
1051 permanently swapped in; but the same is true of any program that draws
1057 .B Latency and Responsiveness
1058 If the subprocess is drawing too quickly and the connection to the X
1059 server is a slow one (such as an X terminal running over a phone line) then
1060 the screensaver might not turn off right away when the user becomes active
1063 demo has this problem if being run in full-speed mode). This can be
1064 alleviated by inserting strategic calls to
1066 in code intended for use as a screensaver. This prevents too much graphics
1067 activity from being buffered up.
1069 .B XFree86's Magic Keystrokes
1070 The XFree86 X server traps certain magic keystrokes before client programs ever
1071 see them. Two that are of note are Ctrl+Alt+Backspace, which causes
1072 the X server to exit; and Ctrl+Alt+F\fIn\fP, which switches virtual consoles.
1073 The X server will respond to these keystrokes even if xscreensaver has the
1074 screen locked. Depending on your setup, you might consider this a problem.
1076 Unfortunately, there is no way for xscreensaver itself to override the
1077 interpretation of these keys. If you want to disable Ctrl+Alt+Backspace
1078 globally, you need to set the \fIDontZap\fP flag in
1079 your \fI/etc/X11/XF86Config\fP file. See the
1083 There is no way (as far as I can tell) to disable the VT-switching keystrokes.
1085 Some Linux systems come with a VT_LOCKSWITCH ioctl, that one could
1086 theoretically use to prevent VT-switching while the screen is locked;
1087 but unfortunately, this ioctl can only be used by root, which means
1088 that xscreensaver can't use it (since xscreensaver disavows its privileges
1089 shortly after startup, for security reasons.)
1091 Any suggestions for other solutions to this problem are welcome.
1094 Apparently there are some problems with XView programs getting confused
1095 and thinking that the screensaver window is the real root window even when
1096 the screensaver is not active: ClientMessages intended for the window manager
1097 are sent to the screensaver window instead. This could be solved by making
1098 xscreensaver forward all unrecognised ClientMessages to the real root window,
1099 but there may be other problems as well. If anyone has any insight on the
1100 cause of this problem, please let me know. (XView is an X11 toolkit that
1101 implements the (quite abominable) Sun OpenLook look-and-feel.)
1103 .B MIT Extension and Fading
1104 The \fBMIT-SCREEN-SAVER\fP extension is junk. Don't use it.
1106 When using the \fBMIT-SCREEN-SAVER\fP extension in conjunction with
1107 the \fBfade\fP option, you'll notice an unattractive flicker just before
1108 the fade begins. This is because the server maps a black window just before
1109 it tells the \fIxscreensaver\fP process to activate. The \fIxscreensaver\fP
1110 process immediately unmaps that window, but this results in a flicker. I
1111 haven't figured a way to get around this; it seems to be a fundamental
1112 property of the (mis-) design of this server extension.
1114 It sure would be nice if someone would implement the \fBSGI SCREEN_SAVER\fP
1115 extension in XFree86; it's dead simple, and works far better than the
1116 overengineered and broken \fBMIT-SCREEN-SAVER\fP extension.
1119 If you're running Irix 6.3, you might find that your monitor is powering down
1120 after an hour or two even if you've told it not to. This is fixed by SGI
1121 patches 2447 and 2537.
1123 .B OpenGL Programs and Visuals
1124 Some of the graphics demos included with xscreensaver make use of the
1125 OpenGL (or MesaGL) 3D library, if it is available. It is possible (even
1126 likely) that \fIxscreensaver\fP's notion of the ``\fIbest\fP'' visual is
1127 not quite right for these GL programs.
1129 The odd thing about GL programs is that, unlike normal X11 programs, they
1130 tend to work best on a visual \fIhalf\fP as deep as the depth of the screen,
1131 since that way, they can do double-buffering. Try it and see, but you will
1132 probably find that, for these particular programs, you should specify the
1133 deepest visual that is half as deep as the screen. (See the discussion
1134 of the \fBprograms\fP resource in the \fIConfiguration\fP section, above.)
1136 For example, on a screen that supports both 24-bit TrueColor and 12-bit
1137 PseudoColor visuals, the 12-bit visual will probably work best (this is true
1138 of base-model SGI Indys: the 0x29 visual is the one you want.)
1140 Oddly, on SGI O2s (machines that have serious hardware support for GL), the
1141 12-bit PseudoColor visual looks awful (you get a black and white, flickery
1142 image.) On these machines, the visual you want turns out to be 0x31.
1143 However, 0x31 is but \fIone\fP of the \fIeight\fP 15-bit TrueColor visuals
1144 (yes, 8, and yes, 15) that the O2 X server provides. This is the only visual
1145 that works properly: as far as
1147 is concerned, all of the 15-bit TrueColor visuals are identical, but some
1148 flicker like mad, and some have deeply weird artifacts (such as hidden
1149 surfaces that show through, as if depth worked backwards!)
1151 I suppose these other visuals must be tied to some arcane hardware feature...
1152 If anyone would care to explain it to me, that would be great.
1154 Your mileage, therefore, may vary dramatically.
1156 .B MesaGL and Voodoo Cards
1157 If you have a 3Dfx/Voodoo card, the default settings for xscreensaver will
1158 run the GL-based graphics demos in such a way that they will not take
1159 advantage of the 3D acceleration hardware. The solution is to change
1160 the \fBprograms\fP entries for the GL hacks from this:
1166 MESA_GLX_FX=fullscreen gears \\n\\
1168 That is, make sure that \fB$MESA_GLX_FX\fP is set to \fIfullscreen\fP, and
1169 don't tell the program to draw on the root window. This may seem strange,
1170 but the setup used by Mesa and these kinds of cards \fIis\fP strange!
1172 For those who don't know, these cards work by sitting between your normal
1173 video card and the monitor, and seizing control of the monitor when it's
1174 time to do 3D. But this means that accelerated 3D only happens in full-screen
1175 mode (you can't do it in a window, and you can't see the output of 3D and 2D
1176 programs simultaniously), and that 3D will probably drive your monitor at a
1177 lower resolution, as well. It's bizarre.
1179 If you find that GL programs only work properly when run as root, and not
1180 as normal users, then the problem is that your \fI/dev/3dfx\fP file is not
1181 configured properly. Check the Linux 3Dfx FAQ.
1184 If you are not making use of one of the server extensions (\fBXIDLE\fP,
1185 \fBSGI SCREEN_SAVER\fP, or \fBMIT-SCREEN-SAVER\fP), then it is possible, in
1186 rare situations, for \fIxscreensaver\fP to interfere with event propagation
1187 and make another X program malfunction. For this to occur, that other
1188 application would need to \fInot\fP select \fBKeyPress\fP events on its
1189 non-leaf windows within the first 30 seconds of their existence, but then
1190 select for them later. In this case, that client \fImight\fP fail to receive
1191 those events. This isn't very likely, since programs generally select a
1192 constant set of events immediately after creating their windows and then
1193 don't change them, but this is the reason that it's a good idea to install
1194 and use one of the server extensions instead, to work around this shortcoming
1197 In all these years, I've not heard of even a single case of this happening,
1198 but it is theoretically possible, so I'm mentioning it for completeness...
1201 There need to be a lot more graphics hacks. In particular, there should be
1202 a simulation of a Lavalite (tm).
1207 to get the default host and display number, and to inform the sub-programs
1208 of the screen on which to draw.
1211 to find the sub-programs to run.
1214 for the directory in which to read and write the \fI.xscreensaver\fP file.
1217 to get the name of a resource file that overrides the global resources
1218 stored in the RESOURCE_MANAGER property.
1220 The latest version can always be found at
1221 http://www.jwz.org/xscreensaver/
1224 .BR xscreensaver\-demo (1),
1225 .BR xscreensaver\-command (1),
1242 .BR decayscreen (1),
1261 .BR interference (1),
1264 .BR kaleidescope (1),
1289 .BR slidescreen (1),
1297 .BR superquadrics (1),
1309 .BR xbouncebits (1),
1320 Copyright \(co 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999
1321 by Jamie Zawinski. Permission to use, copy, modify, distribute, and sell
1322 this software and its documentation for any purpose is hereby granted without
1323 fee, provided that the above copyright notice appear in all copies and that
1324 both that copyright notice and this permission notice appear in supporting
1325 documentation. No representations are made about the suitability of this
1326 software for any purpose. It is provided "as is" without express or implied
1329 Jamie Zawinski <jwz@jwz.org>. Written in late 1991; first posted
1330 to comp.sources.x on 13-Aug-1992.
1332 Please let me know if you find any bugs or make any improvements.
1333 .SH ACKNOWLEDGEMENTS
1334 Thanks to David Wojtowicz for implementing \fIlockTimeout\fP.
1336 Thanks to Martin Kraemer for adding support for shadow passwords and
1337 locking-disabled diagnostics.
1339 Thanks to the many people who have contributed graphics demos to the package.
1341 Thanks to Patrick Moreau for the VMS port.
1343 Thanks to Mark Bowyer for figuring out how to hook it up to CDE.
1345 And huge thanks to Jon A. Christopher for implementing the Athena dialog
1346 support, back in the days before Lesstif was a viable alternative to Motif.