14 .TH XScreenSaver 1 "16-Jan-98" "X Version 11"
16 xscreensaver - graphics hack and screen locker, launched when the user is idle
19 [\-display \fIhost:display.screen\fP] [\-timeout \fIint\fP] [\-cycle \fIint\fP] [\-nice \fIint\fP] [\-lock] [\-no\-lock] [\-lock\-timeout \fIint\fP] [\-demo] [\-visual \fIvisual\fP] [\-install] [\-no\-install] [\-verbose] [\-silent] [\-xidle\-extension] [\-no\-xidle\-extension] [\-sgi\-extension] [\-no\-sgi\-extension] [\-mit\-extension] [\-no\-mit\-extension] [\-xrm \fIresources\fP]
21 The \fIxscreensaver\fP program waits until the keyboard and mouse have been
22 idle for a period, and then runs a graphics demo chosen at random. It
23 turns off as soon as there is any mouse or keyboard activity.
25 This program can lock your terminal in order to prevent others from using it,
26 though its default mode of operation is merely to display pretty pictures on
27 your screen when it is not in use.
29 The benefit that this program has over the combination of the
33 programs is the ease with which new graphics hacks can be installed. You
34 don't need to recompile (or even re-run) this program to add a new display
37 For the impatient, try this:
40 xscreensaver-command -demo
42 After a few seconds, the screen should go black, and a dialog box should
43 appear in the upper right corner. This is \fIDemo Mode\fP.
45 If \fIxscreensaver\fP receives the \fBDEMO\fP ClientMessage, which is done
47 .BR xscreensaver\-command (1)
48 program with the \fB\-demo\fP option, the screensaver will black the screen
49 and pop up a dialog box from which you can examine and experiment with the
52 The dialog box contains a scrolling list, a text field, and a number of
55 Double-clicking on one of the programs in the list will run it. The dialog
56 box will disappear, allowing the program access to the full screen. Clicking
57 the mouse again will bring the dialog box back.
59 Single-clicking in the list will place the indicated program and its args
60 in the text field to be edited. Edit the arguments and hit return to run
61 the program with the parameters you have specified. (Note that these are
62 one-time changes and won't be remembered; to make the changes permanent,
63 you need to edit your X resource file.)
68 Clicking this button will run the next program in the list after the
69 currently-selected one, and will scroll around to the top when it reaches
73 Opposite of Run Next; at the top, it scrolls around to the bottom.
76 This pops up a second dialog box, in which you have the option to
77 interactively change most of the screensaver's operational parameters,
78 such as its timeouts, and whether it should lock the screen. Changing
79 these parameters here will affect only the running \fIxscreensaver\fP
80 process; to make the changes permanent, you need to edit your X resource
84 Returns to normal screensaver operation.
87 This causes the X resource database to be re-read, to pick up any changes
88 you might have made. This works by causing the screensaver process to exit
89 and then restart itself with the same command-line arguments. This is just
90 like the \fI\-restart\fP argument to
91 .BR xscreensaver\-command (1)
92 except that when executed from this button, the screensaver will
93 automatically return to demo mode after restarting.
96 accepts the following command line options:
98 .B \-timeout \fIminutes\fP
99 The screensaver will activate after the keyboard and mouse have been idle
100 for this many minutes. Default 10.
102 .B \-cycle \fIminutes\fP
103 After the screensaver has been running for this many minutes, the currently
104 running graphics hack sub-process will be killed (with \fBSIGTERM\fP), and a
105 new one started. If this is 0, then the graphics hack will not be changed:
106 only one demo will run until the screensaver is deactivated by user activity.
109 .B \-nice \fIinteger\fP
110 The sub-processes created by \fIxscreensaver\fP will be ``niced'' to this
111 level, so that they are given lower priority than other processes on the
112 system, and don't increase the load unnecessarily. The default is 20.
114 (Higher numbers mean lower priority; see
119 Enable locking: before the screensaver will turn off, it requires you to
120 type the password of the person who launched the screensaver, or the root
121 password. (Note: this doesn't work if the screensaver is launched
124 because it can't know the user-id of the logged-in user.)
127 Disable locking. This is the default.
129 .B \-lock\-timeout \fIminutes\fP
130 This is how long after the screensaver activates that locking is enabled.
131 For example, if this is 5, and \fI\-timeout\fP is 10, then after 10 minutes,
132 the screen would blank. If there was user activity at 12 minutes, no password
133 would be required. But, if there was user activity at 15 minutes or later
134 (\fI\-lock\-timeout\fP minutes after activation) then a password would be
135 required. The default is 0, meaning that if locking is enabled, then
136 a password will be required as soon as the screensaver activates.
139 Enter the interactive demo mode immediately after startup. Normally
140 demo mode is invoked via the
141 .BR xscreensaver\-command (1)
142 program, but this is a shortcut for new users. See below for a description
143 of how demo-mode works.
145 .B \-visual \fIvisual\fP
146 Specify which X visual to use by default. Legal values are:
150 Use the screen's default visual (the visual of the root window.)
154 Use the visual which supports the most colors. Note, however, that the
155 visual with the most colors might be a TrueColor visual, which does not
156 support colormap animation. Some programs have more interesting behavior
157 when run on PseudoColor visuals than on TrueColor.
160 Use a monochrome visual, if there is one.
163 Use a grayscale or staticgray visual, if there is one and it has more than
164 one plane (that is, it's not monochrome.)
167 Use the best of the color visuals, if there are any.
170 where \fIclass\fP is one of \fBStaticGray\fP, \fBStaticColor\fP,
171 \fBTrueColor\fP, \fBGrayScale\fP, \fBPseudoColor\fP, or \fBDirectColor\fP.
172 Selects the deepest visual of the given class.
175 where \fInumber\fP (decimal or hex) is interpreted as a visual id number,
178 program; in this way you can have finer control over exactly which visual
179 gets used, for example, to select a shallower one than would otherwise
184 Note that this option specifies only the \fIdefault\fP visual that will
185 be used: the visual used may be overridden on a program-by-program basis.
186 See the description of the \fBprograms\fP resource, below.
190 Install a private colormap while the screensaver is active, so that the
191 graphics hacks can get as many colors as possible. This is the
192 default. (This only applies when the screen's default visual is being
193 used, since non-default visuals get their own colormaps automatically.)
194 This can also be overridden on a per-hack basis: see the discussion of
195 the \fBdefault\-n\fP name in the section about the \fBprograms\fP resource.
198 Use the default colormap.
206 .B \-xidle\-extension
207 Use the \fBXIDLE\fP server extension to decide whether the user is idle.
208 This is the default if \fIxscreensaver\fP has been compiled with support
209 for this extension. On X11R4 or X11R5 systems, the XIdle method is faster
210 and more reliable than what will be done otherwise, so use it if you can.
212 .B \-no\-xidle\-extension
213 Don't use the \fBXIDLE\fP server extension.
216 Use the SGI \fBSCREEN_SAVER\fP server extension to decide whether the user
217 is idle. This is the default if \fIxscreensaver\fP has been compiled with
218 support for this extension (which is the default on SGI systems.). If it
219 is available, the \fBSCREEN_SAVER\fP method is faster and more reliable than
220 what will be done otherwise, so use it if you can.
222 .B \-no\-sgi\-extension
223 Don't use the SGI \fBSCREEN_SAVER\fP server extension.
226 Use the \fBMIT\-SCREEN\-SAVER\fP server extension to decide whether the user
227 is idle. This is the default if \fIxscreensaver\fP has been compiled with
228 support for this extension. However, this extension is flaky, so it's use
229 is not really recommended. (It also makes the \fIfade\fP option not work
232 .B \-no\-mit\-extension
233 Don't use the \fBMIT\-SCREEN\-SAVER\fP server extension.
235 \fIxscreensaver\fP understands the following resources:
238 .B timeout\fP (class \fBTime\fP)
239 Same as the \fI\-timeout\fP command-line option. Default 10 minutes.
241 .B cycle\fP (class \fBTime\fP)
242 Same as the \fI\-cycle\fP command-line option. Default 10 minutes.
244 .B nice\fP (class \fBNice\fP)
245 Same as the \fI\-nice\fP command-line option. Default 10.
247 .B lock\fP (class \fBBoolean\fP)
248 Same as the \fI\-lock\fP command-line option.
250 .B lockTimeout\fP (class \fBTime\fP)
251 Same as the \fI\-lock\-timeout\fP command-line option.
253 .B passwdTimeout\fP (class \fBTime\fP)
254 If the screen is locked, then this is how many seconds the password dialog box
255 should be left on the screen before giving up (default 30.) This should not
256 be too large: the X server is grabbed for the duration that the password
257 dialog box is up (for security purposes) and leaving the server grabbed for
258 too long can cause problems.
260 .B verbose\fP (class \fBBoolean\fP)
261 Same as the \fI\-verbose\fP command-line option.
263 .B xidle\fP (class \fBBoolean\fP)
264 Same as the \fI\-xidle\fP command-line option.
266 .B fade\fP (class \fBBoolean\fP)
267 If this is true, then when the screensaver activates, the current contents
268 of the screen will fade to black instead of simply winking out. This only
269 works on displays with writable colormaps, that is, if the screen's default
270 visual is a PseudoColor visual. Default true. A fade will also be done when
271 switching graphics hacks (when the \fIcycle\fP timer expires.)
273 .B unfade\fP (class \fBBoolean\fP)
274 If this is true, then when the screensaver deactivates, the original contents
275 of the screen will fade in from black instead of appearing immediately. This
276 only works on displays with writable colormaps, and if \fIfade\fP is true
277 as well. Default false.
279 .B fadeSeconds\fP (class \fBTime\fP)
280 If \fIfade\fP is true, this is how long the fade will be in
283 .B fadeTicks\fP (class \fBInteger\fP)
284 If \fIfade\fP is true, this is how many times a second the colormap will
285 be changed to effect a fade. Higher numbers yield smoother fades, but
286 may make the fades take longer than the specified \fIfadeSeconds\fP if
287 your server isn't fast enough to keep up. Default 20.
289 .B visualID\fP (class \fBVisualID\fP)
290 Same as the \fI\-visual\fP command-line option. Default \fBdefault\fP.
292 .B installColormap\fP (class \fBBoolean\fP)
293 Same as the \fI\-install\fP command-line option. Default true.
295 .B captureStderr\fP (class \fBBoolean\fP)
296 Whether \fIxscreensaver\fP should redirect its standard-error stream to the
297 window itself. Since its nature is to take over the screen, you would not
298 normally see error messages generated by the screensaver or the programs it
299 runs; this resource will cause the output of all relevant programs to be
300 drawn on the screensaver window itself instead of written to the controlling
301 terminal of the screensaver driver process. Default true.
303 .B captureStdout\fP (class \fBBoolean\fP)
304 Like \fBcaptureStderr\fP but for the standard-output stream. Default true.
306 .B font\fP (class \fBFont\fP)
307 The font used for the stdout/stderr text, if \fBcaptureStdout\fP or
308 \fBcaptureStderr\fP are true. Default \fB*\-medium\-r\-*\-140\-*\-m\-*\fP
309 (a 14 point fixed-width font.)
311 .B textForeground\fP (class \fBForeground\fP)
312 The foreground color used for the stdout/stderr text, if \fBcaptureStdout\fP
313 or \fBcaptureStderr\fP are true. Default: Yellow.
315 .B textBackground\fP (class \fBBackground\fP)
316 The background color used for the stdout/stderr text, if \fBcaptureStdout\fP
317 or \fBcaptureStderr\fP are true. Default: Black.
319 .B programs\fP (class \fBPrograms\fP)
320 The graphics hacks which \fIxscreensaver\fP runs when the user is idle.
321 The value of this resource is a string, one \fIsh\fP-syntax command per line.
322 Each line must contain exactly one command -- no semicolons, no ampersands.
324 When the screensaver starts up, one of these is selected at random, and
325 run. After the \fIcycle\fP period expires, it is killed, and another
328 If the value of this resource is empty, then no programs will be run; the
329 screen will simply be made black.
331 If the display has multiple screens, then a different program will be run
334 Note that you must escape the newlines; here is an example of how you
335 might set this in your \fI.Xdefaults\fP file:
339 xscreensaver.programs: \\
341 ico -r -faces -sleep 1 -obj ico \\n\\
342 xdaliclock -builtin2 -root \\n\\
343 xv -root -rmode 5 image.gif -quit \\n
347 Make sure your \fB$PATH\fP environment variable is set up correctly
348 \fIbefore\fP xscreensaver is launched, or it won't be able to find the
349 programs listed in the \fIprograms\fP resource.
351 To use a program as a screensaver, two things are required: that that
352 program draw on the root window (or be able to be configured to draw on
353 the root window); and that that program understand ``virtual root''
354 windows, as used by virtual window managers such as \fItvtwm\fP. (Generally,
355 this is accomplished by just including the \fI"vroot.h"\fP header file in
356 the program's source.)
358 If there are some programs that you want to run only when using a color
359 display, and others that you want to run only when using a monochrome
360 display, you can specify that like this:
363 mono: mono-program -root \\n\\
364 color: color-program -root \\n\\
368 More generally, you can specify the kind of visual that should be used for
369 the window on which the program will be drawing. For example, if one
370 program works best if it has a colormap, but another works best if it has
371 a 24-bit visual, both can be accommodated:
374 PseudoColor: cmap-program -root \\n\\
375 TrueColor: 24bit-program -root \\n\\
379 (This sort of thing used to be accomplished with the \fIcolorPrograms\fP
380 and \fImonoPrograms\fP resources, but those resources have now been removed;
381 a warning will be issued if they are used.)
383 In addition to the symbolic visual names described above (in the section
384 about the \fI\-visual\fP command-line option) one other visual name is
385 supported in the \fIprograms\fP list:
389 This is like \fBdefault\fP, but also requests the use of the default colormap,
390 instead of a private colormap. (That is, it behaves as if
391 the \fI\-no\-install\fP command-line option was specified, but only for
392 this particular hack.) This is provided because some third-party programs
393 that draw on the root window make assumptions about the visual and colormap
394 of that window: assumptions which xscreensaver can violate.
397 If you specify a particular visual for a program, and that visual does not
398 exist on the screen, then that program will not be chosen to run. This
399 means that on displays with multiple screens of different depths, you can
400 arrange for appropriate hacks to be run on each. For example, if one screen
401 is color and the other is monochrome, hacks that look good in mono can be
402 run on one, and hacks that only look good in color will show up on the other.
406 Normally you won't need to change the following resources:
409 .B bourneShell\fP (class \fBBourneShell\fP)
410 The pathname of the shell that \fIxscreensaver\fP uses to start subprocesses.
411 This must be whatever your local variant of \fB/bin/sh\fP is -- in particular,
412 it must not be \fBcsh\fP.
414 .B windowCreationTimeout\fP (class \fBTime\fP)
415 When server extensions are not in use, this controls the delay between when
416 windows are created and when \fIxscreensaver\fP selects events on them.
419 .B pointerPollTime\fP (class \fBTime\fP)
420 When server extensions are not in use, this controls how
421 frequently \fIxscreensaver\fP checks to see if the mouse position or buttons
422 have changed. Default 5 seconds.
424 .B initialDelay\fP (class \fBTime\fP)
425 When server extensions are not in use, \fIxscreensaver\fP will wait this many
426 seconds before selecting events on existing windows, under the assumption that
427 \fIxscreensaver\fP is started during your login procedure, and the window
428 state may be in flux. Default 30 seconds.
430 .B overlayStderr\fP (class \fBBoolean\fP)
431 If \fBcaptureStderr\fP or \fBcaptureStdout\fP are True, and your server
432 supports ``overlay'' visuals, then the text will be written into one of
433 the higher layers instead of into the same layer as the running screenhack.
434 Set this to False to disable that (though you shouldn't need to.)
436 When it is time to activate the screensaver, a full-screen black window is
437 created on each screen of the display. The window or windows is given the
438 appropriate properties so that, to any subsequently-created programs, it
439 will appear to be a ``virtual root'' window. Because of this, any program
440 which draws on the root window (and which understands virtual roots) can be
441 used as a screensaver.
443 When the user becomes active again, the screensaver windows are unmapped and
444 the running subprocesses are killed by sending them \fBSIGTERM\fP. This is
445 also how the subprocesses are killed when the screensaver decides that it's
446 time to run a different demo: the old one is killed and a new one is launched.
448 Before launching a subprocess, \fIxscreensaver\fP stores an appropriate value
449 for \fB$DISPLAY\fP in the environment that the child will recieve. (This is
450 so that if you start \fIxscreensaver\fP with a \fI-display\fP argument, the
451 programs which \fIxscreensaver\fP launches will draw on the same display;
452 and so that the child will end up drawing on the appropriate screen of a
453 multi-headed display.)
455 When the screensaver turns off, or is killed, care is taken to restore
456 the ``real'' virtual root window if there is one. Because of this, it is
457 important that you not kill the screensaver process with \fIkill -9\fP if
458 you are running a virtual-root window manager. If you kill it with \-9,
459 you may need to restart your window manager to repair the damage. This
460 isn't an issue if you aren't running a virtual-root window manager.
462 For all the gory details, see the commentary at the top of xscreensaver.c.
464 You can control a running screensaver process by using the
465 .BR xscreensaver\-command (1)
468 You can run \fIxscreensaver\fP from your xdm session, so that the
469 screensaver will run even when nobody is logged in on the console.
470 Simply add \fB"xscreensaver &"\fP to your \fI/usr/lib/X11/xdm/Xsetup\fP
471 file. Because \fIxdm\fP grabs the keyboard, keypresses will not make
472 the screensaver deactivate, but any mouse activity will.
474 Make sure you have \fB$PATH\fP set up correctly in the Xsetup script, or
475 \fIxdm\fP won't be able to find \fIxscreensaver\fP, and/or \fIxscreensaver\fP
476 won't be able to find its graphics hacks.
478 (If your system does not seem to be executing the \fIXsetup\fP file, you
479 may need to configure it to do so -- the traditional way to do this is
480 to make that file the value of the \fIDisplayManager*setup\fP resource
481 in the \fIxdm-config\fP file. See the man page for
485 Users may want to add \fB"xscreensaver-command -restart"\fP to their
486 startup scripts, so that the screensaver will be reinitialized with
487 their private resource settings when they log in.
489 It is safe to run this program as root (as \fIxdm\fP is likely to do.) If
490 run as root, \fIxscreensaver\fP changes its effective user and group ids to
491 something safe (like \fI"nobody"\fP) before connecting to the X server
492 or launching user-specified programs.
494 Locking doesn't work if the screensaver is launched by \fIxdm\fP. To get
495 around this, you can run the screensaver from \fIxdm\fP without locking,
496 and kill and restart it from your personal X startup script to enable
497 locking; for example, by using this pair of commands:
500 xscreensaver-command -exit ; xscreensaver
502 .SH USING CDE (COMMON DESKTOP ENVIRONMENT)
503 The easiest way to use \fIxscreensaver\fP on a system with CDE is to simply
504 switch off the built-in CDE screensaver, and use \fIxscreensaver\fP instead;
505 and second, to tell the front panel to run
506 .BR xscreensaver\-command (1)
507 with the \fI\-lock\fP option when the \fILock\fP icon is clicked.
509 To accomplish this involves five steps:
512 \fB1: Switch off CDE's locker\fP
513 Do this by turning off ``\fIScreen Saver and Screen Lock\fP'' in the
514 Screen section of the Style Manager.
516 \fB2: Edit sessionetc\fP
517 Edit the file \fI~/.dt/sessions/sessionetc\fP and add to it the line
522 This will cause \fIxscreensaver\fP to be launched when you log in.
523 (As always, make sure that xscreensaver and the graphics demos are on
524 your \fB$PATH\fP; the path needs to be set in \fI.cshrc\fP
525 and/or \fI.dtprofile\fP, not \fI.login\fP.)
527 \fB3: Create XScreenSaver.dt\fP
528 Create a file called \fI~/.dt/types/XScreenSaver.dt\fP with the following
536 EXEC_STRING xscreensaver-command -lock
541 This defines a ``lock'' command for the CDE front panel, that knows how
542 to talk to \fIxscreensaver\fP.
544 \fB4: Create Lock.fp\fP
545 Create a file called \fI~/.dt/types/Lock.fp\fP with the following
552 CONTAINER_NAME Switch
553 CONTAINER_TYPE SWITCH
557 PUSH_ACTION XScreenSaver
558 HELP_TOPIC FPOnItemLock
562 This associates the CDE front panel ``Lock'' icon with the lock command
563 we just defined in step 3.
566 Select ``\fIRestart Workspace Manager\fP'' from the popup menu to make
567 your changes take effect. If things seem not to be working, check the
568 file \fI~/.dt/errorlog\fP for error messages.
570 .SH USING HP VUE (VISUAL USER ENVIRONMENT)
571 Since CDE is a descendant of VUE, the instructions for using xscreensaver
572 under VUE are similar to the above:
576 \fB1: Switch off VUE's locker\fP
577 Do this by turning off ``\fIScreen Saver and Screen Lock\fP'' in the
578 Screen section of the Style Manager.
580 \fB2: Edit vue.session\fP
581 Edit the file \fI~/.vue/sessions/home/vue.session\fP and add to it
584 vuesmcmd -screen 0 -cmd "xscreensaver"
586 This will cause \fIxscreensaver\fP to be launched when you log in.
587 (As always, make sure that xscreensaver and the graphics demos are on
588 your \fB$PATH\fP; the path needs to be set in \fI.cshrc\fP
589 and/or \fI.profile\fP, not \fI.login\fP.)
591 \fB3: Edit vuewmrc\fP
592 Edit the file \fI~/.vue/vuewmrc\fP and add (or change) the Lock control:
598 PUSH_ACTION f.exec "xscreensaver-command -lock"
602 This associates the VUE front panel ``Lock'' icon with the xscreensaver
607 (This is not a bug, but) note that as of release 1.32, the \fBcolorPrograms\fP
608 and \fBmonoPrograms\fP resources are no longer used: they have been
609 supplanted by the extended syntax of the \fBprograms\fP resource (which is
610 described above, in the \fIX Resources\fP section.)
613 If you are not making use of one of the server extensions (\fBXIDLE\fP,
614 \fBSGI SCREEN_SAVER\fP, or \fBMIT-SCREEN-SAVER\fP), then it is possible, in
615 rare situations, for \fIxscreensaver\fP to interfere with event propagation
616 and make another X program malfunction. For this to occur, that other
617 application would need to \fInot\fP select \fBKeyPress\fP events on its
618 non-leaf windows within the first 30 seconds of their existence, but then
619 select for them later. In this case, that client \fImight\fP fail to receive
620 those events. This isn't very likely, since programs generally select a
621 constant set of events immediately after creating their windows and then
622 don't change them, but this is the reason that it's a good idea to install
623 and use one of the server extensions instead, to work around this shortcoming
627 Although this program ``nices'' the subprocesses that it starts,
628 graphics-intensive subprograms can still overload the machine by causing
629 the X server process itself (which is not ``niced'') to suck a lot of
630 cycles. Care should be taken to slow down programs intended for use as
631 screensavers by inserting strategic calls to
635 (or making liberal use of any \fI\-delay\fP options which the programs
638 Also, an active screensaver will cause your X server to be pretty much
639 permanently swapped in; but the same is true of any program that draws
645 .B Latency and Responsiveness
646 If the subprocess is drawing too quickly and the connection to the X
647 server is a slow one (such as an X terminal running over a phone line) then
648 the screensaver might not turn off right away when the user becomes active
651 demo has this problem if being run in full-speed mode). This can be
652 alleviated by inserting strategic calls to
654 in code intended for use as a screensaver. This prevents too much graphics
655 activity from being buffered up.
658 Locking doesn't work if the screensaver is launched by \fIxdm\fP.
659 The reason for this is that when it is launched by \fIxdm\fP, the
660 screensaver process is owned by some standard user id (such as \fIroot\fP
661 or \fIdaemon\fP) instead of the user who is logged in on the console:
662 because the screensaver was started \fIbefore\fP anyone was logged in.
663 In order for the screensaver to prompt for the password of the person
664 who had logged in from \fIxdm\fP, it would need to know who that user was,
665 and there is no reliable and safe way to figure that out. (And even if
666 there was, there would be some other security issues here as well.)
668 So if you want to use it as a locker, you must start it with your user id.
669 If it has already been started by \fIxdm\fP, you can kill it with
670 \fBxscreensaver\-command -exit\fP, and then start it again as you.
672 .B Locking and root logins
673 An implication of the above is that if you log in as \fIroot\fP on the
674 console, xscreensaver will refuse to lock the screen (because it can't tell
675 the difference between \fIroot\fP being logged in on the console, and a
676 normal user being logged in on the console but xscreensaver having been run
679 The solution to this is simple: you shouldn't be logging in on the console
680 as \fIroot\fP in the first place (what, are you crazy or something?) You
681 should log in as you, and
683 to \fIroot\fP as necessary. People who spend their day logged in
684 as \fIroot\fP are just begging for disaster.
687 If you get an error message like ``couldn't get password of \fIuser\fP''
688 then this probably means that you're on a system in which the
690 library routine can only be effectively used by root. If this is the case,
691 then \fIxscreensaver\fP must be installed as setuid to root. Care has
692 been taken to make this a safe thing to do.
694 It also may mean that your system uses shadow passwords instead of the
695 standard \fIgetpwent\fP interface; in that case, you may need to change
696 some options with \fIconfigure\fP and recompile.
698 If you change your password after xscreensaver has been launched, it will
699 continue using your old password to unlock the screen until xscreensaver
700 is restarted. This turns out to be kind of hard to fix. (But remember,
701 kids! Unix security doesn't do much more than keep honest people honest...)
703 .B Colormap lossage: TWM
704 The \fBinstallColormap\fP option doesn't work very well with the
706 window manager and its descendants.
708 There is a race condition between the screensaver and this window manager,
709 which can result in the screensaver's colormap not getting installed
710 properly, meaning the graphics hacks will appear in essentially random
711 colors. (If the screen goes white instead of black, this is probably why.)
717 window managers don't seem to have this problem. The race condition exists
718 because X does not provide a way for an OverrideRedirect window to have its
719 own colormap, short of grabbing the server (which is neither a good idea, nor
720 really possible with the current design.) What happens is that, as soon as
721 the screensaver installs its colormap, \fBtwm\fP responds to
722 the \fBColormapNotify\fP event that is generated by re-instaling the default
723 colormap. Apparently, \fBtwm\fP doesn't \fIalways\fP do this; it seems to do
724 it regularly if the screensaver is activated from a menu item, but seems to
725 not do it if the screensaver comes on of its own volition, or is activated
726 from another console. Any thoughts on this problem are welcome...
728 .B Colormap lossage: XV, XAnim, XEarth
729 Some programs don't operate properly on visuals other than the default one,
730 or with colormaps other than the default one. See the discussion of the
731 magic "default-n" visual name in the section about the \fBprograms\fP
732 resource. When programs only work with the default colormap, you need to
733 use a syntax like this:
735 default-n: xv -root image-1.gif -quit \\n\\
736 default-n: xearth -nostars -wait 0 \\n\\
738 It would also work to turn off the \fBinstallColormap\fP option altogether,
739 but that would deny extra colors to those programs that \fIcan\fP take
743 Apparently there are some problems with XView programs getting confused
744 and thinking that the screensaver window is the real root window even when
745 the screensaver is not active: ClientMessages intended for the window manager
746 are sent to the screensaver window instead. This could be solved by making
747 xscreensaver forward all unrecognised ClientMessages to the real root window,
748 but there may be other problems as well. If anyone has any insight on the
749 cause of this problem, please let me know. (XView is an X11 toolkit that
750 implements the (quite abominable) Sun OpenLook look-and-feel.)
752 .B MIT Extension and Fading
753 When using the \fBMIT-SCREEN-SAVER\fP extension in conjunction with
754 the \fBfade\fP option, you may notice an unattractive flicker just before
755 the fade begins. This is because the server maps a black window just before
756 it tells the \fIxscreensaver\fP process to activate. The \fIxscreensaver\fP
757 process immediately unmaps that window, but this results in a flicker. I
758 haven't figured a way to get around this; it seems to be a fundamental
759 property of the (mis-) design of this server extension.
761 .B Lesstif (Motif clone)
762 Demo mode is buggy if XScreenSaver was compiled against really old versions
763 Lesstif; if you use Lesstif, use version 0.82 or newer.
766 If you compiled against the Athena widget toolkit, the dialog boxes are
767 pretty ugly, especially the password dialog. Use Motif! If you don't
768 have OSF Motif, use GNU Lesstif, it's free: http://www.lesstif.org/
771 If you're running Irix 6.3, you might find that your monitor is powering down
772 after an hour or two even if you've told it not to. This is fixed by SGI
773 patches 2447 and 2537.
776 There need to be a lot more graphics hacks. In particular, there should be
777 a simulation of a Lavalite (tm).
782 to get the default host and display number, and to inform the sub-programs
783 of the screen on which to draw.
786 to find the sub-programs to run.
789 to get the name of a resource file that overrides the global resources
790 stored in the RESOURCE_MANAGER property.
792 The latest version can always be found at
793 http://people.netscape.com/jwz/xscreensaver/
796 .BR xscreensaver\-command (1),
828 .BR kaleidescope (1),
861 .BR superquadrics (1),
883 Copyright \(co 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
884 by Jamie Zawinski. Permission to use, copy, modify, distribute, and sell
885 this software and its documentation for any purpose is hereby granted without
886 fee, provided that the above copyright notice appear in all copies and that
887 both that copyright notice and this permission notice appear in supporting
888 documentation. No representations are made about the suitability of this
889 software for any purpose. It is provided "as is" without express or implied
892 Jamie Zawinski <jwz@netscape.com>. Written in late 1991; first posted
893 to comp.sources.x on 13-Aug-1992.
895 Please let me know if you find any bugs or make any improvements.
897 Thanks to David Wojtowicz for implementing \fIlockTimeout\fP.
899 Thanks to Martin Kraemer for adding support for shadow passwords and
900 locking-disabled diagnostics.
902 Thanks to the many people who have contributed graphics demos to the package.
904 Thanks to Patrick Moreau for the VMS port.
906 Thanks to Mark Bowyer for figuring out how to hook it up to CDE.
908 And huge thanks to Jon A. Christopher for implementing the Athena dialog
909 support, back in the days before Lesstif was a viable alternative to Motif.