
                              XScreenSaver

            a screen saver and locker for the X window system
                            by Jamie Zawinski

To build on Unix:

  -  ./configure
  -  make
  -  make install

The `configure' shell script will attempt to figure out which options are
appropriate for your system, and will create config.h and the various
Makefiles for you.  Run `configure --help' to see how to override these
choices, or to specify things like the default installation directory.
The file `INSTALL' gives a general overview of use of these sorts of
configure scripts (those generated by the GNU autoconf system.)
The most important hint is probably this:

   ./configure --includedir=/opt/Motif/include --libdir=/opt/Motif/lib

To build on VMS, see README.VMS.

If you think you've found a bug, please let me know; but first, read
the enlosed `README.debugging' file to find out what kind of information
would be most helpful to include in your bug report.

                              ============

The xscreensaver program waits until the keyboard and mouse have been idle
for a period, and then runs a graphics demo chosen at random.  It turns off
as soon as there is any mouse or keyboard activity.

The purpose of xscreensaver is to display pretty pictures on your screen 
when it is not in use, in keeping with the philosophy that unattended 
monitors should always be doing something interesting, just like they do 
in the movies.

However, xscreensaver can also be used as a screen locker, to prevent
others from using your terminal while your are away.

The benefit that this program has over the combination of the xlock and
xautolock programs is the ease with which new graphics hacks can be
installed: you don't need to recompile this program to add a new display
mode, you just change some resource settings.  Any program which can be
invoked in such a way that it draws on the root window of the screen can
now be used as a screensaver without modification.  The programs that
are being run as screensavers don't need to have any special knowledge
about what it means to be a screensaver.

The XIDLE, MIT-SCREEN-SAVER, and/or SGI SCREEN_SAVER server extensions
will be used if you have them.

The dialog boxes (for locking and demo-mode) look best using Motif, but
can be configured to use Athena widgets instead.

Also included are several graphics hacks for use as screensavers.  There's
nothing magic about these: they're just programs that draw on the root
window, which are pointed at by the screensaver's default resource settings.

   qix		- My own implementation of this, with many more options
		  than you would have thought qix could have.
   helix	- Generates spirally "stringart" patterns.
   pedal	- Draws a different kind of spirally pattern.
   rorschach	- Random inkblot patterns.
   attraction	- A bouncing ball demo, or a qix-like demo, or a wild
		  color-cycling thing, with some odd rules.
   greynetic	- Random colored/stippled rectangles.
   rocks	- Flying through an asteroid field.
   blitspin	- Rotate a bitmap using bitblts.
   imsmap	- Generates random maps or cloud formations.
   hypercube	- 2d projection of a hypercube rotating on all four axes.
   slidescreen	- Divides the screen into a grid and plays a 16-puzzle on it.
   decayscreen	- A melting effect.
   puzzle	- Turns the screen into a jigsaw puzzle and shuffles it.
   halo		- Random circular patterns.
   pyro		- Fireworks.  Looks a lot like the version in xlock.
   hopalong	- Fractals.  I snarfed this code from xlock.
   flame	- Fractals.  Also from xlock.
   noseguy	- A guy with a big nose wanders around the screen saying
		  things.  I snarfed this code from xnlock.
   maze		- This is the X maze demo modified to take a -root option
		  so that it works with xscreensaver.
   lmorph	- morphing line drawings.
   bubbles	- condensation forms on your monitor, then pops.
   deco		- Generates Brady-Bunch-era wall paneling.
   moire	- Circular interference patterns.
   moire2	- More moire.
   kaleidescope	- Groovy, man.
   swirl	- Swirly color-cycling patterns.
   bouboule	- Spinning bubbles on a transparent ball.
   braid	- Draws random color-cycling braids around a circle.
   drift	- Drifting recursive fractal cosmic flames.
   vines	- Small, curvy geometric patterns.
   galaxy	- Spinning, colliding galaxies.
   grav		- Orbital simulation and/or cloud chamber.
   ifs		- Spinning, colliding iterated-function-system shapes.
   julia	- Animated rendition of the Julia set.
   laser	- Moving radiating lines.
   lightning	- Crackling fractal lightning bolts.
   penrose	- Quasiperiodic tilings.
   sierpinski	- two-dimensional Sierpinski triangle.
   slip		- Sucks your desktop through a jet engine.
   spiral	- Circular color-cycling interference patterns.
   strange	- Animating strange attractors.
   flag		- A waving flag of an arbitrary bitmap or text.
   sphere	- Draws a bunch of shaded spheres.
   forest	- grows a fractal forest.
   lisa		- draws animated full-loop lisajous figures.
   lissie	- another lisajous path.
   goop		- Squishy transparent oil-and-bubble images
   starfish	- Radially-symmetric throbbing colormap-hacking blobs.
   munch	- The classic 1962-vintage "munching squares" hack.
   rd-bomb      - Reaction-diffusion fractals.
   coral        - Simulation of coral growth, sort of.
   fadeplot	- Draws a swimming ribbon.
   mountain	- Generates mountains on a square grid.
   triangle	- Generates mountains on a triangular grid.
   worm		- Draws wiggly worms.
   rotor	- Draws a rotating spiral pattern.
   ant		- A cellular automaton.
   xjack	- Simulates a schizophrenic typist.
   xlyap	- Calculates and displays Lyapunov exponents.
   gears	- Draws interlocking rotating gears (GLX only.)
   morph3d	- Draws shiny shape-changing 3d forms (GLX only.)
   superquadrics - More shiny shape-changing 3d forms (GLX only.)
   pipes	- Generates a field of intertwined plumbing (GLX only.)
   rubik	- Solves a Rubik's Cube (GLX only.)
   sproingies	- Marble Madness meets Q-Bert (GLX only.)
   stairs	- Draws Escher's infinite staircase (GLX only.)
   cage		- Draws Escher's impossible cage (GLX only.)
   moebius	- Draws Escher's Moebius Strip II (GLX only.)

All of these will pop up their own window unless given that -root option.
See their man pages for more details.

Other reasonable things to use as screensavers, if you have them, are

  xdaliclock -root -builtin2	- melting digital clock
  xswarm -r 2>&-		- swimming sperm
  xwave -root			- random 3d graphs
  xbouncebits			- bounce arbitrary bitmaps around
  ico -r -p8 -faces -sleep 1	- it's dull, but it's there
  xv -root file.gif -quit	- they don't all have to animate!
  xsplinefun			- bouncing splines
  xfishtank -c black -d -r 1	- fish (use version 2.0 or later)
  xmountains -b			- very realistic generated mountains
  xtacy -root			- various eye candy
  xearth -wait 0 -timewarp 400	- the earth as seen from space
  /usr/demos/bin/bongo		- an SGI GL demo
  /usr/demos/bin/ep -S		- another: the stunning ElectroPaint.
				  (Compile hacks/xscreensaver-sgigl.c
				  to use these with xscreensaver.)

You can get most of these from the contrib directory on ftp.x.org.  If you
know of (or write) any other interesting programs that can be used as
screensavers, please let me know!

The latest version of xscreensaver is always available on the web at
http://people.netscape.com/jwz/xscreensaver/.

	-- Jamie Zawinski <jwz@netscape.com>


Changes since 2.15:	Made `flag' able to do XPM images.
			New look for the xscreensaver logo (`xroger').
			Fixed compilation error on Suns with adjunct passwords.
			Got multi-architecture builds working again.
			Some configure tweaks for building on HPUX and Solaris.
			Fixed bug in decayscreen.
			Fixed typo i passwd.c.
			Made `cynosure' not die when colormap is full.
Changes since 2.14:	Added `cynosure' hack.
			Added `moire2' hack.
			Tweaked `erase.c' some more.
			Made unfading a bit smoother.
			Added `vidwhacker' hack (not installed by default.)
			Added `stairs' hack.
			Split `escher' into `cage' and `moebius', as per
			xlockmore.
			Changed subprocess handling to use sigaction() instead
			of signal() if it's available (this is necessary for
			SCO but should work fine on other systems too.)
			Various other tweaks.
Changes since 2.13:	Better fix for the Motif drag-and-die lossage.
			Put in some kludges to work around a LessTif bug.
			XScreenSaver is known to work with LessTif 0.82 now.
			Made fading work on high-end SGI video hardware.
			Fixed another SGI-specific bug in screen grabbing;
			will the madness never cease?
			Fixed another crash in `xlyap'.
Changes since 2.12:	Made `decayscreen' do directions other than down.
			Improved `puzzle'.
			Fixed a crash in `xlyap'.
			Added CDE info to the man page, removed `cde.txt'.
			Configure tweaks for Zippy.
			Turned off the signal handling in `bubbles' because
			it was sometimes failing to die.
			Added `hacks/xscreensaver-sgigl.c' to make it possible
			to run SGI's ElectroPaint hack (/usr/demos/bin/ep)
			with xscreensaver.  Finally!
			Fixed a buffer overrun in the locking code that some
			wily, malicious cracker must have slipped in.
			Disabled Motif drag-and-drool in the dialog box
			buttons, since it's broken in some old versions of
			Motif.
Changes since 2.11:	Added `README.debugging'.
			Added `puzzle' hack.
			Added `xlyap' hack.
			Added "default-n" as a visual name, so that one can
			have -install on by default, but turn it off for
			certain poorly-behaved hacks (like xv.)
			Added support for grabbing frames of external video
			(on SGI) to the screen-grabbing hacks (decayscreen,
			slidescreen, slip, blitspin, and puzzle.)
			Improved look of tiles in `slidescreen'; fixed its
			color allocation problem.
Changes since 2.10:	Tweaked `blitspin', added it to the default list.
			Added `lissie', `mountain', `triangle', `worm',
			`rotor', and `ant' from xlockmore.
			Updated `sierpinski', `galaxy', and `lisa'.
			Thickened the lines in `braid' and `lmorph'.
			Updated VMS makefiles.
			Renamed `fract' to `vines'.
			Added `xjack' hack.
			Made a few more hacks use erase.c, and added a few
			more wipe styles.
			Fixed compilation problem with Sun's version of OpenGL.
			Added ability to use sigaction() instead of signal()
			to work around a SCO kernel bug.
Changes since 2.09:	Fixed colormap bugs in `rd-bomb'; sped up `coral'.
			Configure tweaks for *BSD.
Changes since 2.07:	New hacks `rd-bomb' and `coral'.
			New version of `maze' with some new algorithms.
			New colorized version of `rocks'.
			Fixed a bug in qix on 64-bit machines.
			Fixed a bug in the -time option.
			Fixed a bug in configure related to LessTif.
Changes since 2.06:	Minor header tweaks in windows.c and flag.c.
			Made multi-architecture (VPATH) builds work properly.
			Merged new GL stuff from xlockmore (rubik, morph3d.)
			Fixed intermittent crashes in `imsmap' and `munch'.
			Added `fadeplot' hack from xlockmore.
Changes since 2.05:	Merged in VMS support from Patrick Moreau.
Changes since 2.04:	Fixed a MIT-SCREEN-SAVER-related crash, and tweaked 
			configure to detect the extra-random -Xss library.
Changes since 2.03:	HP configure tweaks.  Detect and warn about LessTif.
			Fixed low-color behavior of `goop', `pyro', `starfish',
			`greynetic', `flame', `halo', and `moire'.
Changes since 2.02:	Fixed flicker in `pipes'.  Fixed 3d in `bouboule'.
			Added `munch' hack.
			Added basic dependencies to the Makefile.in files.
Changes since 2.01:	Fixes for compiling with the MIT saver extension.
			Made the yow/fortune program be a configure option.
			Various configure tweaks.
Changes since 2.00:	Added `goop' and `starfish' hacks.
			Added colomap cycling to `halo'.
			Made `attraction' use the new colormap allocator.
			Added better $PATH diagnostics.
			There was a bug in frand!  Color selection should be
			much improved now.
Changes since 1.34:     Converted to use `configure' instead of `imake'.
                        ANSI C is now required.
			Added Kerberos locking support, from Nat Lanza.
                	Made the stderr text use overlay planes, if possible.
			Reworked the xlockmore compatibility stuff again.
			Added `gears', `superquadrics', `escher', `pipes',
			and `sproingies' hacks (depend on OpenGL.)
Changes since 1.33:	Fixed some bugs, made fading be a little smoother.
Changes since 1.32:	Made it work with multi-headed displays.
			Generalized sub-process management (Unix sucks!)
			Added interactive mouse frobbing to Julia.
			Added (untested) support for HPUX shadow passwords.
			Made normal non-shadow passwords be checked if the
			shadow passwords aren't accessible for some reason.
Changes since 1.31:	Removed *colorPrograms and *monoPrograms resources:
			made it possible to specify the desired visual on a
			per-hack basis.
			Cleaned up / restructured the driver: no more globals.
			Made the Motif and Athena dialogs share more code.
			Probably fixed some Athena colormap-installation bugs.
			Fixed screen grabbing (cmap) on SGI 12-bit PseudoColor.
			Fixed divide-by-zero in bright random colormaps.
			Added an improved version of xlock's `flag' hack.
			Made unfading work better, and not flicker on SGIs.
			Added `sphere', `forest', `lisa' hacks from xlockmore.
			Added (untested) support for SunOS Adjunct passwords.
Changes since 1.30:	Improved colors and colormap cycling of many hacks.
			Cleaned up xlockmore compatibility layer.
			Made `blitspin' able to grab an image off the screen.
			Ported `swirl' and `bouboule' hacks from xlockmore.
			Made the driver more careful about not leaving bits on
			the screen, or allowing other windows to raise 
			themselves: it now re-blanks the screen every so often.
			Added `-time' option to `xscreensaver-command'.
			Improved SGI screen-grabbing some more: now it can grab
			TrueColor screens into PseudoColor windows and have the
			colors still come out semi-reasonably.
Changes since 1.29:	Made `slidescreen' and `decayscreen' work better on
			SGIs when windows of different visuals are present, by
			using the XReadDisplay() extension to get a true 24-bit
			image out of the frame buffer.
			Made `noseguy' be in color, if compiled with XPM.
			Ported `braid', `drift', `fract', `galaxy', `grav', 
			`ifs', `julia', `laser', `lightning', `penrose',
			`sierpinski', `slip', `spiral', and `strange' hacks
			from xlockmore.
			Merged `hopalong' hack with a more recent version.
			Added `cde.txt'.
Changes since 1.27:	Added `deco', `moire', and `kaleidescope' hacks.
			Merged in support for non-Motif locking and demo mode.
			Made `blitspin' and `bubbles' work in TrueColor.
			Fixed a stupid bug I introduced in `imsmap'.
			Added `poly' and `gravity' options to `qix'.
Changes since 1.26:	Added support for SGI SCREEN_SAVER extension.
			Made `fade' and `unfade' work on 8-bit SGIs.
			Made the dialog boxes more Motify.
			Added `bubbles' hack.
Changes since 1.25:	Added `lmorph' hack.
			Added viscosity and mouse-control to attraction.
			Fixed possible bad color choices in qix and attraction.
			Added ramp-mode to halo.
			Added a new RNG, which is faster and more portable
			than using the RNG in libc.
			Made locking work on SCO.
			Various other minor tweaks that I don't remember.
Changes since 1.24:	Made it capture the stdout/stderr of its subprocesses
			and present them on the screensaver window itself.
			Made demo mode work correctly with non-default visuals
			and color maps, instead of always using the defaults.
			Added -visual argument to all included screenhacks.
			Support for the R6 MIT-SCREEN-SAVER server extension.
			Made the demo mode list scroll properly.
			Added `pedal' hack.
Changes since 1.23:	Fixed some private-colormap oddities in slidescreen,
			decayscreen, and xroger.  Fixed apparent conservation-
			of-mass problem in pyro; made the shrapnel round.
Changes since 1.22:	Minor tweaks for IRIX5; fixed locking race condition.
Changes since 1.21:	Minor tweaks for X11R6.
			Fixes for non-default visuals.
Changes since 1.20:	Fixed bug in color blitspin; added default image.
			Added diagnostics to noseguy.  Fixed off-by-one
			error in flame.  Added some missing casts.
Changes since 1.18:	Added `flame' hack.
			Fixed a minor Motif dialog text field bug.
			Fixed yet another XPointer-not-defined-in-R4 bug.
Changes since 1.17:	Added support for shadow password files.
			Fixed some Motif-related locking bugs.
			Added diagnostics when locking is disabled.
			Made blitspin able to use the XPM library.
			Added `decayscreen' hack.
Changes since 1.16:	Added `halo' hack.
Changes since 1.15:	Portability fixes.
Changes since 1.14:	Broke the driver up into more source files.
			Moved the hacks into their own directory.
			Made all `time' parameters accept the 00:00:00 syntax,
			so that even the parameters which are normally read as
			minutes can be specified in seconds.
			Added colormap cycling to `imsmap'.
			Made hyper work with K&R compilers.
Changes since 1.13:	Added `orbit' option to `attraction' hack.
			Added `lock-timeout' option.
			Cleaned up options of `maze' hack.
Changes since 1.8:	Added demo mode, and locking.
			Added `maze' hack.
			Added `norotate' option to `rocks' hack.
