============================== FracBlank 1.8 ==============================
===========================================================================
A  screen  blanker  to  be used with Kickstart 2.x, written by Olaf `Olsen'
Barthel.   ©  Copyright  1991 by Olaf `Olsen' Barthel, Giftware, all rights
reserved.
   No  guarantee  of any kind is made that the program(s) described in this
document are 100% reliable.  You use this material on your own risk.

================================= Purpose ================================
===========================================================================
FracBlank is yet another custom screen blanker created to live in symbiosis
with  Kickstart  2.x  and  the Commodities Exchange toolkit, similar to the
`Blanker' program to be found in Tools/Commodities, just more wonderful.
   Apart  from the usual job (turning the screen black after a given period
of  time to prevent the phosphorus of your monitor from burning in) it will
draw  some neat patterns while mouse and keyboard are inactive.  Instead of
bouncing polygons, the Amiga logo, the Boing!  ball or other assorted items
around the screen, real plane fractals (yes, real fractals) will be drawn.
   The algorithm employed comes from the September 1986 issue of Scientific
American;  some of you who are familiar with OpenWindows Version 2 (such as
running  on  the  Sun4) will know it from the popular `xlock' program.  The
patterns  created  may  remind  you  of  spiders'  webs,  lace  or even the
Chladnian  patterns  formed  by  grains  of  sand strewn across a vibrating
surface.   I  haven't seen an implementation of this algorithm on the Amiga
yet, so it was time to program it ;-)

============================== Installation ===============================
===========================================================================
I  have  provided  two  versions of `FracBlank', one has been compiled with
standard  Motorola  FFP  support  (this one will run on any Amiga which has
Kickstart  2.x  installed), the other one will only work on Amiga computers
which  have  an  MC68020/030  and  an  FPU68881/882  (or MC68040) installed
(namely the A3000/T/UX line of computers).
   Drop the approriate file into your WbStartup drawer or add the line `run
>nil:  <nil:  fracblank' to your `s:user-startup' file.
   There  are  a  number  of  command  line  switches  available which also
correspond  to  tooltype  entries  to  be  changed/created by selecting the
approriate icon and choosing the Workbench item `Information...':

CX_PRIORITY...... The  Cx priority to assign this tool to.  You may want to
                  change  this  value  if  there is more than one Commodity
                  tool    running   to   use  the  same  key  sequences  as
                  `FracBlank'.   The  one  which  has  the  higher priority
                  assigned will receive the keystrokes first.

CX_POPKEY........ The  keys to press to open the `FracBlank' control panel.
                  The  control  panel allows you to set the hotkeys, adjust
                  the timeouts, to  select the hotkeys and to terminate the
                  program.

CX_POPUP......... This   is  a  boolean  switch  which  determines  whether
                  `FracBlank' is to open the control panel on startup or to
                  remain quiet.  Place `yes' here to open it.

BLANKSCREEN...... The keys to depress to force the screen blanker to become
                  active.  If the blanker is already active, pressing these
                  keys will cause the pattern to change.

MONO............. There are two display modes available for the patterns to
                  be  drawn:   high  resolution  monochrome  mode  and  low
                  resolution  multicolour mode.  Place `yes' here to select
                  high resolution monochrome mode.

CYCLE............ In multicolour mode the program can either use a fixed 32
                  colours  palette,  or  a  dynamically changing 75 colours
                  palette.  Place `yes' here to use the 75 colours palette.

SCREENTIMEOUT.... The  number  of seconds to wait before the screen blanker
                  is  activated.   This  period of time must elapse without
                  any  mouse movements or keys being pressed.  If the value
                  placed here is zero, screen blanking will be disabled.
                     You  may  either enter the number of seconds (60, 120,
                  etc.)  or  provide  a  string of the format mm:ss (11:30,
                  12:25, etc.).

PATTERNTIMEOUT... While  the  screen  blanker  is  running,  the  number of
                  seconds  to wait before changing the fractal pattern.  If
                  the  value  placed  here  is  zero, a single pattern will
                  remain.
                     You  may  either enter the number of seconds (60, 120,
                  etc.)  or  provide  a  string of the format mm:ss (11:30,
                  12:25, etc.).

   Running  `FracBlank'  twice  will cause it to open the control panel; to
terminate  `FracBlank'  send  it  a  ^E signal (such as by `break 3 e' with
`FracBlank'  running  as  CLI  task  3) or conjure up the control panel and
press the `Quit' gadget.

==================== Author's Request & Gift-Ware fee =====================
===========================================================================
By  releasing  this program and the accompanying source code as Gift-Ware I
do  not  place any obligations on you, feel free to share this program with
your  friends (and enemies) to study and to learn from it.  But, should you
feel the need to make any contributions, send them to:

                               Olaf Barthel
                             Brabeckstrasse 35
                            D-3000 Hannover 71

                        Federal Republic of Germany

   (If you don't have an idea about what to contribute:  I am still looking
for  old  Infocom  adventure  games,  since they are no longer available in
Germany)

   I  may  also  answer  questions  asked  via  electronic  mail.  My email
addresses are:

                    Z-Net: O.BARTHEL@A-Link-H
                   Usenet: o.barthel@a-link-h.zer.sub.org
                           cbmvax.commodore.com!cbmehq!sourcery!olsen

   The  entire  FracBlank  package  may  be  noncommercially redistributed,
provided  that  the  package is always distributed in its complete form.  A
small  copy  fee  for  media  costs  is  okay  but  any  kind of commercial
distribution is strictly forbidden!
   Comments  and  suggestions  how  to  improve  this program are generally
appreciated!

=============== Revision history (most recent change first) ===============
===========================================================================
1.8	Numerous bug fixes and some enhancements.

1.7	Removed sprite blanker code, replaced it by a user copper list.

1.6	Added cycle gadget.

1.5	Added multicolour mode.

1.4	The  sprite  pointer  used  to  pop  up  randomly now and then; the
	interrupt  server  has  been  rewritten  to turn off the sprite DMA
	twice instead of only once.

1.3	Added VBlank interrupt server (disables sprites), idea turned up by
	Adam  Keith  Levin's  `Disabling  Sprite  DMA From a Vertical Blank
	Interrupt' article published in AmigaMail November/December 1989.

1.2	First public release.

1.1,1.0	Before written history.