GST Fractal Generator

INSTRUCTIONS

GST FRACTAL GENERATOR
=====================

Introduction
============

Welcome  to the GST Fractal Generator,  the program that  exploits 
the Atari ST graphics to the full.   With this program you will be 
able to generate and display the most fantastic graphic images you 
could  imagine,  yet  they are derived from a  deceptively  simple 
mathematical  formula.   We  hope you have as much fun  using  the 
Fractal Generator as we had writing it!

You  may  make  backup  copies of this  disk  for  your  own  use,  
however,  YOU MUST NOT DISTRIBUTE OR MARKET THIS SOFTWARE TO THIRD 
PARTIES IN ANY FORM WHATSOEVER.

Copyright (C) 1986, GST Holdings Limited.  All rights reserved.


Printing the Manual
===================

This document is the instruction manual for the Fractal Generator.  
To print it,  return to the Desktop,  then double-click on READ.ME 
and click the Print option.


Fractal Geometry
================

Fractal  Geometry is a modern branch of mathematics  pioneered  by 
mathematician Benoit B Mandelbrot,  fellow at  IBM Thomas J Watson 
Research Center in New York.

Fractal Geometry is the study of a family of shapes that cannot be 
described by conventional geometry.   A principal feature of these 
shapes  is  that  the complexity of  their  appearance  cannot  be 
reduced  by examining them with greater magnification.   The  best 
known physical example of this is the snowflake.

The  GST Fractal Generator allows you to explore  the  theoretical 
fractal  shape known as the Mandelbrot Set.   For  those  familiar 
with mathematics, this is the map of iterations of the formula:

          2
     Z = Z + C

where C is a point in the complex plane and Z is initially zero.
  
For each point C,  this formula is iterated until Z>2 or a defined 
maximum  number of iterations is exceeded.   The actual number  of 
iterations  performed for each point is represented on the  screen 
as a colour.

For those unfamiliar with mathematics,  the Mandelbrot Set is  one 
of the most complicated and beautiful objects you can draw.

If  you want to read more about Fractal Geometry,  we suggest  you 
start with the August 1985 edition of Scientific American.


Running the Fractal Generator Program
=====================================

If  you have a colour monitor,  ensure you are in LOW  resolution, 
then double-click the FRACTALC.PRG icon.

If  you have a monochrome monitor,  double-click the  FRACTALM.PRG 
icon.

The program will recolour the desktop to black and white  stipple, 
then it displays a menu bar,  a Contour window and a window called 
Adam  which shows the complete Mandelbrot set which has been  pre-
drawn and loaded from disk.


Operating the Microscope Zoom Feature
=====================================

When  you load the Fractal Generator it will default  to  Generate 
mode  in Medium resolution and Low precision (these values can  be 
changed by using the drop-down menus).

To operate the zoom, drag a rubber box around the area you wish to 
magnify  using the mouse.   This area will be highlighted and  you 
will  be asked to confirm your selection.   If  you  confirm,  the 
program will draw a white box in the parent window to indicate the 
position and a new fractal image will be drawn in a child window.

This  process can be repeated several times (until you run out  of 
RAM), but only the last four images will be shown on the screen at 
any one time.

You will be surprised how far you can zoom in, because the Fractal 
Generator has a magnification factor of up to 8 million times!


Searching and Manipulating the Family Tree
==========================================

The  fractal images stored in RAM and displayed on the screen  are 
arranged  as a family tree.   To search and manipulate this  tree, 
select Display mode from the View menu.

To  move from the Child window to the Parent  window,  use  Select 
parent in the Command menu.

To  move from the Child window to one of its own  children,  click 
the mouse within the appropriate white box in the window.   If you 
click within the intersection of two boxes,  the smaller one  will 
be selected.

To delete the current Child window from RAM,  select Delete  child 
from the Command menu.   Note that the program will  automatically 
re-sort the tree at this stage to avoid leaving "orphan" images in 
RAM.

To switch back to fractal generation mode,   select Generate  from 
the View menu.

Using these facilities you can create a family tree of interesting 
images that can be saved and reloaded from disk.


Changing Resolution
===================

Resolution defines the minimum size of the colour block used  when 
drawing the fractal image.   Select either Coarse,  Medium or Fine 
resolution  from the Options menu.    Each finer resolution  level  
will  take  around three times longer to draw  than  the  previous 
level.

When you are generating a fractal image you can choose to halt the 
process  at  the end of each resolution pass by holding  down  the 
mouse button until a message appears.

You can also redraw an existing Child window at higher  resolution 
by  choosing  the required options and then  selecting  Regenerate 
from the Command menu.


Changing Precision
==================

Precision  defines  the maximum number of times that  the  fractal 
generation formula is iterated before deciding that the point lies 
within  the Mandelbrot Set,  indicated by painting a black  colour 
block.

Select Low, Medium or High precision from the Options menu.

At  high  magnification  levels you will need  High  precision  to 
display fine detail,  but beware:   if your image displays a large 
area  within  the  Mandelbrot Set,  it will take a  long  time  to 
generate.

You  can also redraw an existing Child window at higher  precision 
by choosing the required option and then selecting Regenerate from 
the Command menu.


Reading Fractal Images from Disk
================================

You  can  read a pre-stored fractal image from disk  by  selecting 
Load  fractal  in the command menu.   This will display  the  File 
Selector showing all files with the .FRC extension.  Select one of 
these  and it will be read into RAM and inserted into  the  family 
tree.

If  you select auto Palette from the Options menu,  the new  image 
will reset the contour and colour maps to those in use when it was 
saved.

After  reading an image from disk,  the Adam window is redrawn  to 
enable you to search the tree for the loaded image.

Some  fractal images are already stored on disk,  but  these  will 
only work with a colour monitor, monochrome images will have to be 
generated from scratch.


Writing Fractal Images to Disk
==============================

You  can save your current Child window to disk by selecting  Save 
child in the command menu.   This will display the File  Selector.  
Choose  an existing name or type a new name for your file  (use  a 
.FRC extension),  then click OK.   The Child window together  with 
the contour map and colour palette will be saved to disk.


Full Size Blow-up Images
========================

Select Blow-up mode from the View menu to show a large version  of 
your  current  Child  window.   This is  generated  in  ultra-fine 
resolution and ultra-high precision,  so it may take some time  to 
generate,  particularly  if your image contains a lot  of  "inside 
black" points.

You  cannot  recontour your image or save it to  disk  in  Blow-up 
mode, so ensure that these are done before you draw the blow-up.

When the blow-up has been generated,  the program will ask whether 
to return to menu operation.  If you select OK the picture will be 
cleared,  otherwise  the picture will be displayed with the  mouse 
disabled.  Click the mouse to regenerate the prompt.

To return to normal display after drawing a blow-up image,  select 
Panels display from the View menu.


Recolouring Your Fractal Image
==============================

Use  the  ST Control Panel to change the colour  of  your  fractal 
image.   If  you save the image to disk,  the colour map  will  be 
saved too.


Recontouring Your Fractal Image
===============================

Use  the Contour window to modify the colour gradient by  dragging 
the mouse in the colour boxes to change their size.   Then  select 
Recontour  from the Command menu to redraw the Child  window.   If 
you save your fractal to disk, the colour map will be saved too.

You  can automatically recontour each image you draw by  selecting 
auto Contour from the Options menu.


Modifying the Fractal Generator Program
=======================================

The sources of the Fractal Generator are provided on disk.   These 
are written in GST C with assembler inserts.  Each source file has 
a .C extension.

Also included are the files FRACTAL.LNK (the link control file for 
the  GST  Linker) and FRACTAL.LIB (a special library for  for  the 
Fractal Generator program).

To  modify  the  program you will need  a  GSTC  Compiler,  please 
contact your dealer for details.

THE SOURCE FILES ARE COPYRIGHT (C) 1986 GST HOLDINGS LIMITED.  YOU 
ARE NOT PERMITTED TO DISTRIBUTE OR MARKET MODIFIED VERSIONS OF THE 
FRACTAL GENERATOR PROGRAM IN ANY FORM WHATSOEVER.


Exit from the Fractal Generator
===============================

To  exit from the Fractal Generator,  select Quit in  the  Command 
menu.  The program will exit to the GEM Desktop.