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EnigmA Amiga Run 1995 October
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EnigmA AMIGA RUN 01 (1995)(G.R. Edizioni)(IT)[!][issue 1995-10][Aminet 7].iso
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fract
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IFS Fractal Generator Version 1.0 (Frac)
========================================
This program and documentation is (C) Copyright Trefor Southwell 1995.
Frac is shareware and may be freely distributed provided you do not charge
any money for it.
If you like this program or would like to suggest any improvements then
please contact me:-
email: trefor@flevel.demon.co.uk
Snail: Trefor Southwell
31, Ashley Hill
Montpelier
Bristol
BS6 5JA
About Frac
==========
Frac allows the user to design and view IFS (Iterated Function Systems)
fractals on their Amiga.
Currently only affine transformations are supported. The transformations
can be entered in either scale/angle or matrix format.
Frac is not designed to just display pretty pictures, it is really for
people who are interested in fractals.
Frac was written using Dice C V3.01 Commercial. The GUI was designed on
gadtoolsbox.
Sorry the manual is not very good, I haven't had time to improve it much.
Using Frac
==========
1. Installation
===============
Just extract the archive in a suitable directory and then run frac.
2. The basics
=============
a. Generating an IFS.
---------------------
By clicking on the GO button frac will start to generate the IFS in the
display window. If you want to stop it at any time, click on the STOP
button.
The IFS can be gererated in 3 ways:
1) Recursive
The IFS is generated by recursivley plotting dots.
You can set the number of iterations by changing
the ITERS value on the control panel.
2) Random
The IFS is build up randomly out of dots. This is the
fastest method of drawing and gives you a basic image
very quickly. The random method keeps drawing until you
click the stop button.
3) Bitmap
The IFS is build up by iterations performed on the
contents of the window as a bitmap. This is very slow
but allow you to see how the IFS is working.
You can change the drawing method by clicking on the button next to the
method you require.
If you want your image to be updated every time you change something then
enable the autodraw checkbox.
b. Zooming and panning
----------------------
To re-centre the display about a chosen point just click on the display
where you want the new centre to be.
To zoom in by a factor of 1.5 click on the ZIN button.
To zoom out by a factor of 1.5 click on the ZOUT button.
If you have autodraw on then the IFS will be re-displayed immediatley,
otherwise you will see a dotted box which shows the selected zoom, you can
then click GO to redraw.
If you have got lost zooming around then generate the fractal in either
random or recursive mode and then click on the AUTO button. This will set
the range to view the whole fractal again.
c. Loading and saving
---------------------
A number of examples have been included with frac.
To load a set of IFS codes into frac click on the load button. Select the
file you wish to load.
To save a set of IFS codes click on the save button and select the filename
you wish to save the codes as.
All you settings for frac are stored with the IFS codes. If you save the
codes with autodraw on then when they are loaded frac will start drawing
immediatley.
d. Coordinates
--------------
If you click on the COORD box then you can view and change the current
window coordinates.
3. Editing IFS's
================
Click on the IFS button to bring up the editing window. You can now select
the affine transformation you wish to edit with the TRANS slider bar.
a. Entering values
------------------
You can type values into the matrix as decimals or fractions e.g.
0.333333
or
1/3
You can change the mode between degrees (DEGS) or radians (RADS).
You can change between scale/angle (ANGLE) and matrix format (MATRIX).
Warning: When you change the mode your numbers will NOT be converted.
Scale/Angle Mode
-----------------
The ANGLEX and ANGLEY fields are used to set the amount of rotation that
the transformation performs. Setting ANGLEX and ANGLEY to the same amount
makes the rotation circular.
The SCALEX and SCALEY fields are used to set the amount of scaling
performed in the X and Y axis.
Matrix Mode
-----------
The values you enter form a 2x2 matrix which is then multiplied by the
coordinates. The matrix is:
[ ScaleX | ScaleX(Y) ]
[ ScaleY(X) | ScaleY ]
Common Fields
-------------
The MOVEX and MOVEY fields are used to give the transformation a
translation (movement) in the X and Y axis.
The WEIGHT field is used in random mode to set the probability that each
transformation is selected. If all transformations have a weight of 1 then
their probabilities are equal.
b. Adding/Deleting Transformations
----------------------------------
You can add a new transformation at the end of the list by clicking on the
NEW button
You can delete the current transformation by clicking on the DELETE button.
You can't delete a transformation if you only have 1 left.
c. Previewing your IFS
----------------------
Drawing
-------
You can preview your IFS using the tools at the bottom left of the IFS
Codes window.
If you click on the View button then the preview is drawn in the display
window.
If you turn on AUTODRAW while you are editing the IFS codes then your
preview will be updated as you alter the values.
The preview is generated from a black square. When a transformation is
applied the new square is shown. The top side of the square is a different
color so you can tell which way up it is.
Negative axis
-------------
The NEG checkbox when set means the preview rectangle will cover the
negative part of the axis. Set this when your IFS code has some negative
coordinates.
Drawing method
--------------
The SINGLE/ALL/TOGETHER selector is used to choose how the preview will be
rendered.
When SINGLE is selected only the current Transformation will be shown on
the preview.
When ALL is selected all Transformations will be shown on the preview.
They will not however interact.
When TOGETHER is selected the transformations will be applied all together.
This gives a preview of what the IFS will look like.
Iterations
----------
You can set the number of iterations in the preview by altering the Iters
field.
If you want to disable the interations then set the ONCE/ITERS selector to
once.
===========================================================================