Resource Library: Graphics/graphics-16000.iso/msdos/fractal/frcal040/readme.doc

Text File | 1993-04-15 | 13KB | 255 lines

    ┌──── ┌────┐ ┐           Timothy Harris
    │     │    │ │           5 Burnham Park Road
    │     ├────┤ │           Peverell
    └──── │    │ └───        Plymouth,
    ─────        ────        ENGLAND, PL3 5QB
          v4·00              [e-mail]

To execute CAL type `CAL' with the current directory set to the one in
which the CAL.EXE, CAL.OVR and CAL.CFG files reside. CAL will run on a
floppy-disk-only machine but copying all the files to the hard drive and
executing them from there (run `INSTALL.BAT' to do this for you) will allow
for quicker access to the help information.

CAL is public domain and you are therefore encouraged to give copies of it
to other people - however these copies must be in an unmodified form and
any charge made must be for media and distribution costs only.

The latest version is available from me on receipt of a blank disk and SAE,
or a cheque for £2·20 - remember to specify what type of disk you are using.

Hardware requirements:

CAL will work on almost any machine described as `PC-Compatible that
uses the DOS operating system. A maths coprocessor is not required but,
if fitted, will allow images to be created several times more quickly.
All operations can be performed using the keyboard, although using a mouse
is easier for many operations. Calculations can be performed more
accurately and more quickly on machines fitted with a 386sx processor
or better, but the program is still compatible with older machines.

Improved image quality is available with super VGA graphics cards offering
256 colours from a palette of 262144. Provision will be made for the new
cards allowing 32768 colours on the screen at once as soon as I can get
hold of the technical specifications of such a card.

Due to the large size of the program, and the fact that the computer only
stores part of it in memory at once, CAL is best used running from a hard
drive. If this is not possible, but around 2MB of expanded or extended
memory is available, install the RAMDRIVE.SYS utility supplied with DOS
(see DOS reference guides) and run CAL from the ramdrive. CAL can use
expanded memory for storing pieces of the code, resulting in slight
improvements in execution speed. CAL does not require, nor does it
use, extended memory.

Recent additions to CAL:

1. CAL now automatically detects if a 386 processor (or better) is
   being used and will use an improved integer arithmetic algorithm
   if possible.

2. Recently added fractal types:
      - Sierpinski triangle
      - L-Systems
      - Composite images (this allows options such as loading a saved
                   image in the form of a sphere or 3D landscape)
      - Logistic equation and associated Julia sets
      - Flip-Mandelbrot image
      - Images from applying Newton's method to zⁿ-1=0
      - Gumowski and Mira attractor
      - Symmetrical attractors
      - Quaternion Julia sets
      - Gingerbread person

   A total of 21 fractals are now available from CAL - and the user defined
   formula option can be used to create many more. 36 demonstration
   user defined formulae are provided which show the range of functions
   that are available and provide a basis for producing your own sets
   of equations.

3. A data compression algorithm is used for saving images, which means that
   less disk space is usually required for keeping a collection of pictures.
   Additionally a new option - save details only - has been added which
   stores only the information needed to recreate the fractal (typically
   around 1K) rather than the complete image.

   For details on these fractals, and any others that are available,
   select the Current fractal types option from the Welcome to CAL! help
   screen. This is available by pressing F1 as soon as CAL has loaded.

4. A batch drawing mode has been added which will scan the disk for any
   unfinished images and complete them. This can be used overnight, or
   when the computer is not going to be used for a while, to finish off
   any images that there was not time to complete in one go.

5. Improvements have been made to the user defined formula option which
   allows trigonometry to be performed on complex numbers. Formulae can
   be changed without leaving CAL by using a built-in editor.

6. The user defined formulae option has also been improved to allow fractals
   such as the Henon Attractor (where individual points are plotted instead
   of an image covering the whole screen) to be entered. Additionally,
   fractal formulae created using Fractint and saved in an FRM file can be
   imported to and exported from CAL.

   The functions available in the user defined formulae option have also
   been increased. Along with standard arithmetic and trigonometric functions
   are FLIP (used to swap the real and imaginary parts of a complex number),
   ABS (which converts a negative number to a positive one, but keeps
   positive numbers positive) and SIGN which returns is a number is
   positive, negative or zero. See the example formulae in the user defined
   formulae option for how these functions can be used.

7. A faster Lyapunov algorithm is available which typically speeds up drawing
   of this fractal by two to four times.

8. Commonly used functions can be selected using hot-keys from anywhere in
   the program.  Ctrl-D    -    Draw
                 Ctrl-C    -    Continue
                 Ctrl-Z    -    Zoom in
                 Ctrl-P    -    Palette editor

9. CAL.ICO is an icon for use with CAL if it is being run from Windows.

10.CAL can now export images to the PCX file format, compatible with most
   graphics editing / printing programs.

11.The user interface for the fractal selection lists has been modified
   slightly - as in previous versions the cursor keys can be used to select
   a fractal, but now it is also possible to type in the name directly
   to choose it. In the case of User Defined Formulae, IFS fractals and
   L-Systems the \ or / keys may be used, when the fractal list is on
   screen, to call up the menu for adding, deleting or renaming formulae.

12.The compilation of user defined formulae has been made significantly
   faster and the addition of MIN and MAX functions allows for more
   elaborate colouring. See the Internal Colouring examples in the list
   of user defined formulae.

An introduction to CAL:

1. As an introduction press Return as soon as CAL has loaded to draw
   the default image. If your copy of the CAL files is the same as the
   set that I distribute this should be the Mandelbrot set in the
   256 colour 320x200 mode that is now supported on most computers. If
   your machine will not use this mode then read the steps below about
   configuring the program.

2. Selecting the graphics resolution... All video cards allow for a
   variety of types of display. On earlier models this may be a choice
   between a low resolution (i.e. blocky) image with several colours
   or a less blocky image in black and white. Later systems have been
   capable of 16 colours and most new graphics cards are capable of
   displaying 256 colours on the screen at once.

   The type of resolution and number of colours to use are chosen
   from the `Display mode' option in the `Configurations' menu. Menu
   choices are made using the cursor keys to change the highlighted
   option and return to select it. If you are using a monochrome display
   and find the text lacks contrast then run cal by typing `CAL /M' which
   will cause a black and white palette to be used in text modes. Full
   colours will still be available (if your display supports them) when
   drawing an image.

   There are four different types of graphics mode, each progressively
   more advanced than the one before:

   CGA - one of the original graphics standards and only really included
   for machines which do not support more modern displays or to provide
   a quick overview of a detailed image. At best you can have four colours
   on the screen and the image does appear very blocky. However, CGA modes
   are present on almost all computers, including older portable machines.

   EGA - EGA allows sixteen colours to be used, although you do not have
   control over them to the same degree as is present with later standards.
   The resolution is also better - meaning that curves appear less blocky
   and images are more detailed.

   VGA - VGA appears to the user as an extension to EGA which allows you
   to use even higher resolution and to choose the colours that are used
   from a palette of colours available from the graphics card.

   SVGA - Super VGA is present on most new machines and allows images to
   be produced using 256 colours, allowing for such effects as gradual
   shifts from one colour to another. The resolution available in SVGA
   means that you can see a lot of detail in images but the extra
   calculations needed to calculate this detail can slow down drawing.
   If you are using SVGA modes you must tell CAL which make of graphics
   card is inside the computer (see next section).

3. Configuring the graphics card... It is necessary to set options
   about which type of graphics card you are using before any images
   may be created in a super VGA display mode. You can change the settings
   at any time you want since all the configuration options are contained
   within the CAL program itself.

   The type of graphics card is chosen in the `SVGA Card Type' option
   in the `Options' menu. You should be presented with a list of
   about fourteen different types of display card. If the one that you
   have fitted is listed there (this is often shown immediately upon
   powering up the computer) then select that option and it will be
   stored in the configurations file. Note that there are differences
   between graphics cards by the same manufacturer (e.g. some Tseng
   cards work in different ways to others, even though the image on
   the screen appears the same), so it may be necessary to try each
   of the variations of the card listed.

   If you cannot find your card listed, or do not know what type of card
   is fitted to the machine, then try each one in turn until you get
   successful results. It is best to have a moderate resolution SVGA
   mode selected during these tests (e.g. 640x480 with 256 colours) since
   the better standardisation between manufacturers means that non-SVGA
   modes will work with any graphics card.

   During configuration you may sometimes get a disjointed image. This
   is caused by the similar - although not quite identical - methods of
   accessing the graphics display employed by some manufacturers. Another
   of the SVGA card types will probably give the correct image.

4. The current fractal type to draw (e.g. Henon attractor, Mandelbrot
   set etc...) is chosen from the `Select fractal' option in the
   `Fractal' menu. Use the up and down cursor keys so that the arrow
   points at the fractal that you would like to draw and press the
   return key.

5. Further details about using CAL are available using the context sensitive
   help facilities. Press F1 at any time during the program and use the
   cursor keys to highlight the topic on which you would like more
   information before pressing return. The escape key will cancel the help
   mode.

6. Whilst drawing a fractal, S can be used at any time to store the image
   on disk. It can be loaded at a later stage and continued - it is not
   necessary to wait for the image to be complete before saving it.

Should you encounter any difficulties with CAL, if you have suggestions for
improvements, new fractal algorithms you would like included in future
versions or queries of any kind then do not hesitate to contact me.

Demonstration images:

Since complete images can be very large, demonstration pictures have
been stored in a compressed for so that only the bare minimum of data
is kept. To see the demonstration images, change to the directory in
which CAL resides and start CAL. Choose Batch Mode from the Load/Save
menu and select Start. The images will be automatically drawn and
saved. The Load option can then be used to load them again.

It is probably best to ensure CAL is correctly configured for your
graphics card before doing this - see above - because the demonstration
images were designed to look best in a 256 colour VGA graphics mode. If
this mode is not available then select the best possible resolution
with the largest number of colours from the Display option in the
Options menu. The demonstration images are called DEMO1.CGF, DEMO2.CGF
etc... When drawing the demonstration images the currently selected
display mode will be used.

Copies of CAL on larger capacity disks (720K upwards) may have additional
images, which are already complete, supplied with them. These include
examples of the Lyapunov fractal (this is very impressive, but can be
slow to calculate without a co-processor) and composite image option.
The latter shows the facilities for creating 3D-landscapes and moulding
images onto a sphere.

Timothy Harris