ifsPaint

License ------- This program is copyright ¸1997 Berthold Daum. You are allowed to use this program free of charge for noncommercial purposes. You are allowed to distribute this program as long as no files of this package are omitted or modified. Contact ------- lichtbild pty ltd 21 margate st beaumaris, vic 3193 australia email: lichtbild@compuserve.com www: http://ourworld.compuserve.com/homepages/lichtbild Introduction ------------ This program is the result of heavy programming during a JAL flight from Sydney to Tokyo. The first fractal paintings were created during the connecting flight from Tokyo to Frankfurt. It was good fun - better than Solitaire. But then, my PSION doesn't have Solitaire. Basics ------ IFS (iterated function scheme) is based on the work of Michael Barnsley. Published in: Fractals Everywhere by M.Barnsley, Academic Press, 1988. IFS provides an iterative algorithm to produce fractal images of high complexity from a very small set of parameters. Each IFS image is defined by a set of contracting functions (Fi) Fi: X(n+1) = Ai*X(n) + Bi where X(n) is a point vector, Ai is a transfor- mation matrix and Bi is a translation vector. In geometrical terms each function (Fi) scales, rotates and translates. The painting process starts by selecting a random point in the unit square as an iteration point. A new point is computed by randomly selecting a function (Fi) according to its probability Pi and applying this function to the iteration point. Now the process is repeated by using the new point as iteration point, and so on. The process never stops. This implementation ------------------- IFSpaint supports up to 32 generating functions per drawing (most drawings use not more thn 6 or 7 functions. The drawing space is 2-dimensional, so the X(n) and Bi are 2-tupels, and the Ai are 2x2 matrices. The file format is compatible with the file format of the popular FRACTINT program. However, FRACTINT can store several images in one file, but IFSpaint supports only one image per file. When reading multi-image-files, IFSpaint will read only the first image in the file. Also, 3D files are not supported. Installation ------------ IFSpaint runs on S3a, S3c, Siena, S3a-Emulator 1. Create a directory \IFS\ on any disk. 2. Copy all files *.IFS to this directory. 3. Copy IFSPAINT.OPA into an \APP\ directory on any disk. 4. Install IFSPAINT.OPA to the system screen (PSION-I) How to use ---------- The best way to learn about IFS is to open an example file and to experiment with the settings. Each parallelogram shown on the screen represents one function. The parallelogram shows how the unit square is transformed by the function. The unit square itself is shown as a box with rounded corners. To select a function press TAB. The selected function is displayed in black. To modify a function, first select an operation (Scale, Rotate, Translate, Probabilty) by pressing the diamond key or a letter (S,R,T,P). Then use the cursor keys to perform the selected operation. To create a new function press "+". To remove a function press "-" or DEL. For more keyboard shortcuts press HELP. An "Overflow" error indicates that you created a non contracting function. IFSpaint will undo the last operation. Probabilities: Probabilities control how often a function is applied. IFSpaint will always enforce a sum of 1.0 over all function probabilities. "Equalize" enforces identical probabilities for all functions. "Normalize" enforces probabilities proportional to the area size of each function. Preferences control screen layout and computing mode: "integer" works faster, "floating point" preciser. IFSpaint can save images in IFS file format or as bitmap (PIC). To edit IFS files, you may want to install IFSedit.ALS into an \APP\ directory. If you choose to edit an IFS file with WORD you must save the file as TEXT. To print an image or to convert into other file formats (GIF, BMP, PCX), save the image as bitmap, and use products such as PocView or PicPoc to print or convert the image. If you create interesting images, make the IFS files available to others. You can also send us these files - we will include the best into future releases. You may want to include your name with the title line. Warning ------- Because the iteration does not stop and continues drawing, your PSION will not switch off, as long as IFSpaint is active.