diff options
Diffstat (limited to '')
| -rw-r--r-- | plug-ins/ifs-compose/README.ifscompose | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/plug-ins/ifs-compose/README.ifscompose b/plug-ins/ifs-compose/README.ifscompose new file mode 100644 index 0000000..cbaa331 --- /dev/null +++ b/plug-ins/ifs-compose/README.ifscompose @@ -0,0 +1,83 @@ +IfsCompose +---------- + +IfsCompose is a plug-in for GIMP that allows +the creation of Iterated Function System fractals by direct +manipulation onscreen of the component transforms. + + +IFS Fractals +------------ + +You may be familiar with IFS's from the screen +hack 'Flame'. They are also the basis of fractal image compression. + +For a brief introduction to IFS's see Foley and van Dam, et +al,. _Computer Graphics, Principles and Practice_, 2nd Ed., +(Addison Wesley, 1990). + +The standard references in the field are Michael Barnsley's books (though +I haven't looked at them yet): + +M. Barnsley, _Fractals Everywhere_, Academic Press Inc., 1988. +M. Barnsley and L. Hurd, _Fractal Image Compression_, Jones and +Bartlett. + +Briefly, you take a point and repeatedly apply one of a set of +transformations to it, choosing randomly between them, and plot the +point at each step. An interesting result (the Collage Theorem) says +that if you can find a set of transformations that break up an image +into smaller copies of itself, then the resulting fractal exactly +reproduces the original image. For example, here is a classic image +of a leaf and the same image with the four component transforms +colored distinctively. + +But the best way to appreciate this may to install this program and +try it out. I've extended the basic concept as found in +Foley and van Dam to include transformations in color space as +well as in real space. + +Installation +------------ +The included Makefile should work with minor modifications on most +systems if you have installed Gimp normally. Put the resulting binary +in ~/.gimp/plug-ins or the system-wide plug-ins directory. + +The included files gtkaspectframe.c/.h implement a modified frame +widget that guarantees that the aspect ratio of the child widget +remains constant when the parent is resized. It's sort of specialized, +but if you think it would be useful for other purposes, let me know +and I'll lobby for its inclusion in the standard gtk. + +Use +--- +The interface is somewhat complex and it may take you a little while +to get the hang of it. (There are 19 parameters for each +transformation in your fractal, after all). The best way to learn is +probably to start by making small changes, and seeing what they +do. Click on the transformations (represented by polygons) in the +design window to manipulate them interactively. + +Button-1: rotate/scale +Button-2: distort +Button-3: move + +If you hold down shift while clicking, you can select multiple polygons +to apply the transformation to. + +Try not to click too near the center of a polygon, as this will +amplify your actions. + +Note that if you render onto an image with an alpha channel, the +background will be transparent (very useful for compositing several +fractals), otherwise the background will be the current background. + +There are tutorials and some example images at: + + http://www.gtk.org/~otaylor/IfsCompose/ifs_tutorial/tutorial.html + http://tigert.gimp.org/gimp/ifs-compose/ + + +Have fun! + +Owen Taylor |