Random art in Python

I get asked every so often to release the source code for my random art project. The original source is written in Ocaml and is not publicly available, but here is a simple example of how you can get random art going in python in 250 lines of code.

Download source: randomart.py

The idea is to generate expression trees that describe an image. For each point `(x,y)` of the image we evaluate the expression and get a color. A color is represented as a triple `(r,g,b)` where the red, green, blue components are numbers between `-1` and `1`. In computer graphics it is more usual to use the range `[0,1]`, but since many operations are symmetric with respect to the origin it is more convenient to use the interval `[-1,1]`. I kept the program as simple as possible, and independent of any non-standard Python libraries. Consequently, a number of improvements and further experiments are possible:

• The most pressing problem right now is that the image is displayed as a large number of rectangles of size 1×1 on the tkinter Canvas, which consumes a great deal of memory. You will not be able to draw large images this way. An improved version would use the Python imagining library (PIL) instead.
• The program uses a simple RGB (Red Green Blue) color model. We could also use the HSV model (Hue Saturation Value), and others. One possibility is to generate a palette of colors and use only colors that are combinations of those from the palette.
• Of course, you can experiment by introducing new operators. If you are going to play with the source, your first exercise should be a new operator. Make sure it maps the range `[-1,1]` back to `[-1,1]`.
• The program uses cartesian coordinates. You could experiment with polar coordinates.