Function: julia (<x>, <y>, ...<options>...) Creates a graphics file with the representation of the Julia set for the complex number (<x> + i <y>). The parameters <x> and <y> must be real. The file is created in the current directory or in the users directory, using the XPM graphics format. The program may take several seconds to run and after it is finished, a message will be printed with the name of the file created.
The points which do not belong to the Julia set are assigned different colors, according to the number of iterations it takes the sequence starting at that point to move out of the convergence circle of radius 2. The maximum number of iterations is set with the option <levels>; after that number of iterations, if the sequence is still inside the convergence circle, the point will be painted with the color defined by the option <color>.
All the colors used for the points that do not belong to the Julia set will have the same <saturation> and <value>, but with different hue angles distributed uniformly between <hue> and (<hue> + <huerange>).
<options> is an optional sequence of options. The list of accepted options is given in a section below.
(%o1) true (%i2)