The drawing packages are supported by two simple libraries for defining geometric locations and colors. The geometry package defines a single class Posn that represents a position on the canvas with Cartesian integer valued x and y coordinates.

The colors package defines the IColor interface that is implemented by six singleton classes for colors black, blue, green, red, yellow, and white. In our implementation the interface IColor defines a single method public Color thisColor() that converts the instance of IColor to Java Color. Every color class also implements the toString method to simplify the display of its value.

The Javadocs for the colors library.

The Javadocs for the geometry library.