Defines a special canvas type object and override drawing methods to make the postscript code.

Defines a TPSPattern object that handles creation of patterns to be used in fill and paint operations.

TPostScript manages a list of patterns and inserts the definitions into the postscript code and manages when they are changed.

A pattern definition can access pattern definitions within the same postscript object, as long as the TPSPattern object pointer is placed into the canvas pen/brush at the time the new pattern is made.

Author: Tony Maro