As said in the Command Line section, PHP_UML converts programming data from one format to another format. Between the two, it builds a UML model.
At the current moment, PHP_UML can read XMI and PHP, and can generate XMI, PHP and HTML.
If you want to write your own input format, you
can program your own implementation
of PHP_UML_Input_ImporterFileScanner
.
If you want to write your own output format, you
can program your own implementation
of PHP_UML_Output_Exporter
(either by traversing the model, like the "HtmlNew" implementation does, either by XSLT applied on XMI, like the implementation "Html" does).
For a better understanding of the program's guts, have a look at its class diagram, available in the docs folder (PHP_UML_simplified_class_diagram.png).
If you are interested in the PHP_UML project, and want to participate, do not hesitate to contact me.