HTMLDOC converts Hyper-Text Markup Language ("HTML") input files into indexed 
HTML, Adobe(r) PostScript(r), or Adobe(r) Portable Document Format ("PDF") 
files.  HTMLDOC supports most HTML 3.2 elements, some HTML 4.0 elements, and 
can generate title and table of contents pages. The 1.8.x releases do not 
support stylesheets.  HTMLDOC can be used as a standalone application, in a 
batch document processing environment, or as a web-based report generation 
application.  No restrictions are placed upon the output produced by HTMLDOC.

This requires fltk.