Andrey Radchenko's Delphi HPGL
Andrey Radchenko's Delphi (5) component that can be used to create an application for viewing HPGL/2 plot files. It is currently very hard to find on the Internet, so I have made it available here.
Of the versions I found in the past, this one gives the best results. Note that Andrey made this component for Delphi 5; I have not tested it on newer Delphi versions.
Update January 2012. Richard Ranson (http://radiosystemdesign.com/) has improved the component to support text (labels). The component, including a sample program, is available here. Richard used Delphi 7, so the component can be used in that version.