Artifex Software is suing Palm over the PDF (Portable Document Format) viewer in Palm's Pre smartphone, it said on Thursday.
Artifex alleges that Palm has copied Artifex's PDF rendering engine, called muPDF, and integrated it into the Palm Pre's PDF viewer application without the proper licensing conditions.
Artifex requires that an entire application must be licensed under the GNU General Public License (GPL) if muPDF is part of the application.
If the software is not licensed under the GNU GPL, then Artifex requires a commercial license in order to use muPDF, according to the company's licensing terms.
Artifex alleges that Palm has done neither and has filed a lawsuit in the U.S. District Court for the Northern District of California.
Palm's documentation for the Pre includes a mention of muPDF, which it says has been licensed under the GNU GPL.
Palm Europe did not reply to questions about the lawsuit. The Pre was announced at the Consumer Electronics Show in January and went on sale in the U.S in June.