S3 Graphics, the VIA subsidiary being bought by HTC, filed a complaint against Apple with the US International Trade Commission and US District Court of Delaware for patent infringement. This is a separate complaint from the one its current parent company filed last week, and specifically focuses on two patents covering 3D rendering and VGA controller circuitry.

The patents in question were applied for in the 1990s and are listed as:

The suit takes aim at Apple's iPhone, iPad, and iPod touch products, along with the company's desktop and notebook computers.  S3 Graphics' complaint with the ITC complaint seeks a US import ban on infringing Apple products, while the Delaware case focuses on monetary damages.

This is not the first time that Apple and S3 have been engaged in a legal spat with the U.S. International Trade Commission. Back in July, the graphics firm was awarded a partial victory as judge James Gildea found Apple guilty of infringing on three claims from two patents regarding "Fixed-rate block-based image compression with inferred pixel values" within its Mac OS X operating system. HTC, which is also targeting Apple in courts, announced plans to buy S3 from VIA in July for $300 million, giving it some leverage in potential cross-licensing negotiations down the line.