SAN FRANCISCO — Drawing on compromising emails and the disappointing launch of Apple Maps, lawyers for Samsung Electronics Co. have sought to portray Apple Inc. as a company that lost its way after the blockbuster launch of the iPhone.

The smartphone and tablet makers are again feuding over patents in the U.S. District Court for the Northern District of California. Philip Schiller, Apple’s senior vice president of Worldwide Marketing, testified this week about the commercial success of the company’s iPhone and iPad, as he has in two previous patent trials with Samsung.