US stock futures are up this morning on Tuesday, with a focus on Designer Brands Inc. (NYSE: DBI) and Casey's General Stores, Inc. (NASDAQ: CASY). Designer Brands is expected to report earnings of 23 cents per share on revenue of $737.85 million before the opening bell. Its shares rose 2.2% to $4.26 in after-hours trading. On the other hand, Casey's General Stores exceeded expectations with first-quarter earnings of $5.77. For more details, visit Benzinga.com.