SAN FRANCISCO — Samsung Electronics Co. on Thursday lifted the wraps on its latest smartphone, the Galaxy S4, in a bid to maintain its leading position in the fast-growing mobile-phone market.

The new device sports a 5-inch, high-definition touch screen and new “eye-tracking” technology, matching rumors leading up to the launch event at New York’s Radio City Music Hall, which was also broadcast over the Web.

The Galaxy S4 is expected to become the flagship smartphone offering from the South Korean electronics giant, which has become the world’s largest seller of smartphones _ and the most significant competitor to Apple Inc.

At the event in New York, Samsung showed off new features for the Galaxy S4, including the ability for users to control the device with gestures and eyesight, without touching the screen.

It will also include the S Translator to translate foreign languages, and includes a feature called “Knox” to safeguard corporate data.

The new Galaxy S4 will launch in more than 150 countries beginning in late April. That may give the device a significant head start against the next iPhone from Apple, which most analysts do not expect until sometime in the September quarter at the earliest.

Samsung may also ratchet up competitive pressure against BlackBerry and Nokia Corp., two smaller smartphone makers working to revive their businesses.

• Dan Gallagher, MCT Campus