The app developer Rovio wants you to take out your smartphone at the movie theater.

To promote the release of "The Angry Birds Movie," which opens on Friday in the United States, Rovio is offering bonus content for its newest mobile game, Angry Birds Action, to those who open the app while in the theater. (The incentive comes as the credits roll at the end of the movie.) The cross-platform marketing strategy is part of Rovio's efforts to reinvigorate its Angry Birds brand and transform the company into a global media powerhouse.

The original Angry Birds game, which was released in 2009 and became a time-consuming yet irresistible distraction, is the top paid mobile app of all time. But sales have flagged and the company has struggled, despite efforts to diversify into consumer products and reduce its reliance on mobile games.

Rovio, a privately held company based in Finland, reported an annual loss in 2015 of 13 million euros, or about $15 million.

The movie was developed as part of the company's desire to evolve beyond apps, said Tuomo Korpinen, president of the company's Rovio Animation unit and formerly of DreamWorks Animation. "The idea was that this was needed to compete with the best out there, the Disneys, the Pixars, the DreamWorks."

Rovio had already moved into producing animated shorts, which were released in its games and later on ToonsTV, the company's mobile platform for distributing original series and third-party content. But executives wanted to further expand the Angry Birds franchise.

"We started diving into what makes a brand," said Mikael Hed, executive chairman of Rovio Animation. "We noticed that big brands in entertainment are connected to storytelling."

So Rovio took a risk, deciding to develop and finance a feature-length film, which reportedly cost $80 million to make. The movie "is a natural evolution of wanting to tell the story of our characters," said Mr. Korpinen, who goes by Tommy.

The feathered friends will be given limbs and voices for the first time, a strategic decision that Rovio waited until the movie to introduce. "We wanted to keep it a clean slate, no limitations in terms of their dialogue and tone of their voice," Mr. Hed said. "We had total freedom for creating our characters within the movie."

To market the film, Rovio played to its core strength as a digital developer. In addition to the extra content offered to moviegoers, Rovio is offering content through its licensing partners, like H&M, Hasbro, Lego and McDonald's. Packaged products include "BirdCodes" that can be scanned with a smartphone to unlock bonus material such as power-ups for Angry Birds Action, mini-games and augmented reality experiences.

"Because our core, or DNA, is that we are a digital company, we were able to execute these types of programs," Mr. Korpinen said.