Finnish company Digia has opened an office in the U.S. in an effort to boost the commercial usage of a cross-platform application and user interface framework Qt, it said on Tuesday.

In March, Digia announced it was acquiring Nokia's Qt Commercial licensing and services business. Nokia kept control of the software itself.

Qt is designed to let developers write and deploy applications across desktop, mobile and embedded OSes without rewriting the source code. It is available either as open source or under a commercial license. Companies that want to use the latter for its embedded and desktop systems can now turn to Digia.

Half of Digia's Qt customers -- about 3,500 were included in the deal with Nokia -- are based in North America. Some of the employees Digia took over from Nokia are also based there. So it made sense for the company to open an office, according to Harri Paani, senior vice president at Digia.

The push is also a result of a growing interest for Qt Commercial in North America. Sales in the second quarter exceeded expectations, driven by license renewals and new "large-scale" deals, the company said without providing any details. The company is releasing its second quarter results next week, Paani said.

The new office, which is in Santa Clara, California, will be responsible for Qt Commercial development, licensing, support and services for Qt Commercial customers in the region.

Digia has also put in place its own build and release system for Qt for embedded and desktop environments.

The commercial version of Qt allows individual developers or companies to keep their source code proprietary. That gives them the freedom to use, modify and license their application with no obligation to share the code, according to Digia.

The ability to do that is especially useful for companies in the defense, aerospace and medical industries where there are restrictions on using open source, it said.

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