Monero, a privacy-focused cryptocurrency, implements its official desktop wallet software using Qt. MuseScore, an open-source, multiplatform notation software OBS, a libre cross-platform screencast software Orange data mining suite ParaView open-source cross-platform application for interactive, scientific visualization qBittorrent cross-platform free and open-source BitTorrent client QGIS geographic information system Qtractor Audio multitrack recorder and editing software QuiteRSS Feed Reader Retroshare F2F communication platform Roblox Studio a game creation tool used on the Roblox platform Scribus desktop publishing software Sibelius music composition and notation software Source 2 engine tools a 3D video game engine developed by Valve Stellarium, a planetarium program Subsurface, a software for logging and planning scuba dives initially designed and developed by Linus Torvalds SuperCollider, an environment and programming language for real-time audio synthesis and algorithmic composition Teamviewer, a computer software package for remote control, desktop sharing, online meetings, web conferencing and file transfer between computers Telegram, a messaging client available for Windows, Mac and Linux VirtualBox OS virtualization software VLC media player Wireshark, a packet analyzer WPS Office XaoS, a real-time fractal zoomer XnView MP Organizations using Qt Qt is utilized by a wide range of companies and organizations such as AMD Blizzard Entertainment BMW Crytek Daimler AG Electronic Arts European Space Agency DreamWorks LG Lucasfilm Microsoft Panasonic Philips Robert Bosch GmbH Samsung Siemens Tesla Tomtom Volvo German Air Traffic Control HP Walt Disney Animation Studios Valve Nokta Qt software architecture Qt concepts Qt is built on these key concepts: Complete abstraction of the GUI When first released, Qt used its own paint engine and controls, emulating the look of the different platforms it runs on when it drew its widgets. This made the porting work easier because very few classes in Qt really depended on the target platform; however, this occasionally led to slight discrepancies where that emulation was imperfect. Recent versions of Qt use the native style APIs of the different platforms, on platforms that have a native widget set, to query metrics and draw most controls, and do not suffer from such issues as often. On some platforms (such as MeeGo and KDE) Qt is the native API. Some other portable graphical toolkits have made different design decisions; for example, wxWidgets uses the toolkits of the target platform for its implementations. Signals and slots A language construct introduced in Qt for communication between objects which makes it easy to implement the observer pattern while avoiding boilerplate