Qt (software) in the context of D-Bus

A color picker (also color chooser or color tool) is a graphical user interface widget, usually found within graphics software or online, used to select colors and, in some cases, to create color schemes (the color picker might be more sophisticated than the palette included with the program). Operating systems such as Microsoft Windows or macOS have a system color picker, which can be used by third-party programs (e.g., Adobe Photoshop).

Orca is a free and open-source, flexible, extensible screen reader from the GNOME project for individuals who are blind or visually impaired. Using various combinations of speech synthesis and braille, Orca helps provide access to applications and toolkits that support AT-SPI (e.g., the GNOME desktop, Mozilla Firefox/Thunderbird, OpenOffice.org/LibreOffice and GTK, Qt and Java Swing/SWT applications).

The name "Orca", which is another term for a killer whale, is a nod to the long-standing tradition of naming screen readers after aquatic creatures, including the Assistive Technology product on Windows called JAWS (which stands for Job Access With Speech), the early DOS screen reader called Flipper, and the UK vision impairment company Dolphin Computer Access.

UTF-16 (16-bit Unicode Transformation Format) is a character encoding that supports all 1,112,064 valid code points of Unicode. The encoding is variable-length as code points are encoded with one or two 16-bit code units. UTF-16 arose from an earlier obsolete fixed-width 16-bit encoding now known as UCS-2 (for 2-byte Universal Character Set), once it became clear that more than 2 (65,536) code points were needed, including most emoji and important CJK characters such as for personal and place names.

UTF-16 is used by the Windows API, and by many programming environments such as Java and Qt. The variable-length character of UTF-16, combined with the fact that most characters are not variable-length (so variable length is rarely tested), has led to many bugs in software, including in Windows itself.

Within computing, cross-platform software (also called multi-platform software, platform-agnostic software, or platform-independent software) is computer software that is designed to work in several computing platforms. Some cross-platform software requires a separate build for each platform, but some can be directly run on any platform without special preparation, being written in an interpreted language or compiled to portable bytecode for which the interpreters or run-time packages are common or standard components of all supported platforms.

For example, a cross-platform application may run on Linux, macOS and Microsoft Windows. Cross-platform software may run on many platforms, or as few as two. Some frameworks for cross-platform development are Codename One, ArkUI-X, Kivy, Qt, GTK, Flutter, NativeScript, Xamarin, Apache Cordova, Ionic, and React Native.

Qt Group Plc (Qt is pronounced "cute") is a software company headquartered in Espoo, Finland. It was formed following the acquisition of Qt by Digia, but was later spun off into a separate, publicly traded company.

The company oversees the development of the Qt framework alongside the Qt Project, and provides tools for UI design, software development, quality assurance and testing, as well as expert consulting services.

In a graphical user interface (GUI), a graphical widget (also graphical control element or control) is an element of interaction, such as a button or a scroll bar. Controls are software components that a computer user interacts with through direct manipulation to read or edit information about an application. User interface libraries such as Windows Presentation Foundation, Qt, GTK, and Cocoa, contain a collection of controls and the logic to render these.

Each widget facilitates a specific type of user-computer interaction, and appears as a visible part of the application's GUI as defined by the theme and rendered by the rendering engine. The theme makes all widgets adhere to a unified aesthetic design and creates a sense of overall cohesion. Some widgets support interaction with the user, for example labels, buttons, and check boxes. Others act as containers that group the widgets added to them, for example windows, panels, and tabs.

KDE Frameworks is a collection of libraries and software frameworks readily available to any Qt-based software stacks or applications on multiple operating systems. Featuring frequently needed functionality solutions like hardware integration, file format support, additional graphical control elements, plotting functions, and spell checking, the collection serves as the technological foundation for KDE Plasma and KDE Gear. It is distributed under the GNU Lesser General Public License (LGPL). As of September 2025, the latest stable release is KDE Frameworks 6 (KF6).