QPainter and 2D graphics

Qt comes with an advanced windowing, painting, and typography system. The most important classes in the Qt GUI module are QWindow and QGuiApplication. This module includes classes for 2D graphics, imaging, fonts, and advanced typography. Additionally, the GUI module comes with classes for integrating windowing systems, OpenGL integration, event handling, 2D graphics, basic imaging, fonts, and text. Qt's user interface technologies use these classes internally, but they can directly be used to write applications that use low-level OpenGL graphics APIs.

Depending on the platform, the QWindow class supports rendering with OpenGL and OpenGL ES. Qt includes the QOpenGLPaintDevice class, which allows the use of OpenGL accelerated QPainter rendering and several convenience classes. These convenience classes simplify writing code in OpenGL by hiding the complexities of extension handling and the differences between OpenGL ES 2.0 and desktop OpenGL. QOpenGLFunctions...