Glitz: Hardware Accelerated Image Compositing Using OpenGL

In recent years 2D graphics applications and window systems tend to use more demanding graphics features such as alpha blending, image transformations and antialiasing. These features contribute to the user interfaces by making it possible to add more visual effects as well as new usable functionalities. All together it makes the graphical interface a more hospitable, as well as efficient, environment for the user. Even with today’s powerful computers these tasks constitute a heavy burden on the CPU. This is why many proprietary window systems have developed powerful 2D graphics engines to carry out these tasks by utilizing the acceleration capabilities in modern graphics hardware. We present Glitz, an open source implementation of such a graphics engine, a portable 2D graphics library that can be used to render hardware accelerated graphics. Glitz is layered on top of OpenGL and is designed to act as an additional backend for cairo, providing it with hardware accelerated output. Furthermore, an effort has been made to investigate if the level of hardware acceleration provided by the X Window System can be improved by using Glitz to carry out its fundamental drawing operations.