Compositing concepts for the presentation of graphical application windows on embedded systems

Abstract

Modern automotive systems feature multiple displays used to render 2D and 3D graphical applications to provide functionalities like driving assistance and entertainment. The performance of the hardware used in automotive environments differs greatly from what is commonly available on desktop workstations, since automotive embedded systems are limited by power consumption and size. The windowing system supporting the graphical applications displayed on board must therefore achieve a greater level of efficiency compared to those used on desktop systems. The compositor, the component of the windowing system that is responsible to draw the content of the applications on screen, must therefore be efficient in the bitblitting operations, especially by minimizing the overdraw that occurs in case of overlapping windows. A concept for a compositor was developed, which features a data structure designed for storing overlapping windows and a set of algorithms to optimize the bitblitting operations. The compositor, using a prediction model that represents the time requirements of the bitblitting commands, is able to reduce the bitblitting time by choosing at runtime the best strategy to draw windows on screen.