Software

A GUI platform is usually highly OS-dependent. It is impossible to compare GUI platforms without taking the OS into account. The following software processes are involved in GUI usage. First, the OS handles hardware interrupts generated by a user. It then produces events for the GUI platform. The latter delivers events to the GUI application, which catches events through an event loop. Thereafter, the application instructs the platform as to how the GUI should change. The platform coordinates GUIs of different applications, determines how the screen changes, generates new screen pixel data, and then calls OS services to update the screen. Interrupt handling, event processing and screen updating are the three basic steps in the above process. The software perspective is summarized in Figure 2.

Figure 2: A software perspective for GUI energy consumption.