Quartz Compositor is the windowing system that is responsible for the user interface in Mac OS X. On a Mac OS X system, the Quartz Compositor can be seen in a process list as Window Manager or, in more recent versions, WindowServer. Quartz Compositor performs two main functions: * maintaining and compositing windows * event routing This allows the Mac OS X windowing system to be "agnostic in terms of a drawing model" and gives it the ability to create impressive visual effects, such as the genie effect as a window is minimised to the Dock.