The Quartz Compositor is the display server and window manager of the Mac OS X window system. Its main tasks are similar to those of a Wayland compositor, so the management and representation of the window and the pre-processing and transfer of input events.
Each window is saved as a bitmap. It contains additional information such as the position (including Z- index) and form of presentation, the alpha channel (transparency) and also for edge smoothing necessary information. The application represents its contents by writing their information in this bitmap. This can be done by the relevant subsystems ( Quartz 2D, QuickDraw, OpenGL, Cocoa, etc.). Quartz Compositor combines the individual windows and calculated the displayed image. By this method, the obtained information ( alpha channel ) and other pre-processing, the representation can be done very effectively (eg minimizing effects, window overview, ...).
In his role as a window manager Quartz Compositor also has an event management, events (events) like keystrokes, mouse movements and clicks between stores, filters and forwards. Each program represents what window has its own event management, the Quartz Compositor filled with the events that relate to his window.
Since Mac OS X 10.2 Quartz Compositor is extended by Quartz Extreme, which the ad is displayed using OpenGL. The individual windows are hereby textures in a 3D context. Thus, the accelerated imaging capabilities of modern hardware are directly exploited, which considerably accelerates the surface representation.
Quartz Extreme but correspondingly higher hardware requirements: Sun, Apple continues to activate it, a Macintosh requires the graphics card at least 16 MB of graphics memory features ( GeForce 2 MX, ATI Radeon, Intel GMA or later ) and controlled with AGP or PCI Express will. In fact, Quartz Extreme requires only a 3D graphics card that can represent textures that have no power of two size, so it also works with PCI graphics cards (such as the Radeon 7000/9000 ) and with 8 MB of video memory, but you need the external program PCI Extreme! , to activate it, and it may be due to the high load on the PCI bus be impaired as when playing DVDs.
In Mac OS X 10.4 also Quartz 2D Extreme ( Q2DE ) was introduced, which increases in a similar way, the speed of the representation of 2D elements and extends the display options. Although the system is included, but for reasons of stability, and because it is not yet supported by all video card drivers, not enabled by default. Currently, its activation must still be done via the "Quartz Debug " tool, which is part of Xcode 2.0, and is not persistent, ie is not saved on shutdown. For a permanent activation, it would be necessary to directly edit a configuration file.