Compositing window manager

A compositing manager, or compositor, is software that provides applications with an off-screen buffer for each window. The compositing manager composites the window buffers into an image representing the screen and writes the result into the display memory. A compositing window manager is a window manager that is also a compositing manager. Compositing managers may perform additional processing on buffered windows, applying 2D and 3D animated effects such as blending, fading, , rotation, duplication, bending and contortion, shuffling, blurring, redirecting applications, and translating windows into one of a number of displays and virtual desktops. Computer graphics technology allows for visual effects to be rendered in real time such as drop shadows, live previews, and complex animation. Since the screen is double buffered, it does not flicker during updates. The most commonly used compositing managers and compositing window managers include: for Linux, BSD, Hurd and OpenSolaris using the X Window System: the Compiz, KWin, Xfwm, Enlightenment, and Mutter compositing window managers and the xcompmgr and picom compositors; for Linux and BSD using Wayland: the Weston, KWin, and Mutter compositing window managers; for Windows: the Desktop Window Manager; and for macOS: the Quartz Compositor. The window manager sends each window a message to repaint itself whenever appropriate (such as when it is resized, or when another window passes in front of it). With a stacking manager, the repainting process can become corrupted when a program that is slow, unresponsive or buggy does not respond to messages in a timely manner. A malicious program can cause the system to appear unstable by simply neglecting to repaint its window.