A re-parenting window manager is an X Window System window manager that adopts all other windows.
The X Window System is a windowing system for bitmap displays, common on Unix-like operating systems.
A window manager is system software that controls the placement and appearance of windows within a windowing system in a graphical user interface. Most window managers are designed to help provide a desktop environment. They work in conjunction with the underlying graphical system that provides required functionality—support for graphics hardware, pointing devices, and a keyboard, and are often written and created using a widget toolkit.
In the X Window System, every window has a parent window, which may be either the root window or another window. Windows that are children of the root window are called top-level windows. When a top-level window is created, a re-parenting window manager changes that window's parent to be a second new window created by the window manager for this purpose. This allows the window manager to decorate the windows with window decorations and title bars as well as allows advanced control over the windows' operation required, for example, by virtual window managers.
In the X Window System, every window is contained within another window, called its parent. This makes the windows form a hierarchy. The root window is the root of this hierarchy. It is as large as the screen, and all other windows are either children or descendants of it.
In graphical user interfaces, the window decoration is a part of a window in most windowing systems.
Technically, a reparenting window manager registers with the X server to be notified when a top-level window is mapped (attempts to become visible). When such an event is generated, the window manager creates a frame window, and in most cases also a title bar window. The frame window then becomes the parent of both the main window and the title bar window. Other forms of decoration, such as buttons, window title, etc., may also be created; these would normally be parented by the title bar window. [1]
X.Org Server is the free and open-source implementation of the display server for the X Window System stewarded by the X.Org Foundation.
In computer programming, event-driven programming is a programming paradigm in which the flow of the program is determined by events such as user actions, sensor outputs, or messages from other programs or threads. Event-driven programming is the dominant paradigm used in graphical user interfaces and other applications that are centered on performing certain actions in response to user input. This is also true of programming for device drivers.
Virtually all modern window managers are re-parenting, although earlier window managers, such as the uwm window manager, were not. Exceptions to that rule are dwm, cwm, PLWM, ratpoison and xmonad, due to a lack of any typical window decorations used by these window managers, and also Compiz which drew the decorations separately up until version 0.9.0, where it became a re-parenting window manager to allow it to run in a non-composited mode. Even though stumpwm does not draw typical window decorations, it reparents windows in a parent frame to display outlines.
The Ultrix Window Manager (uwm) is a historic standard window manager software for the X Window System from X11R1 through X11R3 releases. In fact, it was the only X11-compatible window manager as of X11R1.
dwm is a dynamic, minimalist tiling window manager for the X Window System that has influenced the development of several other X window managers, including xmonad and awesome. It is externally similar to wmii, but internally much simpler. dwm is written purely in C for performance and security in addition to simplicity, and lacks any configuration interface besides editing the source code. One of the project's guidelines is that the source code will never exceed 2000 lines, and options meant to be user-configurable are all contained in a single header file.
cwm is a stacking window manager for the X Window System. While it is primarily developed as a part of OpenBSD's base system, portable versions are available on other Unix-like operating systems.
