An X window manager
is a window manager
which runs on top of the X Window System
, a windowing system
mainly used on Unix-like
Unlike the Mac OS (Apple Macintosh) and Microsoft Windows platforms, which have historically provided a vendor-controlled, fixed set of ways to control how windows and panes display on a screen, and how the user may interact with them, window management for the X Window System was deliberately kept separate from the software providing the graphical display. The user can choose between various third-party window managers, which differ from one another in several ways, including:
- customizability of appearance and functionality:
- textual menus used to start programs and/or change options
- docks and other graphical ways to start programs
- multiple desktops and virtual desktops (desktops larger than the physical monitor size), and pagers to switch between them
- consumption of memory and other system resources
- degree of integration with a desktop environment, which provides a more complete interface to the operating system, and provides a range of integrated utilities and applications.
How X window managers work
When a window manager is running, some kinds of interaction between the X server
and its clients
are redirected through the window manager. In particular, whenever an attempt to show a new window is made, this request is redirected to the window manager, which decides the initial position of the window. Additionally, most modern window managers are reparenting
, which usually leads to a banner being placed at the top of the window and a decorative frame being drawn around the window. These two elements are controlled by the window manager rather than the program. Therefore, when the user clicks or drags these elements, it is the window manager that takes the appropriate actions (such as moving or resizing the window).
Window managers are also responsible for icons. Indeed, icons do not exist at the X Window System core protocol level. When the user requests a window to be iconified, the window manager unmaps it (makes it non-visible) and takes the appropriate actions to show an icon in its place. Some window managers do not support icons.
While the main aim of a window manager is to manage the windows, many window managers have additional features such as handling mouse clicks in the root window, presenting panes and other visual elements, handling some keystrokes (e.g., Alt-F4 may close a window), deciding which application to run at start-up, etc.
Specialised types of window managers
Several specialised types of window manager exist.
Virtual window managers
A virtual window manager
is a window manager that uses virtual screens, whose resolution can be higher than the resolution of one's monitor/display adapter
. This environment is very useful when one wishes to have a large number of windows open at the same time. A number of virtual window managers have been made, including FVWM
Tiling window managers
A tiling window manager
is a window manager with an organization of the screen into mutually non-overlapping frames (hence the name tiling
), as opposed to the traditional approach of coordinate-based stacking of objects (windows) that tries to emulate the desk paradigm.
The following is a list of tiling window managers.
Popular X window managers
Compositing window managers
Other X window managers