Classes of Window Managers
Window managers are often divided into three classes. These classes are aimed at describing how windows are drawn and updated.
- Compositing window managers: Compositing window managers give all windows the possibility to be first created and drawn separately and then put together and displayed in various different 2D and 3D environments. This provides a great deal of variety in interface look and feel, and advanced 2D and 3D visual effects. Mac OS X can be mentioned as a good example within the context of the first operating system to be packaged with a compositing window manager.
- Stacking window managers: All window managers which possess overlapping windows and are not characterized as compositing window managers are called stacking window managers. Stacking window managers allow every window to overlap with another one by drawing background windows first. This methodology is referred to as painter’s algorithm. In case of changes it is sometimes required that all windows are re-stacked or repainted which usually involves redrawing every window. However in order to place a background window in the front, it is usually only demanded that one window gets redrawn, because background windows may have bits of other windows painted and placed over them successfully erasing those areas that are covered.
- Tiling window managers: Tiling window managers paint all windows on-screen by positioning them above / below each other and side by side. In other words the screen has to be organized into mutually non-overlapping frames. Microsoft Windows 1.0 for instance used tiling. Of course there is a variety of tiling window managers for The X Window System available.
- Dynamic window manager: Dynamic window managers are able switch dynamically between tiling or floating window layout. Strictly speaking there exists great variety of dynamic window managers for The X Window System.
Selected window manager systems do allow installing a wide range of different widgets with diverse and respective specific functions. An Online Marketing Agency would for instance install widgets that do make it possible to control and supervise important ranking positions of essential keywords within the search engine result pages. An AdWords Agency, however, would focus its attention on widgets that enable the comprehensive control of the whole budget when it comes to the most important and most essential AdWords campaigns. Widgets like these could easily be set up on the root window of the respective window manager in order to keep important ranking and budget changes in view.
Furthermore it can be said that X window managers are able to re-parent applications. This means that while initially all applications are adopted by the root window, an application started within the root window can be adopted by another. Window managers which operate under the X window system adopt applications from the root window and re-parent them to window decorations. Another intended use of re-parenting consists in allowing the contents of one window to be added to another. By way of example a flash player application can be re-parented to a browser window. Consequently the already mentioned flash player application can appear to the naked eye as supposedly being part of that program. All in all re-parenting window managers can therefore arrange one or more programs into the same window in order to combine easily tiling and stacking in various ways.