View source for The desktop environment

Depending on the [[graphics]] capabilities of your machine, it might be possible to engage a user interface based on pixels rather than character cells. These are typically referred to as GUIs (Graphical User Interfaces), and have underpinned the vast majority of interactive computing for many years. Most GUIs are minor variations on idioms of the ''desktop environment'', that is:
* Interactive applications present sets of distinct ''windows'', objects of varying opacity taking dynamic size in 2 dimensions
** The contents of the windows, subject to overlap, are controlled by the application
** Decorators of the windows, subject to overlap, are usually controlled by the application
** Graphic presentation is typically influenced by a ''[[GUI#Theming|theme]]'' -- an instance of a presentation engine's parameters
* Windows are partitioned among ''workspaces'', 2D objects having size corresponding to the display
** Each workspace provides a z-axis on which its windows are at least [http://en.wikipedia.org/wiki/Partially_ordered_set partially ordered]
** Some systems support association of windows with more than one workspace at a time
* A ''root window''
* In every system known to this author, a total order is induced upon the workspaces, and only one workspace is shown at a time
** Workspaces are projected onto windows on a new workspace by tools such as Compiz's [http://wiki.compiz.org/Plugins/Expo Expo] and [http://wiki.compiz.org/Plugins/Scale Scale], Vista's [http://en.wikipedia.org/wiki/Windows_Flip_3D Windows Flip 3D], or MacOS's [http://en.wikipedia.org/wiki/Expos%C3%A9_%28Mac_OS_X%29 Exposé].
** The total ordering is sometimes associated with a regular polytope, but this seems a specious association from a topological perspective
** '''''A single workspace exhibiting [http://en.wikipedia.org/wiki/Simply_connected_space non-simple connection]/[http://en.wikipedia.org/wiki/Genus_%28mathematics%29 dynamic genus], starting and ending as an e.g. sphere possessing [http://en.wikipedia.org/wiki/Metric_expansion_of_space dynamic local metric], seems a fascinating and natural one. Has this not been pursued? -- [[User:Dank|nickblack.atl]] ([[User talk:Dank|talk]])'''''
GUIs are by no means always available, for instance when using a serial terminal, when recovering during a broken [[booting|boot]], or when they are not installed (by default, [[SprezzOS 1]] does not install any GUI components). In this case, interaction is limited to a pure [[The shell environment|shell environment]].
==GUIs==
The standard [[Graphics#Raster_Output|compositor/rasterizer]] on Linux is currently [[X.org]] atop a mix of kernel- and userspace Direct Rendering Infrastructure, plus a compositing window manager. Alternatives include [[Wayland]] and [[DirectFB]].
* A rasterizer provides an interface by which applications can render to a framebuffer.
** Without a rasterizer, all applications must speak cooperatively to the physical framebuffer.
* A compositing rasterizer provides virtual framebuffers to applications, which are projected via some transform to the true framebuffer.
** In the absence of a composting rasterizer, applications must cooperatively implement effects along the Z axis<blockquote>One might say that non-destructive overlapping is a Z-axis effect. While this is true, non-destructive overlapping can be implemented via recoverable, linear XOR transforms, and thus the overlapping bitmap itself is sufficient information to recover the original bitmap. Thus the distinction is meaningful. - [[User:Dank|nickblack.atl]] ([[User talk:Dank|talk]])</blockquote>
===Display Managers===
A '''[http://en.wikipedia.org/wiki/X_display_manager_%28program_type%29 display manager]''' is essentially a graphic equivalent of the console environment's <tt>getty</tt> apparata. They typically runs independently of window managers (indeed, they are more tightly bound to desktop environments and session managers than window managers), with privileges similar to those of the <tt>login</tt> process. XDMCP can be used to communicate with a display manager running remotely, though I wouldn't recommend it. Sprezzatech currently recommends use of Light-DM, unless one is making use of the [[KDE]] desktop environment, in which case KDM is recommended. Please note that GDM is recommended by the GNOME team for GNOME sessions, though our experience with LightDM in this capacity has been very positive. Note that only LightDM, Orthos, and XDM aim to support desktop environment independence, facilitating a single display manager experience across multiple session types. All display managers known to this author allow for selection from various session types, when present.
{| class="wikitable" border="1"
|+ Comparison of Display Managers
! Name
! Package
! Project of origin
! Notes
|-
| LightDM
| light-dm
| [[X.org]]
| GTK/[[KDE]]/Razor-QT/Unity frontends
|-
| GDM3
| gdm3
| [[GNOME|GNOME 3]]
| Theming completely incompatible with GDM2
|-
| GDM2
| gdm
| [[GNOME|GNOME 2]]
|
|-
| KDM
| kdm
| [[KDE]]
| Uses QT
Themeable using [[KDE]] GUI tools
|-
| Orthos
| not yet packaged
| Independent
| Pure OpenGL, highly configurable
|-
| XDM
| xdm
| X11R3
| As ugly as they come
|-
|}
===Window Managers===
===Desktop Environments===

==Theming==
SprezzOS's default theme is [[Allotrion]].

==See Also==
* ''[[Graphics]]'' from the SprezzOS Handbook
* ''[[The shell environment|The Shell Environment]]'' from the SprezzOS Handbook

{{Handbook}}

[[CATEGORY: SprezzOS Manual]]