The X Window System logo

In computing, the X Window System (commonly X11 or X) is a network-transparent windowing system for bitmap displays. This article details the protocols and technical structure of X11. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Memory (Random Access Memory) Look up computing in Wiktionary, the free dictionary. ... KDE 3. ... “Computer Networks” redirects here. ... A windowing system is a graphical user interface (GUI) which uses the window as one of its primary metaphors. ... Suppose the smiley face in the top left corner is an RGB bitmap image. ...

The X client-server model and network transparency

X is based on a client-server model. An X server program runs on a computer with a graphical display and communicates with various client programs. The server accepts requests for graphical output (windows) and sends back user input (keyboard, mouse). Client/Server is a network application architecture which separates the client (usually the graphical user interface) from the server. ...

In X Window, the server runs on the user's computer, while the clients may run on a different machine. This is the reverse of the common configuration of client-server systems, where the client runs on the user's computer and the server runs on a remote computer. This reversal often confuses new X users. The X Window terminology takes the perspective of the program, rather than the end-user or the hardware: the remote programs connect to the X server display running on the local machine, and thus act as clients; the local X display accepts incoming traffic, and thus acts as a server.

In this example, the X server takes input from a keyboard and mouse and displays to a screen. A web browser and a terminal emulator run on the user's workstation, and a system updater runs on a remote server but is controlled from the user's machine. Note that the remote application runs just as it would locally.

The communication protocol between server and client runs network-transparently: the client and server may run on the same machine or on different ones, possibly with different architectures and operating systems. A client and server can communicate securely over the Internet by tunneling the connection over an encrypted connection. X Window System client-server example diagram. ... An example of a web browser (Internet Explorer), displaying the English Wikipedia main page. ... Apple Terminal. ... In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication. ... “Computer Networks” redirects here. ... A typical vision of a computer architecture as a series of abstraction layers: hardware, firmware, assembler, kernel, operating system and applications (see also Tanenbaum 79). ... // An operating system (OS) is a set of computer programs that manage the hardware and software resources of a computer. ... This article describes how security can be achieved through design and engineering. ... A tunneling protocol is a network protocol which encapsulates one protocol or session inside another. ...

Design principles

Bob Scheifler and Jim Gettys set out the early principles of X as follows (as listed in Scheifler/Gettys 1996): Robert W. Scheifler (born 1954) is a computer scientist. ... Jim Gettys is a computer programmer. ...

• Do not add new functionality unless an implementor cannot complete a real application without it.
• It is as important to decide what a system is not as to decide what it is. Do not serve all the world's needs; rather, make the system extensible so that additional needs can be met in an upwardly compatible fashion.
• The only thing worse than generalizing from one example is generalizing from no examples at all.
• If a problem is not completely understood, it is probably best to provide no solution at all.
• If you can get 90 percent of the desired effect for 10 percent of the work, use the simpler solution. (See also Worse is better.)
• Isolate complexity as much as possible.
• Provide mechanism rather than policy. In particular, place user interface policy in the clients' hands.

The first principle was modified during the design of X11 to: "Do not add new functionality unless you know of some real application that will require it." X has largely kept to these principles since. The reference implementation is developed with a view to extension and improvement of the implementation, whilst remaining almost entirely compatible with the original 1987 protocol. Worse is better, also called the New Jersey style, is the name of a computer software design approach (or design philosophy) in which simplicity of both interface and implementation is more important than any other system attribute (including correctness, consistency, and completeness). ...

X Window System core protocol

Main article: X Window System core protocol

Communication between server and clients is done by exchanging packets over a network channel. The connection is established by the client, which sends the first packet. The server answers by sending back a packet stating the acceptance or refusal of the connection, or with a request for a further authentication. If the connection is accepted, the acceptance packet contains data for the client to use in the subsequent interaction with the server. The X Window System logo The X Window System core protocol[1][2][3] is the base protocol of the X Window System, which is a networked windowing system for bitmap displays used to build graphical user interfaces on Unix, Unix-like, and other operating systems. ...

After connection is established, four types of packets are exchanged by the client and the server over the channel:

1. Request: The client requests information from the server or requests it to perform an action.
2. Reply: The server responds to a request. Not all requests generate replies.
3. Event: The server sends an event to the client, e.g., keyboard or mouse input, or a window being moved, resized or exposed.
4. Error: The server sends an error packet if a request is invalid. Since requests are queued, error packets generated by a request may not be sent immediately.

The X server provides a set of basic services. The client programs realize more complex functionalities by interacting with the server.

Windows

A possible placement of some windows: 1 is the root window, which covers the whole screen; 2 and 3 are top-level windows; 4 and 5 are subwindows of 2. The parts of window that are outside its parent are not visible.

What is usually called a window in other graphical user interfaces is a top-level window in the X Window System. The term window is also used for windows that lie within another window, that is, the subwindows of a parent window. Graphical elements such as buttons, menus, icons, etc. are all realized using windows. Image File history File links Some_X_windows. ... A graphical user interface (GUI) is a type of user interface which allows people to interact with a computer and computer-controlled devices which employ graphical icons, visual indicators or special graphical elements called widgets, along with text labels or text navigation to represent the information and actions available to...

A window can only be created as a subwindow of a parent window. This causes the windows to be arranged in a tree, that is, a hierarchy. The root of this hierarchy is called the root window, which is automatically created by the server. The top-level windows are exactly the direct subwindows of the root window. Visibly, the root window is as large as the screen, and lies behind all other windows. A labeled tree with 6 vertices and 5 edges In graph theory, a tree is a graph in which any two vertices are connected by exactly one path. ... A hierarchy (in Greek: , derived from — hieros, sacred, and — arkho, rule) is a system of ranking and organizing things or people, where each element of the system (except for the top element) is subordinate to a single other element. ... In the X Window System the background or desktop i. ...

Identifiers

All data about windows, fonts, etc. is stored in the server. The client knows identifiers of these objects—integers it can use as names for them when interacting with the server. For example, if a client wishes a window to be created, it requests the server to create a window with a given identifier. The server creates a window and associates it with the identifier. The identifier can be later used by the client to request, for example, a string to be drawn in the window.

Identifiers are unique to the server, not only to the client; for example, no two windows have the same identifier, even if created by two different clients. A client can access any object given its identifier, even if the object has been created by another client.

Attributes and properties

Every window has a predefined set of attributes and a set of properties, all stored in the server and accessible to the clients via appropriate requests. Attributes are data about the window, such as its size, position, background color, etc. Properties are pieces of data that are attached to a window. Contrary to attributes, properties have no meaning at the level of the X Window core protocol. A client can store arbitrary data in a property of a window.

A property is characterized by a name, a type, and a value. Properties are similar to variables in imperative programming languages, in that the application can create a new property with a given name and of a given type and store a value in it. Properties are associated to windows: two properties with the same name can exist on two different windows while having different types and values. In computer science and mathematics, a variable is a symbol denoting a quantity or symbolic representation. ... In computer science, imperative programming, as opposed to declarative programming, is a programming paradigm that describes computation in terms of a program state and statements that change the program state. ...

Properties are mostly used for inter-client communication. For example, the property named WM_NAME is used for storing the name for the window; window managers typically read this property and display the name of the window at the top of it.

The properties of a window can be shown using the xprop program. In particular, xprop -root shows the properties of the root window, which include the X resources (parameters of programs). In the X Window System, the X resources comprise parameters of programs such as the name of the font used in the buttons, the background color of menus, etc. ...

Events

Events are packets sent by the server to the client to communicate that something the client may be interested in has happened. A client can request the server to send an event to another client; this is used for communication between clients. For example, when a client requests the text that is currently selected, an event is sent to the client that is currently handling the window that holds the selection.

The content of a window may be destroyed in some conditions (for example, if the window is covered). Whenever an area of destroyed content is made visible, the server generates an Expose event to notify the client that a part of the window has to be drawn.

Other events are used to notify clients of keyboard or mouse input, of the creation of new windows, etc.

Some kinds of events are always sent to client, but most kinds of event are sent only if the client previously stated an interest in them. This is because clients may only be interested in some kind of events. For example, a client may be interested in keyboard-related event but not in mouse-related events.

Color modes

The way colors are handled in the X Window Systems sometimes confuse users, and historically several different modes have been supported. Most modern applications use TrueColor (24-bit color, 8 bits for each of red, green and blue), but old or specialist applications may require a different color mode. Many commercial specialist applications use PseudoColor. Truecolour (or Truecolor, Millions on a Macintosh) graphics is a method of storing image information in a computers memory such that each pixel is represented by three or more bytes. ...

The X11 protocol actually uses a single 32-bit unsigned integer for representing a single color in most graphic operations, called a pixelvalue. When transferring primary colors intensity, a 16 bits integer is used for each colour component. The following representations of colors exist; not all of them may be supported on a specific device. A primary color is a color that cannot be created by mixing other colors in the gamut of a given color space. ...

• DirectColor: A pixel value is decomposed into separate red, green, and blue subfields. Each subfield indexes a separate colormap. Entries in all colormaps can be changed.
  • TrueColor: Same as DirectColor, except that the colormap entries are predefined by the hardware and cannot be changed. Typically, each of the red, green, and blue colormaps provides a (near) linear ramp of intensity.
• GrayScale: A pixel value indexes a single colormap that contains monochrome intensities. Colormap entries can be changed.
  • StaticGray: Same as GrayScale, except that the colormap entries are predefined by the hardware and cannot be changed.
• PseudoColor (Chunky): A pixel value indexes a single colormap that contains color intensities. Colormap entries can be changed.
  • StaticColor: Same as PseudoColor, except that the colormap entries are predefined by the hardware and cannot be changed.

See also: X11 color names

In chunky or packed pixel frame buffer organization, the bits defining each pixel are grouped together. ... In computing, on the X Window System, X11 color names are represented in a simple text file, which maps certain strings to RGB color values. ...

Xlib and other client libraries

Main article: Xlib

Most client programs communicate with the server via the Xlib client library. In particular, most clients use libraries such as Xaw, Motif, GTK+, or Qt which in turn use Xlib for interacting with the server. Xlib is an X Window System protocol client library in the C programming language. ... Xlib is an X Window System protocol client library in the C programming language. ... Xaw is short for the Athena widget set, which is a set of widgets to implement simple user interfaces based upon the X Toolkit Intrinsics. ... Screenshot of an application that uses the Open Motif toolkit Motif (or capitalized MOTIF) is a graphical widget toolkit for building graphical user interfaces under the X Window System on Unix and other POSIX-compliant systems. ... GTK+, or the GIMP Toolkit, is one of the two most popular widget toolkits for the X Window System for creating graphical user interfaces. ... In computer programming, Qt is a cross-platform application development framework, widely used for the development of GUI programs, and, since the release of Qt 4, also used for developing non-GUI programs such as console tools and servers. ... Xlib is an X Window System protocol client library in the C programming language. ...

Inter-client communication

The X Window core protocol provides mechanisms for communication between clients: window properties and events, in particular the client-to-client message events. However, it does not specify any protocol for such interactions. These protocols are instead governed by a separate set of inter-client communication conventions.

The Inter-Client Communication Conventions Manual specifies the protocol for the exchange of data via selections and the interaction of applications with the window manager. This specification has been considered difficult and confusing; consistency of application look and feel and communication is typically addressed by programming to a given desktop environment. In computing, the Inter-Client Communication Conventions Manual (almost universally referred to by its initials, ICCCM) is a standard for X Window System clients to interoperate on a single server. ... Look and feel refers to design aspects of a graphical user interface - in terms of both colours, shapes, layout, typefaces, etc (the look); and, the behaviour of dynamic elements such as buttons, boxes, and menus (the feel). It is used in reference to both software and websites. ...

The Inter-Client Exchange protocol (ICE) specifies a framework for building protocols for interaction between clients, so that a specific protocol can be built at the top of it. In particular, the X Session Management protocol (XSMP) is a protocol based on ICE that mandates over the interaction between applications with the session manager, which is the program that takes care of storing the status of the desktop at the end of an interactive session and recovering it when another session with the same user is started again. In Human-Computer Interaction, session management is the process of keeping track of a users activity across sessions of interaction with the computer system. ...

Newer conventions are included in the freedesktop specifications, including the drag-and-drop convention Xdnd used for transferring data by selecting it and dragging in another window and the embedded application convention Xembed which details how an application can be run in a subwindow of another application. freedesktop. ...

Selections, cut buffers, and drag-and-drop

Main article: X Window selection

Selections, cut buffers, and drag-and-drop are the mechanisms used in the X Window System to allow a user to transfer data from a window to another. Selections and cut buffer are used (typically) when a user selects text or some other data in a window and paste in another one. Drag-and-drop is used when a user selects something in a window, then clicks on the selection and drags it into another window. Selections, cut buffers, and drag-and-drop are the mechanisms used in the X Window System to allow a user to tranfer data from a window to another. ...

Since the two windows may be handled by two different applications, data transfer requires two different clients connected with the same X server to interact. The X Window core protocol includes some types of requests and events that are specific to selection exchange, but the transfer is mainly done using the general client-to-client event sending and window properties, which are not specific to selection transfer.

Data to be transferred between clients can be of different types: it is usually text, but can also be a pixmap, a number, a list of objects, etc.

Selections and drag-and-drop are active mechanisms: after some text has been selected in a window, the client handling the window must actively support a protocol for transferring the data to the application requesting it. On the contrary, cut buffers are a passive mechanism: when the user selects some text, its content is transferred to a cut buffer, where it remains even if the application handling the window terminates and the window is destroyed.

Window manager

Main article: X window manager

A window manager is a program that controls the general appearance of windows and other graphical elements of the graphical user interface. Differences in the look of X Window System in different installations is mainly due to the use of different window managers or different configurations of the window manager. An X window manager is software that controls the placement and appearance of windows under the X Window System, a windowing system mainly used on Unix-like systems. ... A graphical user interface (GUI) is a type of user interface which allows people to interact with a computer and computer-controlled devices which employ graphical icons, visual indicators or special graphical elements called widgets, along with text labels or text navigation to represent the information and actions available to...

The window manager takes care of deciding the position of windows, placing the decorative border around them, handling icons, handling mouse clicks outside windows (on the “background”), handling certain keystrokes (for example, iconifying a window when ALT-F4 is pressed), etc.

X Window, without a window manager: no decorative frames, no icons, and no popup menus on the root window.

From the point of view of the X server, the window manager is not different from the other clients. The initial position and the decorative borders around windows are handled by the window manager using the following requests: Image File history File links Download high resolution version (960x768, 179 KB) Summary X Window, without a window manager Licensing File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (960x768, 179 KB) Summary X Window, without a window manager Licensing File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

1. an application can request the server not to satisfy requests of mapping (showing) subwindows of a given window, and to be sent an event instead;
2. an application can request changing the parent of a window.

The window manager uses the first request to intercept any request for mapping top-level windows (children of the root window). Whenever another application requests the mapping of a top-level window, the server does not do it but sends an event to the window manager instead. Most window managers reparents the window: they create a larger top-level window (called the frame window) and reparent the original window as a child of it. Graphically, this corresponds to placing the original window inside the frame window. The space of the frame window that is not taken by the original window is used for the decorative frame around the window (the “border” and the “title bar”). In the X Window System, every window has a parent window. ...

The window manager manages mouse clicks in the frame window. This allows for example to move or resize the window when the user clicks and drags on the border or on the title bar.

The window manager is also responsible for the handling of icons and related visual elements of the graphical user interface. Icons do not exist at the level of the X Window core protocol. They are implemented by the window manager. For example, whenever a window has to be “iconified”, the window manager FVWM unmaps the window, making it not visible, and creates a window for the icon name and possibly another window for the icon image. The meaning and handling of icons is therefore completely decided by the window manager: some window managers such as wm2 do not implement icons at all. FVWM with internationalization features and some additional modules. ... A screenshot of wm2 running wm2 is a minimalistic window manager for the X Window System written by Chris Cannam, author of Rosegarden. ...

Session manager

Main article: X session manager

Roughly, the state of a session is the “state of the desktop” at a given time: a set of windows with their current content. More precisely, it is the set of applications managing these windows and the information that allow these applications to restore the condition of their managed windows if required. An X session manager is a program that saves and restore the state of sessions. In the X Window System, an X session manager is a session management program, a program that can save and restore the current state of a set of running applications. ... In Human-Computer Interaction, session management is the process of keeping track of a users activity across sessions of interaction with the computer system. ...

The most recognizable effect of using a session manager is the possibility of logging out from an interactive session and then finding exactly the same windows in the same state when logging in again. For this to work, the session manager program stores the names of the running applications at logout and starts them again at login. In order for the state of the applications to be restored as well (which is needed to restore the content of windows), the applications must be able to save their state of execution upon request from the session manager and load it back when they start again.

The X Window System include a default session manager called xsm. Other session managers have been developed for specific desktop systems: for example, ksmserver is the default session manager of KDE. KDE (K Desktop Environment) (IPA: ) is a free software project which aims to be a powerful system for an easy-to-use desktop environment. ...

X display manager

Main article: X display manager

The X display manager is the program that shows the graphical login prompt in the X Window System. More generally, a display manager runs one or more X servers on the local computer and accepts incoming connections from X servers running on remote computers. The local servers are started by the display manager, which then connects to them to present the user the login screen. The remote servers are started independently from the display manager and connect to it. In this situation, the display manager works like a graphical telnet server: an X server can connect to the display manager, which starts a session; the programs of this sessions run on the same computer of the display manager but have input and output on the computer where the X server runs (which is the computer in front of the user). In the X Window System, an X display manager runs as a program, allowing starting a session on an X server from the same or another computer. ... In the X Window System, an X display manager runs as a program, allowing starting a session on an X server from the same or another computer. ... For the packet switched network, see Telenet. ...

XDM is the basic display manager supplied with the X Window System. Other display manager include GDM (GNOME), KDM (KDE), WDM (using the WINGs widget set used in Window Maker) and entrance (using the architecture used in Enlightenment v.17). XDM (in full, the X Window Display Manager) is the default display manager for the X Window System. ... GDM (the GNOME Display Manager) provides an alternate display manager for the X Window System. ... This article needs additional references or sources for verification. ... In computing, KDM (KDE Display Manager) is a graphical login interface for computers using Unix-like operating systems. ... KDE (K Desktop Environment) (IPA: ) is a free software project which aims to be a powerful system for an easy-to-use desktop environment. ... In computing, the WINGs Display Manager (WDM) is a display manager for the X window system. ... Window Maker is a window manager for the X Window System, which allows graphical applications to be run on Unix-like operating-systems. ... In computing, Entrance is the display manager for the Enlightenment window manager for the X Window System. ... Enlightenment, also known simply as E, is a free software/open source window manager for the X Window System which can be used alone or in conjunction with a desktop environment such as GNOME or KDE. It has a rich feature set, including extensive support for themes and advanced graphics...

User interface elements

Early widget toolkits for X included Xaw (the Athena Widget Set), OLIT (OPEN LOOK Intrinsics Toolkit), XView, Motif and Tk. OLIT and XView function as the base toolkits for AT&T and Sun's OPEN LOOK GUI. In computer programming, widget toolkits (or GUI toolkits) are sets of basic building units for graphical user interfaces. ... Xaw is short for the Athena widget set, which is a set of widgets to implement simple user interfaces based upon the X Toolkit Intrinsics. ... Project Athena was a joint project of MIT, Digital Equipment Corporation, and IBM. It was launched in 1983, and research and development ran through June 30, 1991, eight years after it began. ... OPEN LOOK or OpenLook was an early graphical user interface (GUI) specification developed by Sun Microsystems and AT&T in the early 1990s for UNIX workstations. ... SunOS XView calctool XView is a widget toolkit from Sun Microsystems introduced in 1988, providing an OPEN LOOK user interface for X Window System applications. ... Screenshot of an application that uses the Open Motif toolkit Motif (or capitalized MOTIF) is a graphical widget toolkit for building graphical user interfaces under the X Window System on Unix and other POSIX-compliant systems. ... In computing, Tk is an open source, cross-platform widget toolkit, that is, a library of basic elements for building a graphical user interface (GUI). ... AT&T Inc. ... Sun Microsystems, Inc. ... OPEN LOOK or OpenLook was an early graphical user interface (GUI) specification developed by Sun Microsystems and AT&T in the early 1990s for UNIX workstations. ...

Motif provides the base toolkit for the Common Desktop Environment (CDE), which is the desktop environment used on commercial Unix systems such as Solaris, AIX and HP-UX. (Solaris 10 includes both CDE and GNOME, with the latter now the preferred desktop environment.) CDE on Unix (Solaris 8) DECwindows CDE on OpenVMS 7. ... It has been suggested that Desktop metaphor,Paper paradigm be merged into this article or section. ... Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®) is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... Solaris is a computer operating system developed by Sun Microsystems. ... AIX or Aix may be: Aix, a genus of two species of dabbling ducks, the Wood Duck (Aix sponsa) and the Mandarin Duck (Aix galericulata) AIX operating system Athens Internet Exchange, (AIX) a European IXP a place name: Aix-la-Chapelle, or Aachen, a city in Germany in France: Aix... HP-UX (Hewlett Packard UniX) is Hewlett-Packards proprietary implementation of the Unix operating system, based on System V (initially System III). ... This article needs additional references or sources for verification. ...

More modern toolkits include Qt (used by KDE), GTK+ (used by GNOME), wxWidgets, FLTK and FOX. In computer programming, Qt is a cross-platform application development framework, widely used for the development of GUI programs, and, since the release of Qt 4, also used for developing non-GUI programs such as console tools and servers. ... KDE (K Desktop Environment) (IPA: ) is a free software project which aims to be a powerful system for an easy-to-use desktop environment. ... GTK+, or the GIMP Toolkit, is one of the two most popular widget toolkits for the X Window System for creating graphical user interfaces. ... In computing, wxWidgets (Windows and X widgets, formerly known as wxWindows[1]) is a free software/open source, cross-platform widget toolkit; that is, a library of basic elements for building a graphical user interface (GUI) - among a multitude of other things. ... The Fast, Light Toolkit (generally pronounced fulltick) has been developed by Bill Spitzak for 3D graphics programming and has an interface to OpenGL. Nevertheless it is well-suited for application GUI programming in general. ... In computing, the FOX toolkit is an open source, cross-platform widget toolkit, that is, a library of basic elements for building a graphical user interface (GUI). ...

Extensions

The X server was designed to be simple but extensible. As such, much functionality now resides in extensions to the protocol.

At the protocol level, every extension can be assigned new request/event/error packet types. Access to client applications to the functionalities provided by extensions is facilitated by client libraries. The coding of extensions into the current X server implementations is reportedly difficult due to a lack of modularity in the server design. It is a long term goal of the XCB project to automate generating both the client and server sides of extensions from XML protocol descriptions. In computing, XCB (X C Binding) is a C language binding for the X Window System. ...

The following is a partial list of extensions that have been developed, sorted roughly by recency of introduction:

Compiz running on Fedora Core 6 with AIGLX. Accelerated Indirect GLX (AIGLX) is an open source project founded by Red Hat and the Fedora Linux community to allow accelerated indirect GLX rendering capabilities to X.org and DRI drivers. ... In computing, XFixes is an X Window System extension which makes useful additions to the X11 protocol. ... X-Video Motion Compensation, often abbreviated as XvMC, is an extension of the X video extension for the X Window System. ... GLX (initialism for OpenGL Extension to the X Window System) provides the glue connecting OpenGL and the X Window System: it enables programs wishing to use OpenGL to do so within a window provided by the X Window System. ... Xrender (aka X Rendering Extension) introduces digital image composition as the foundation of a new rendering model within the X Window System. ... This article or section does not adequately cite its references or sources. ... Four Head Xinerama Xinerama is an extension to the X Window System which allows applications and window managers to use the two (or more) physical displays as one large virtual display. ... In the X Window System, the X keyboard extension or XKB extends the ability to control the keyboard over what is offered by the X Window core protocol. ... The MIT Shared Memory Extension or MIT-SHM is a X Window System extension for exchange of image data between client and server using shared memory. ... The X video extension, often abbreviated as XVideo or Xv, is a video output mechanism for the X Window System. ... Xv is a shareware program to display and modify digital images under the X Window System. ... The round oclock window. ...

Obsolete extensions

In computing, LBX, or Low Bandwidth X, was a protocol to use the X Window System over network links with low bandwidth and high latency. ... A tunneling protocol is a network protocol which encapsulates one protocol or session inside another. ... PHIGS is an API standard for rendering 3D computer graphics, at one time considered to be the 3D graphics standard for the 1990s. ...

See also

• Xlib
• Intrinsics
• X Window core protocol

Xlib is an X Window System protocol client library in the C programming language. ... Intrinsics (also known as Xt, for X toolkit) is a library used in the X Window System. ... The X Window System logo The X Window core protocol[1][2][3] is the base protocol of the X Window System, which is a networked windowing system for bitmap displays used to build graphical user interfaces on Unix, Unix-like, and other operating systems. ...

References

• Robert W. Scheifler and James Gettys: X Window System: Core and extension protocols, X version 11, releases 6 and 6.1, Digital Press 1996, ISBN 1-55558-148-X
• An Introduction to X11 User Interfaces
• Introduction to X Windows
• Open Source Desktop Technology Road Map (Jim Gettys, 09 Dec 2003)

External links

• X.Org Foundation (official home page)
• X.Org Foundation wiki

• Kenton Lee's pages on X Window and Motif