The Xlib library is a layer on the X server and is a set of functions that are called by applications. These
functions handle tasks such as adding a host, opening a display, manipulating windows, drawing, and
handling events. Xlib calls are translated to protocol requests that are passed either to the local server or
to another server across the network.
Applications are a layer on Xlib. Applications that run on Xlib can be used both by end-users and
application developers. These applications can be the user’s own or those provided with X-Windows.
Beginning-to-experienced end-users can use the provided client programs to run multiple terminals, use
desk accessories, set display and keyboard preferences, use font and graphic utilities, print applications,
and get information on windows and displays. Application developers can use the Motif Toolkit provided to
create and control user interfaces.
A Motif application consists of the X Intrinsics library and the Motif widget set. The X Intrinsics are a basic
set of functions used to define, create, manage, and destroy user interface components. These user
interface components are called widgets and make up the widget set. The Motif widget set is a layer on
the X Intrinsics. Different interfaces can be provided by different widget sets, but they all use the X
Intrinsics.
While the Motif Toolkit provides the building blocks for an interface, the window manager enables you to
control the interface. The window manager acts as an application program. With the window manager, you
can execute other application programs, move them on the screen, resize them, and so on.
X-Windows has standards and conventions that are applicable to all systems with bit-mapped display
terminals. This enables application programmers to spend more time improving their programs and less
time porting to new user-interface platforms. Standards and conventions are provided for the X protocol,
atoms, the Inter-Client Communications Conventions Manual (ICCCM), display manager control protocol
(XDMCP), logical font descriptions (XLFD), and compound text encoding.
Graphics Library is a set of graphics and utility functions that provide high-level and low-level support for
graphics. Graphics Library has become the industry standard for 3-D application development.
The graPHIGS API application programming interface (API), an implementation of the PHIGS and
proposed PHIGS PLUS standards, provides a set of device-independent programming tools that allow
portability across many hardware platforms. The graPHIGS API offers over 500 high-level subroutines to
define, modify, and display hierarchically organized graphics data. Advanced rendering capabilities, such
as lighting and hidden line and hidden surface removal, are included.
The AIX Common Desktop Environment provides you with the ability to run several applications at once on
your screen. Whether you are a beginner or an experienced user, the AIXwindows visual system helps you
manage your work and use the operating system to perform various tasks.
The product you choose to use will depend on your needs. If you are sending 2-D graphics across the
network, you should use X-Windows. However, if you are sending 3-D graphics across a network, you
must use the distributed application processing capability of the graPHIGS API.
If you are working on one system and do not need to send information across a network, the fastest
method would be to use the Graphics Library or graPHIGS API. Using these products would bypass the
server and allow direct adapter access. Although Graphics Library applications typically operate in
immediate mode and applications using the graPHIGS API have traditionally used structure storage, both
products offer retained and nonretained graphics display as well as advanced rendering capabilities.
2 AIXwindows Programming Guide