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Chapter 8: The KDesktop Environment: KDE
The
K Desktop Environment (
KDE) is a network transparent desktop that includes the
standard desktop features, such as a window manager and a file manager, as well as
an extensive set of applications that cover most Linux tasks. KDE is an Internet- aware
system that includes a full set of integrated network/Internet applications, including a
mailer, a newsreader, and a Web browser. The file manager doubles as a Web and FTP
client, enabling you to access Internet sites directly from your desktop. KDE aims to
provide a level of desktop functionality and ease of use found in MAC/OS and Windows
systems, combined with the power and flexibility of the Unix operating system.
KDE version 2.0, also known as Kopernicus, has currently superseded the earlier
1.1 version of KDE. This chapter describes version 2.0. There are many similarities
with version 1.1; however, users familiar with the old KDE will find some important
changes. KDE 2.0 features a new file manager and control center. It includes a new
multimedia architecture based on ARTS (Analog Realtime Synthesizer) for both sound
and video applications. One of the more dramatic changes is KOffice suite of office
applications. The suite is part of the standard KDE 2.0 software package and includes
a professional-level publishing program, an illustrator, and a spreadsheet, among other
applications (see Chapter 20).
The KDE desktop is developed and distributed by the KDE project, which is a large
open group of hundreds of programmers around the world. KDE is entirely free and
open software provided under a GNU public license and is available free of charge
along with its source code. KDE development is managed by a core group: the KDE
Core Team. Anyone can apply, though membership is based on merit.
KDE applications are developed using several supporting KDE technologies. These
include KIO, which offers seamless and modular access of files and directories across
a network. For interprocess communication, KDE uses the Desktop Communications
Protocol (DCOP). KParts is the KDE component object model used to embed an application
within another, such as a spreadsheet within a word processor. The XML GUI uses
XML to generate and place GUI objects such as menus and toolbars. KHTML is a rendering
and drawing engine that supports a range of Internet technologies such as Java, Netscape
plug-ins, and the Secure Sockets Layer (SSL).
Numerous applications written specifically for KDE are easily accessible from the
desktop. These include editors, photo and paint image applications, spreadsheets, and
office applications. Such applications usually have the letter k as part of their name— for
example, KWord or KMail. Provided with the KDE desktop are a variety of tools. These
include calculators, console windows, notepads, and even software package managers.
On a system administration level, KDE provides several tools for configuring your system.
With KUser, you can manage user accounts, adding new ones or removing old ones.
Kppp enables you to connect easily to remote networks with Point-to-Point Protocol (PPP)
protocols using a modem. Practically all your Linux tasks can be performed from the KDE
desktop. KDE applications also feature a built-in Help application. Choosing the Contents
entry in the Help menu starts the KDE Help viewer, which provides a Web page–like
interface with links for navigating through the Help documents. KDE version 2.0 includes
an office application suite called KOffice, based on KDE's KOM/OpenParts technology.
KOffice includes a presentation application, a spreadsheet, an illustrator, and a word
processor, among other components (see Chapter 20 for more details). In addition, an
Interactive Development Environment (IDE), called KDevelop, is also available to help
programmer's create KDE-based software.
KDE was initiated by Matthias Ettrich in October 1996, and it has an extensive
list of sponsors, including SuSE, Caldera, Red Hat, O'Reilly, DLD, Delix, Live, Linux
Verband, and others. KDE is designed to run on any Unix implementation, including
Linux, Solaris, HP-UX, and FreeBSD. The official KDE Web site is www.kde.org, which
provides news updates, download links, and documentation. KDE software packages
can be downloaded from the KDE FTP site at ftp.kde.org and its mirror sites. Several
KDE mailing lists are available for users and developers, including announcements,
administration, and other topics. See the KDE Web site to subscribe. A great many
software applications are currently available for KDE at apps.kde.com. Development
support and documentation can be obtained at developer.kde.org. Various KDE Web
sites are listed in Table 8-1.
Qt and Harmony
KDE uses as its library of GUI tools the Qt library, developed and supported by Troll
Tech (
www.trolltech.com). Qt is considered one of the best GUI libraries available
for Unix/Linux systems. Using Qt has the advantage of relying on a commercially
developed and supported GUI library. Also, using the Qt libraries drastically reduced
the development time for KDE. Troll Tech provides the Qt libraries as open source software that is freely distributable. Certain restrictions exist, however: Qt-based (KDE)
applications must be free and open sourced, with no modifications made to the Qt
libraries. If you develop an application with the Qt libraries and want to sell it, then
you have to buy a license from Troll Tech. In other words, the Qt library is free for free
applications, but not for commercial ones.
The Harmony Project is currently developing a free alternative to the Qt libraries.
Harmony will include all Qt functionality, as well as added features, such as multi-threading
and theming. It will be entirely compatible with any KDE applications
developed using Qt libraries. Harmony will be provided under the GNU library
public license (LGPL). See www.gnu.org/software/harmony for more information.
KDE Desktop
One of KDE's aims is to provide users with a consistent integrated desktop, where
all applications use GUI interfaces (see Figure 8-1). To this end, KDE provides its own
window manager (kwm), file manager (Konqueror), program manager, and desktop panel. You can run any other X Window System–compliant application, such as Netscape,
in KDE, as well as any Gnome application. In turn, you can also run any KDE application,
including the Konqueror file manager, with any other Linux window manager, including
Blackbox, Afterstep, and even Enlightenment. You can even run KDE applications
in Gnome.
When you first start KDE, the initial file manager window is displayed on your screen
showing your current working directory. At the bottom of the screen is the KDE panel.
Located on the panel are icons for menus and programs, as well as buttons for different
desktop screens. The icon for the Applications Starter shows a large K on a cog wheel with
a small arrow at the top indicating it is a menu. Click this icon to display the menu listing
all the applications you can run. The Applications Starter operates somewhat like the Start
menu in Windows. The standard KDE applications installed with the KDE can be accessed
through this menu. You can find entries for different categories such as Internet, Systems,
Multimedia, and Utilities. These submenus list KDE applications you can use. For example,
to start the KDE mailer, select the Mail Client entry in the Internet submenu. To quit KDE,
you can select the Logout entry in the Applications Starter menu. You can also right-click
anywhere on the desktop and select the Logout entry from the pop-up menu. If you leave
any KDE or X11 applications or windows open when you quit, they are automatically
restored when you start up again.
Across the top of the desktop is a menu for desktop operations such as creating
new shortcuts called desktop files for applications and devices (known as kdelink
files in previous versions), as well as accessing open windows or changing to different
virtual desktops. You can bring up the same set of menus by right-clicking anywhere
on the desktop background.
Two icons are initially displayed in the upper-left corner of the desktop, a directory
folder icon labeled Home and the Trash icon. The Home directory folder is a link to
your home directory. Click on it to open the file manager to display the files in your
home directory. The Trash icon operates like the Recycle Bin in Windows or the trash
can on the Mac. Drag items to it to hold them for deletion. The panel initially shows
small icons for the Applications Starter, the window list, your home directory, a terminal
window, and buttons for virtual desktops, among others. The Window List icon looks
like several grouped windows. It displays a list of all open windows and the desktop
they are on. The Home Directory icon shows a folder with a house. Click it to open a
file manager window showing your home directory. The Help Viewer icon is an image
of a book. The Terminal Window icon is a picture of a two computer monitors. Click
this to open a terminal window where you can enter Linux shell commands.
The desktop supports drag-and-drop operations. For example, to print a
document, drag it to the Printer icon. You can place any directories on the desktop by
simply dragging them from a file manager window to the desktop. With KDE 2.0, the
desktop also supports copy-and-paste operations, holding text you copied from one
application in a desktop clipboard that you can then use to paste to another application.
For example, you can copy a Web address from a Web page and then past it into an
e-mail message or a word processing document. This feature is supported by the
Klipper utility located on the Panel....
