KDE

KDE is an international community that develops free software. It produces a desktop environment, a multitude of applications, and development infrastructure for various operating systems such as GNU/Linux, macOS, Windows, etc. The main software components made by KDE are grouped into KDE Frameworks, KDE Plasma and KDE Applications.

KDE applications are translated into approximately 75 languages and are built with the principles of ease of use and modern accessibility in mind. KDE Applications run completely natively on GNU/Linux, BSD, Solaris and Mac OS X. The community mascot is a small dragon named Konqi.

Pillars

Philosophy and use

Kandalf, former KDE pet.

Konqi, current KDE pet.

The KDE environment is based on the principle of customization; all KDE components can be configured to a greater or lesser extent by the user. The most common options are mostly accessible from menus and configuration dialogs. Advanced users can choose to edit the configuration files manually, in some cases gaining greater control over system behavior.

The appearance and functionality of the KDE software is configurable on several levels. Both the window manager (called KWin) and the controls (buttons, menus, etc.) use interchangeable "styles", which define every aspect of their appearance. It is for this reason that the KDE environment does not maintain a single appearance between versions, but instead opts for the most widely accepted one at the time of each new release.

New KDE Pet Created by Tyson Tan

The KDE desktop environment does not behave in a predefined way, but allows the user to customize the system to their liking and comfort. This does not prevent it from being easy to use for new users, a detail that is given great importance.

History

The KDE project was started in October 1996 by German programmer Matthias Ettrich, who wanted to create a unified graphical interface for Unix systems. The name arose as a play on words from CDE (Common Desktop Environment), a desktop environment used by various Unixes.

Originally, the acronym "K" stood for the word "Kool", but its meaning was later abandoned. The other two acronyms, "DE", describe the utility of Plasma as a desktop environment.

KDE 1

KDE 1.0.

On July 12, 1998 KDE 1.0 was released. This version contained a panel (taskbar and application launcher), a desktop on which to place icons, a file manager (Kfm) and a large number of utilities. In November 1998, the Qt toolset was additionally licensed under the free open source Q Public License (QPL). The same year, the KDE Free Qt Foundation was created to ensure that Qt would fall under a variant of the liberal BSD license in the event that Trolltech ceased to exist or did not release any free or open source versions of Qt for 12 months. Debate continued over compatibility with the GNU General Public License (GPL), so in September 2000, Trolltech released the Unix version of the Qt libraries under the GPL, in addition to the QPL, which removed Free Software concerns. Foundation.Trolltech continued to require licenses for the development of proprietary software with Qt.

KDE 2

KDE 2.0.

KDE 2.0, released on October 23, 2000, was almost completely rewritten, introducing major technological improvements. Among them DCOP (Desktop Communication Protocol), KIO, an I/O library, KParts, which is a component object model, which allows one application to integrate another within itself, and KHTML, an engine HTML rendering tool used by Konqueror, which in addition to being a web browser is a file manager. In addition, in this version the visual aspect of the desktop was partially improved.

KDE 3

KDE 3.5.

KDE 3.0 was released in November 2002, and is the evolution of KDE 2. The development of this series was much longer than the previous one. The API changes between KDE 2 and KDE 3 are minor. The look of the interface did not change until KDE 3.1, which saw a major visual theme improvement: Keramik was included as a new default theme along with the Crystal GT icon set and font anti-aliasing. In KDE 3.2 Crystal GT was replaced by Crystal SVG. In KDE 3.4 Keramik was replaced by Plastik.

All versions of KDE 3 are based on Qt 3, which was only released under the GPL for GNU/Linux and Unix-like operating systems, including Mac OS X.

Except for some third-party applications, development of KDE 3 has ceased and its developers no longer apply any type of maintenance to it. However, there is a fork, carried out by other developers, called Trinity.

KDE 4

KDE Plasma 4.10

KDE 4.0, released in January 2008, was completely rewritten^{[citation needed]} based on Qt 4.3. KDE 4 includes many new technologies and technical changes. The central element is a new desktop and panel design, collectively called Plasma that replaces Kicker, KDesktop, and SuperKaramba by integrating its functionality into a single piece of technology, and is intended to be more configurable for those who want to upgrade the old. desktop metaphor. There are a number of new frameworks, including Phonon, a new KDE multimedia interface independent of any specific backend whatever the OS; Solid, an API for networks and portable devices; and Decibel, a new communication framework to integrate all communication protocols on the desktop. A search and metadata framework was also presented, such as the incorporation of Strigi, a file indexing service; and the integration of NEPOMUK with KDE.

KDE Software compilation 4

From version 4.4 there were changes in the nomenclature to reflect the new reality of the project and the community. KDE went from referring to the software (mainly the desktop environment) to being the name of the community that develops it. The software was separated into three different projects:

• KDE Plasma Workspaces (the base of the desktop environment)
• KDE Applications (Applications)
• KDE Developers Plattaform (the libraries and other development tools).

The three components were bundled together under the name KDE Software Compilation for each major release.

KDE Plasma 5

Plasma 5.16

Starting in July 2014, the project again changed its structure. Separated the KDE Software compilation so that KDE Plasma, KDE Applications and KDE Frameworks (successor to KDE developers platform) would have a separate development schedule. On July 15, 2014 Plasma 5 was released. In this version a new default theme called Brisa was released, replacing the Oxígeno theme that came default in KDE 4, however the Oxígeno theme still persists, although in a secondary way in Plasma 5 Plasma 5's graphical interface has been fully migrated to QML, in addition to using OpenGL for hardware acceleration, which translates into a better performance to power consumption ratio. On this occasion, the KDE developers stopped placing their acronyms in the releases. So the new desktop just carries the Plasma name along with the version, omitting the KDE at the beginning like its predecessor desktops did.

Current projects

The KDE community maintains multiple free software projects. Currently what was previously known as the KDE (or KDE Software compilation) consists of three parts:

• KDE Plasma 5, an IU platform for different working environments like Plasma Desktop or Plasma Mobile
• KDE Frameworks, collection of more than 80 bookstores built in QT (formerly known as kdelibs)
• KDE Applications, set of applications developed to work mainly in linux working environments

In addition, there are several other applications that are contained within what is known as "Extragear".

Other projects

KDE neon

Corresponds to a set of repositories supported by a base operating system (Ubuntu in its LTS edition), which keeps the latest versions of the KDE software groups and the QT framework installed.

Development organization

Like many other free projects, KDE is built primarily by the efforts of volunteers. Since several hundred individuals contribute to KDE in various ways (programming, translating, producing art, etc.), organizing the community is complex. Most of the issues are discussed on the different mailing lists of the same.

Contrary to what one might think of such a large community, KDE does not have centralized leadership; Matthias Ettrich, the founder of the KDE project, does not have much weight on the decisions and direction of the KDE project. Important decisions, such as release dates or inclusion of new applications, are made by the main developers on a restricted mailing list. Core developers are those who have contributed to KDE for a long time. Decisions are not made in a formal voting process, but through discussions on mailing lists. Generally this method works very well.

Any user is welcome to report errors they have found in the software ("bug"). It is also possible to make requests about new features (“wish”). It is enough to communicate it, in English, on the website enabled for it: the KDE Bug Tracking System.

In legal and financial matters KDE is represented by KDE e.V., a German non-profit organisation.

Architecture

General

KDE software is written primarily in C++, a language derived from the C programming language with many added functionality, including object-oriented programming.

Despite criticism against this (initially less mature) language, its adoption by KDE has resulted in faster development and shorter release cycles while allowing efficient programs to be produced in fewer lines of source code than those required for the same tasks using structured programming languages (for example: C).

KDE is built on top of the Qt library for programming graphical applications. Qt makes object-oriented programming and component building easy, providing a solid foundation for building any type of graphical application.

After the incorporation in Qt of the Qt Quick technology, which facilitates the development of flexible and modern user interfaces, more and more components of KDE are starting to use the language that it provides, called QML (“Qt Markup Language ”). QML, which is a superset of ECMAScript (JavaScript), is used to define interfaces, while C++ is usually used for program logic (however, it is also possible to implement some logic using QML).

KDE also has its own input/output system called KIO, which can access a local file, a network resource (through protocols like HTTP, FTP, NFS, SMB, etc.), or protocols virtuals (photo camera, compressed file, etc.) with absolute transparency, benefiting all KDE applications. KIO's modular architecture allows developers to add new protocols without requiring modifications to the base system.

Lastly, KParts allows you to include applications inside others, thus avoiding code redundancy throughout the system. Additionally, it has its own HTML engine called KHTML, which is being reused and extended by Apple (to create its Safari browser), and by Nokia.

KDE 3

It uses version 3 of the Qt 3 graphics libraries, and its sound system is a new version of the criticized aRts, already present in KDE 2.

The KHTML engine, used by Konqueror, also comes from KDE 2. The DCOP system was designed for application intercommunication, although it was later replaced by its D-BUS evolution.

KDE SC 4

See also KDE Software Compilation 4

KDE SC 4 is based on the fourth version of Qt, which, in principle, increases performance over the previous version. Revamped libraries and build tools also make it easier to port to non-X11 based platforms, including Microsoft Windows and Mac OS X, as one of the goals of KDE SC 4 is to make it easier to port to different operating systems..

Applications

See also KDE Applications

There are a large number of applications that use the Qt library and others that also use the KDE libraries. Said applications are managed in the KDE Applications project, a branch that consists of a development calendar independent from that of the Frameworks and Plasma. Although they work under any desktop environment or window manager, running under KDE Plasma Workspaces is more efficient.

Technologies

KDE 4.4 with the cube effect of KWin.

Interfaz Netbook from Plasma.

• KDE Frameworks - compilation of all libraries.
• KIO - Allows access to files, websites and other sources with a simple and consistent API.
• Kiosk - Allows to deactivate KDE features to create a more controlled environment.
• KParts - Component framework.
• KWin - Windows composition manager.
• Akonadi - Personal Information Management Framework.
• Plasma - rendering engine of the desktop and panel (GUI).
• Phonon - Multimedia framework.
• Decibel - Communication Framework.
• Nepomuk - Semantic Desktop.
• Solid - Device integration framework.
• Sonnet - Orthographic Corrector.
• ThreadWeaver - Library to use multiprocessors more efficiently.
• WebKit - HTML rendering engine.

Launches

General Information

As the project history (below) shows, the KDE team releases new versions in short periods. They're known for sticking to release plans, and it's rare for a release to be delayed by more than two weeks.

One exception was KDE 3.1, which was delayed for over a month due to a number of security-related issues in the codebase. Maintaining strict release plans in a volunteer project of this size is unusual.

Major Releases

A major release of KDE Plasma or Applications has two version numbers (eg KDE Plasma 5.5).

All releases with the same major version number (KDE 1, KDE 2, KDE 3, etc) are supported in both binary and source code. This means, for example, that any software developed on KDE SC 4.2 will work with all KDE SC 4 releases.

Except during major version changes, alterations never occur with recompilation or source code modification requirements. This maintains a stable Application Programming Interface (API) for KDE application developers. The changes between KDE 1 and KDE 2 were large and numerous, while the API changes between KDE SC 4 and KDE Plasma and Applications 5 were comparatively minor. This means that applications can be easily converted to the new architecture.

As soon as a major release is ready and announced, it is added to the branch of the Subversion repository, while work on the next major release begins in the trunk. A major release takes several months to complete, and many bugs found during this stage are also fixed on the stable branch.

Minor Releases

For minor releases, less spaced release dates are scheduled. A minor release of KDE has three version numbers (eg KDE 1.1.1) and developers focus on fixing bugs and improving minor aspects of programs rather than adding functionality.

KDE and Wikipedia

Kate 16.12

On June 23, 2005 news broke that the KDE project and the Wikimedia Foundation were joining in a cooperative effort. In particular, it is planned to make the content of Wikimedia projects available via a web services interface for KDE programs.

Since KDE 3.5 they have already started to integrate Wikipedia support functions, as an example of this the Kate editor already includes the wiki syntax.

Amarok displays information about Wikipedia artists with the help of a built-in web browser.

Distributions

The following is a list (in table form) of distributions that include the KDE Plasma desktop environment by default.

Criticism

• KDE was criticized at its beginnings because the library on which it developed (Qt), despite following an open source development, was not free. On 4 September 2000, the library began to be distributed under the GPL 2.1 license and the criticisms were gradually discontinued. Currently, and from version 4.5, the library is additionally available under LGPL 2.1.
• Some outsiders criticize the similarity of KDE with the Windows desktop environment. This observation, however, falls on the selection of predefined parameters of the environment; often aimed at facilitating its use to new users, most of whom are used to working with Microsoft's operating systems. However, KDE has a high configuration capacity and in its branch 4 has built-in desktop effects in Plasma and KWin, comparable to Compiz.