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Senin, 05 Juni 2017

In computing, a plug-in (or plugin, add-in, addin, add-on, addon, or extension) is a software component that adds a specific feature to an existing computer program. When a program supports plug-ins, it enables customization. The common examples are the plug-ins used in web browsers to add new features such as search-engines, virus scanners, or the ability to use a new file type such as a new video format. Well-known browser plug-ins include the Adobe Flash Player, the QuickTime Player, and the Java plug-in, which can launch a user-activated Java applet on a web page to its execution on a local Java virtual machine.

A theme or skin is a preset package containing additional or changed graphical appearance details, achieved by the use of a graphical user interface (GUI) that can be applied to specific software and websites to suit the purpose, topic, or tastes of different users to customize the look and feel of a piece of computer software or an operating system front-end GUI (and window managers).

Purpose and examples



source : www.virtuacomputers.com

Applications support plug-ins for many reasons. Some of the main reasons include:

  • to enable third-party developers to create abilities which extend an application
  • to support easily adding new features
  • to reduce the size of an application
  • to separate source code from an application because of incompatible software licenses.

Types of applications and why they use plug-ins:

  • Audio editors use plug-ins to generate, process or analyse sound. Ardour and Audacity are examples of such editors.
  • Email clients use plug-ins to decrypt and encrypt email. Pretty Good Privacy is an example of such plug-ins.
  • Graphics software use plug-ins to support file formats and process images. (c.f. Photoshop plugin)
  • Media players use plug-ins to support file formats and apply filters. foobar2000, GStreamer, Quintessential, VST, Winamp, XMMS are examples of such media players.
  • Packet sniffers use plug-ins to decode packet formats. OmniPeek is an example of such packet sniffers.
  • Remote sensing applications use plug-ins to process data from different sensor types; e.g., Opticks.
  • Text editors and Integrated development environments use plug-ins to support programming languages or enhance development process e.g., Visual Studio, RAD Studio, Eclipse, IntelliJ IDEA, jEdit and MonoDevelop support plug-ins. Visual Studio itself can be plugged into other applications via Visual Studio Tools for Office and Visual Studio Tools for Applications.
  • Web browsers use browser extensions to expand their functionality. Examples include Adobe Flash Player, Java SE, QuickTime, Microsoft Silverlight and Unity.

Mechanism



source : www.thegreenhead.com

The host application provides services which the plug-in can use, including a way for plug-ins to register themselves with the host application and a protocol for the exchange of data with plug-ins. Plug-ins depend on the services provided by the host application and do not usually work by themselves. Conversely, the host application operates independently of the plug-ins, making it possible for end-users to add and update plug-ins dynamically without needing to make changes to the host application.

Programmers typically implement plug-in functionality using shared libraries installed in a place prescribed by the host application. HyperCard supported a similar facility, but more commonly included the plug-in code in the HyperCard documents (called stacks) themselves. Thus the HyperCard stack became a self-contained application in its own right, distributable as a single entity that end-users could run without the need for additional installation-steps. Programs may also implement plugins by loading a directory of simple script files written in a scripting language like Python or Lua.

Mozilla definition



source : help.kaspersky.com

In Mozilla Foundation definitions, the words "add-on", "extension" and "plug-in" are not synonyms. "Add-on" can refer to anything that extends the functions of a Mozilla application. Extensions comprise a subtype, albeit the most common and the most powerful one. Mozilla applications come with integrated add-on managers that, similar to package managers, install, update and manage extensions. The term, "Plug-in", however, strictly refers to NPAPI-based web content renderers. Plug-ins are being deprecated.

History



source : www.rh.gatech.edu

Plug-ins appeared as early as the mid 1970s, when the EDT text editor running on the Unisys VS/9 operating system using the UNIVAC Series 90 mainframe computers provided the ability to run a program from the editor and to allow such a program to access the editor buffer, thus allowing an external program to access an edit session in memory. The plug-in program could make calls to the editor to have it perform text-editing services upon the buffer that the editor shared with the plug-in. The Waterloo Fortran compiler used this feature to allow interactive compilation of Fortran programs edited by EDT.

Very early PC software applications to incorporate plug-in functionality included HyperCard and QuarkXPress on the Macintosh, both released in 1987. In 1988, Silicon Beach Software included plug-in functionality in Digital Darkroom and SuperPaint, and Ed Bomke coined the term plug-in.

See also



source : www.businessinsider.com

  • Applet
  • Shared library

References



source : link.springer.com



source : www.alamy.com

 
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