Widget engine

Not to be confused with widget toolkit.

In computer software, a widget engine is a software service available to users for running and displaying applets on a graphical user interface, such as that of the desktop.

The widget model in widget engines is attractive because of ease of development. Most of these widgets can be created with a few images and about 10 to several hundred lines of XML/JavaScript/VBScript source code. A single host software system, such as a web browser, runs all the loaded widgets. This allows several desktop widgets to be built sharing resources and code.

The term widget engine is not to be confused with that of a widget toolkit. Toolkits are used by GUI programmers, who combine several widgets to form a single application. A widget in a toolkit provides a single, low level interaction, and is prepared to communicate with other widgets in the toolkit. On the other hand, widget engines such as desktop widgets and web widgets are intended for end users. Desktop and web widgets are stand-alone, task-oriented applications which can be composed of several related interactions on its own. Each widget serves only a purpose that is usually addressed by the effort of one GUI widget in a full-scale application.

Types

Desktop widgets

Main article: software widget

The Wikipedia Widget, in Dashboard running under Mac OS X v10.4

Early developer version of Plasma Desktop with Plasmoids

Desktop widgets (commonly just called widgets) are interactive virtual tools that provide single-purpose services such as showing the user the latest news, the current weather, the time, a calendar, a dictionary, a map program, a calculator, desktop notes, photo viewers, or even a language translator, among other things. Examples of widget engines include:

• Dashboard widgets of Apple Macintosh
• Microsoft gadgets in Windows Vista and in the Windows Live system
• Plasmoids are widgets in Plasma, the workspace for the KDE desktop environment.
• Portlets in Google Desktop
• Yahoo! Widgets
• gdesklets, adesklets, and Screenlets in Linux
• Opera widgets on all platforms (desktop, mobile TVs, gaming consoles) using the Opera browser's rendering engine.
• Homescreen widgets in Maemo

Originally, desk accessories were developed to provide a small degree of multitasking, but when real multitasking OSes became available, these were replaced by normal applications.

Blidgets

Blidgets are desktop widgets that connect the user to a blog.

Widget draft standard

On 9 November 2006, the Web Application Formats Working Group in W3C released the first public working draft of Widgets 1.0.^[1]. The intention is to standardise some aspects of widgets. The Opera browser is the first client side widget engine to adopt this draft W3C standard.^[2]. Apache Wookie (Incubating) is the first server side widget engine to adopt this W3C standard. Wookie is a server that manages widget instances and allows them to be embedded in web applications in addition to being provided for client devices such as Opera.

Mobile widgets

Most mobile widgets are like desktop widgets, but for a mobile phone. Mobile widgets can maximize screen space use and may be especially useful in placing live data-rich applications on the device idle-screen/home-screen/"phone-top". Several Java ME-based mobile widget engines exist, but the lack of standards-based APIs for Java to control the mobile device home-screen makes it harder for these engines to expose widgets on the phone-top.

Several AJAX-based native widget platforms are also available for mobile devices.

The growing pervasiveness of mobile widgets is easily understood. While widgets are a convenience in the online world,they can be looked at as near-essential in the mobile world. The reason: the mobile device is small and the interface is often challenging. Wading through large amounts of information in a mobile environment isn't just a nuisance; it's a near impossibility.

One of the biggest challenges of widget development is writing multiple sets of computer code so that a widget will be compatible with multiple operating systems and types of devices.

Companies considering new mobile widgets should evaluate and then deploy applications according to four criteria: the business model, distribution model, server-side application framework and the run-time environment.

Many solutions are growing for mobile widgets. Among them the BONDI initiative whitin OMTP is trying to defragment these solution allowing the same widget to be run on different mobile phones allowing secure access to mobile phone capabilities.

Web widgets

Main article: Web widget

Web browsers can also be used as widget engine infrastructures. The web is an environment well suited to distribution of widgets, as it doesn't require explicit interaction from the user to install new code snippets.

Web widgets have unleashed some commercial interest, due their perceived potential as a marketing channel, mainly because they provide interactivity and viral distribution through social networks. The first known web widget, Trivia Blitz, was introduced in 1997. It was a game applet offered by Uproar.com (the leading online game company from 2000 - 2001) that appeared on over 35,000 websites ranging from Geocities personal pages to CNN and Tower Records. When Uproar.com was acquired by Vivendi Universal in 2001, the widget was discontinued.

TV set widgets

Widgets are also available for TV's.Yahoo! Widget Engine is announced as a component of the next generation TV sets.

Information flow of desktop widgets

A desktop widget is a small footprint application, which resides on the user’s desktop using little desktop space and computer resources, such as HDD and RAM. Its purpose is to provide relevant information to the user in a non-intrusive manner and using few resources. Basically, desktop widgets enable the user to view on demand, encapsulated information from predetermined data sources. Ideally, a desktop widget must present personalized content, based on the user’s preferences. It is supposed to provide the most important information that a user requires on a day to day basis. Most of the desktop widgets are available as free downloads from the vendors’ Web sites.

See also

• Android (operating system)
• Chumby
• Desk Accessory
• GUI widget
• Widget toolkit

Notes and references

1. ^ "Widgets 1.0". World Wide Web Consortium. http://www.w3.org/TR/widgets/. 
2. ^ "Web Specifications Supported in Opera 9". Opera ASA. http://www.opera.com/docs/specs/opera9/#wml.