Macromedia Flash or Flash is a graphics animation program, written and marketed by Macromedia, that uses vector graphics. The resulting files, called SWF (said like swiff) files, may appear in a web page to view in a web browser, or standalone Flash players may "play" them. Flash files occur most commonly in animated advertisements on web pages and rich-media web sites, although prank flash has become common.
In recent PostScript, SVG and PDF, Flash can be used to specify exact positioning of the various page elements. This gives the designer a great degree of control over how the user interface looks, although it may not always be very usable on unexpectedly high- or low-resolution displays.
- Unlike PostScript, SVG and PDF, Flash supports streaming by default (frames load individually).
- Like PostScript, SVG and PDF, Flash uses vector graphics; they may translate into small file sizes which take less bandwidth to transmit than bitmaps do.
- Macromedia has opened the Flash file format, and compatible third-party tools exist.
- Flash Players can run consistently on Microsoft Windows, Mac OS, Linux and various other Unix systems.
- Like HTML, Flash allows the embedding of images, sounds, movies and simple HTML files. Thus it is a multimedia platform. Flash Player 6 also supports two-way streaming of sound and video, thus making it a suitable platform for high-level multi-user applications.
- Flash's embedded ActionScript language (an application of the ECMAScript programming language) allows the creation of simple fill-in-the-blank forms. In Flash MX, Macromedia has extended the ActionScript language to the proposed ECMA Script 4 standard, and programmers can use it to write extensive event-driven GUIs. Flash MX 2004 introduced ActionScript 2.0, which features strong types, interfaces, inheritance and other features of object-oriented programming languages.
- Flash as a format has become widespread. According to Macromedia, 95% of Web users have Flash Player installed. PDAs and cellular phones can feature integrated Flash Players, and an implementation exists for the Java platform.
Disadvantages
Flash also has some disadvantages, and these have caused some of the initial surge in use outside ads to decline, as negative consequences of Flash use become apparent:
- Flash circumvents browser controls which block the display of animation on web pages, allowing ads to display animation even when the end-user has turned off the capability in the browser.
- Flash developers must manually build support for features such as the back button and bookmarking, otherwise these features are not available for users.
- Flash does not use browser settings for font size, etc, so text may appear tiny for vision-impaired people or those with high resolution screens.
- Many Flash pieces re-invent common HTML and browser conventions such as scrollbars, leaving the user to figure out how to get around; and disable features such as mouse wheels (The mouse wheel feature was added in Flash MX 2004).
- Flash content remains inaccessible to most search engines, so sites using Flash experience decreased visibility in search engines unless redesigned to allow for this problem. So far, at least Google (example: [1] (http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=sample+filetype:swf)) will try to read Flash files (much like PDFs). Many people do not see difficulties in searching advertisements as a problem: the use of Flash in ads continues unabated.
- Viewer plugins don't exist for 'all' systems: Macromedia officially supports the GNU/Linux x86, Windows, Mac OS 9/X, Solaris, HP-UX, Pocket PC, OS/2, and IRIX operating systems. Olivier Debon has written an open source version of the Flash 3 player, ports of this exist to numerous operating systems, including the Amiga.
- Because a user agent plug-in plays Flash movies, such movies have limited memory resources available to them: the amount of memory the user agent allocates for the plugin, which varies. This significance of this disadvantage is reduced by the Flash player's internal memory management.
- Though Flash files have an ostensibly "open" format (i.e. it is published), Macromedia retains control of it. Since Flash files do not depend on a truly open standard such as SVG, this reduces the incentive for non-commercial software to support the format. The Macromedia player cannot ship as part of a pure open source, or completely free operating system.
- Due to Flash's graphical nature, it does not degrade gracefully for disabled users. Websites can overcome this by providing alternative content (for example in HTML) or by using the accessibility features built into newer Flash versions. See also computer accessibility.
- Flash does not support internationalization thoroughly.
- Flash demands significant CPU power to display, as it uses a very high degree of graphic abstraction that many video cards cannot accelerate. Particularly, the anti-aliasing utilized by the Flash Player makes heavy use of computer resources.
- The browser plug-in may store and retrieve information on the user's computer, acting much like HTTP cookies and with similar advantages and disadvantages; however, the player sets data size restrictions independently.
- Although this has never posed an actual problem, the plug-in has had security flaws which theoretically may open up a computer to remote attack (see for example [2] (http://www.macromedia.com/v1/handlers/index.cfm?ID=23569) and [3] (http://www.theregister.co.uk/content/55/28645.html) for a December 2002 problem). Note that newer versions of the flash player have fixed this problem.
- The .swf files that Flash generates have security issues. Several available commercial programs can allow someone to extract graphics, sounds, etc. from a .swf file and also view its ActionScript. An open source program called flasm (http://flasm.sourceforge.net) allows users to extract ActionScript from a .swf file as "bytecode", edit it, and then reinsert it into the file. However, swf obfuscation makes the extraction infeasible in most cases.
- Microsoft's Internet Explorer gives a security warning which asks for permission to let a site run ActiveX controls. The warning doesn't specify which site or which controls, so a prudent end-user must look at the source code of all parts of the page before allowing Flash to run -- in case the site, one of the ads on it or a pop-up or pop-under also uses a control which may breach security.
Flash MX 2004, the latest release, addresses several of the disadvantages. See this discussion (http://www.useit.com/alertbox/20001029.html) of Flash and usability.
Competition
In October 1998 Macromedia disclosed the Flash Version 3 Specification to the world on its website. It did this in response to many new and often semi-open formats competing with SWF, such as XARA's Flare and Sharp's Extended Vector Animation formats. Several developers quickly created a C library for producing SWF. February 1999 saw the launch of MorphInk 99, the first non-Macromedia or third party program to create SWF files. Macromedia also hired Middlesoft to create a freely-available developers' kit for the SWF file format versions 3 to 5. Many open and free libraries based on the information released to the public in 1998 and from later study of the SWF file Format, such as the Ming library, exist to produce SWF files on many platforms. Macromedia has made the Flash Files specifications for versions 6 and later available only as a PDF under a NDA agreement.
Many shareware developers produced Flash creation tools and sold them for under $50 USD between 2000 and 2002. In 2003 competition and the emergence of free Flash creation tools, most notably OpenOffice.org, had driven many third-party flash-creation tool-makers out of the market, allowing the remaining developers to raise their prices, although many of the products still cost less than $100 USD and support Actionscript. F4L has started to develop such a tool including an interface similar to Macromedia's.
Adobe wrote a package called Adobe LiveMotion, designed to create interactive animation content and export it to a variety of formats, including SWF. LiveMotion went through two major releases before Adobe cancelled it in 2003.
In November 2003 Microsoft announced that it had started working on a competing product, Sparkle, whose release would coincide with that of their next-generation Windows operating system codenamed Windows Longhorn. The purchase of Creature House Inc.'s assets in September 2003 has led to speculation that their Expression graphics engine would form the basis for the Sparkle product.
Influence
The nature and popularity of Flash has had a large influence in graphic design. Its rotoscoping feature led to the widespread popularity of rotoscoped vector graphics in the default pastel colors of the Flash authoring tools. Many flyers, advertisements, magazines, and even websites which didn't use Flash adopted this graphic style.
File types
- .fla (pronounced "flaw") files contain source material for the flash application. Flash authoring software can edit FLA files and compile them into .swf files. Proprietary to Macromedia, the FLA format in no sense counts as "open".
- .as (or sometimes .actionscript) files contain ActionScript source code in simple source files. FLA files can also contain Actionscript code directly, but separate external .as files often emerge for structural reasons, or to expose the code to versioning applications, and so on.
- .swf (pronounced "swiff") files are completed, published files that cannot be edited.
- .swd files are temporary debugging files used during Flash development. Once finished developing a Flash project these files are not needed and can be removed.
- .asc files contain Server-Side ActionScript, is used to develop efficient and flexible client-server Macromedia Flash Communication Server MX applications.
- .flv files are Flash video files, as created by Macromedia Flash or by Sorenson Squeeze.
- .swc file format for distributing components; it contains a compiled clip, the component’s ActionScript class file, and other files that describe the component.
- .swt (pronounced "swot") files templatized SWF files used by Macromedia Generator.
- .flp XML file with the file extension .flp–for example, myProject.flp. The XML file references all the document files contained in the Flash Project. Flash Projects allow you to group multiple, related files together to create complex applications.
Product history
- FutureSplash Animator (1995) - initial version of Flash with basic editing tools and a timeline
- Flash 1 (December 1996) - a Macromedia re-branded version of the FutureSplash Animator
- Flash 2 (1997) - the object library was added to Flash
- Flash 3 (1998) - the movieclip element, Javascript plug-in integration, transparency and an external stand alone player was added to Flash
- Flash 4 (1999) - internal variables, an input field, advanced Actionscript, and streaming MP#
- Flash 5 (2000) - Javascript like Actionscript, Smartclips, HTML text formatting added
- Flash MX (2002) - UI Components, xml, compression, streaming video codec
- Flash MX 2004 (2004) - text alias, unicode, Actionscript 2, improved streaming video codec
- Flash MX 2004 Pro (2004) - all Flash MX 2004 features plus a form and slide editor, web service integration, OOP (Oriented Object Programming) in ActionScript 2.0
See also
External links
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