What Makes Flash a Special Web-Design Tool?

Flash's early claim to fame was its ability to deliver vector images over the Web. What's the advantage of using vector graphics? Vectors keep file sizes down, and they're scaleable: This means you can maintain control of what a Web site looks like when your viewer resizes the browser window, for example, making the whole thing stay in proportion as the window grows or shrinks.

Another advantage that Flash provides is progressive download capability. Progressive download allows some elements of a Web site to display immediately upon download while more information continues to arrive over the Internet. Both the use of vector images and the use of progressive download enhance the viewer's experience.

Other facets of Flash's appeal include its ability to create original artwork with both Bézier and natural-style drawing tools; its ability to handle imported artwork, sound, and video; and its ability to assist designers and developers in creating animation and interactivity. Over time, Macromedia has enhanced Flash's tools for creating interactivity. Now, Flash contains a full-fledged object-oriented scripting language. ActionScript 2.0 is compliant with the ECMA-262 specification, making it much more like JavaScript. ActionScript 2.0 supports inheritance, strong typing, and the event model.

How Flash Animates

Flash uses standard animation techniques to create the illusion of movement. You create a series of still images, each slightly different from the next. By displaying the images rapidly, one after another, you simulate continuous movement. Flash's animation tools help you create, organize, and synchronize the animation of multiple graphic elements, sounds, and video clips.

Flash File Formats

Flash is both an authoring environment for creating content and a playback system for making that content viewable on a local computer or in a Web browser. You create artwork, animation, and interactivity in Flash-format files. These files have the extension .fla and are often referred to as FLAs. To make that content viewable on the Web, you convert the FLA files to Flash Player format; Flash Player files have the extension .swf. Another name for the playable format is SWF (pronounced swif).

How Flash Delivers

Flash's publishing feature creates the necessary HTML code to display your Flash content in a Web browser. You can also choose alternate methods of delivering Flash contentas animated GIF images, for example, or as a QuickTime movie. Flash creates those alternate files during the publishing process.

About Flash Player

In Flash's early days, the need to use a player to view Flash content was considered a drawback to creating Web content with Flash. Designers feared that users would be reluctant to spend time downloading another helper application for their browsers. But Flash has become the de facto standard for delivering Web rich-media contentespecially interactive vector art and animation on the Weband Flash Player is now widely distributed. Macromedia estimates that more than 97 percent of machines that are being used to access the Internet already have some version of Flash Player installed.