Archive for the ‘Glossary’ Category

File Under: Glossary

Bitmap

A bitmap is a mapped array of pixels that can be saved as a file.

Both JPEG and GIF are bitmap graphic formats. Currently, the only other way to store an image is as a vector graphic. You can’t easily scale bitmap images, but you can control every single pixel and thus achieve many effects impossible in vector graphics. Conversely, vector formats offer advantages of scalability and lower bandwidth requirements. When you compress a bitmapped image, you suck out some of the visual information.

To bypass this, the portable network graphics format (or PNG, pronounced “ping”) was designed to store a single bitmap image for transmittal over computer networks without losing this data.

File Under: Glossary

Embedded Media

These are the types of media you can include in an HTML page, such as audio files, flash or GIF animations.

File Under: Glossary

Loop

A loop is like a programming thought. Say you’re a police officer using a radar gun to catch speeding motorists. If the speed limit is 55 miles per hour, you might say to yourself: “If a car makes my radar gun display a higher value than 55, I’ll pull them over, but until then I will continue to take readings. And perhaps snack on this cruller.” In programming, the statement of this loop would be the action (firing up your motorcycle and chasing the speeder), and the expression would be the evaluation of whether or not the passing car made your radar gun read higher than 55. This is an example of a “while” loop:

  while (carSpeed < 55) {

  carSpeed = readRadar();

  // note:readRadar() should return the latest carSpeed

}



pullEmOver();  // this will only execute once carSpeed is >= 55

File Under: Glossary

Parse


To parse means to break something down into units that can be analyzed. To parse a sentence means to break it down into its parts of speech. In computer terms, a compiler must parse source code so that it can be analyzed and then assembled into object code. An XML parser, for example, is a tool for reading eXtensible markup language documents. XML parsers can pass data to a browser if that data is “well-formed.” XML doesn’t provide an application programming interface (API) to an application, it just passes data to it. Both Microsoft and Netscape include XML parsers in their browsers.

File Under: Glossary

Sitemaps

Until recently, sitemaps were hand-drawn or script-drawn tree diagrams. Now browsers that support eXtensible markup language (XML) offer more elaborate sitemaps as a special feature. The newer sitemaps provide a hierarchical description of a site, written in the resource description framework, an XML application still being developed as a standard by the World Wide Web Consortium. For example, Netscape’s Mozilla finds RDF sitemaps by looking for
<LINK rel=sitemap>
tags in your web pages. This tag tells Mozilla to open the sitemap and then render the site diagram as part of the graphical display of the user agent. While sitemaps themselves may not be the niftiest things in the world, they do occupy a noteworthy position on the web’s timeline as one of the first implementations of RDF.