Post by juju on Apr 4, 2006 4:13:01 GMT -5
Graphics Interchange Format (GIF)
Often pronounced like the peanut butter Jif (the less-preferred pronunciation utilizes a hard “g”), GIF is a file format that became one of the most commonly used for graphic images on the Internet during the late 1980s and early 1990s. Although the format itself is widely used online for free graphics images, the actual LZW compression algorithm (named for developers J. Ziv, A. Lempel, and Terry Welch) used to reduce the file size is owned and licensed by the Pennsylvania-based computer company Unisys. The LZW algorithm is also used in compressing TIFF (Tagged Image File Format) files and other graphics files, but the issues surrounding GIFs have gained greatest prominence due to the format’s popularity.
The GIF format was developed by the online service provider CompuServe for handling vector graphics (or line drawings) on the World Wide Web and released to the online community for free in the late 1980s. JPEG (Joint Photographic Experts Group) is another popular file format type, which handles raster graphics or photographs. As a bit-mapped graphics file format, GIF comes in two versions: 87a and GIF 89a. Generally, images works best as GIFs if they are simple line art, logos, or icons. Because the format can only handle about 256 colors, photographs and other detailed graphic images often aren’t preserved well as GIFs.
Despite its wide circulation as a free format, rumors circulated in 1995 that Unisys was planning to force everyone using GIFs to pay a royalty (as a backlash exploded among computer users, the company focused on software developers who were using their compression technology gratis and unlicensed commercial uses). To crack down on the software makers, Unisys demanded that all Web sites that used unlicensed software to create GIFs pay $5,000 to obtain a license from the company.
Such hard-line tactics angered online activists enough that a group of technicians developed a patent-free graphics format, dubbed PNG (Portable Network Graphics). But the spread of the PNG format was hampered by foot-dragging among developers of major Web browsers such as Netscape and Internet Explorer. Because these browsers were slow to offer technology letting users utilize PNGs, their use spread slowly despite their superiority to GIFs (PNGs, for example, compress true color images better and store palette-based images better than GIFs).
Adding to GIFs’ popularity is their capability for animation. Animated GIFs combine several images into a single GIF file—programs sift through the images in a stream to produce the animation—producing a file much smaller than Java applets, for instance. The popularity of GIFs also ensures animated GIFs are supported by all major Web browsers. Still, activist groups such as the League for Programming Freedom encourage users to “burn all GIFs,” circulating free software that converts GIFs to the PNG format, offering tips to cartoonists for creating PNG images, and spotlighting noteworthy GIF-free Web sites.
~~~~~~~~~~~~~~~~~~~
animated GIF
A graphics file that displays a set of images in succession fast enough to simulate movement on a Web page. Web developers can program the images to loop endlessly for a continuously moving image, such as a hand waving, or they can program the images to appear a specific number of times and then stop, such as a ball dropping once. Most browsers can handle animated GIFs, and they are relatively easy to make. However, the images are considerably smaller than other animations, like Java applets.
Often pronounced like the peanut butter Jif (the less-preferred pronunciation utilizes a hard “g”), GIF is a file format that became one of the most commonly used for graphic images on the Internet during the late 1980s and early 1990s. Although the format itself is widely used online for free graphics images, the actual LZW compression algorithm (named for developers J. Ziv, A. Lempel, and Terry Welch) used to reduce the file size is owned and licensed by the Pennsylvania-based computer company Unisys. The LZW algorithm is also used in compressing TIFF (Tagged Image File Format) files and other graphics files, but the issues surrounding GIFs have gained greatest prominence due to the format’s popularity.
The GIF format was developed by the online service provider CompuServe for handling vector graphics (or line drawings) on the World Wide Web and released to the online community for free in the late 1980s. JPEG (Joint Photographic Experts Group) is another popular file format type, which handles raster graphics or photographs. As a bit-mapped graphics file format, GIF comes in two versions: 87a and GIF 89a. Generally, images works best as GIFs if they are simple line art, logos, or icons. Because the format can only handle about 256 colors, photographs and other detailed graphic images often aren’t preserved well as GIFs.
Despite its wide circulation as a free format, rumors circulated in 1995 that Unisys was planning to force everyone using GIFs to pay a royalty (as a backlash exploded among computer users, the company focused on software developers who were using their compression technology gratis and unlicensed commercial uses). To crack down on the software makers, Unisys demanded that all Web sites that used unlicensed software to create GIFs pay $5,000 to obtain a license from the company.
Such hard-line tactics angered online activists enough that a group of technicians developed a patent-free graphics format, dubbed PNG (Portable Network Graphics). But the spread of the PNG format was hampered by foot-dragging among developers of major Web browsers such as Netscape and Internet Explorer. Because these browsers were slow to offer technology letting users utilize PNGs, their use spread slowly despite their superiority to GIFs (PNGs, for example, compress true color images better and store palette-based images better than GIFs).
Adding to GIFs’ popularity is their capability for animation. Animated GIFs combine several images into a single GIF file—programs sift through the images in a stream to produce the animation—producing a file much smaller than Java applets, for instance. The popularity of GIFs also ensures animated GIFs are supported by all major Web browsers. Still, activist groups such as the League for Programming Freedom encourage users to “burn all GIFs,” circulating free software that converts GIFs to the PNG format, offering tips to cartoonists for creating PNG images, and spotlighting noteworthy GIF-free Web sites.
~~~~~~~~~~~~~~~~~~~
animated GIF
A graphics file that displays a set of images in succession fast enough to simulate movement on a Web page. Web developers can program the images to loop endlessly for a continuously moving image, such as a hand waving, or they can program the images to appear a specific number of times and then stop, such as a ball dropping once. Most browsers can handle animated GIFs, and they are relatively easy to make. However, the images are considerably smaller than other animations, like Java applets.