GIF thumbnail

Computer users choose GIF

This story appeared in the October 1987 issue of Online Today, CompuServe's magazine for CIS users. See also “Get the picture,” a June 1989 Online Today feature about graphics.

Graphics Interchange Format focuses on clarity, flexibility

Steve Wilhite

Greg Miller

Developing decoders for GIF: Wilhite works with many micro models.

Horror stories about incompatible microcomputers may be humorous when everyone is in a good mood, but they are certainly the nemesis of any serious computer user. The frustration is no laughing matter when a person wants to transfer some data or a graphics image, and the system doesn’t cooperate.

Both hobbyists and professionals have been trying to develop the programs and equipment that will come close to solving incompatibilities and let machines “talk” to one another. Graphics fans simply want to be able to upload or download graphic images in some sort of reasonable time frame. Much progress has been made in text-file transfer, but graphics has presented a much more complex challenge.

Now, with the introduction of Graphic Interchange Format (GIF)—pronounced “jif”—a universal exchange format for high-resolution graphic images is available to microcomputers without regard to hardware compatibility. The beauty of the GIF concept is its flexibility. Beyond overcoming the hardware incompatibility issue, it stores and transmits raster-based graphic data in a compressed form. “A sophisticated compression algorithm makes it the major reason that people would use a service such as CompuServe to exchange graphics screens,” says Craig Knouf, product manager for VIDTEX products. With compression ratios varying from 2:1 up to 8:1 of the original memory size, this space compression results in a time compression, so an image stored in the CompuServe system can be captured and downloaded rapidly.

Beyond the compressed format, “the other side is receivers—decoders and viewers in the micros—that can accept, digest a GIF file and appropriately display it on the screen,” says Steve Wilhite, a principal software engineer who helped develop GIF. At this point, CompuServe has GIF decoders available for the Apple Macintosh, Commodore Amiga and IBM PC compatibles with CGA, EGA or VGA graphics capability, and Atari ST machines. And Wilhite says there will soon be decoders available for other models of micros. GIF-support software is available through appropriate CompuServe hardware forums. GIF images are also available in the Picture Support Forum. “We can have monochrome or color GIF files,” says Wilhite. “Then it’s a matter of the resolution your screen has.” Images on GIF can be any resolution; they are not restricted by computer graphics hardware.

Images, stored and/or uploaded from a digitizer, can contain as many as 256 simultaneous colors from a palette of 16 million, each of which is defined in terms of red, green and blue components. Although such massive color display capabilities should be available with VGA graphics capability on the new IBM models announced in April, many presently available systems will rely on the GIF decoder to translate the image into a lesser 32-color scheme. But vast improvements should be near. “Remember,” says Wilhite, “that we had a graphics format code called RLE, which was black and white, low resolution and 256 by 192 pixels. Now that’s a rather severe limitation. But when it was developed four or five years ago, personal computers used in the home didn’t have high resolution.” Now many of them demonstrate much finer resolution and GIF is the method to let these newer personal computers show their capabilities.

Jif

Pronounced like the peanut butter.

Online Today Oct 1987 cover

CompuServe is handling the GIF protocol in a unique way. Most important: the protocol is public-domain. “And we want it to be an industry standard,” says Knouf. “We want to assist developers to create products quickly and with our assistance.” So Knouf and Rob Vitolins, graphics product manager, have established very specific guidelines for developers. “At present we have more than 50 developers,” says Vitolins. “Some are doing it strictly for an in-house need, including one government agency.” Knouf adds, “To date, these developments have added an encoder and decoder for the Apple IIgs and improved decoders for the IBM PCs, Atari STs and Amigas.” The technology will be broadly available so as to promote the intention of its universal use.

Although one long-term goal is real-time transfer of images, there are many uses for GIF beyond the hobbyist’s curiosity of manipulating graphics. CompuServe subscribers can upload images converted from “paint” programs or other applications by using encoder programs or by first digitizing and then encoding. But GIF will also allow combinations of text and images to be scanned simultaneously, rather than being stored separately, and assembled at some later moment. This may have implications in archive and publishing projects.

Online, CompuServe plans to convert the art gallery of the Picture Support Forum, the Missing Children’s Database files and the Weather areas to GIF, says Knouf. The technology also will be used in medical, radiographic and astronomical imaging. In fact, NASA wants to provide telescopic images online and let amateur astronomers use their microcomputers and creativity for image analysis. GIF has a sophistication that can be applied easily on such CAD/CAM workstations as the Apollo. And with GIF’s speed, the idea of online slide shows now becomes feasible.

“GIF is still in the early stages of development,” says Vitolins. Eventually there will be host-based software to generate the weather maps, stock charts and other synthesized forms of graphics. These real-time graphics should be available by the end of this year.

Yvonne Heather Burry

(Back to CompuServe nostalgia index.)[2010-02-23]