Web Design: Vector graphics in the clear

THERE IS a saying that seems to be used all too often when referring to the Web and its various technological offshoots: "The future is now." This has to be one of the dumbest phrases ever coined and shows how amazingly short-sighted some people can be. The fact is that, despite how advanced the technology we have right now seems, it is nothing compared with what is around the corner. In the case of Web graphics, if all the future offers designers is bit-map (http://www. independent.co.uk/net/980629ne/story4.html), the Web is in big trouble.

One person with his finger on the pulse of Web graphics is David Brailsford, the Dunford Professor of Computer Science at the University of Nottingham. He has been studying the problems of "Electronic Documents" for 18 of his 30 years as a computer scientist and has recently become involved with the question of vector graphics on the Web. At the September 1998 Seybold conference (one of the most influential conferences in the computer world), he set out the framework for the panel discussing Web graphics. Who better with whom to discuss what the future holds for them?

Jason Cranford Teague: In your view what is wrong with the standard bit-map Web graphic formats (GIF, JPEG and PNG)?

David Brailsford: These are acceptable for true photographs but are a poor choice for vector graphics because they are bulky and inherently unscalable.

JCT: What's on the horizon that will improve on this?

DB: The recent proposals involving Flash, the Vector Markup Language (VML) and Precision Graphic Markup Language (PGML) point the way forward. Flash is a very creditable start, but it is likely that the World Wide Web Consortium (W3C) will want Extensible Markup Language (XML) notation rather than binary code. VML is OK for business graphics but does not have (neither does Flash, for that matter) any facilities for clipping to paths. For example, it can not clip portions of a bit-map photo to the interior areas of an outline font. Adobe's PGML does have this graphic sophistication.

JCT: Who is proposing these standards?

DB: Adobe (supported by Sun, Corel, Netscape and IBM) proposed PGML in April of this year to the Web consortium. Shortly thereafter, Macromedia put the Flash spec. into the public domain (what a coincidence!) In May, Microsoft (supported by Macromedia, HP and others) proposed VML. VML and PGML aren't all that different. Both are more or less PostScript friendly, for example. But basically, VML's sophistication stops at a stage just about adequate for business graphics. However, VML, like PGML, uses XML syntax.

JCT: PGML and VML use XML notation, but how will this work for graphic artists who are not programmers? How is XML notation an advantage for creating graphics?

DB: Packages such as Adobe Illustrator will generate PGML (or VML) code rather than requiring designers to hack it in by hand. However, PGML and VML code is directly editable for tweaking and tuning purposes, whereas Flash isn't.

JCT: So these three formats are competing with each other to be the Web's vector format. Which one do you see becoming the standard?

DB: I fervently hope that the W3C's Scalable Vector Graphics (SVG) working group will become the universally adopted standard. Companies now involved in the SVG working group proposals are Adobe, Netscape, Microsoft, IBM, Sun, Corel, HP, Autodesk, Visio and Xerox

JCT: So what will the SVG working group be doing?

DB: At Seybold San Francisco, in the Web Graphics session, I "set the scene" for presentations by Adobe, Macromedia and Microsoft. In the two days after that session, all parties came together under the chairmanship of Chris Lilley (from W3C) to amalgamate the best aspects of PGML and VML and to come up with an agreed single standard by a deadline of August 1999. This new merged standard will be called Scalable Vector Graphics (SVG).

JCT: How will SVG be an improvement over the graphic formats we are already using?

DB: As well as scalability, emerging Web standards in other areas offer better font handling, better colour management and more. Both VML and PGML offer XML-compliant ways of specifying graphics that are good candidates for text-compression technology (LZW, Zip etc) and this may make a binary format unnecessary (but the W3C hasn't ruled out the idea of a binary version).

JCT: So instead of reducing the quality of the image to compress a graphic, you would compress the code used to make the graphic, as with a zipped text file?

DB: Yes, that's right. The W3C isn't ruling out that SVG may have a "binary" option if file size gets to be a huge problem. But the feeling is that PGML/VML/SVG offer good opportunities for text compression because of repeated strings such as etc. So binary may not be necessary. One of my researchers here at Nottingham is currently looking at Flash-PGML conversion followed by ZIP compression on the PGML to see how much bigger/smaller that end result is compared with the Flash original.

JCT: Are there any drawbacks to these formats?

DB: The big headaches coming up will occur if traditional print designers really do see SVG as the way to bridge the gap between the printed page and the Web. Welcome though it may be to have a wide variety of type faces available, this raises the prospects of (a) how will font downloading be accomplished? (b) will users demand genuinely integrated page and document behaviour from the Web, which until now has relied on links to create amorphous but dynamic documents with pieces pulled in from here there and everywhere?

JCT: Do you think that vector graphics will eventually become as ubiquitous as bit-map graphics are now or will they be mostly relegated to special uses?

DB: Once Web designers have the tools to create SVG, I think there will be major take-up and a lot of interest.

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