Once upon a time... (A fairytale of magic pictures) ----------------- "A kind of HTML, the codingsystem used for the layout of webpages, but then for graphics". That's what SVG is about. SVG is an abbreviation of Scalable Vector Graphics and describes how something is to be presented. The thickness of the lines, the patterns to fill planes, color distribution, masks and filters for effects like smooth flows, and more. In August of this year a international conference on SVG is held in Enschede and Ruud Steltenpool# is one of the organisers. In this edition of OpenMagazine he tells, mostly by using a fairytale, what makes SVG so interesting. ----------------------------- by Ruud Steltenpool The little girl open*s the 'story-book' (2 screens fit together as pages with a computer and a wireless connection integrated) and sees a young lady, a princess of course, standing next to a pond, her face *the same as* as the girl's own. "Shall i tell you a story?", asks the princess and the kid silently mumbles "yes, pwease". "Once upon a time..." starts the princess and unfolds the story while the words appear one by one on the other page. The drawings change along accordingly, not really continuously moving images, but more like a richly illustrated book. When the little girl touches the dwarf picture in front of her, the princess departs slightly from her story and tells about the dwarf, who in turn also makes himself heard. Yesterday the dwarf was a unicorn and tomorrow a magical bird maybe, cause the story changes based on interaction with the girl. Stories can get saved - "same as yesterday" says the girl - or it can be a never ending story growing with the child. Maybe in interaction with the stories of hundreds of thousands of other children. "Scalable Vector Graphics" is the quite imposing term for these pictures, the words and the connections. A bit of technical speach, that next to the obvious, carries along lots of extra meaning. Many people that work with it, therefore rather use the abbreviation SVG, because the full variant sells it short. A better description of this technology might be 'magical pictures'. Pixels An ordinary picture in a page is usually far from magical, whether it's a local document or on a webpage or whatever. Apart from maybe the place and size in the page, they contain no information about themselves. Of course you can make such an ordinary picture clickable (link it), maybe even make the result dependent on where you click and add a short description in HTML that might serve as a pop-up text. This however changes nothing to the fact that the picture is just a bunch of colored pixels, without any built-in meaning. No semantics, as its called in computerlingo. Now imagine you do are able to put this meaning in. So every element in the image - the princess, the pond, the dwarf, maybe even the horn of the unicorn - would hold enough information to identify itself. Or enough information to change the representation of itself or its surrounding, for example by moving, turning, growing, shrinking or changing the colors. Also imagine that this image can communicate with the internet, save information about itself, renew stories, maybe communicating with other stories so in case of common story lines one could start a joined adventure. It are all possibilities of SVG. SVG in essence is a language that describes images in text. It describes how something must be presented: the thickness of the lines, the patterns to fill the planes, color distribution, masks and filters for subtle effects. And more. So only at the final moment of presenting this description is calculated into pixels. Also it can flourish images into animations: movements along complicated paths, a poisoned apple fluently going from sickly purple to tempting red, or the girl that grows after drinking from the bottle saying "Drink me". SVG controls the flow of text across a page, how it appears and disappears, and even the complete shape of the letters. And also the connections with the web and retrieving new content, or sending the story of the girl to another computer where the next step of the adventure is determined. XML Just as HTML made the rise of the World Wide Web possible as a common language for describing webpages, SVG builds on XML for the notation of its data. XML is THE language for web communication and its use is rapidly spreading. This common language (strictly specified by the World Wide Web Consortium (W3C), an organisation responsible for most languages on the web) has made possible a whole series of common and because of that powerful tools. SVG is therefore easily combinable with other XML-languages such as MathML, MusicML, CML (Chemical Markup Language) or a different variant or new designed-by-you XML-format. Together they form a part of the gradually forming semantic web, of which SVG is the rendering language. Now you might think "that sounds like a fairytale, that is to good to be true". Or "what do I need then, what does that cost me?". But as you might have already expected based on some hints: SVG is an open standard. So without having to pay licensing costs or royalties, you or the manufactorer of the 'story book', can freely use the format. And because it is just as all XML languages only plain text (compare: "view source" with HTML), you don't need special software to create it. Also it can, for example on a webserver, easily be generated. And you can apply many of the technologies surrounding HTML to SVG too (like Javascript and CSS). So it doesn't cost much extra time/money to learn create it. SVG is therefore sometimes called "the HTML of graphics". "Is there nothing special I need then?". You need a SVG viewer. You can freely download one, but sometimes you already have one, usually without knowing it. On computers it often comes along with other software. On mobile phones a pre-installed SVG-viewer is really becoming nothing special at all. There are an estimated billion handsets in use that support it and the web is progressively becoming more mobile. It's not unlikely that your MMS, game or other mobile service uses SVG. Also the first hardware implemented viewers are for sale. At the creating side as well, as text editors and the widely present "save as SVG" in graphical editors, there are also more SVG-specific visual and code editors available. With that SVG eases cooperation between 'coders' and 'clickers'. Concluding we can say that SVG adds freedom to your creativity and helps in communicating your ideas. "A good picture is worth a thousand words" goes the expression. I hope these approximately thousand words inspire you to multiples :-) And the princess? She of course lived happily ever after. THE END (with thanks to Kurt Cagle (understandingxml.com) for helping on this story) relevant links: http://svg.pagina.nl SVG links page http://www.svgopen.org/2005 SVG Open 2005 Conference and Exhibition Ruud Steltenpool of the university of Twente (applied physics) is one of the organisers of the SVG conference that takes place in Enschede, the Netherlands, from August 15 to 18. ------------------------------------------ SVG Open 2005 in the Netherlands ! After Zurich, Vancouver and Tokyo, the SVG Open Conference and Exhibition, the conference on Scalable Vector Graphics, will this year take place in Enschede (August 15 to 18). It will reflect the versatility of this 'HTML of graphics' with subjects ranging from specialist technical visualisations to interactive multimedia art on your website or mobile phone. Next to paper presentations the program will also feature courses and workshops (both beginner and advanced level) and ample opportunity to meet the international SVG community. People are hereby also invited to submit proposals (short abstracts) for papers, panel discussions and courses and workshops (but hurry!) or response or questions. On the website (www.svgopen.org) you can find a lot more information, including photos of the location, promo to spread, a news mailinglist, the prices and the dates: August 15 to 18. Take part and, from August 15 to 18, be part of the varied and creative crowd, with among others an artist from the United States, some interested from Hengelo, a programmer from Australia and a scientist from TNO (the dutch knowledge organisation for companies, government and societal organisations. SVG Open 2005 is organised by the University of Twente (UT), "het Telematica Instituut" and the International Institute for Geo-Information Science and Earth Observation (ITC). -----------------------