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An Introduction to VML.

 California 
 Cupertino  
 Microsoft  
 Wu, Peter  
 		Peter  Wu
Lead Program Manager,  Microsoft 
 10000 Torre Ave.
Cupertino  (California)  95014 
Email: petewu@microsoft.com

Biographical notice

Peter Wu is a Lead Program Manager at Microsoft. He has worked on the graphics features in several releases of the very successful Office applications over the past 5 years. Currently, he is working on the Internet graphics standards support in the upcoming Office 2000 release. Peter is a co-author of the Vector Markup Language (VML) proposal to the W3C as a vector graphics standard for the web. Peter has an M.S. in Computer Science from Duke University and B.A. in Computer Science and Mathematical Science from Rice University.

 VML 
Vector Markup Language
 W3C 
World Wide Web Consortium
 

Introduction.

  Vector Markup Language, or VML for short, is a high quality 2-D vector graphics format for the web that integrates with existing web standards. With VML, you can easily edit, exchange, and deliver graphics to the web.
  Autodesk Inc., Hewlett-Packard Co., Macromedia Inc., Microsoft Corp. and Visio Corp. are co-authors of the VML specification. The World Wide Web Consortium (W3C) has acknowledged their joint submission of VML.
  This session gives a high-level introduction to VML. We are interested in hearing your feedback on VML and how it can continue to be improved to better serve your needs as web publishers and developers.
 GIF, Graphics Interchange Format 
 JPEG 
 PNG 
 

What’s wrong with graphics on the web today?

  Today, graphics present a number of challenges for many web authors.
  Firstly, web graphics are hard to author. Graphics authoring and page authoring are not well integrated. Authors must use a separate set of applications for authoring graphics and authoring the page. And then there is an extra step of plugging in their graphics into their page. Also, graphics authoring often requires conversion among several formats and maintaining multiple files to allow further editing. For example, suppose you need to include a simple diagram on your web page. You may want to use a vector-based graphics application to draw the diagram. But then you need to export it in GIF (or JPEG or PNG) format for the web. Now suppose you would like to make a few updates to the diagram. It is difficult to do editing directly on the GIF image because it is a "flat" image, so you need to keep around a copy of the diagram in the application's native format for further editing. Once you have made your updates to the original diagram, you must export is as GIF again. The revision cycle requires several steps and there are multiple files to maintain.
  Secondly, the widely supported formats for web graphics, GIF, JPEG, and PNG, are all raster formats, and raster formats have a number of limitations. Raster graphics are typically very large in file size. Because of the large file sizes, web authors are limited to using graphics that are small in dimensions and low in resolution to keep download times reasonable. Raster graphics also do not scale well; they are targeted for a specific size and resolution. Lack of good scaling limits web authors' ability to design graphics that adapt to different screen sizes.
 HTML, Hypertext Markup Language 
 

VML addresses problems with graphics on the web.

  VML is designed to address these problems with web graphics.
  VML greatly simplifies the authoring process. Graphics and page and authoring can be seamlessly integrated, because the graphics format (VML) and page format (HTML) are seamlessly integrated together. This integration greatly reduces the amount of work web authors need to do to add graphics to their pages. Additionally, because VML is designed for editing, exchange, and delivery it is not necessary to maintain multiple files as you are working on your graphics. For the diagram example given above, VML serves as the web delivery format as well as the editing format, so you do not need to export in another format. Revisions to the diagram can be done in a single step!
  VML also avoids the limitations that raster formats impose by adding vector graphics capabilities. Vector graphics allow you to create very compact files that download fast and stream well. Vector graphics are also scalable and high resolution. This gives you the flexibility of using larger graphics without requiring larger files or sacrificing quality.
 DOM, Document Object Model 
Declarative
 XML 
 

VML is an application of XML.

  VML uses XML for the many benefits it provides:
 
  • Standard. Because VML is based on the XML standard, it will be compatible with a wide range of web applications. The data is in a format that browsers, authoring tools, server applications, searching/indexing tools, link management tools, and document management tools can access.
    •  
  • Structured. XML provides the structure that is needed by vector graphics. Containment hierarchy, inheritance, and linking are examples of the type of sophistication that a vector graphics format requires and XML provides.
    •  
  • Object model. The document object model (DOM) goes hand-in-hand with the structured file format. All of the graphics properties are exposed to developers to modify dynamically which allow easy and powerful interactivity and animation.
    •  
  • Integration with HTML. XML is a good foundation for a web graphics format because of its tight integration with HTML. Graphics often need to be integrated with rich text, tables, hyperlinks, and other page elements. Authors can do this easily using a combination of VML and HTML.
    •  
  • Declarative. VML is a declarative language. Unlike a procedural language, no programming is required to author content. Also, for good data interchange among applications, it is very important that the format is declarative. XML is very well suited for declarative formats.
    •  
  • Text-based. Human readability of VML and XML is a real boon to developers. It makes VML easy to learn and work with. For example, to learn how a particular attribute works, it is easy to modify it in any text editor and load the page in the browser to try out how it works. It is also easy to write small programs such as Perl scripts that generate VML.
    •  CSS, Cascading Style Sheets 
     

    VML integrates well with web standards.

      VML leverages existing web standards. It is an application of XML 1.0, and as a consequence, all VML content is exposed in the DOM. VML can be used in conjunction with HTML 4.0 and CSS 2.0. CSS properties cascade properly through VML content. Also, VML uses the box positioning model that is defined in CSS 2.0, rather than defining a new model.
      VML complements existing web graphics standards. VML is not intended to be a replacement format for GIF, JPEG, or PNG; rather, it is complimentary. GIF, JPEG, and PNG images can be used in conjunction with VML. For example, you can use a JPEG image as a tiled fill for a VML shape. VML also allows you to apply basic transforms on raster images such as cropping, color adjustment, and rotation. Authors can continue to use raster formats for the things they are well-suited for including photographs, textures, and screenshots. VML gives authors a powerful combination of vector capabilities and raster graphics.
      VML has been proposed to the W3C as a web standard. The specification is publicly available (http://www.w3.org/TR/NOTE-VML) for developers to learn about and provide feedback on. The W3C has formed a working group for Scalable Vector Graphics where several member organizations, including Microsoft, will work together on developing a next generation standard for web graphics. VML and other graphics standard proposals serve as references for the discussions and work towards a standard.
     

    VML support in core Microsoft products.

      Microsoft will be supporting VML in its upcoming platform and application releases. Internet Explorer 5.0 will include integrated VML support. VML support in Office 2000 will allow users to save Office Art graphics as editable elements in their HTML pages for delivery to the Web. VML will preserve the full fidelity of Office Art objects and allow "round tripping"; that is, the HTML file can be opened and edited back in an Office application with no loss of quality. Microsoft’s new platform for multimedia developers, Chromeffects will also support VML.

    Microsoft Office 2000 Logo

    Microsoft Internet Explorer Logo

     

    Quotes from the VML Press Release

      "Autodesk is a strong advocate for interoperability between design, drawing and office applications, as evidenced by its own public data formats, DXF and DWF, which are used widely in many software packages," said Anne Bonaparte, senior director of the design team solutions group at Autodesk. "VML as a standard offers users the promise of even more compatibility, as well as ease of use and reuse of intelligent vector data on the Web."
      "This proposal is a solution to one of the last missing pieces in document layout on the Web," said Carolyn Ticknor, vice president of Hewlett-Packard's LaserJet solutions group. "The whole Internet community will benefit from faster download speeds, higher-quality graphics printing and lower network overhead."
      "Our collaboration on VML represents the next step in our goal to deliver compelling, interactive vector content, even over low-bandwidth Internet connections," said Norm Meyrowitz, president, Macromedia products group at Macromedia Inc. "Just as the open Flash binary file format (.swf) enables standard playback of vector graphics and animation, VML will provide content developers with an open XML text-based standard for exchange across a variety of tools and platforms. We look forward to extending our family of Web software to support VML in future versions."
      "The Web community has been asking for a high-quality, easy-to-use 2-D vector graphics standard for some time," said David Cole, vice president of the Web client and consumer experience division at Microsoft. "VML meets their needs with faster graphics downloading for end users and easier graphics editing and manipulation for HTML authors and designers. VML will be a key specification in our future platforms and applications."
      "VML's flexibility and extensibility has led Visio Corp. to support wholeheartedly its adoption as a Web standard for vector graphics," said Ted Johnson, executive vice president and chief technology officer of Visio. "With VML, Visio users will be able to create, edit and publish their business diagrams and technical drawings to the Web while preserving all the intelligent object behavior that distinguishes the Visio SmartShapes technology."
     

    Summary.

      In summary, Microsoft is working with industry partners on advancing the state of web graphics with VML. Please let us know your feedback on VML and how it can be improved to better serve your needs.
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