Generating Slides from Enhanced Media Content |
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Extended Abstract |
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| February, 25th 2003 | |||||||||||||||||||
Summary |
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| This document describes the representation of a multi-functional slide sheet presentation using the Scalable Vector Graphics (SVG) format and its generation from a complex XML document via XSLT. | |||||||||||||||||||
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| The 'Knowledge Factory', or wwr-project (referred as 'wwr' [2]), is a venture, run by twelve German universities. It aims to generate multimedia enhanced lectures for Computer Engineering (Technical Informatics). Unlike other projects in Germany, wwr is not targeted solely at students. It is specifically designed to allow for a differentiation between the content provided for lecturers and their target audience. That is, the content provided for lecturers contains didactic hints or anecdotes, which may not be included in the students’ version. Having established the purpose of wwr, the next goal was to provide script, online and slide versions of the lectures/presentations. It is necessary to differentiate between online and paper versions, because the online version allows for the inclusion of animation, sounds etc., which, of course, cannot be included in script versions. In order to compensate for its “technological shortcomings”, the script version is designed to include static pictures and special text-elements. The content in wwr is written in XML-notation. This notation contains detailed information about the content of a document/presentation [1]. |
Figure1: Visualisation of conception |
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| The members of wwr needed a way to demonstrate the contents of their presentations (within lectures, symposiums, etc.) as slides. The features of SVG, combined with the fact that the wwr’s content is XML-text based (on wwr’s own XML Schema) influenced the design team’s decision to utilise SVG. Using SVG also made it possible to develop a product that is platform independent – something that is crucial if wwr’s slide format is to achieve broad acceptance. | |||||||||||||||||||
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| To ensure these acceptance, there also had to be imposed high demands upon the viewing tool. This new tool had to be as functional and comfortable as possible. This aim led the design team to produce the following minimal requirements for a new viewing tool: | |||||||||||||||||||
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| Focussing upon the process of XSL-Transformations, it was necessary for the design team to keep its design objectives in mind. In order to ensure that the transformed documents can be presented in any format (as a slide show, as script, or online) an attribute called ‘target’ was introduced. As within wwr, creation of presentations is left to individual academic staff, all they need do is to define the target, be it slide, script, or online, at the time of creating their presentation. | |||||||||||||||||||
| It was decided that the best way to develop an XSL-Transformation is a modular approach. The Advantages of a modular system are obvious: better overview, easy debugging, the ease with which enhancements can be implemented, etc. | |||||||||||||||||||
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<list target="slide" ordered="no"> <litem><text>line #1 of a list</text></litem> <litem><text>second item in list</text></litem> </list> The above XML-input clearly describes output that is formatted as a list, in which each member of the list is marked with a bullet [&9702;]. This list is translated to text within the SVG-slide using code which follows the format detailed below: <text x=".." y="..">&9702; line #1 of a list</text> <text x=".." dy="..(+..*fontsize)">&9702; second item in list</text> |
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| Instead of looking at the implementation of specific tags, let us consider the slide implementation itself. The approach is a simple one - displaying one sheet after another. For this purpose, it is necessary to save, load and change variables - say: counting! The pure language of SVG does not cater for such an operation, so it is necessary to resort to the ECMA-script-engine, which allows for the showing and hiding of individual slides. Each slide is assigned a number as a unique identifier and is displayed once the value of the counting variable reaches that number. | |||||||||||||||||||
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| The viewing tool designed by the design team has proven to be capable of dealing with marked-up XML-content for lectures and automatically generating multi-functional slide presentations. This type of presentation is highly customizable to meet the needs of the individual. The tool was designed to meet a demand expressed by the staff of wwr and will be widely used both within wwr and by institutions affiliated with wwr. | |||||||||||||||||||
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