Extending SVG with Constraints

Jojada J. Tirtowidjojo, School of Computer Science and Software Engineering, Monash University, Clayton Campus, VIC 3800, Australia jojada@csse.monash.edu.au

Kim Marriott, School of Computer Science and Software Engineering, Monash University, Clayton Campus, VIC 3800, Australia marriott@csse.monash.edu.au

Bernd Meyer, School of Computer Science and Software Engineering, Monash University, Clayton Campus, VIC 3800, Australia bernd.meyer@acm.org

Keywords

SVG, constraints, semantic zooming, differential scaling, semantic preserving manipulation

Abstract

The current SVG specification does not yet provide for truly flexible layout in the context of different viewer requirements and browser capabilities such as screen size and available fonts. The problem is that an SVG specification gives absolute positions and sizes for its elements and only performs uniform scaling. This is not powerful enough. Displaying a diagram in very different contexts may require radically different layout. We suggest that this problem can be rectified by adding two additional capabilities to the SVG specification: semantic zooming and differential scaling. We describe how by adding constraints and alternative layouts for groups of SVG elements we can provide SVG with these capabilities. Our prototype system demonstrates the feasibility of our concepts.