Dynamic planar map illustration

There are many types of illustrations that are easier to create in planar-map-based illustration systems than in the more common stacking-based systems. One weakness shared by all existing planar-map-based systems is that the editability of the drawing is severely hampered once coloring has begun. The paths that define the areas to be filled become divided wherever they intersect, making it difficult or impossible to edit them as a whole. Live Paint is a new metaphor that allows planar-map-based coloring while maintaining all the original paths unchanged. When a user makes a change, the regions and edges defined by the new paths take on fill and stroke attributes from the previous regions and edges. This results in greater editing flexibility and ease of use. Live Paint uses a set of heuristics to match each region and edge in a changed illustration with a region or edge in the previous version, a task that is more difficult than it at first appears. It then transfers fill and stroke attributes accordingly.