What are extension points and how do you use them?

One great thing about the options that you can use is that they are are already implemented. If not, and if they are available as part of Protovis but just not in CCC, you are able can make use of the extension points. So, with extension points you are able to use properties/options that are not implemented directly in CCC. They are one of the great features of CCC charts, because they provide almost direct access to the underlying Protovis marks.

When setting an extension point, we should specify its name and value. The name is a combination of a CCC identification and the Protovis property name separated by an underscore (_). For instance, to define the fill style for the legend, you would need to define legendArea_fillStyle and set a color. First you need to set the visual element, followed by (_) and by the extension point property.

There are no ways to handle the right-click action in CCC, nor is there the possibility to directly listen...