Filtering Fisheye Views next up previous
Next: Logical Fisheye Views Up: Fisheye Views Previous: Distorting Fisheye Views

Filtering Fisheye Views

Figure 35: Polar Filtering Fisheye View of Attributed Syntax Tree

Filtering fisheyes [SaBr94, Sa96b] show many details at the focus point, but they filter graphical objects that are far from the focus point. This improves the visibility of the main structure, which would probably go lumpy with all the shrunk, unimportant details far from the focus point. Thus, objects are filtered according to their visual worth. The visual worth depends on the distance to the focus point and on an a priori importance (api) of the nodes and edges of a graph, which is given in the graph specification. For instance, in an attributed syntax tree, the main structure is the tree, thus it has an larger api than the attributes. The user can select the threshold level of detail (lod) to influence the amount of visible objects. An object is visible if tex2html_wrap_inline3018 , where x is the distance to the focus point and h is the function calculating the visual worth. Properties of h:

A function commonly used for filtering fisheyes (S(x) is the transformed size of a node in distance x in the picture, the parameters c, d, e > 0):


Georg Sander
Thu Aug 1 15:27:34 PDT 1996