1. A VLSI layout editor, comprising: a first memory that stores a canonical expression of a VLSI layout having a plurality of layers; and a display controller coupled to the first memory that generates a displayable representation of ordered layers of the VLSI layout that tracks changes in a user viewpoint, wherein the displayable representation comprises a precomputed image that represents a portion of the VLSI layout, and wherein the precomputed image is used in two or more user viewpoints.