. . . . "the root of the content tree then return the default background color (e.g. white) P = parent(C) for each child K of P if K is different from C and K is a rectangle and K encloses G then return the color of K return FindBackground(G, P) } The test for K enclosing G can be performed, for example, using the bounding box for K and G to ensure that the corners of the bounding box of G are within the c" .