US Patent 7853887 Detection and preview of graphical elements within a graphic

In an embodiment, hidden graphical elements in a graphic are detected by generating a first bitmap based on a plurality of graphical elements and a second bitmap based on a first subset of the plurality of graphical elements where the first subset omits a first graphical element of the plurality of elements and includes a second graphical element of the plurality of elements. The first bitmap is then compared with the second bitmap to determine if they match. If they match, the first graphical element is considered to be hidden by the second graphical element.