Abstract: A virtual view tree for representing a document. A virtual view tree is maintained by an application, rather than a renderer (e.g., graphics rendering library) called upon by the application to display the document. The view tree is virtual in that nodes need not be created until they are to be displayed. When instructed to display the document, the renderer requests nodes and their attributes. The nodes may be cached while the renderer works on their content, but may be removed from memory anytime thereafter. Only a subset of the virtual view tree's nodes is stored at one time, and only in non-persistent storage. The application includes various APIs for navigating a virtual view tree, describing its attributes and caching its nodes. The APIs may be directly accessible to the renderer or may be invoked by subsystems of the application (e.g., client, tree navigation and caching subsystems).

Abstract: Method and apparatus for rasterizing a resolution-independent page description for printing. A peeker (gap between two visible edges in vector representation that is narrower than a printer pixel) is identified between a first visible edge and a second visible edge, and a color adjustment is made to at least one of the edges. In one embodiment, a side of the second visible edge facing a side of the first visible edge is identified. The color of the identified side of the first visible edge is changed based on the color of the identified side of the second visible edge. The color adjustment is advantageous in connection with methods of trapping.