Abstract: A method and apparatus for addressing the problem of combining a plurality of Page Description Language (PDL) separation color files to create a display list of objects that represents the composite or combined output image as described by the PDL separation files. Furthermore, any conflicts about the z-order of the display list is resolved by correctly ordering the objects in the display list to the extent that the ordering is significant. The need to produce a display list of objects that represents the composite or combined output image arises from digital preproofing, a technique of proofing and editing the output color image for production from images obtained from a proofing device other than the actual production printer.

Abstract: A system and process for digital printing processes commands to draw a trapezoidal image by initially rendering those commands into an intermediate representation based on pixel rows. Depending on the dimensions of the trapezoid or the regularity of the offset of the end pixels of each pixel row from the end pixels of an adjacent pixel row, data representing the trapezoid are sent to a display list as either individual pixel data, pixel row data, or a compact grouping of data derived from the intermediate representation.