SYSTEM AND METHOD FOR OPTIMISING HALFTONING PRINTER PERFORMANCE

A method of rendering a plurality of graphical objects of an image on a scanline basis, with each scanline having at least one run of pixels, and each run of pixels being associated with at least one of the graphical objects such that the pixels of the run are within edges of the at least one graphical object, includes the steps of decomposing each of the graphical objects into at least one edge representing the corresponding graphical object, and sorting one or more arrays containing the edges representing the graphical objects of the image. At least one of the arrays is sorted in an order from a highest priority graphical object to a lowest priority graphical object. Additional steps include, for each run of pixels of each scanline, determining edges of the graphical objects defining the run, graphical objects contributing to the run of pixels and edges of the contributing graphical objects, using the one or more arrays, and generating the run of pixels by halftoning pixel data within the edges of a highest priority contributing graphical object, if the highest priority contributing graphical object is opaque, otherwise, compositing data associated with the highest priority contributing graphical object and one or more further contributing graphical objects, and halftoning the composited data.