An apparatus for recording an object-based image one pixel at a time in scanline order includes an optimization module for generating a set of compositing messages corresponding to a first pixel and generating a reduced set of compositing messages from the set of compositing messages, and a pixel compositing module which, in addition to compositing the first pixel using the set of compositing messages, stores a result or partial result of the compositing of the first pixel. The pixel compositing module utilizes the reduced set of compositing messages and the stored result or partial result to composite at least one subsequent pixel, and the first pixel and the at least one subsequent pixel form part of a run of pixels along a scanline of the image between adjacent edges of objects in the object-based image.