1. A computer implemented method for controlling an image rendering device to merge intermediate representations of a page to be rendered, the method comprising: receiving a page description language representation of the page, the page description language representation having a plurality of sequential graphic objects ordered by drawing order; forming a plurality of groups of sequentially adjacent graphic objects of the plurality of sequential objects, each group being associated with a z-order according to the drawing order; generating an intermediate representation from each of the groups, wherein at least two of the intermediate representations are generated concurrently; creating a data structure comprising records each corresponding to one of the intermediate representations, a priority of each of the records, and a status of generating the corresponding intermediate representation; merging by the image rendering device, in the z-order, at least two intermediate representations consecutive in the z-order to form a merged intermediate representation independently of an intermediate representation preceding, in the z-order, the at least two intermediate representations, wherein the at least two intermediate representations are selected using the priority and status of the records in the created data structure; and merging, by the image rendering device using the created data structure, the merged intermediate representation and the intermediate representation preceding the merged representation in the z-order to render the page.