On the Pagination of Complex Documents

The pagination problem of complex documents is in placing text and floating objects on pages in such a way that each object appears close to, but not before, its text reference. Current electronic formatting systems do not offer the pagination quality provided by human experts in traditional bookprinting. One reason is that a good placement of text and floating objects cannot be achieved in a single pass over the input. We show that this approach works only in a very restricted document model; but in a realistic setting no online algorithm can approximate optimal pagination quality. Globally computing an optimal pagination critically depends on the measure of quality used. Some measures are known to render the problem NP-hard, others cause unwanted side effects. We propose to use the total number of page turns necessary for reading the document and for looking up all referenced objects. This objective function can be optimized by dynamic programming, in time proportional to the number of text blocks times the number of floating objects. Our implementation takes less than one minute for formatting a chapter of 30 pages. The results compare favorably with layouts obtained by Word, FrameMaker, or LTEX, that were fine-tuned by expert users.