A set of pattern headers is used to replicate repeating patterns used in digitally-simulated halftone screens. The use of pattern headers is suited to digital processing systems which are most efficient when processing data having dimensions which are an integer power of two, yet permits generation of...http://www.google.com.au/patents/US5179640?utm_source=gb-gplus-sharePatent US5179640 - Generating repeating patterns from a pattern header
