Image rendering process and apparatus

摘要

An apparatus for creating a page image which may include complex graphics information for display on a continuous synchronous raster output device by generating bands of graphics information which use an amount of memory which is less than the amount which would be needed to store a complete page image, said apparatus comprising: a) means for receiving and interpretting commands in a page description language which define the page image to be output; b) means for generating a set of graphics orders from the interpretted page description language commands such that: i) said graphics orders can be processed into bands of bitmap images rich can delivered to the output device at a speed required by the output device; and ii) while the graphics information in a first one of said bands is being output by said output device, the bitmap images for a second one of said bands is being generated; c) means for generating said bands of bitmap images from said graphics orders; d) means for outputting said bands of bitmap images to said output device.