Hewlett-packard Company

Burton H Poppenga

Russell Campbell

Terrence M Shannon

Timothy P Blair

Richard M Dow

A multi-resolution capable printer includes a critical operations memory buffer for enabling critical page print operations to occur without flushing the video buffers and without waiting for returned-in memory to heal into larger free blocks. The critical operations buffer thus enables improved constant printer throughput and reduced 'pausing' during a multi-page print job. The critical operations buffer is dynamically sized to the resolution of the current page being printed. Thus, at higher resolution configurations, the critical operations buffer is reduced in size to allow the video buffers to increase in size to accommodate the higher resolution. At lower resolution configurations, the critical operations buffer is increased in size and the video buffers are decreased in size to accommodate the lower resolution. Advantageously, the total combined pre-reserved memory area utilized by the critical operations buffer and the video buffers remains constant. The critical operations buffer is utilized for large contiguous memory allocation requests, pre-rasterization operations, compressing operations, rendering character bitmaps, scaling and rotating raster objects, building vector paths, defragmenting the memory, and the like.

Memory partitioning for multi-resolution pauseless page printing

Apparatus for processing and displaying binary pixel image data includes a printer for receiving image data and for presenting the image data as bilevel pixel values. The printer includes a processor for altering the received image data into an output image. A host processor stores multi-bit-per-pixel image data and further includes image processing software and data transmission circuitry coupled to the printer. The host processor compares the bilevel pixel data size and the multi-bit-per-pixel data size and, based upon a size relationship determined from the comparison, processes the multi-bit-per-pixel image data into bilevel pixel values in either the printer or the host processor so as to transmit the least amount of image data between the host processor and the bilevel printer.

Image processing load balancing for a host processor with a connected

A processor unit converts source image data to a rasterized monochrome bit map and includes a random access memory, a storage memory containing a gray scale conversion table, dithering matrices, procedures for determining destination image dithering tiling locations, scaling conversion procedures and sub routines for establishing a gray scale value array indexed to a bit mask array. The processor unit performs a method of converting source image data to a rasterized compressed monochrome bit map which involves a conversion cycle for converting source pixels to gray scale value and output position bits within the two arrays. Testing is performed to determine all of the source pixels converted to the same gray scale value, and if so, a read ahead cycle commences, reading ahead in the source pixel row for as long as the unconverted source image data bytes are the same as for those converted in the conversion cycle. The converted output position bits of the converted source pixels are dithered. Optionally, an attempt is made to generate a compressed data repeated run entry with a default to a literal run entry based upon dithering of only the converted source pixel output position bits and a count of repeating source pixels.

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Boise, ID, United States of America

Burton H Poppenga