Canon Kabushiki Kaisha

Krzysztof Adam Koziarz

Paul William Morrison

Stuart James Warren

Tatiana Dudina

Christopher Keith Dowell Wade

Sergey Derevyanko

Matthew Thomas Imhoff

A method of rendering pages in a graphics rendering system operating in a multi-threaded mode. A plurality of pages to be rendered is received in the graphics rendering system, each of the plurality of pages having associated producing tasks and consuming tasks. Upon identifying one or more failed consuming tasks from the associated consuming tasks, generation of further producing tasks are suspended. Data associated with the identified one or more failed consuming tasks are processed by switching from the multi-threaded mode to a single threaded mode using memory freed in response to completion of processing of one or more of the remaining plurality of consuming tasks. One or more of the plurality of pages associated with the processed data are rendered.

Memory error recovery for complex page RIP

A method of controlling memory usage in a graphics rendering system. The method comprises converting a plurality of layers of graphical objects to an intermediate format representation, the layers being formed by grouping the graphical objects into a plurality of layers based on a first complexity threshold; and in response to detecting a memory shortage condition in execution of the graphics rendering system, determining a second complexity threshold based on the detected memory shortage condition, the second complexity threshold being lower than the first complexity threshold. The method also comprises identifying a layer of the plurality of layers based on the second complexity threshold, the identified layer being different to a layer which triggered the memory shortage condition, and converting the identified layer of graphical objects to the intermediate format representation to release memory occupied by graphical objects of the identified layer.

Method, apparatus and system for rendering a graphical representation within limited memory

A method for managing memory use in a graphics processing system receives a plurality of objects to be reproduced on an output medium, the output medium being divided into a plurality of bands. Objects falling within a band are stored in a corresponding local band memory and shared objects intersecting the band and at least one other band in at least one shared memory arena. Each shared memory arena is associated with a band counter defining the number of bands referencing said shared memory arena. The local band memory is associated with a data structure storing a shared memory arena identifier of the at least one shared memory arena where the shared objects intersecting the band are stored. The method facilitates release of the at least one shared memory arena in response to rasterizing the band selected for rasterizing based on the plurality of shared memory arena identifiers.

Y-Z banding/layering for complex page rip

A method of generating a region-based representation of a document is disclosed. A global compositing sequence is generated based on a predetermined rule, using fill data and at least one compositing operation associated with a plurality of objects of the document, to form an object-based representation of the document. The region-based representation of the document is generated based on a further compositing sequence determined for regions formed using the object-based representation. The method also determines whether at least one of the regions satisfies the predetermined rule using a relative arrangement of the objects in the object-based representation. Where the region satisfies the predetermined rule, a reference to the global compositing sequence is created. Where the region does not satisfy the predetermined rule, a local compositing sequence is generated using fill data and compositing operations associated with the objects contributing to the region.

Method, apparatus and system for generating an intermediate region-based representation of a document

A page description language representation of the page is received, the page description language representation having a plurality of sequential graphic objects ordered by drawing order. One or more groups of sequentially adjacent graphic objects of the plurality of sequential objects is formed according to the drawing order. An intermediate representation for each of the groups is generated, the intermediate representation comprising a set of regions where each region of the set of regions is associated with a set of operations required to render at least one of the adjacent graphic objects of one of the groups that intersect the region. An adjacently located set of the intermediate representations is merged to render the page.

Method, apparatus and system for determining a merged intermediate representation of a page

A method of encoding an edge of a graphical object. The edge is segmented into a plurality of straight segments. A sequence of offset values representing one of the plurality of segments from a starting position, is determined. At least one of the offset values in the sequence is modified to obtain a modified sequence of offset values. The method determines a precision level at which the modified sequence is to be encoded to represent the segment. The precision level determines a size of a portion of offset values to be repeated in the sequence of offset values.

Encoding of rasterised graphic objects

An image compression algorithm () and complementary decompression algorithm () are disclosed. The compression algorithm () maintains a set of reference points (and), each reference point having a predetermined spatial relationship with a current pixel (). An adjustment along scanlines of the reference points is determined. Each of the reference points (and) is then adjusted by the determined adjustment. A search for a match between one of the strings of consecutive previously scanned pixels including one of the adjusted reference pixels and the string of consecutive pixels including the current pixel is then conducted, and if a match is found, then an identifier for the reference pixel included in the match and the length of the matching string of consecutive pixels are encoded to an output stream.

Growing community of inventors

Denistone, Australia

Krzysztof Adam Koziarz