Method and apparatus for processing data for a visual-output device with reduced buffer memory requirements
First Claim
1. A method of producing a page representation including at least two representation types on a page by a raster output device, the method comprising the steps of:
- receiving data defining the page representation;
dividing the page into a plurality of contiguous regions containing collectively at least a portion of the page representation;
identifying separate data for each region corresponding to the portion of the page representation contained in that region;
determining at least one type of representation or combination of types of representations for the portion of the page representation defined by the data associated with each of the regions containing data;
rasterizing the identified data for each of the regions containing data;
providing a plurality of different algorithms for compressing the data associated with corresponding different representation types and combinations of representation types;
selecting algorithms corresponding to each of the determined representation types and combinations of representation types for each region;
compressing the rasterized data for each region with an algorithm corresponding to each of the determined types of representations for that region;
storing the compressed data for each region; and
serially for each region, reading the stored data associated with the region, decompressing the read data, and transmitting the decompressed data to the raster output device.
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Abstract
A two-dimensional page representation to be printed has a combination of text, graphic and image representation types. A data memory stores data representative of the page representation. A program memory stores program instructions including a plurality of different algorithms for compressing data associated with corresponding different representation types and their combinations. A processor is coupled to the data and program memories for (a) identifying separate data for each of a plurality of regions containing collectively the page representation, with the data for each region corresponding to the portion of the page representation contained in that region; (b) determining the types of representations and boundaries of each type of representation and the combinations of types contained in each region; (c) rasterizing and compressing the data associated with the determined types of representations for each region with algorithms based on selected compression factors; (d) storing sequentially the compressed data for each region; and (e) when needed for printing, sequentially for each region, reading the corresponding stored data, decompressing the read data, and transmitting the decompressed data to the print device for printing.
143 Citations
23 Claims
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1. A method of producing a page representation including at least two representation types on a page by a raster output device, the method comprising the steps of:
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receiving data defining the page representation; dividing the page into a plurality of contiguous regions containing collectively at least a portion of the page representation; identifying separate data for each region corresponding to the portion of the page representation contained in that region; determining at least one type of representation or combination of types of representations for the portion of the page representation defined by the data associated with each of the regions containing data; rasterizing the identified data for each of the regions containing data; providing a plurality of different algorithms for compressing the data associated with corresponding different representation types and combinations of representation types; selecting algorithms corresponding to each of the determined representation types and combinations of representation types for each region; compressing the rasterized data for each region with an algorithm corresponding to each of the determined types of representations for that region; storing the compressed data for each region; and serially for each region, reading the stored data associated with the region, decompressing the read data, and transmitting the decompressed data to the raster output device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A system for producing a page representation comprising:
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a raster output device; input means for receiving data defining the page representation; at least one data memory means for storing raster data representative of the page representation; and at least one computer means including program memory means for storing computer program instructions including a plurality of different algorithms for compressing data and at least one compression factor having a determinable value, and processing means coupled to the input means, the raster output device, the data memory means and the program memory means for executing the stored program instructions, the processing means being responsive to input data for (a) identifying separate data for each of a plurality of regions containing collectively the page representation, the data for each region corresponding to the portion of the page representation contained in that region;
(b) determining the value of the at least one compression factor for the data identified for at least one of the regions;
(c) rasterizing the identified data for each region containing data;
(d) selecting at least one compression algorithm for compressing the data identified for each region, including selecting at least one algorithm for the at least one of the regions corresponding to the value of the at least one compression factor;
(e) compressing the data for each region containing data with the selected at least one algorithm;
(f) storing the compressed data for each region containing data; and
(g) after compressing the data, serially, for each region, reading the stored data associated with the region, decompressing the read data, and transmitting the decompressed data to the raster output device;the raster output device being responsive to the decompressed data for producing the page representation.
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Specification