Method and apparatus for processing data for a visual-output device with reduced buffer memory requirements

• US 5,506,944 A
• Filed: 06/06/1995
• Issued: 04/09/1996
• Est. Priority Date: 11/10/1992
• Status: Expired due to Term

• Current Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Original Assignee: Adobe Systems Incorporated (Adobe Inc.)
• Inventors: Gentile, Ronald S.
• Primary Examiner(s): Bayerl, Raymond J.
• Assistant Examiner(s): SAX, STEVEN PAUL
• Application Number:
  US08/486,133
• Time in Patent Office: 308 Days
• Field of Search: 358/296, 395/114, 395/115, 395/110, 395/111, 395/101, 395/116, 395/108
• US Class Current: 358/1.15
• CPC Class Codes: G06K 15/00 Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printersprinting or plotting combined with another operation, e.g. with conveying, G06K17/00
• CPC Class Codes: G06K 15/181 Receiving print data characterized by its formatting, e.g. particular page description languages
• CPC Class Codes: G06K 15/1851 parted in a plurality of segments per page
• CPC Class Codes: G06K 15/1865 by compressing the rasterized print data
• CPC Class Codes: G06K 2215/0065 Page or partial page composition
• CPC Class Codes: G06K 2215/0071 Post-treatment of the composed image, e.g. compression, rotation
• CPC Class Codes: G06T 11/60 Editing figures and text; Combining figures or text
• CPC Class Codes: G06T 9/005 Statistical coding, e.g. Huffman, run length coding
• CPC Class Codes: G06T 9/007 Transform coding, e.g. discrete cosine transform
• CPC Class Codes: H03M 7/30 Compression speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N; Expansion; Suppression of unnecessary data, e.g. redundancy reduction
• CPC Class Codes: H04N 1/41 Bandwidth or redundancy reduction by scanning H04N1/17 ; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00

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 programs 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.

Claims

1. A method of printing a two-dimensional page representation on a page having a maximum area, using a print system having at least one data memory coupled to at least one data processor and a print device coupled to at least one of the data processors, the page representation including a combination of text, graphic and image representation types, the method comprising the steps of:

inputting into a processor data defining the page representation as a combination of the different types of representations;

dividing the page into a plurality of contiguous parallel bands containing collectively the page representation;

identifying separate data for each band corresponding to the portion of the page representation contained in that band;

rasterizing the assigned data for each band;

determining the types of representations and boundaries of each type of representation contained in each band;

assigning the data for each representation type in each band to a region of that band corresponding to the boundaries of the representation of that type in that band;

providing a plurality of different algorithms for compressing data associated with corresponding different representation types;

providing at least one compression factor other than the representation type, which compression factor has a determinable value;

determining the value of each of the at least one compression factor;

selecting algorithms corresponding to the value of the compression factor and to the determined representation types and combinations of representation types for each region;

compressing the rasterized data for each region of each band with the selected algorithms;

storing the compressed data and associated information identifying the bands, representation types and combinations of representation types, and algorithms used to compress the associated data; and

sequentially for each band;

reading and decompressing the corresponding stored data; and

transmitting sequentially the decompressed data to the print device for printing the page representation.

2. A method according to claim 1 further comprising the steps of providing data defining a set of primitive elements having known representations, with each primitive element representing a portion of the page representation;

and the step of identifying further comprises assigning for each band primitive elements representative of the portion of the page representation in that region; and

the step of compressing comprises compressing the data corresponding to the assigned primitive elements in each region.

3. A method according to claim 1 wherein the regions of at least one band overlap and the step of dividing further includes dividing the regions of each band that overlap into at least one combination subregion corresponding to at least one combination of different representation types associated with the regions that overlap.

4. A method according to claim 3 wherein the step of selecting includes selecting at least one of the compression algorithms according to the at least one combination of different representation types;

and the step of compressing includes compressing data associated with the at least one combination subregion according to the selected at least one of the compression algorithms.

5. A method according to claim 1 wherein the step of providing the compression factor includes providing a plurality of compression factors comprising a target compression ratio, a target visual quality of the page representation, and a target computational complexity;

and the step of selecting includes selecting at least a first compression algorithm if at least one of the compression factors has a value that has a predetermined relationship to a first value.

6. A system for printing a two-dimensional page representation on a page having a maximum area, the page representation including a combination of text, graphic and image representation types, the system comprising:

a print device;

input means for inputting data defining the page representation as a combination of different types of representations;

data memory means for storing data representative of the page representation; and

computer means including program memory means for storing computer program instructions including a plurality of different algorithms for compressing the defining data associated with corresponding different representation types and instructions defining at least one compression factor in addition to representation type and having a value determinable in association with a page representation, and processing means coupled to the input means, print device, data memory means and 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 adjacent parallel bands containing collectively the page representation, the data identified for each band corresponding to the portion of the page representation contained in that band;

(b) rasterizing the assigned data for each band;

(c) determining the types of representations and boundaries of each type of representation contained in each band;

(e) determining the value of each of the at least one compression factor;

(f) assigning the data for each representation type in each band to a region of that band corresponding to the boundaries of the representation of that type in that band;

(g) selecting at least one algorithm for compressing the rasterized data for each region corresponding to the value of the at least one compression factor and to the determined representation type or combination of representation types;

(h) compressing the rasterized data for each band with the selected algorithms;

(f) storing the compressed data for each band and data identifying;

the bands, the regions of each band, the determined representation type or combination of representation types of each region, and the algorithms used to compress the data associated with each region; and

(g) after compressing the data, for each band, reading the corresponding stored data, decompressing the read data, and transmitting the decompressed data to the print device;

the print device being responsive to the transmitted data for printing the page representation.