Image processing apparatus, drawing processing method, and computer program

• US 20040027617A1
• Filed: 03/18/2003
• Published: 02/12/2004
• Est. Priority Date: 03/18/2002
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Ishihara, Hiroshi
• Granted Patent: US 7,369,277 B2
• Time in Patent Office: Days
• US Class Current: 358/3.13
• 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

Abstract

A drawing instruction processor refers to a bitmap line table that shows whether the bit arrays in the row unit are the same in the order of concentrations. The drawing instruction processor decides whether dither patterns to be used for the adjacent specified drawing ranges are the same, by referring to the BLT, and links the drawing ranges to which the same pattern can be applied. Based on this, the drawing processor carries out a batch writing using a dither pattern prepared in advance into the specified range in the page memory. The dither pattern to be used for the drawing is prepared by linking a plurality of the same basic patterns to have a length corresponding to the length of the word length. As a result of such an arrangement, it is possible to achieve a high-speed processing.

Claims

1. An image processing apparatus comprising:

an input unit that inputs a graphic drawing instruction based on image data;

a drawing processing unit that obtains and holds a bitmap pattern corresponding to the specified concentration, based on the input graphic drawing instruction to fill an optionally specified range in a page memory using a specified concentration, calculates a coordinate position of holding the bitmap pattern corresponding to the specified coordinate position in the page memory, and writes the drawing data using the bitmap pattern of the corresponding specified concentration in a tiled pattern, into the specified range in the page memory, following the obtained coordinate position; and

an output unit that outputs the drawing data written in the page memory, to an output apparatus, wherein

the drawing processing unit decides whether the bitmap patterns to be used in adjacent specified drawing ranges are the same, links the specified drawing ranges to which the same bitmap pattern can be applied based on a result of the decision made, specifies again the drawing range in the page memory, and batch writes the bitmap pattern into the adjacent specified drawing ranges.

2. The image processing apparatus according to claim 1, wherein

the bitmap pattern to be used for the batch writing is a pattern in which the bitmap forms a matrix shape, and a part of the same row has the same bit array in the order of concentrations, and the pattern of the same bit array is held at any one of a low concentration side and a high concentration side, and

the drawing processing unit specifies a bitmap pattern corresponding to a specified concentration, by using a conversion table that a non-holding concentration side uses to refer to the pattern of the same bit array.

3. The image processing apparatus according to claim 2, wherein the image processing apparatus holds the conversion table in advance.

4. The image processing apparatus according to claim 2, further comprising a conversion table preparing unit that prepares the conversion table when the apparatus starts up.

5. The image processing apparatus according to claim 1, further comprising:

a word boundary bitmap pattern preparing unit that prepares a word boundary bitmap pattern, which has repetitions of the bitmap patterns corresponding to the concentrations, to have a length that coincides with a word boundary, wherein

the drawing processing unit uses the pattern prepared by the word boundary bitmap pattern preparing unit when batch writing the pattern into the page memory based on the repetitions of the same bitmap pattern following the drawing instruction to draw a plurality of pixels.

6. The image processing apparatus according to claim 5, wherein the bitmap pattern has a bitmap in a matrix shape, and the word boundary bitmap pattern prepared by the word boundary bitmap pattern preparing unit for each row are stored into a storage area of a continuous address.

7. The image processing apparatus according to claim 5, further comprising a unit that caches the word boundary bitmap pattern that the word boundary bitmap pattern preparing unit has prepared, using a combination of concentrations and rows as a unit.

8. The image processing apparatus according to claim 7, further comprising:

a cache managing unit that adds a concentration and a bitmap pattern row coordinate as attribute information to the cached word boundary bitmap pattern, and manages at least one of registration, abandoning, and searching of the word boundary bitmap pattern by using the attribute information.

9. The image processing apparatus according to claim 8, wherein the cache managing unit clears the cache memory when the word boundary bitmap pattern overflows the cache memory in excess of a quantity specified in advance as a total memory capacity necessary for the caching.

10. The image processing apparatus according to claim 1, wherein

at the time of drawing the plurality of adjacent pixels, the drawing processing unit draws the pixels for each line of a main scanning direction in the address order of the page memory.

11. The image processing apparatus according to claim 1, wherein the concentration specified by the graphic drawing instruction is a gradation expressed in a predetermined number of bits, and the bitmap pattern corresponding to the specified concentration is a dither pattern that expresses a pseudo gradation.

12. The image processing apparatus according to claim 1, wherein the image processing apparatus prepares a dither pattern for each kind of pixels to be drawn, and has a unit that changes over the dither patterns corresponding to the kings of pixels included in the graphic drawing instruction.

13. The image processing apparatus according to claim 11, wherein

the concentration specified by the graphic drawing instruction is a color concentration of each of cyan, magenta, yellow, and blacK (CMYK) colors that are used to draw a color image, and the bitmap pattern corresponding to the specified concentration is a dither pattern used for each of the colors to express a pseudo gradation.

14. The image processing apparatus according to claim 11, further comprising a unit that prepares the dither pattern based on a threshold value table.

15. The image processing apparatus according to claim 14, further comprising a conversion table preparing unit that prepares a conversion table based on the threshold value table.

16. The image processing apparatus according to claim 5, wherein the drawing processing unit decides whether the specified concentrations included in the drawing instruction to draw the plurality of adjacent pixels are the same, and draws these pixels by using the word boundary bitmap pattern when it is decided that the specified concentrations are the same.

17. The image processing apparatus according to claim 16, wherein the drawing processing unit decides whether the specified concentrations are the same in the graphic drawing instruction that specifies a clip area, decides whether the clip area is in the unit of pixels that have been decided to have the same concentrations, and draws the clip area based on a result of this decision.

18. A drawing processing method comprising:

an input step of inputting a graphic drawing instruction based on image data; and

a drawing processing step of obtaining and holding a bitmap pattern corresponding to the specified concentration, based on the input graphic drawing instruction to fill an optionally specified range in a page memory using a specified concentration, calculating a coordinate position of holding the bitmap pattern corresponding to the specified coordinate position in the page memory, and writing the drawing data using the bitmap pattern of the corresponding specified concentration in a tiled pattern, into the specified range in the page memory, following the obtained coordinate position, wherein

the drawing processing step is for deciding whether the bitmap patterns to be used in adjacent specified drawing ranges are the same, linking the specified drawing ranges to which the same bitmap pattern can be applied based on a result of the decision made, specifying again the drawing range in the page memory, and batch writing the bitmap pattern into the adjacent specified drawing ranges.

19. The drawing processing method according to claim 18, wherein

the bitmap pattern to be used for the batch writing is a pattern in which the bitmap forms a matrix shape, and a part of the same row has the same bit array in the order of concentrations, and the pattern of the same bit array is held at any one of a low concentration side and a high concentration side, and

the drawing processing step is for specifying a bitmap pattern corresponding to a specified concentration, by using a conversion table that a non-holding concentration side uses to refer to the pattern of the same bit array.

20. The drawing processing method according to claim 18, further comprising:

a word boundary bitmap pattern preparing step of preparing a word boundary bitmap pattern, which has repetitions of the bitmap patterns corresponding to the concentrations, to have a length that coincides with a word boundary, wherein

the drawing processing step is for using the pattern prepared at the word boundary bitmap pattern preparing step, at the time of batch writing the pattern into the adjacent specified drawing ranges in the page memory based on the repetitions of the same bitmap pattern following the drawing instruction to draw a plurality of pixels.

21. The drawing processing method according to claim 20, further comprising:

a step of adding a concentration and a bitmap pattern row coordinate as attribute information to the word boundary bitmap pattern prepared at the word boundary bitmap pattern preparing step, caching the added pattern, and managing at least one of registration, abandoning, and searching of the word boundary bitmap pattern by using the attribute information.

22. The drawing processing method according to claim 18, wherein at the time of drawing the plurality of adjacent pixels, the drawing processing step is for drawing the pixels for each line of a main scanning direction in the address order of the page memory.

23. The drawing processing method according to claim 20, wherein the drawing processing step is for deciding whether the specified concentrations included in the drawing instruction to draw the plurality of adjacent pixels are the same, and batch writing these pixels by using the word boundary bitmap pattern when it is decided that the specified concentrations are the same.

24. A computer program containing instructions, which when executed on a computer, causes the computer to realize:

an input step of inputting a graphic drawing instruction based on image data; and

a drawing processing step of obtaining and holding a bitmap pattern corresponding to the specified concentration, based on the input graphic drawing instruction to fill an optionally specified range in a page memory using a specified concentration, calculating a coordinate position of holding the bitmap pattern corresponding to the specified coordinate position in the page memory, and writing the drawing data using the bitmap pattern of the corresponding specified concentration in a tiled pattern, into the specified range in the page memory, following the obtained coordinate position, wherein

the drawing processing step is for deciding whether the bitmap patterns to be used in adjacent specified drawing ranges are the same, linking the specified drawing ranges to which the same bitmap pattern can be applied based on a result of the decision made, specifying again the drawing range in the page memory, and batch writing the bitmap pattern into the adjacent specified drawing ranges.