JPH10260801A - Information processor and information processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform page binding by deciding bandwidth so that a plotting object and bound boundary may not overlap each other as much as possible. SOLUTION: A command analyzing part 1704 analyzes data string of a page description language that is received from a host, and an expansion processing part 1705 produces a plotting image in band memory 1710. A bandwidth data creation processing part 1709 calculates the size of an object by using data a bounding box and character line spacing and calculates bandwidth so that it may not overlap on an object. A clipping processing 1713 calculates intersection coordinate of the contour of the object and band boundary and updates it to a vector data string within a band range when a plotting object projects from the band range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus and an information processing method for performing a drawing process with a small memory capacity.

[0002]

2. Description of the Related Art Conventionally, in a printing system that outputs output information to a printing apparatus based on a printer driver of a host computer, when outputting output information created based on an application to a printer, a drawing command transmitted from an OS is used. Is output to the printer as a printer output control command based on the printer driver.

In the case of a printer having a page description language development function such as Post Script, a printer driver converts a drawing command of the OS into a page description language of the printer and transmits the command to the printer. An image is created, and the image data is sent to the printer engine to perform printing.

In the case of a printing system having a raster type printer which does not have a page description language developing function,
The printer driver develops an image on the host computer and transmits the image data to the printer.

In any case, there is a step of performing command analysis and expansion processing to create image data on the semiconductor memory before performing printing processing by the printer engine.

[0006] In the expansion processing, vector calculations such as affine transformation and linear approximation are performed on each object (drawing target: characters, figures, images, etc.) to generate a vector data string (display list). In the case of color printing, image processing in a format that can be printed by a printer engine is performed by performing pixel conversion processing such as color conversion processing and pseudo gradation processing.

By the way, in the case of color printing, a plurality of gradations (for example, 256 gradations for each color) are provided for each pixel in each of CMYK (C: cyan, M: magenta, Y: yellow, K: black).
In this case, the data amount of the image is 4 MB × 4 colors × 8 bits = 12 when the resolution is 600 DPI, the gradation is 8 bits for each color, and the maximum paper size is A4.
8 MB, and a huge page memory is required to store them. Further, even in the case of monochrome printing, 4 MB is required at a resolution of 600 DPI, and when the resolution becomes higher, the memory cost cannot be ignored. FIG. 16 shows a technique for suppressing a memory cost and forming an inexpensive printing system.
Page banding technology. As shown in FIG. 16A, the page banding uses a band memory having a storage capacity for one band divided into n in the sub-scanning direction instead of a full page memory having a storage capacity for one page of a document. The image data is created for each band based on the display list and transmitted to the printer engine.

[0008]

In the conventional page banding technique, since the band width is constant, there is a high probability that a drawing target object such as a character, a graphic, or an image overlaps the boundary of the band. FIG. 16 (b)
As shown in (1), it is necessary to perform rasterization by clipping processing, and in a document having a large number of objects, there is a problem that the overhead of the clipping processing increases and the throughput of the printing system becomes slow.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to minimize the overlap between a drawing target object and a band boundary.
An information processing apparatus and an information processing method for determining a bandwidth are provided.

[0010]

In order to achieve the above object, an information processing apparatus according to the present invention is an information processing apparatus for creating a drawing image by page banding, and includes a drawing object included in a document page. It is characterized by comprising means for calculating the size of the object and means for calculating the bandwidth according to the object size.

According to the above configuration of the present invention, since the bandwidth is set so as not to overlap the object to be drawn as much as possible, the overhead of clipping can be reduced and the throughput of the printing system can be improved.

By mounting the band memory and a processing circuit for rasterizing on the same LSI chip, these signal processes can be executed at high speed.

[0013]

Embodiments of the present invention will be described below.

FIG. 2 is a diagram for explaining the concept of the page banding method according to the present invention. FIG.
5 is a flowchart showing an outline of a processing flow of the present invention.

FIG. 3 is an explanatory diagram showing a method of determining a bandwidth using a bounding box.
FIG. 18 is a flowchart showing an outline of a processing flow for obtaining the size of the object. FIG. 5 is an explanatory diagram showing the binding box data. FIG.
4 shows the result of sorting the objects of FIG. 3 in the ascending order in the y direction. FIG. 7 is a flowchart illustrating the calculation of the bounding box of the overlapping object. FIG. 8 shows FIG.
8 is a processing result when the example of FIG. FIG.
9 is a flowchart illustrating bandwidth calculation. FIG.
12 are supplementary explanatory diagrams of the flowchart of FIG.

In the process of developing a page description language such as Post Script, coordinate data of a rectangle circumscribing an object called a bounding box shown in FIG. 2 is usually managed in order to efficiently perform clipping. In the present invention, as shown in FIG. 4, the size of the object is obtained using the data of the bounding box and the line spacing of the character (S401), and the bandwidth is calculated so as not to overlap the object (S402). Therefore, as shown in FIG. 2, the bandwidth is not always constant within the page because it depends on the object.

If the paper length direction is the y direction, the y-axis projections may overlap, as in object 2 and object 3 in FIG. If there is an overlap, as shown in FIG. 3, the overlapping objects are combined into one object, and a bounding box circumscribing the overlap object is obtained. For example, FIG. 3 shows the bounding box 1 of the object 2 and the object 3 as one overlapping object.

In order to obtain the object size in step S401, as shown in the flowchart of FIG. 18, first, bounding box data managed by the expansion processing is acquired (S1901). As shown in FIG. 5, the bounding box data includes coordinate data of an upper left point and a lower right point of a rectangle circumscribing the object when the upper left corner of the sheet is set as the origin.

In the development process of the page description language, a user coordinate system is used as a virtual coordinate system that always has a fixed relation to a page so that development can be performed regardless of the resolution characteristics of an output device. Vector operation processing such as affine transformation and linear approximation is basically performed on the user coordinate system. Immediately before rasterizing the expansion processing, coordinate conversion is performed from the user coordinate system to a device coordinate system in consideration of the output device resolution. . Although any coordinate system may be used in the present invention, it is assumed that coordinate conversion is performed so that the coordinate system of various variables shown in FIG.

After obtaining the bounding box data, next, the y at the upper left point of the bounding box data
The objects are sorted in the y direction in ascending order with respect to the coordinate values (S1902). FIG. 6 shows the result of sorting the objects of FIG. Next, based on the sorting result, y
Obtain objects overlapping in the direction and calculate the bounding box of the overlapping objects (S190)
3).

Here, step S1903 will be described in detail with reference to the flowchart of FIG. 7 using FIG. 3 as an example. First, in step S701, the number of objects (N) included in a page of a document is counted. In the case of FIG. 3, N = 4
It is. Then, each parameter is initialized. In step S702, objects overlapping in the y direction are extracted. If they overlap, the bounding box data of the overlapping object circumscribing the two overlapping objects is obtained. At this time, since the objects have already been sorted, it is not necessary to update the upper left point of the bounding box, and steps S705 to S707
Updates only the coordinates of the lower right point of the bounding box. In FIG. 3, the object 2 and the object 3 overlap, and the bounding box data is updated as a duplicate object 1 collectively. When the objects overlap, the two objects are reduced to one when the objects overlap. Therefore, the number of objects as the duplicate objects is smaller than the number of objects immediately after sorting, and the object number changes. Therefore,
Even if the objects do not overlap, step S703,
In step S704, the bounding box data is updated so that no inconsistency occurs in the object numbers.

By the above processing, for example, in the case of FIG. 3, the duplicate object data shown in FIG. 8 is obtained. Also,
The variable Num in the flowchart of FIG. 7 is set with the number of objects considering duplication as a result of this processing.

Next, step S4 in the flowchart of FIG.
The bandwidth calculation of 02 will be described in detail with reference to the flowchart of FIG.

First, in step S901, in addition to the margin (α) and the allowable bandwidth (Band.Permitted) shown in FIG. 3, each used variable such as a paper length (Paper.Length) and a band number (Band.No) is used. Is initialized. The margin α is for preventing the overlapping object's bounding box from overlapping the lower side of the band. The allowable bandwidth is
The bandwidth obtained from the mounted memory. The paper length is the length of the paper used for print output.

At steps S902 to S904, S,
The variable values of W and B are obtained. The variable S is the difference in y coordinate between the upper left point of the band and the upper left point of the overlapping object. Variable W
Is the height of the duplicate object. The variable B is S,
This is a provisional bandwidth determined by the sum of W and α.

Since the bandwidth cannot be larger than the allowable bandwidth, it is determined in step S905 whether the provisional bandwidth is larger than the allowable bandwidth.

As shown in FIG. 10, if the provisional bandwidth B is larger than the allowable bandwidth, in steps S909 to S912, the provisional bandwidth B is divided by the allowable bandwidth, and the result is set as the required bandwidth. .

If the provisional bandwidth B is smaller than the allowable bandwidth, in steps S906 to S908, the provisional bandwidth B is set to the required bandwidth.

As shown in FIG. 11, if the object does not exist on the page of the document, step S9
13 to S915, the range is divided by the allowable bandwidth,
Set the required bandwidth.

By the above processing, for example, bands 0 to 2 shown in FIG. 3 are determined. In addition, as a result of performing the above processing for one page, as shown in FIG. 12, the bandwidth of each band is obtained for Band.No.

FIG. 13 is an explanatory diagram showing a method of determining a bandwidth different from that of FIG. FIG. 15 is a flowchart illustrating a method of calculating a bandwidth using the line interval data.

When the object to be rendered is a character string as shown in FIG. 13, the bandwidth can be determined using the line spacing data RW. In this case, the size of the object is set to RW
Then, the bandwidth can be calculated in substantially the same manner as in the case of FIG. Using the flowchart of FIG.
A method of calculating a bandwidth using W will be described below.

First, in step S1501, the allowable bandwidth (Band.Permitted) and the paper length (Pap) shown in FIG.
er.Length) and other variables used such as band number (Band.No) are initialized.

In step S1502, the temporary bandwidth B is set to RW.

As in the case of FIG. 3, since the bandwidth cannot be larger than the allowable bandwidth, in step S1503,
It is determined whether the provisional bandwidth is larger than the allowable bandwidth. If the provisional bandwidth B is larger than the allowable bandwidth,
In steps S1507 to S1510, the provisional bandwidth B is divided by the allowable bandwidth, and the result is set as the required bandwidth.

If the provisional bandwidth B is smaller than the allowable bandwidth, in steps S1504 to S1506, the provisional bandwidth B is set to the required bandwidth.

Steps S1511 to S151 are performed to the extent that the object does not exist on the page of the document.
At 3, the range is divided by the allowable bandwidth to obtain the required bandwidth.

FIG. 15 shows the configuration of a color printing system to which the page banding method of the present invention is applied. FIG. 1 shows a printer controller L including a memory and a CPU.
It is a functional block diagram of SI. FIG. 17 is a flowchart showing a series of print processing of the print system of FIG.

The printer of the present color printing system has a function of developing a page description language.

In FIG. 15, reference numeral 1601 denotes a host computer for transmitting a drawing command described in a page description language. Reference numeral 1602 denotes a printer controller LSI1 which analyzes and renders the drawing command and transmits drawing image data to the printer engine 1603.
602. 1603 is a printer controller LS
A printer engine that prints an image on paper based on transmission data from I1602. 1604
Are input / output devices such as a hard disk, an operation panel, and a keyboard.

In FIG. 1, reference numeral 1701 denotes a host interface for connecting to a host computer.
Reference numeral 1702 denotes an I / O device interface for connecting to input / output devices such as a hard disk, a display panel, and a keyboard. Reference numeral 1703 denotes a printer engine interface for connecting to a printer engine. The command analysis unit 1704 analyzes the data string of the page description language received from the host, and
05 creates an executable command. Expansion processing unit 17
05 generates the drawing image in the band memory 1710 by executing the command. Display list creation unit 1
Reference numeral 706 creates a vector data sequence to be input to the rasterizing process. A rasterization processing unit 1707 paints characters and graphics based on the display list. The color processing unit 1708 performs gamma correction, color conversion, and pseudo gradation for each pixel of image data having gradation. The bandwidth data creation processing unit 1709 performs the processing shown in FIG.
The processing indicated by is performed. That is, the size of the object is obtained using the data of the bounding box and the line spacing of the character, and the bandwidth is calculated so as not to overlap the object. The affine transformation processing unit 1711 performs matrix operation processing such as translation, rotation, and scaling. The path construction processing unit 1712 calculates a vector data sequence in which the outline of a character or figure is approximated by a straight line. When the object to be drawn is out of the band range, the clipping processing unit 1713 obtains the coordinates of the intersection of the outline of the object and the band boundary and updates the vector data string within the band range. The gamma correction processing unit 1714 performs gamma correction, which is nonlinear density conversion. The color conversion processing unit 1715 uses R
Each density value on the GB surface is converted into each density value of CMYK. The pseudo gradation processing unit 1716 expresses the density values of multiple gradations of each surface of CMYK by area gradation.

According to the present invention, the LSI shown in FIG. 1 has a one-chip configuration equipped with the above-described functions including a memory, so that it is easy to increase the data width of data transfer between the units and to improve the transfer rate. Therefore, the processing performance can be greatly improved. The bandwidth data creation processing unit 1709 can set the allowable bandwidth by using the value of the memory capacity mounted on the LSI. Further, the memory for temporarily storing the data string of the page description language received from the host computer, the display list created by the display list creating unit 1706, and the like may be the same memory means as the band memory.

Next, the operation of the printing system of FIG. 15 and the operation of the printer controller LSI 1602 of FIG. 1 will be described with reference to the flowchart of FIG. First, step S18
In 01, color document data of an application is created on the host computer 1601. Since the color document data created by the application on the host computer 1601 is described by the drawing command of the OS of the host computer 1601, the printer driver converts the data into a page description language supported by the printer in step S1802. In step S1803, the printer manager transmits the converted color document data to the printer controller.

Generally, the color information used by the drawing command of the OS is of the RGB (red, green, blue) type, so that when printing, it is necessary to convert the color information into the CMYK type which is the color information of the color material of the printer. is there. This conversion is performed by the printer driver or by the controller if the printer controller has a color conversion function. In this embodiment, since the controller has a color conversion function, the color information is transmitted to the printer controller in RGB.

In step S1804, the host interface 1701 of the printer controller LSI 1602
Receives a page description language data string for one document. In step S1805, the command analysis unit 1704 analyzes the data sequence in order from the beginning, and sequentially creates commands executable by the expansion processing unit 1705. The expansion processing unit 1705 executes the command at the same time as the generation of the command, and the display list creation unit 1706 creates a display list in step S1806. In step S1807, in which a display list for one page is created, the bounding box data or line spacing data of all objects included in the page is obtained. Calculate the width.

The display list is updated to the band range by clipping in step S1809 based on the display list and the bandwidth data created in the above-described process, and rasterization processing (S1810) and color processing (S18) are performed.
1811), the engine transmission process (S1812) is repeated for the number of bands included in one page (S1813). Further, S1805 to S1 until all commands are processed.
813 is repeated to end the print processing of one document.

In the case of a laser printer, step S18
If the band development processing of 09 to S1811 is slower than the engine transmission processing of 1812, there is a problem of so-called picture omission in which printing is performed without drawing anything on paper in the slowed part. Therefore, the band expansion processing requires a higher speed than the engine speed. However, according to the present embodiment, such an inconvenience hardly occurs because the clipping overhead of the band expansion processing can be reduced.

In this embodiment, the processing for creating the bandwidth data is included in the processing of the printer controller, but may be included in the processing of the printer driver of the host computer.

[0049]

As described above, according to the present invention, since the bandwidth is set according to the drawing target object included in the page of the document, the overhead of clipping can be reduced and the small memory configuration for performing the page banding can be obtained. The printing system throughput is improved. In addition, since the expansion processing is performed at a high speed, a problem such as a missing image which occurs when the expansion processing is slower than the engine transmission is less likely to occur. In addition, high-speed signal processing can be realized by mounting the band memory and a circuit that executes signal processing on the same LSI.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a printer controller LSI.

FIG. 2 is a diagram for explaining the concept of a page banding method.

FIG. 3 is an explanatory diagram showing a method for determining a bandwidth.

FIG. 4 is a flowchart showing an outline of a processing flow of the present invention.

FIG. 5 is an explanatory diagram showing binding box data.

FIG. 6 shows a result of sorting objects in ascending order in the y direction.

FIG. 7 is a flowchart illustrating the calculation of a bounding box of an overlapping object.

8 is a processing result when the example of FIG. 3 is processed in FIG. 7;

FIG. 9 is a flowchart illustrating bandwidth calculation.

FIG. 10 is a supplementary explanatory diagram of the flowchart in FIG. 9;

FIG. 11 is a supplementary explanatory diagram of the flowchart in FIG. 9;

FIG. 12 is a supplementary explanatory diagram of the flowchart in FIG. 9;

FIG. 13 is an explanatory diagram showing a method of determining a bandwidth different from that of FIG. 3;

FIG. 14 is a flowchart illustrating a method of calculating a bandwidth using line spacing data.

FIG. 15 is an embodiment of a color printing system to which the page banding method of the present invention is applied.

FIG. 16 is an explanatory diagram of a conventional page banding technique.

FIG. 17 is a flowchart showing a series of print processing of the print system of FIG. 16;

FIG. 18 is a flowchart illustrating an outline of a processing flow for obtaining the size of an object.

[Explanation of symbols]

1601 host computer, 1602 printer controller LSI, 1603 printer engine, 16
04 I / O device, 1701 Host interface section, 1702 I / O device interface section, 1703 Printer engine interface section,
1704: Command analysis unit, 1705: Expansion processing unit, 1
Reference numeral 706: display list creation unit, 1707: rasterization processing unit, 1708: color processing unit, 1709: bandwidth data creation processing unit, 1710: band memory, 171
DESCRIPTION OF SYMBOLS 1 ... Affine conversion processing part, 1712 ... Path construction processing part, 1713 ... Clipping processing part, 1714 ... Gamma correction processing part, 1715 ... Color conversion processing part, 1716 ... Pseudo gradation processing part.

Claims (9)

[Claims] An information processing apparatus for creating a drawing image by page banding, wherein the information is managed by changing a bandwidth according to the content of a document. 2. An information processing apparatus for creating a drawing image by page banding, wherein the information is managed by changing a bandwidth according to a size of a drawing target object included in a document. 3. An information processing apparatus for creating a drawing image by page banding, comprising: means for calculating a size of a drawing target object included in a page of a document;
An information processing apparatus, comprising: means for calculating a bandwidth according to the object size. 4. An information processing apparatus for creating a drawing image by page banding, wherein a bandwidth used for drawing changes within a range of an allowable bandwidth determined from a mounting memory. 5. The information according to claim 3, wherein the means for determining the size of the object to be drawn determines the coordinate value of the bounding box as one overlapping object for objects whose projections on the y-axis overlap. Processing equipment. 6. The method according to claim 5, wherein, when calculating the bandwidth, the sum of the height of the overlapping object, the y coordinate difference between the upper left point of the band and the upper left point of the overlapping object, and a fixed fixed value α. An information processing device characterized by a bandwidth. 7. An information processing apparatus according to claim 3, wherein when the object to be rendered is a character string, the bandwidth is determined using line spacing data. 8. An information processing apparatus according to claim 6, wherein when the obtained bandwidth is larger than the allowable bandwidth, the bandwidth is divided by the allowable bandwidth. 9. An information processing apparatus for creating a drawing image by page banding, comprising: means for obtaining a size of a drawing target object included in a page of a document;
An information processing apparatus comprising: means for calculating a bandwidth according to the object size; and a memory for storing the drawing target object based on the calculated bandwidth.