JP2010157040A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quicken drawing processing by deleting the other object graphics included in one object graphic. <P>SOLUTION: An image forming apparatus is configured of an object list creation part 303 for creating an object list from one or more object graphics included in print data, and for storing it according to a prescribed drawing sequence; an object list deletion part 304 for contrasting a previously drawn object graphic with an object graphic drawn later, and for, when the previously drawn object graphic is included in the object graphic drawn later, deleting the object list from that corresponding to the previously drawn object graphic; and a page rasterization part 306 for performing image formation based on the object graphic corresponding to the object list which has not been deleted by the object list deletion part 304. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that speeds up drawing processing by thinning out object graphics that are not drawn.

In an image forming apparatus such as a printer or a scanner, the processing speed is remarkably improved by increasing the speed of a processor, increasing the capacity of a memory, improving data compression technology, and the like.
However, since high-end image forming apparatuses are expensive, the number of users is limited. In reality, there are very few users who can benefit from high speed.

For this reason, there has been proposed an image processing apparatus aimed at improving the speed of bitmap processing by reducing the storage area of an intermediate list (display list) formed before drawing (for example, Patent Document 1).
According to such an image processing apparatus, it is possible to realize high speed while following the conventional apparatus configuration.
FIG. 7 is an explanatory diagram for explaining a conventional drawing process used in the image forming apparatus according to Patent Document 1.
As shown in the figure, the image processing apparatus described in Patent Document 1 has an intermediate list when a drawing area of a graphic 701 drawn first is included in a drawing area of a graphic 702 drawn later. The intermediate list of the figure 701 is deleted from the storage means.
That is, the speed is increased by reducing the number of drawing objects.

JP 2001-88367 A (first page, FIG. 1)

However, in the image processing apparatus as described above, since it is necessary to determine whether or not all the intermediate lists are included, the following problem has occurred.
That is, since the required number of processes increases synergistically in proportion to the number of intermediate lists to be compared, a phenomenon occurs in which the processing speed decreases when the number of intermediate lists is large.
For example, FIG. 8 is an explanatory diagram for explaining a problem in a conventional drawing process.
Here, in the intermediate list shown in the figure, it is assumed that the drawing order is set in the order of the figure 801, the figure 802,.
For this reason, for example, for the graphic 802, it is determined whether or not the graphic completely includes the graphic 801.
Further, regarding the graphic 803, it is determined whether or not the graphic completely includes the graphic 801 and the graphic 802.

Therefore, when drawing n figures, it is necessary to perform the above inclusion determination n · (n−1) / 2 times.
Moreover, in the intermediate list, if the target graphic is complicated, it is divided into simple primitive graphics for the convenience of calculation, so the number of determinations further increases.
For example, when one figure in the intermediate list is a star like the figure 803, it is necessary to make an inclusion determination for each of the figures 803a to 803e, which increases the processing burden accordingly.
As described above, the simplification of the drawing process performed to reduce the burden of the drawing process increases the load due to the determination process corresponding to the pre-processing, and instead reduces the drawing speed.

  The present invention has been proposed in order to solve the problems of the conventional techniques as described above, and by effectively deriving object figures unnecessary for drawing from the object list and deleting them in advance, An object of the present invention is to provide an image forming apparatus that prevents the drawing speed from being lowered and realizes a smooth drawing process.

  In order to achieve the above object, an image forming apparatus according to the present invention creates an object list from one or more object figures included in print data, and stores the object list in accordance with a predetermined drawing order; An object figure corresponding to an object figure drawn ahead when the object figure drawn earlier is included in the object figure drawn later after comparing the object figure drawn later and the object figure drawn later An object list deleting unit that deletes a list, and an image forming unit that forms an image based on an object graphic corresponding to the object list that has not been deleted by the object list deleting unit.

  According to the image forming apparatus of the present invention, the drawing burden can be reduced and the drawing speed can be improved.

  A preferred embodiment of an image forming apparatus according to the present invention will be described below with reference to FIGS.

[First embodiment]
The image forming apparatus according to the first embodiment of the present invention uses an object list created from an object graphic extracted from print data to be drawn in accordance with a predetermined drawing order based on a print command described in the print data. By storing, object figures are sequentially connected in a list structure.
The image forming apparatus creates a display list (object graphics divided into primitive graphics) based on the object list, and performs drawing through bitmap processing.
Therefore, unlike the conventional image forming apparatus in that the object list is created in the previous stage of creating the display list, it is also possible to simplify the drawing process using this object list. It is a feature of the forming apparatus.

First, the object list according to the present embodiment will be described below with reference to FIGS.
The object list is a coded object graphic attribute. Here, as attributes, there are position coordinates, width, height, drawing command code, and the like necessary for drawing a figure, and the object list includes information necessary for drawing the corresponding object figure. Accordingly, the object graphic is drawn based on the corresponding object list.
FIG. 1 is a schematic diagram showing the object list according to the present embodiment based on the drawing order of corresponding object graphics.
That is, as shown in FIG. 1A, in the order of drawing the object graphic, each object is represented as (n−1) th object list 101 → nth object list 102 → (n + 1) th object list 103. The list is stored in chronological order.

Here, in the present embodiment, an example will be described of processing when an object graphic drawn first is included in an object graphic drawn later.
FIG. 2 is an explanatory diagram for explaining processing when one object graphic is included in another object graphic in the present embodiment.
Here, FIG. 2A shows an example in which an object graphic 201 (triangle) drawn first is included in an object graphic 202 (trapezoid) drawn thereafter.
As shown in the figure, when both the object graphic 201 and the object graphic 202 are drawn, the object graphic 201 is overwritten by the object graphic 202, so the object graphic actually is as shown in the left figure of FIG. 201 is never displayed.
Therefore, in such a case, even if the object graphic 201 is excluded from the drawing target, there is no problem in drawing, and this makes it possible to omit drawing processing such as bitmap processing.
On the other hand, when color mixing or transparency is set, it is necessary to display the object graphic included as shown in the right diagram of FIG.
However, such special figures can be used to reduce the burden of inclusion determination, which is the preprocessing, by excluding them from the above omission (see the second embodiment).

  The image forming apparatus according to the present embodiment uses such a principle. As shown in FIG. 1, when an object graphic 102 drawn first is included in an object graphic 103 drawn later, The object list corresponding to the object graphic 102 is deleted. As a result, the object graphic 102 is excluded from the drawing target, thereby speeding up the drawing process (see FIG. 1B).

Next, the configuration of the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a block diagram illustrating the configuration of the image forming apparatus according to the present embodiment. 3, the image forming apparatus according to the present embodiment includes a print data reception storage unit 301, a PDL analysis unit 302, an object list creation unit 303, an object list deletion unit 304, a display list creation unit 305, and a page rasterization unit 306. . Each of these components is realized when a control unit such as a CPU (Central Processing Unit) provided in the image forming apparatus executes a predetermined program.
The print data reception storage unit 301 buffers print data received from a host computer or the like in a storage unit such as a memory.
The PDL analysis unit 302 analyzes the print data buffered by the print data reception storage unit 301 by a so-called interpreter. Specifically, the object graphic is extracted from the print data, and the attributes set for each object graphic are extracted.

The object list creation unit 303 creates an object list based on the attribute of the object graphic analyzed and extracted by the PDL analysis unit 302, and stores it in a storage unit such as a memory according to a predetermined drawing order. (Corresponds to the object list creation means of the present invention).
The object list deletion unit 304 determines whether or not an object graphic drawn first is included by an object graphic drawn later (this determination is hereinafter referred to as inclusion determination). As a result of the inclusion determination, when the object graphic drawn first is included by the object graphic drawn later, the object list corresponding to the object graphic drawn first is deleted (this book) This corresponds to the object list deletion means of the invention.)

The display list creation unit 305 divides the object graphic into simple shapes (primitive graphics) and stores them as a display list in order to efficiently page rasterize the object graphic corresponding to the object list.
The page rasterizing unit 306 converts the graphic data stored in the display list into a bitmap and forms an image (corresponding to the image forming means of the present invention).

As described above, according to the image forming apparatus of this embodiment, a plurality of object figures to be drawn are extracted from print data, and an object list is created.
Then, the inclusion determination is performed for the object graphic corresponding to the created object list.
As a result, when the object graphic drawn first is included in the object graphic drawn later, the object list corresponding to the object graphic drawn first is deleted.
Also, such inclusion determination is not performed in units of primitive graphics as in the prior art, but is performed in units of object graphics.
Therefore, the drawing speed such as bitmap processing can be improved, and an image forming apparatus excellent in convenience can be realized.

[Second Embodiment]
Next, an image forming apparatus according to the second embodiment of the present invention will be described.
The image forming apparatus according to this embodiment is roughly the same as that of the first embodiment, but the object list creation unit 303 calculates the bounding box area of each object graphic (as the bounding box area calculation unit of the present invention). And the maximum rectangular area is further calculated (operation as the maximum rectangular area calculating means of the present invention), and the object list deletion unit 304 is different in that inclusion determination is performed for these areas.
Specifically, when the bounding box area of the object graphic drawn first is included in the maximum rectangular area of the object graphic drawn later, the object list deletion unit 304 corresponds to the object graphic drawn first. The drawing process is simplified by deleting the object list.

FIG. 4 is an explanatory diagram for explaining the bounding box area, the maximum rectangular area, and the inclusion determination using these according to the present embodiment.
First, the bounding box area is the smallest rectangular area that encompasses the entire object graphic.
For example, as shown in the left diagram of FIG. 4A, when an object graphic 401 is targeted, a minimum rectangular area 402 circumscribing the object graphic 401 is referred to as a bounding box area.

On the other hand, the maximum rectangular area is an area formed inside an object graphic that does not intersect each other and that does not have a concave portion and a convex portion, and includes two parallel sides that form the object graphic and its end points. A rectangular region formed by a perpendicular line.
For example, as shown in the right diagram of FIG. 4A, when an object graphic 403 is targeted, a rectangular area 404 inscribed in the object graphic 403 is referred to as a maximum rectangular area.
Therefore, as in the example shown in FIG. 4B, an object graphic that does not have two parallel sides, an object graphic that intersects with each other, an object graphic that has a concave portion or a convex portion, etc. It is processed as an object graphic that does not have a region and is not subject to inclusion determination. That is, such a non-target graphic is excluded from the inclusion determination processing target in advance, thereby suppressing the burden of inclusion determination according to the present embodiment.

The position information of the bounding box area and the maximum rectangular area obtained in this way is stored in advance in a memory or the like, and used for subsequent inclusion determination and deletion of the object list according to the determination.
For example, as shown in FIG. 4C, the bounding box area 402 of the object figure 401 (triangle) drawn first is compared with the maximum rectangular area 404 of the object figure 403 (trapezoid) drawn thereafter, When the bounding box area 402 is completely covered by the maximum rectangular area 404 as shown in the left figure of FIG. 4C, the object list corresponding to the object graphic 401 is deleted.
On the other hand, when the bounding box area 402 is not completely included in the maximum rectangular area 404 as shown in the right figure of FIG. 4C, the object list corresponding to the bounding box area 402 is excluded from the deletion target.

  As described above, by using the bounding box area and the maximum rectangular area, it is possible to reduce a burden related to area specification and inclusion determination, and it is possible to speed up the drawing process.

Next, an operation procedure of the image forming apparatus according to the second embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a flowchart showing an operation procedure of the image forming apparatus according to the second embodiment of the present invention.

As shown in FIG. 5, first, in the image forming apparatus, the print data reception storage unit 301 receives print data from a host computer or the like (not shown) (S501).
Then, the PDL analysis unit 302 interprets the drawing command described in the received print data (S502). Specifically, an object graphic constituting print data and its attribute data (position information, etc.) are acquired.
Next, the object list creation unit 303 performs conversion processing such as position determination, enlargement / reduction, and transformation of the acquired object graphic, and then creates an object list corresponding to the object graphic and stores it in the memory. (S503).

Here, the object list deletion unit 304 determines whether or not the object graphic corresponding to the object list is a special graphic that can be excluded from inclusion determination (S504). Specifically, it is determined whether or not the object graphic is a target of color mixing or transmission.
As a result of step S504, when the object graphic to be processed is not the target of color mixing / transmission (S504: NO), the object list creation unit 303 calculates the bounding box area of the object graphic based on the position information of the object graphic. (S505). The object list creation unit 303 adds the obtained bounding box area to the object list in association with the object graphic and stores it.

  Subsequent to step S505, the object list creation unit 303 calculates the maximum rectangular area of the object graphic based on the position information of each object graphic (S506). The object list creating unit 303 adds the obtained maximum rectangular area to the object list in association with the object graphic and stores it.

As a result of step S504, when the object graphic to be processed is a transparent or mixed color target (S504: YES), the object list creation unit 303 is excluded from the inclusion determination target as a target including another object graphic. A code or the like that can be identified is added to the object list and stored in association with the object graphic (S507).
Specifically, a flag or the like indicating that the object list is not included is added to the object list.
Needless to say, even if an object graphic is a target of transparency or color mixing, it can be included in another object graphic.
Further, the processing from step S503 to step S507 is repeatedly executed until the page discharge command is executed.

Next, the object list deletion unit 304 determines whether or not the object figure located at the i-th drawing position (where i = 2,..., Indicates the number of object figures) includes other object figures. Determination is made (S508).
Specifically, if the i-th object graphic does not correspond to the object list to which a code or the like that can be identified as being out of inclusion determination in step S507 is added, the i-th object graphic is another It is determined that the object includes the object graphic.

As a result of step S508, when the i-th object graphic is a target including other object graphic (S508: YES), the object list deletion unit 304 determines that the j-th (where j = 1,..., I-1). ) Is determined whether it is a target included in the i-th object graphic (S509). (In the second embodiment, regardless of the result of step S507, it is determined that the j-th object graphic is a target included in the i-th object graphic. (The same applies to the first embodiment.) ))
As a result of step S509, when it is determined that the jth object graphic is a target included in the ith object graphic (S509: YES), the object deletion unit 304 sets the bounding box area B of the jth object graphic. The maximum rectangular area R _i of _j and the i-th object figure is compared (step S510).

  If it is determined in step S508 that the i-th object graphic is not a target that includes another object graphic (S508: NO), the process of loop 3 is performed for the next object graphic without performing the inclusion determination. If it is determined in step S509 that the j-th object graphic is not a target included in another object graphic (S509: NO), the process of loop 4 is performed for the next object graphic without performing the inclusion determination.

In response to step S510, the object list deletion unit 304 determines whether or not the maximum rectangular area R _i includes the bounding box area B _j (step S511).
As a result, when it is determined that the bounding box area B _j is included in the maximum rectangular area R _i (S511: YES), the object list deletion unit 304 deletes the j-th object graphic from the object list (step S51). S512).
On the other hand, as a result of step S511, when it is determined that the bounding box area B _j is not included in the maximum rectangular area R _i (S511: NO), the process of loop 4 is performed for the next object figure without performing the inclusion determination.
When processing for all object figures to be processed is completed for each of loop 3 and loop 4, the process proceeds to step S513.
In step S513, the display list creation unit 305 creates a display list based on the object graphic corresponding to the object list.
Then, the page rasterizing unit 306 performs a bitmap process on the graphic data of the display list, thereby completing a desired drawing process (S514).

As described above, as in the first embodiment, the image forming apparatus according to the second embodiment obtains each object graphic to be drawn, and excludes the included object graphic from the drawing target when inclusion of the object graphic is permitted. Basically, the drawing speed is improved by deleting the object list corresponding to the object graphic.
However, the image forming apparatus according to the second embodiment is different from the first embodiment in that the comparison is not performed simply on the object graphic itself to be drawn but on a simple rectangular area.
In other words, by replacing with a simple rectangular area that approximates an object figure, arithmetic processing related to area recognition and inclusion determination can be performed easily and quickly.
In addition, specific object graphics such as an object graphic that does not have a maximum rectangular area and an object graphic that is set to color mixing / transparency are excluded from inclusion determination targets, thereby reducing the processing load.
For this reason, according to the image forming apparatus of this embodiment, a higher-speed drawing process is possible compared with 1st embodiment.

[Third embodiment]
Next, an image forming apparatus according to the third embodiment of the present invention will be described.
The basic configuration of the image forming apparatus according to this embodiment is the same as that of each of the above-described embodiments, but the area area calculation unit of the present invention obtains the area of the bounding box area or the area of the maximum rectangular area. The method is characterized in that a target object graphic is narrowed down by comparing with a predetermined reference value.
Specifically, the present embodiment is realized by incorporating the following process in the stage before inclusion determination in each of the above-described embodiments.

FIG. 6 is a flowchart showing the procedure of the pre-processing for inclusion determination performed in the image forming apparatus according to the third embodiment of the present invention.
First, the object list deletion unit 303 determines whether or not the maximum rectangular area of the object graphic to be processed is larger than a predetermined reference value (S601).
For example, 50% or 80% of the page area is set as the reference value.
As a result of step S601, when the maximum rectangular area is larger than the predetermined reference value (S601: YES), the object list deletion unit 303 is a target whose object figure can include other object figures, and other objects. It is stored in the storage unit as an object that can be included in the figure (S602).
On the other hand, in step S601, when the maximum rectangular area is not larger than the predetermined reference value (S601: NO), the object list deletion unit 303 stores that the object graphic is excluded from objects including other object graphics. (S603).

Following step S603, the object list deletion unit 303 determines whether the bounding box area of the object graphic is larger than a predetermined reference value (S604).
For example, 10% or 5% of the page area is set as the reference value.
If the bounding box area is larger than the predetermined reference value as a result of step S604 (S604: YES), the object list deletion unit 303 stores in the storage unit that the object graphic is excluded from the objects included in other object graphics. It is memorized (S605).
On the other hand, when the bounding box area is not larger than the predetermined reference value in step S604 (S604: NO), the object list deletion unit 303 stores that the object graphic is a target that can be included in another object graphic. (S606).
Note that the processing in steps S601 to S606 described above is incorporated immediately after step S506 in the flowchart of FIG. Then, depending on the contents stored in steps S601 to S606, the determinations in steps S508 and S509 are performed. Since other procedures are the same as those in the second embodiment, description thereof will be omitted.

As described above, according to the image forming apparatus according to the present embodiment, the number of target object figures can be further reduced by incorporating the above-described preprocessing.
For this reason, it becomes possible to suppress the burden of inclusion determination and process drawing more smoothly.

The image forming apparatus of the present invention has been described with reference to the preferred embodiment. However, the image forming apparatus according to the present invention is not limited to the above-described embodiment, and various modifications may be made within the scope of the present invention. It goes without saying that is possible.
For example, the image forming apparatus of the present invention may be not only a printer apparatus but also various image processing apparatuses such as a copying machine, a facsimile machine, and a scanner.
Further, the image forming apparatus of the present invention may be configured by installing a program in a personal computer or the like connected to these image processing apparatuses.
Furthermore, it is possible to further increase the speed by processing in parallel the steps of creating the object list, creating the display list from the object list, and converting the display list into a bitmap.

  The present invention can be suitably used for image forming apparatuses such as printers, copiers, and multifunction machines.

It is the schematic diagram which represented each object figure which comprises the object list which concerns on this embodiment based on the drawing order. It is explanatory drawing for demonstrating the process in case one object figure is included in another object figure in this embodiment. 1 is a block diagram illustrating a configuration of an image forming apparatus according to a first embodiment of the present invention. It is explanatory drawing for demonstrating the bounding box area | region based on 1st embodiment of this invention, the largest rectangular area | region, and the inclusion determination using these. 6 is a flowchart showing an operation procedure of the image forming apparatus according to the second embodiment of the present invention (first stage). 6 is a flowchart showing an operation procedure of the image forming apparatus according to the second embodiment of the present invention (second stage). 10 is a flowchart illustrating a pre-processing procedure for inclusion determination performed in the image forming apparatus according to the third embodiment of the present invention. It is the 1st explanatory view for explaining the conventional drawing processing. It is explanatory drawing for demonstrating the problem in the conventional drawing process.

Explanation of symbols

301 Print Data Reception Storage Unit 302 PDL Analysis Unit 303 Object List Creation Unit 304 Object List Deletion Unit 305 Display List Creation Unit 306 Page Rasterization Unit

Claims (8)

An object list creating means for creating an object list from one or more object figures included in the print data and storing the object list according to a predetermined drawing order;
When an object figure drawn earlier is compared with an object figure drawn later, and the object figure drawn earlier is included in the object figure drawn later, the object figure drawn earlier An object list deleting means for deleting the object list corresponding to
An image forming apparatus comprising: an image forming unit that forms an image based on an object graphic corresponding to an object list that has not been deleted by the object list deleting unit. Maximum rectangular area calculation means for calculating a maximum rectangular area of each of the one or more object figures;
A bounding box area calculating means for calculating a bounding box area of each of the one or more object figures,
The object list deletion means includes
The object list corresponding to an object graphic drawn earlier is deleted when the bounding box area of the object graphic drawn first is included in the maximum rectangular area of the object graphic drawn later. Image forming apparatus.   The image forming apparatus according to claim 2, wherein the object list deleting unit excludes an object graphic that does not have the maximum rectangular area from object graphics to be drawn later, from the object graphics to be drawn later in the comparison target.   4. The object list deleting means excludes an object graphic whose maximum rectangular area is smaller than a predetermined reference value from object graphics drawn after the object graphic drawn after being subjected to the comparison. The image forming apparatus described.   3. The object list deleting means excludes an object graphic whose bounding box area is larger than a predetermined reference value from among the object graphics drawn earlier, from the object graphics drawn earlier as the comparison target. The image forming apparatus according to any one of claims 1 to 4.   The maximum rectangular area is an area formed inside an object graphic in which the sides do not intersect with each other and no concave and convex portions exist, and two parallel sides forming the object graphic and its end points are suspended. 5. The image forming apparatus according to claim 2, wherein the image forming apparatus is a rectangular region formed by a vertical line that is a leg.   6. The image forming apparatus according to claim 2, wherein the bounding box area is a minimum rectangular area that includes the entire object graphic.   8. The object list deletion unit according to claim 1, wherein an object graphic for which color mixing or transparency is set among object graphics to be drawn later is excluded from object graphics to be drawn after being subjected to the comparison. The image forming apparatus according to one item.

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