JPH1011593A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the overlap of plotting elements with each other at the time of executing page description languages in parallel. SOLUTION: Image plotting instructions divided by a job sequence generation means 1 are executed in parallel in plural plotting means 2a, 2b' and the overlap of the plotting elements is judged in an overlap judgment means 3. An area division means 4 divides a prescribed area into two relatively prime parts. A tree constituted of nodes with the position of the straight line of the boundary as a value is constituted and the tree expresses the spatial arrangement of the plotting elements. A tree data management means 5 registers an image in the node at the end of the tree. Tree data is constituted of image groups classified by systems where the plotting areas are not overlapped. In overlap judgment, such tree is searched for and the plotting elements to be the object of overlap judgment are specified from a division area where the plotting element which is newly given is arranged so as to execute comparison. A job management means 6 takes out partial image element information of the plotting means 2a, 2b... based on tree data and synthesizes them in an image memory 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus in which an instruction sequence expressed in a language for describing an image is executed in parallel by a plurality of instruction processing devices to obtain image information. .

[0002]

2. Description of the Related Art A server-type printing apparatus shared by many users must accept print requests from many host apparatuses and interpret and execute print information described in a page description language. No. When used from many host devices at the same time, the printing device interprets and executes print information described in a page description language sequentially,
There has been a problem that the waiting time from obtaining a print request to obtaining a result becomes long. This situation has been exacerbated with an increase in printing resolution.

In order to solve the above problem and execute image formation at a high speed, a technique for interpreting and executing a drawing command in parallel has been proposed. For example, PCT / JP91 / 0
According to the technology disclosed in Japanese Patent No. 0456, a print screen forming process is shared by a plurality of computers distributed on a network. Here, the print screen is divided into a band shape or a mesh shape, and each computer is responsible for forming an image of the divided region, so that the drawing operation is performed in parallel as a plurality of processes. Therefore, a pre-processing of dividing a drawing operation of a non-overlapping figure into a series of drawing operations is required.

[0004] Many of the currently widely used page description languages are designed on the premise of sequential execution. To execute them in parallel, a part which can be executed in parallel is specified, and a page description language suitable for a plurality of processors is specified. Is required. At this time, if there is an image forming command that overwrites the execution result of a certain partial image forming command, a correct final image cannot be obtained unless the order of overlapping between them is preserved.

[0005] The following techniques have been proposed to solve the above problems. According to the technique disclosed in Japanese Patent Application Laid-Open No. 7-104987, an image operation procedure in a document print program is analyzed and generated, and it is determined whether or not rendering can be executed in parallel, by determining a pixel having been image-formed so far and the next A parallel execution code is generated by direct comparison with a pixel formed by execution.

[0006]

When a page description language designed for sequential execution is executed in parallel for high-speed image formation, the correct final order must be maintained unless the order of overlapping drawing elements is preserved. Since no image can be obtained, processing for detecting overlap is required.

However, in the above-described conventional parallel drawing method, whether a certain partial image formation does not interfere with another image formation, that is, depending on the order of image formation, an image formed by another image is overwritten by an image that should be below it. It is necessary to determine whether or not there is a possibility of erroneous processing of whether an image from another image formation overwrites an image that should be on it. It is necessary to examine this overlapping relationship between all the image elements in the image forming one screen, and it takes a processing time proportional to the square of the number of image elements. Therefore, when an image element is divided into several hundred or more fine granularities, the load of the preprocessing for the overlap determination becomes very large, and the effect of the parallel processing originally intended to speed up the processing is greatly impaired. There was a problem that would be.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an image forming apparatus capable of detecting, at high speed, overlapping of drawing elements for parallel execution of a page description language. I do.

[0009]

According to the present invention, in order to solve the above-mentioned problems, in an image forming apparatus for obtaining pixel information by executing an image drawing command described in a page description language, A job sequence creating unit that creates a job sequence composed of a plurality of instruction jobs of the image rendering command by dividing the image rendering command into instruction units, and individually receives the instruction jobs from the job sequence creating unit and executes the respective instructions. A plurality of drawing units for developing pixel information from a job, an overlap determination unit that receives the command job and determines whether or not a drawing area overlaps when executing between command jobs, and according to a determination result of the overlap determination unit, Area dividing means for dividing a drawing plane into disjoint partial areas having no overlapping drawing areas; and The pixel information is formed into a tree structure by a sequence of disjoint partial regions from the division result of the division unit, and the configured tree is searched for at the time of the overlap determination by the overlap determination unit and belongs to the partial region to be determined. A tree data management unit in which an instruction job is specified, and an instruction job from the job sequence creation unit is distributed to the plurality of drawing units, and the plurality of drawing units refer to the tree data in the tree data management unit. A job management unit for extracting the expanded partial pixel information; and a region having only an area for holding the pixel information corresponding to the drawing plane, and writing the partial pixel information extracted from the plurality of drawing units by the job management unit. And an image memory for synthesizing an image with the image forming apparatus.

According to such an image forming apparatus, in registering a drawing element, in order to represent the spatial arrangement of the drawing element, an area dividing means divides an area into two disjoint parts, and creates tree data. The management means constructs a tree composed of nodes whose values are the straight lines at the boundaries, and registers an image at the terminal node of the tree. The overlap judging means searches for a tree configured as described above and specifies a drawing element to be subjected to overlap judgment. To search for drawing elements to be subject to overlap determination,
Determines which side of the new given drawing element is on the straight line divided into two disjoint parts, and overlaps the drawing element included in the partial area where the given drawing element is placed. It is the target of the judgment. The tree data is updated by the overlap determination. The job management unit reads out the developed partial pixel information from the drawing unit in accordance with the overlapping dependency relationship based on the tree data, and forms an image by combining the partial pixel information in the image memory.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the principle configuration of the present invention. The image forming apparatus according to the present invention includes: a job sequence creating unit that creates a job sequence including a command job of a plurality of image drawing commands in response to an image drawing command;
A plurality of drawing means 2a, 2 for executing individual instruction jobs
, b, 2c,..., overlap determining means 3 for determining the overlapping relationship of the drawing areas at the time of execution between the command jobs, and the drawing plane is not overlapped according to the determination result of the overlap determining means 3. Area dividing means 4 for dividing into disjoint partial areas, tree data managing means 5 for converting pixel information into a tree structure from the division result of the area dividing means 4, a plurality of drawing means 2a, 2b, 2c, , And extracting the partial pixel information expanded by the plurality of drawing units 2a, 2b, 2c,..., And the partial pixel information extracted according to the overlapping relationship represented by the tree data And an image memory 7 for synthesizing an image by writing the image.

The job sequence creating means 1 divides an image drawing instruction into instruction units and creates a job sequence consisting of a sequence of instruction jobs. The job management means 6
The divided instruction job is transferred to a plurality of drawing units 2a, 2b, 2
c,... and a plurality of drawing means 2a, 2
are driven in parallel to execute respective drawing commands. At the same time, the overlap judging means 3 judges whether or not there is an overlap between the drawing area when the divided instruction job is executed and the drawing area when the immediately preceding instruction job is executed. At this time, the overlap judging unit 3 searches the tree formed by the tree data managing unit 5 and specifies the instruction job belonging to the partial area to be judged. When updating the tree data in the tree data management means 5 according to the determination result of the overlap determination means 3, the area dividing means 4 divides the drawing plane into disjoint partial areas having no overlapping drawing areas and performs drawing. Set logical boundaries with non-overlapping areas in the plane. The job management unit 6 refers to the tree data of the tree data management unit 5 and reads out the partial pixel information developed by the plurality of drawing units 2a, 2b, 2c,... While considering the overlapping relationship of the drawing regions. , These are stored in the image memory 7
And write the image.

Accordingly, in order to represent the spatial arrangement of the drawing elements when detecting the overlap of the drawing elements, the tree data management means 5 uses the area dividing means 4 to divide a straight line obtained by dividing a certain area into two disjoint parts. A tree composed of nodes as values is formed, and a formed image is registered at a terminal node of the tree. Since the overlap judging means 3 searches for a tree configured as described above, a drawing element to be subjected to overlap judgment is specified at high speed. At the time of tree search by the tree data management means 5, it is determined which side of a straight line divided into two disjoint portions the drawing element to be subjected to overlap determination is determined. Since the drawing elements in the area determined not to have no overlap are not subjected to the overlap determination, the number of overlap determinations between the drawing elements can be reduced, and the entire image forming process can be sped up.

Next, an example in which the first embodiment of the present invention is applied to a printing system loosely coupled by a network will be described. FIG. 2 is a block diagram showing a configuration of a printing system to which the image forming apparatus of the present invention is applied.
The illustrated image forming apparatus 10 includes client computers 31, 32, 33,
Are connected, and a print engine 40 for outputting a processing result is connected. Image forming apparatus 1
0 is a command analysis device 11 connected to the local area network 20 and a plurality of graphic drawing units 12a, 12b,
, 12c, 12d, 12e,...
, An image memory 14 and a printer interface 15 via a shared bus 16. The instruction analysis device 11 includes a lexical analysis unit 11a, an instruction execution unit 11b, a description division unit 11c, an overlap determination unit 11d, and a tree data management unit 11e.

The lexical analyzer 11 of the instruction analyzer 11
a, the instruction execution unit 11b and the description division unit 11c correspond to the job sequence creation unit 1 shown in FIG. 1, the overlap determination unit 11d of the instruction analysis unit 11 corresponds to the overlap determination unit 3, and the tree data of the instruction analysis unit 11 The management unit 11e corresponds to the tree data management unit 5, a part of the functions of the overlap determination unit 11d and the tree data management unit 11e corresponds to the area division unit 4, and a plurality of graphic drawing units 12a, 12b, 12c, 12
d, 12e,... are drawing means 2a, 2b, 2c,.
, The graphic synthesizing unit 13 corresponds to the job management unit 6, and the image memory 14 corresponds to the image memory 7.

In the image forming apparatus 10 according to the present invention,
The print job created by the client computers 31, 32, 33,... Is sent to the command analyzer 11 via the local area network 20. In the command analyzer 11, the contents of the received print job are analyzed by the lexical analyzer 11a. The command execution unit 11b sequentially converts the print job into an internal format. Subsequently, as a result of the analysis by the lexical analysis unit 11a, when a drawing command of a partial graphic is detected,
The description division unit 11c divides the drawing command of the partial graphic into a single partial graphic or a series of a plurality of partial graphics. The output of the description division unit 11c is a sequence of descriptions of the partial figures as a result of the division, which are operable in parallel and have graphic buffers 12a, 12b, 12c,
12d, 12e,..., And their graphic drawing units 12a, 12b, 12c, 12d, 12e,.
The drawing of the partial figure is performed in.

The output of the description division unit 11c is sent to the overlap judgment unit 11d at the same time, and it is judged whether or not there is any overlap with the partial figures generated so far. The output of the overlap judging unit 11d is sent to a tree data management unit 11e, where it is managed in an expression using a tree structure. The graphic synthesizing unit 13 refers to the information on the overlapping relationship between the partial graphics represented by the tree data held by the tree data management unit 11e and refers to the graphic drawing units 12a, 12b, 12c, 12c.
The graphic data drawn in d, 12e,... and held in the respective local buffers are read out as appropriate.
The image data is sent to the image memory 14 corresponding to the drawing plane for the page.
The image memory 14 combines the sent graphic data,
Generate an image for one page. The contents of the image memory 14 thus generated are sent to the print engine 40 via the printer interface 15 and printed out.

Next, the operation will be described in detail with reference to a specific example of a print job input to the image forming apparatus 10. FIG. 3 is a diagram illustrating an example of a screen created by the client. According to the illustrated drawing example, a square figure F1 is first created on an arbitrary client computer using an arbitrary image editing software, and a black circle figure F2 is created on the square figure F1. A large white circle figure F3 is created in a completely enclosing form. next,
A triangular figure F4 is created so as to partially include the figure F1, and a black circle figure F5 and a white circle figure F6 including the figure F5 are created.

The information of the figures F1 to F6 created by using the image editing software is transmitted to the command analyzer 11 of the image forming apparatus 10 as a PDL program generated by, for example, a printer driver installed in the client computer. You. A drawing command sequence for drawing such figures F1 to F6 is described as follows.

FIG. 4 is a diagram showing an example of analysis in the instruction analyzer. FIG. 4A shows a list of a drawing command sequence input to the command analysis device 11 of the image forming apparatus 10. According to this list, the graphics drawing commands 51 to 56 corresponding to the graphics F1 to F6 are the graphics F1, F2, F3, F4,
It is described in the order of F5 and F6.

The lexical analyzer 11a of the command analyzer 11 reads and analyzes the input drawing command sequence one character at a time, and the command execution unit 11b analyzes the contents of the analyzed figure drawing command, for example, the type and coordinates of the figure. Converts parameters such as value and size to internal format. Subsequently, the description division unit 11c detects a command representing the type of a figure to be actually drawn from the drawing command sequence. More specifically, as indicated by the underline in the list of FIG. 4B, “rectfill”, which is a graphic drawing command for a filled square, “fill”, which is a graphic drawing command for filling an arc, and an outline "Strok" which is a drawing command of a line along
e "is detected. When the contour drawing command or the painting command is detected, the description division unit 11c
Determines that the sequence of instructions analyzed so far defines one figure, and divides it as a job. That is, as shown in FIG.
It is divided into six partial graphic descriptions corresponding to.

The partial graphic descriptions divided in this way are written in the graphic drawing sections 12a, 12b, 12c, 12d, 12
are sent to different graphic drawing units, and a graphic drawing command is executed there to be developed into pixel information. The assignment of the graphic drawing units is sequentially performed by the graphic synthesizing unit 13 to the currently open graphic drawing units. The divided partial graphic description is sent to the overlap judging unit 11d simultaneously with the transmission to the graphic drawing unit.

In the following, it is assumed that the overlap between two figures is determined using their circumscribed rectangles. However, in the present invention, this determination is not limited to the method using the circumscribed rectangle. For example, a polygon such as a convex hull that includes the target figure or an arbitrary figure that includes the target figure is used. May be used. Alternatively, the determination may be made using only the boundary of the figure or using an area including the inside.

The circumscribed rectangle of the figure can be easily obtained by the instruction execution unit 11b by, for example, storing the maximum and minimum values of the x coordinate value and the y coordinate value when generating the internal representation.

First, a method for determining the overlap between two circumscribed rectangles will be described. FIG. 5 is a flowchart showing the principle of the overlap determination procedure using a circumscribed rectangle. Here, it is assumed that the circumscribed rectangle of the two figures is represented by a set of four numerical values, and each numerical value represents the value of the x coordinate and the y coordinate of the upper left point and the lower right point of the rectangle.

Therefore, first, the maximum values of the x coordinate and the y coordinate of the upper left point of the two circumscribed rectangles are determined by the variables Lx and Ly.
And the minimum value of the x and y coordinates of the lower right point
x and Hy are set respectively (step S1). Subsequently, comparison is made of variables relating to the x coordinate and the y coordinate of the two circumscribed rectangles (step S2). That is, Lx <Hx
Is determined, and whether Ly <Hy is satisfied. If both are satisfied, it is determined that there is an overlap, and the process ends. If both comparisons are not satisfied, it is determined that there is no overlap, and the processing ends.

The determination of the presence or absence of the overlap can be made when two circumscribed rectangles are given for the following reasons. Given an orthographic projection of a rectangular area onto a certain axis, this forms a wide range of values. If the two ranges overlap, the ends of the overlap region are those on the right of the left boundaries of the two ranges and those on the left of the right boundaries, which appear in this order from left to right. If the two ranges do not overlap, their order of appearance is reversed. The overlap determination procedure in FIG. 5 utilizes such a property.

A procedure for performing the overlap determination between the already generated tree data and the circumscribed rectangle of the newly input figure in the tree data management unit 11e using the above-described overlap determination procedure will be described below.

FIG. 6 is a flowchart showing a procedure for performing the overlap judgment. In the overlap determination procedure, first, a circumscribed rectangle of the input figure is generated (step S11).
A tree representing a series of already generated graphics is searched (step S12), and an overlap determination is performed (step S13).
This overlap determination is performed using the procedure shown in FIG.
The tree search procedure will be described later.

In the overlap judgment in step S13,
If an overlap is detected, a new tree is generated and its figure is registered (step S14), and the process ends. In the overlap determination, if no overlap is detected, a node is generated in the current tree, the figure is registered, and preparation is made for the next search (step S15).

The registration to the tree of a figure is performed as follows. First, the area to which the figure belongs is specified. This has already been done in the search for overlap detection. Next, a straight line is determined which divides the region into a region to which the figure given this time and the figure already registered in the tree belong, and a node having the coordinates of the straight line as a value is generated. Then, the divided partial areas are assigned to the branches of this node. By adding the node thus generated to the tree, a new divided area is defined, and a figure is additionally registered therein.

Each of the straight lines dividing the region is either a horizontal line or a vertical line. The horizontal line and the vertical line may be anywhere between the two figures, but in the present embodiment, the horizontal line and the vertical line are arranged at the uppermost and leftmost positions, respectively, among the positions that can be arranged.

By using such an arrangement procedure, a series of non-overlapping figures is represented by a tree structure reflecting its spatial arrangement. In order to determine the overlap between the figure registered in this tree and the newly given figure, it is only necessary to specify an area where the figure is arranged and to perform the overlap determination only with the figure included therein. . For this reason, it is not necessary to examine all the figures registered in the tree, and the load of the overlap determination processing is greatly reduced.

Next, a procedure for searching a tree to specify an area will be described. FIG. 7 is a flowchart showing a tree search procedure. In the procedure of FIG. 7, first, the arrangement relationship between the straight line of the tree node and the circumscribed rectangle of the given figure is checked, and it is determined whether or not the boundary is vertical (step S21). Here, if the straight line dividing the region is a vertical line, the x coordinate of the upper left point of the circumscribed rectangle of the given figure is represented by B
The x coordinate of the lower right point is set to Bu in l (step S22). If it is determined in step S21 that the straight line dividing the region is a horizontal line, the y coordinate of the upper left point of the circumscribed rectangle of the given figure is set to Bl, and the y coordinate of the lower right point is set to Bu (step S21). S23). Next, the previously set values of Bl and Bu are compared with the value of the boundary line. First, the x or y coordinate values of the boundary line are Bl and Bu.
(Step S24), and if Bl <boundary line <Bu, it is determined that the circumscribed rectangle of the given figure intersects the straight line of the node, and Are recursively searched for both branches exiting from (step S25). Further, the positional relationship between the boundary line and Bu is determined (step S26), and if boundary line ≧ Bu, it is determined that the circumscribed rectangle of the given figure is on the left side of the vertical line of the node or above the horizontal line. , Recursively search for the corresponding branch (step S27). Finally, the positional relationship between the boundary line and Bl is determined (step S28),
If the boundary ≤ Bl, it is determined that the circumscribed rectangle of the given figure is on the right side of the vertical line of the node or below the horizontal line, and a recursive search is performed for the corresponding branch (step S29). In this way, if the circumscribed rectangle of the given figure intersects the straight line of the node, both branches exiting the node are searched recursively, and the circumscribed rectangle of the given figure is the straight line of the node. If on either side of
The corresponding branch is searched recursively. In any case, the search ends when the terminal node, that is, the partial figure is reached.

As a result, the instruction sequence is divided into non-overlapping graphic sequences. At the same time, each of the partial figures is subjected to the graphic drawing unit 12 without scheduling.
a, 12b, 12c, 12d, 12e,... are drawn and held in a local buffer. Each drawing result is read from the local buffer by the graphic combining unit 13 and combined with the contents of the image memory 14, that is, the contents of the image memory 14 are overwritten.

At this time, in order to correctly reproduce the order of the overlap, the following may be performed. That is, when combining the drawing result of a certain partial figure with the contents of the image memory 14,
It is sufficient to check that there is no uncombined figure belonging to tree data generated before the tree data to which the figure belongs. Another figure belonging to the same tree data as a certain figure may remain. This is because, since a series of figures that do not overlap in one tree data is registered, changing the synthesis order between these figures does not affect the overlapping relationship.

The operation of the overlap judging unit 11d and the tree data managing unit 11e when the above procedure is applied to the drawing example of FIG. 3 will be described. Here, the divided graphic descriptions are simultaneously written in the graphic drawing units 12a, 12b, 12c, 12d,
It is assumed that the figure is sent to any one of 12e,... And drawn, and the drawn figure is appropriately read by the figure combining unit 13 and combined with the image memory 14.

FIG. 8 is a diagram showing the positional relationship of the graphic to be overlapped, and FIG. 9 is a diagram showing the tree structure after the overlap is determined.
The overlap determination unit 11d determines the circumscribed rectangle BB1 (250, 20) from the description 51 (FIG. 4) relating to the input figure F1.
0, 375, 225), and the circumscribed rectangle BB2 (325, 187.5, 35)
0,212.5). By applying the overlap determination procedure of FIG. 5, the circumscribed rectangle BB1 and the circumscribed rectangle BB
2 is determined to be overlapped.

Since the overlap between the figures F1 and F2 has been detected, the figures F1 and F2 are registered in different trees. That is, the figure F1 is registered under the tree T1, and the figure F2 is registered under the tree T1.
2, and these are managed by the tree data management unit 11e. The descriptions corresponding to the figures F1 and F2 are sent to, for example, the figure drawing units 12a and 12b, respectively, and drawn.

FIG. 10 is a diagram showing the positional relationship of the graphic subject to overlap judgment, and FIG. 11 is a diagram showing the tree structure after the overlap judgment. Next, overlap determination is performed on the figures F2 and F3. The circumscribed rectangle of the figure F3 is obtained from the circumscribed rectangle BB3 (300, 100, 450,
250) is obtained. Circumscribed rectangle BB2 and circumscribed rectangle B
From B3, it is determined that the figures F2 and F3 overlap. Since the overlap is detected, the figure F3 is registered in a tree T3 different from the figure F2, as in the above case. The description 53 corresponding to the figure F3 is assigned, for example, by the figure drawing unit 12c, and is drawn here.

FIG. 12 is a diagram showing the positional relationship of the graphic subject to overlap judgment, and FIG. 13 is a diagram showing the tree structure after the overlap judgment. Next, overlap determination is performed on the figures F3 and F4. The circumscribed rectangle of the figure F4 is obtained from the description 54 related to the figure F4 based on the circumscribed rectangle BB4 (150, 150, 273,
250) is obtained. Circumscribed rectangle BB3 and circumscribed rectangle B
From B4, it is detected that the circumscribed rectangles of the graphic F3 and the graphic F4 do not overlap. Therefore, the figure F4 is registered in the tree T3 including the figure F3. This tree T3
At the time of registration, a node N1 having a value as a straight line 61 (FIG. 12) that divides a space into two disjoint regions including respective rectangles is generated below the tree T3. The branch from the node N1 corresponds to the area divided by the straight line 61, and each figure is registered at the tip of the branch. In this case, the node N having a value of x = 275 of the straight line 61
1 is generated, the node N1 has branches corresponding to the region x <275 and the region x> 275, and the figure F4 and the figure F3 are registered at the ends of each branch, thereby forming a tree as shown in FIG. You. A description 5 corresponding to FIG.
4 is sent to, for example, the graphic drawing unit 12d and drawn.

FIG. 14 is a diagram showing the positional relationship of the graphic to be overlapped, and FIG. 15 is a diagram showing the tree structure after the overlap is determined. Next, the overlap determination with respect to the graphic F5 is performed on the tree T3 composed of the graphic F3 and the graphic F4 described above. The circumscribed rectangle BB5 (137.5,
112.5, 162.5, and 137.5) are in the region of x <275, and follow the corresponding branch to reach the figure F4 on the left side of x = 275, which is the figure to be overlapped with the figure F5. . As a result of the overlap determination for the figures F5 and F4, it is detected that these figures F4 and F5 do not overlap. As a result, it is found that the figure F5 does not overlap with all the figures registered in the tree T3, and a node N2 having a value of y = 137.5 of the straight line 62 is generated. F5 is registered. After registration, the tree T3 changes as shown in FIG. The description 55 corresponding to the figure F5 is sent to, for example, the figure drawing unit 12e, and the figure F5 is drawn.

FIG. 16 is a diagram showing the positional relationship of the graphic to be overlapped, and FIG. 17 is a diagram showing the tree structure after the overlap determination. Next, the overlap determination for the figure F6 is performed.
First, a circumscribed rectangle BB6 (100, 10
0, 200, 200). In the search of the tree T3, if the branch of x <275 is followed, it can be seen that the straight line 62 of y = 137.5 intersects the circumscribed rectangle BB6. At this time, the overlap determination is performed by tracing the branches on both sides of the node N2. For example, by following y <137.5 and performing the overlap determination with the graphic F5, the overlap is detected. No search is required. As a result, the figure F6 is registered in a new tree T4 different from the tree T3. The description 56 corresponding to the figure F6 is, for example, the figure drawing unit 12a already finished drawing the figure F1 and
3 is overwritten in the image memory 14,
The figure is sent to the figure drawing unit 12a, where the figure F6 is drawn.

As a result, the figure group of FIG. 3 includes a tree T1 including the figure F1, a tree T2 including the figure F2, a figure F3, and a figure F
Tree T3 including figure 4 and figure F5, tree T4 including figure F6
Is decomposed into four trees. When synthesizing these figures in the image memory, they may be performed in the following order. First,
After the completion of the combining of the figure F1 registered in the tree T1 with the image memory 14, the combining of the figure F2 registered in the tree T2 with the image memory 14 is performed. Then, after the completion of the combining of the figure F2 registered in the tree T2 with the image memory 14, the figures F3, F4, and F5 registered in the tree T3 are combined with the image memory 14. At this time, since the figures registered in the same tree do not overlap each other, the figure F
3, the order of combining the figure F4 and the figure F5 may be arbitrary, and may be combined in the order in which drawing by the figure drawing unit is completed. Next, after the completion of combining all of the figures F3, F4, and F5 registered in the tree T3 into the image memory 14, the combining of the figure F6 registered in the tree T4 into the image memory 14 is performed. Do. As a result of the above combination, a final image that correctly reflects the overlapping order is created on the image memory 14.

The printer interface 15 sends the final image on the image memory 14 thus obtained to the print engine 40, and the print engine 40 prints the final image, completing the printing of the graphic shown in FIG. .

Next, an example in which the second embodiment of the present invention is applied to a printing system loosely coupled by a network will be described. FIG. 18 is a block diagram showing another configuration of a printing system to which the image forming apparatus of the present invention is applied. The illustrated image forming apparatus 10 includes client computers 31, 32,
, And a print engine 40 for outputting a processing result. The image forming apparatus 10 includes a command analysis device 11 connected to a local area network 20 and a plurality of graphic drawing units 12a, 1
2b, 12c, 12d, 12e,..., A graphic synthesizing unit 13, an image memory 14, and a printer interface 1
5 are connected via a shared bus 16. The instruction analyzer 11 includes a lexical analyzer 11a and an instruction executor 11b.
, Description division unit 11c, overlap determination unit 11d, tree data management unit 11e, template data storage unit 11f
It is composed of That is, in the second embodiment, a template data storage unit 11f is added to the configuration shown in FIG.

In the image forming apparatus 10 according to the present invention,
The print job created by the client computers 31, 32, 33,... Is sent to the command analyzer 11 via the local area network 20. In the command analyzer 11, the contents of the received print job are analyzed by the lexical analyzer 11a. The command execution unit 11b sequentially converts the print job into an internal format. Subsequently, as a result of the analysis by the lexical analysis unit 11a, when a drawing command of a partial graphic is detected,
The description division unit 11c divides the drawing command of the partial graphic into a single partial graphic or a series of a plurality of partial graphics. The output of the description division unit 11c is a sequence of descriptions of the partial figures as a result of the division, which are operable in parallel and have graphic buffers 12a, 12b, 12c,
12d, 12e,..., And their graphic drawing units 12a, 12b, 12c, 12d, 12e,.
The drawing of the partial figure is performed in.

The output of the description division unit 11c is sent to the overlap judgment unit 11d at the same time, and it is judged whether or not there is an overlap with the partial graphics generated so far. The output of the overlap judging unit 11d is sent to a tree data management unit 11e, where it is managed in an expression using a tree structure. At this time, the tree data management unit 11e uses the tree data stored in advance in the template data storage unit 11f as a template of an expression using the above-described tree structure. This template represents a predetermined region division, and a node corresponds to a partial region of a page. Therefore, a graphic description belonging to the defined partial area is registered below this node.

The graphic synthesizing unit 13 refers to the information on the overlapping relationship between the partial graphics represented by the tree data held by the tree data management unit 11e, and refers to the graphic drawing units 12a, 1a.
2b, 12c, 12d, 12e,..., And appropriately reads the graphic data held in the local buffer, and the image memory 14 corresponding to the drawing plane for one page.
Send to The image memory 14 combines the sent graphic data to generate an image for one page. The contents of the image memory 14 thus generated are stored in the printer interface 1.
5 to the print engine 40 for printing.

Here, the lexical analyzer 11a and the instruction executor 1
1b, the operation of the description division unit 11c, and the operation of the overlap determination unit 11d are the same as those in the first embodiment shown in FIG. Lexical analysis unit 11a, instruction execution unit 11b, description division unit 11c, and overlap determination unit 11
As a result of the operation d, the instruction sequence is divided into non-overlapping graphic sequences and registered in the tree data held by the tree data management unit 11e. The template stored in the template data storage unit 11f is used as the registered tree data. This template will be described below.

FIG. 19 is an explanatory diagram showing a method of constructing tree data using a template. FIG. 19 shows a drawing plane 71 on which the image memory 14 combines partial graphics. The drawing plane 71 is divided into four partial areas 71a, 71b, 71c, and 71d in the illustrated example. The tree structure of the spatial arrangement corresponding to these area divisions is generated in advance as a template 81 and is held in the template data storage unit 11f. Therefore, when the tree data management unit 11e registers a figure, the tree data management unit 11e reads a template 81 representing a predetermined area division from the template data storage unit 11f, and registers the template 81 in a tree branch corresponding to a partial area including the figure. become.
The operation of extracting a group of figures belonging to a specific partial area can be easily realized by searching for a tree corresponding to the partial area.

At this time, if the divided partial area represented by the template 81 is defined as a horizontal band and the image memory 14 is limited to a capacity corresponding to the width of this band, a band buffer suitable for an ink jet printer or the like can be used. It is possible to easily configure the image forming apparatus that has been used, and high-speed processing can be realized because drawing is performed in parallel within a band.

As another embodiment in which a template 81 representing a predetermined area division is used, as shown in FIG. 19, partial areas 71a, 71b, 71c, 71d of a divided page are used. A plurality of parallel processors 91 for graphic drawing processing in which a group of figures belonging to each are connected in the form of a mesh, for example, as shown in the figure.
a, 91b, 91c, and 91d. This is particularly suitable when, when configuring an image forming apparatus on a massively parallel architecture computer in which a plurality of processors are connected in a form such as a mesh or a torus, a page is divided and processed by reflecting the connection form of the processors. Therefore, high-speed processing can be realized.

[0054]

As described above, according to the present invention, there is provided an instruction analyzing apparatus having a job sequence creating means for dividing an image drawing instruction, an overlap judging means, an area dividing means, and a tree data managing means. Thus, for non-overlapping graphics, the graphics are synthesized in the order in which the graphics are completed, so that the graphics can be synthesized without waiting for the graphics to be loaded with a high load, and the entire operation can be performed at high speed.
Further, since a graphic sequence having a dependency on a drawing order can be easily specified, scheduling based on dependency analysis can be performed, which contributes to an improvement in operation efficiency of a drawing system.

Further, by specifying a figure to be subjected to overlap determination by narrowing down a figure group, it is possible to efficiently detect drawing elements overlapping each other and to immediately proceed to the synthesis processing after the overlap determination. In addition, it is possible to realize a parallel drawing process without performing complicated scheduling.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a printing system to which the image forming apparatus of the present invention is applied.

FIG. 3 is a diagram illustrating an example of a screen created by a client.

FIG. 4 is a diagram illustrating an example of analysis in the instruction analysis device.

FIG. 5 is a flowchart showing the principle of an overlap determination procedure using a circumscribed rectangle.

FIG. 6 is a diagram illustrating a flowchart of a procedure for performing overlap determination.

FIG. 7 is a flowchart showing a tree search procedure.

FIG. 8 is a diagram (part 1) illustrating a positional relationship of a graphic subject to overlap determination;

FIG. 9 is a diagram (part 1) illustrating a tree structure after an overlap determination;

FIG. 10 is a diagram (part 2) illustrating a positional relationship of a graphic subject to overlap determination;

FIG. 11 is a diagram (part 2) illustrating the tree structure after the overlap determination.

FIG. 12 is a diagram (part 3) illustrating a positional relationship of a graphic subject to overlap determination;

FIG. 13 is a diagram (part 3) illustrating the tree structure after the overlap determination.

FIG. 14 is a diagram (part 4) illustrating a positional relationship of a graphic as an overlap determination target;

FIG. 15 is a diagram (part 4) illustrating the tree structure after the overlap determination.

FIG. 16 is a diagram (part 5) illustrating the positional relationship of the overlap determination target graphic;

FIG. 17 is a diagram illustrating a tree structure after the overlap determination (part 5);

FIG. 18 is a block diagram illustrating another configuration of a printing system to which the image forming apparatus according to the invention is applied.

FIG. 19 is an explanatory diagram showing a method of configuring tree data using a template.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Job sequence creation means 2a, 2b, 2c Drawing means 3 Overlap judgment means 4 Area division means 5 Tree data management means 6 Job management means 7 Image memory 10 Image forming apparatus 11 Command analysis apparatus 11a Lexical analysis section 11b Command execution section 11c Description Division unit 11d Overlap determination unit 11e Tree data management unit 11f Template data storage unit 12a, 12b, 12c, 12d, 12e Graphic drawing unit 13 Graphic synthesizing unit 14 Image memory 15 Printer interface 16 Shared bus 20 Local area network 31, 32, 33 Client computer 40 print engine

Claims (6)

[Claims] 1. An image forming apparatus for obtaining pixel information by executing an image drawing command described in a page description language, wherein the image drawing command is divided by a command unit of the image drawing command and the plurality of images are divided. A job sequence creating unit that creates a job sequence composed of an instruction job of a rendering instruction; a plurality of rendering units that individually receive the instruction jobs from the job sequence creating unit and develop pixel information from the instruction job; Overlap determining means for receiving a job and determining whether or not the drawing areas overlap when executing between instruction jobs; and, according to the determination result of the overlap determining means, the drawing plane is converted into disjoint partial areas having no overlapping of the drawing areas. A region dividing unit to be divided, and a sequence of disjoint partial regions from the division result of the region dividing unit according to the job sequence Tree data management means for configuring the pixel information into a tree structure, and for specifying an instruction job belonging to a partial area to be determined by searching for the configured tree at the time of the overlap determination by the overlap determination means; A job management means for distributing the instruction job from the sequence creation means to the plurality of drawing means, and extracting partial pixel information developed by the plurality of drawing means with reference to tree data of the tree data management means; An image memory having an area only for holding pixel information corresponding to a drawing plane, and writing partial pixel information extracted from the plurality of drawing units by the job management unit to synthesize an image. An image forming apparatus comprising: 2. The image forming apparatus according to claim 1, wherein the area dividing unit divides the drawing plane into disjoint partial areas by one of a horizontal line and a vertical line. 3. The image forming apparatus according to claim 1, wherein the area dividing unit divides the drawing plane into a plurality of band-shaped areas by a horizontal line. 4. A tree data template representing tree data by dividing the drawing plane into a plurality of fixed partial area groups is stored, and the tree data management unit configures the tree data. 2. The image forming apparatus according to claim 1, further comprising a tree data template storage unit configured to add tree data below the data template. 5. An instruction analyzing apparatus for analyzing an interference relationship between image drawing commands in an image forming apparatus for obtaining image information by executing image drawing commands described in a page description language in parallel. A job sequence creating means for creating a job sequence composed of a plurality of command jobs of the image drawing command by dividing the image job into command units of the image drawing command; Overlap determining means for determining the presence / absence of overlap; area dividing means for dividing a drawing plane into disjoint partial areas having no overlapping of drawing areas according to the determination result of the determining means; and area dividing means according to the job sequence. The pixel information is formed into a tree structure by a sequence of disjoint partial regions from the division result of Instruction analyzing apparatus characterized by at instruction jobs belonging to the constructed partial regions tree be judged is searched was is and a tree data management unit identified. 6. An image forming method for obtaining pixel information by executing an image drawing command described in a page description language, wherein the image drawing command is divided by a command unit of the image drawing command and a plurality of the image drawing commands are divided. A job sequence consisting of the command jobs is created, and the divided image drawing commands are individually executed in parallel to develop each pixel information in parallel. Analyzing, dynamically determining the synthesis order of each of the pixel information expanded in parallel with reference to the analysis result of the overlapping relationship of the drawing areas, synthesizing the pixel information according to the determined synthesis order, and forming an image. Forming an image.