JP2017001387A - Information processing apparatus, information processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a waiting time of a rendering process which occurs between areas when a rendering process is performed based on an intermediate data created for each area from PDL data. An information processing device that generates intermediate data for converting input print data into raster image data, in which an image object drawn on the image is encoded based on the print data. It has a decoding means for decoding compressed data and a rendering means for generating raster image data by rendering each region of the image while referring to the image data of the image object held by the holding means. The decoding means is the compressed data of the image object drawn in the attention area and the image object drawn in the subsequent area of the attention area while the rendering means is generating the raster image data of the attention area. Decode at least part of the compressed data. [Selection diagram] Fig. 1

Description

  The present invention relates to an information processing apparatus and an information processing method for generating image data from data described in a page description language (PDL).

  When printing an image on a recording medium, print target data described in a page description language (PDL) is received via a communication medium such as a network. For output by an image forming apparatus such as a printer, data described in PDL is converted into raster image data by executing RIP (Raster Image Processor) processing on the data described in PDL. Specifically, first, an interpreter dedicated to the image forming apparatus (printer) to print interprets the data described by the received PDL, and the intermediate data creation unit creates intermediate data based on the interpreted result. Further, a rendering process is executed based on the intermediate data, and raster image data is generated. The raster image data generated by the RIP processing as described above is subjected to predetermined image processing, converted into print data that can be printed by the image forming apparatus, and the printer prints based on the print data. In such a printer system, in order to reduce the amount of memory for storing intermediate data, a method of generating intermediate data for each of a plurality of areas obtained by dividing image data for one page into strips is known.

  Patent Document 1 discloses a method for creating intermediate data by dividing so that adjacent areas partially overlap when an image object straddles the boundary of the area when dividing the intermediate data for each area. Disclosure. Further, Patent Document 2 discloses a method of changing the division position when an image object straddles a plurality of regions.

JP 2001-306275 A JP 2003-72161 A

  In the RIP processing, when compressed image data is included as an object in a region to be rendered, rendering processing is started after decompressing necessary compressed data. Therefore, according to the methods disclosed in Patent Literature 1 and Patent Literature 2, it is necessary to wait for necessary image data to be decompressed every time rendering processing based on intermediate data created for each region is performed. Occurs.

  Therefore, an object of the present invention is to reduce the waiting time of rendering processing that occurs between regions when rendering processing is performed based on intermediate data created for each region.

  In order to solve the above problems, the present invention provides an information processing apparatus for converting print data representing an input image to be printed into raster image data, and an image object drawn on the image based on the print data Decoding means for decoding the encoded compressed data, first holding means for holding image data of the image object obtained as a result of the decoding means decoding the compressed data, and the holding means for holding Rendering means for generating raster image data by rendering each area of the image with reference to image data of the image object, and the decoding means generates raster image data of the attention area by the rendering means While the compressed data of the image object drawn in the attention area, Serial characterized by decoding at least a portion of the compressed data of the image object to be drawn in a subsequent region of the region of interest.

  According to the present invention, when rendering processing is performed based on intermediate data created for each region, it is possible to reduce the waiting time of rendering processing that occurs between regions.

Block diagram showing the overall configuration of the image forming apparatus Diagram showing an example of an image to be printed The block diagram which shows the detailed structure of the raster image data generation part in 1st Embodiment. The figure explaining the timing of the process in the image data and raster image data generation of printing object The block diagram which shows the detailed structure of a PDL processing part, and the figure which shows an example of intermediate data Diagram showing an example of schedule data The figure explaining the rendering processing based on the intermediate data created for each area Diagram showing an example of intermediate data Flow chart of intermediate data creation processing and raster image data generation processing Flow chart of intermediate data creation processing Detailed flowchart of predecessor task creation processing The figure explaining the process order in the raster image data generation process by 1st Embodiment The block diagram which shows the detailed structure of the PDL process part 105 in 2nd Embodiment. Flow chart of intermediate data creation processing Flowchart of processing by the PDL processing unit 105 and the raster image data generation unit 106

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the structure shown in the following Examples is only an example, and this invention is not limited to the structure shown in figure.

<First Embodiment>
(overall structure)
FIG. 1 is a block diagram showing an overall configuration of an image forming apparatus 100 applicable to the first embodiment. The image forming apparatus 100 includes a CPU 101, a ROM 102, a RAM 103, an input unit 104, an image processing unit 107, and an output unit 108. Further, the image forming apparatus 100 includes a PDL processing unit 105 and a raster image data generation unit as information processing apparatuses, and each component in the image forming apparatus 100 is connected via a bus 109.

  The CPU 101 comprehensively controls arithmetic processing and the operation of each unit of the image forming apparatus 100 by reading and executing a program stored in the ROM 102. A RAM (Random Access Memory) 103 is a readable / writable memory, and is a storage medium for temporarily storing various data such as image data. The input unit 104 receives data to be printed (hereinafter referred to as PDL data) described in a page description language transferred from a host PC or server (not shown), and stores it in the RAM 103.

  The PDL processing unit 105 analyzes the PDL data in page units received by the input unit 104 and converts it into intermediate data. The PDL data includes object information in the data to be printed and information indicating the position where the object is drawn on a page basis. The print page 200 shown in FIG. 2A will be described as an example of data to be printed. An image object 201, an image object 202, and a text object 203 are drawn on the print page 200. In the case of the print page 200, the PDL data includes information for reproducing each object and a drawing position for each object. Specifically, the data includes compressed data (hereinafter, compressed data) of the image objects 201 and 202, text information indicating the color and type of text, and information such as a background color. PDL data generally exists as files of various formats. Therefore, the PDL processing unit 105 converts the PDL data into intermediate data in a format that can be processed by the raster image data generation unit 106 in the image forming apparatus 100. At this time, the PDL processing unit 105 also creates schedule data for controlling the timing of rendering processing and decoding processing described later in the raster image data generation unit 106, and outputs the schedule data as part of the intermediate data.

  The raster image data generation unit 106 generates raster image data based on the intermediate data created by the PDL processing unit 105. Details of the PDL processing unit 105 and the raster image data generation unit 106 will be described later.

  The image processing unit 107 performs predetermined image processing on the raster image data generated by the raster image data generation unit 106 to generate print data. The output unit 108 is a printer engine using an inkjet method or an electrophotographic method. The output unit 108 forms an image on the recording medium according to the print data generated via the image processing unit 107.

(Detailed Configuration of Raster Image Data Generation Unit 106)
First, a detailed configuration of the raster image data generation unit 106 will be described with reference to FIG. In the first embodiment, the raster image data generation unit 106 includes a control unit 301, a rendering unit 302, and a decoding unit 303. The raster image data generation unit 106 has a decode buffer 304 for storing data. In the present embodiment, the rendering unit 302 and the decoding unit 303 function when the CPU 101 executes a computer program. However, the present invention is not limited to this example, and a part or all of it may be configured by dedicated hardware such as an ASIC or an electronic circuit.

  The rendering unit 302 performs a rendering process for each preset band based on the intermediate data. As shown in FIG. 2B, an area assigned with numbers 1 to 6 as identification information is a processing unit of the rendering unit 302 and is called a rendering band here. The rendering band is an area in the output space of the print page 200 whose height is a predetermined number of pixels and whose width is the page width. The height of the rendering band is set according to the processing speed and the memory capacity that can store the generated raster image data.

  The decoding unit 303 decodes image data (hereinafter, compressed data) compressed in a predetermined encoding format such as an image object among objects drawn on a print page. In the first embodiment, the compressed data of the image objects 201 and 202 are read out as necessary, and decoded every predetermined height. Here, the unit area where the image object is decoded is called a decode band. Two areas indicated by identification information a, b, c, d, and e in FIG. 2B represent processing units in the decoding unit 303. It can be seen that the image object 201 is divided into two regions of decode bands a and b, and the image object 202 is divided into three regions of decode bands c, d, and e. By decoding for each decoding band in this way, for example, when processing the rendering band 1, it is only necessary to decode not the entire image object 201 but the half area thereof. Therefore, decoding for each decoding band leads to efficient decoding processing and reduction of the decoding buffer 304. The height of the decode band is set according to the capacity of the decode buffer 304 that stores the decoded image data. The decode buffer 304 can store the image data decoded for each decode band. In the first embodiment, the decode buffer 304 has a capacity capable of storing data for three decode bands.

  Here, the processing order of rendering and decoding processing will be described with reference to FIG. The rendering unit 302 can start the rendering process of the rendering band to be processed after all the compressed data necessary for the rendering band to be processed has been decoded. That is, after the decoding of the decoding band a necessary for the rendering band 1 is completed, the rendering unit 303 can start the rendering process for the rendering band 1.

  On the other hand, the decoding unit should not rewrite or delete image data drawn in the rendering band being processed from the decoding buffer 304 while the rendering unit 302 is rendering. When the decoding unit 303 completes decoding of the decoding band c, the decoding buffer 304 stores the image data of the decoding bands a, b, and c, and there is no free space. The rendering band 2 being processed by the rendering unit 302 requires the image data of the decoding bands a and b, and the image data of the decoding band c is necessary for the next rendering process. Therefore, the decoding unit 303 waits for the rendering process of the rendering band 2 by the rendering unit 303 to be completed. When the rendering unit 303 proceeds to the processing of the rendering band 3, decoding of the decoding band d is started. The decoding unit 303 overwrites the decoded image data of the decoding band d on the area where the image data of the decoding buffer a is stored.

  As described above, there is a dependency between the rendering process and the decoding process as to whether the process can be started. Note that the fact that the decode buffer 304 has a capacity for three decode bands means that image data of three decode bands can be drawn for one render band. Therefore, the capacity of the decode buffer 304 is designed in consideration of the maximum number of decode bands drawn in one rendering band and the cost of memory capacity.

  The control unit 301 controls processing in each of the rendering unit 302 and the decoding unit 303 according to the intermediate data. The intermediate data includes information indicating a decoding band necessary for processing each rendering band and information indicating a rendering band that does not require each decoding band. The control unit 301 reads these pieces of information from the intermediate data, instructs the rendering unit 302 and the decoding unit 303 to start processing, and receives processing completion notification. The intermediate data will be described later.

(Detailed configuration of the PDL processing unit 105)
A detailed configuration and intermediate data of the PDL processing unit 105 will be described with reference to FIG. The PDL processing unit 105 functions as each processing unit when the CPU 101 executes a computer program. As described above, the PDL processing unit 105 creates intermediate data in a format that can be processed by the raster image data generation unit 106 based on the PDL data for one page. The PDL processing unit 105 includes a PDL interpreter 501 and an intermediate data creation unit 502. The PDL interpreter 501 interprets the PDL data, converts it into a drawing command, and outputs it to the intermediate data creation unit 502.

  The intermediate data creation unit 502 includes a rendering data creation unit 503, a compressed data creation unit 504, and a schedule data creation unit 505. The rendering data creation unit 503 creates rendering data 511 in a format that can be processed by the rendering unit 302 for each rendering band, based on the rendering command interpreted by the PDL interpreter 501. As described above, an area corresponding to a predetermined number of pixels (in this case, 64 pixels) in the main scanning direction and a predetermined number of pixels in the sub-scanning direction in the output space of the print page is set as a rendering band unit.

  The rendering data 511 includes area information included in the rendering band and object information for drawing an object in each area. As described above, as the object information, color information for drawing an area in a single color, image information for drawing an image object in the area, and the like are generated. When an image object straddles a plurality of rendering bands, information on the image object is included in rendering data corresponding to both rendering bands. However, the rendering position of the image object in the raster image data and the area used for rendering of the image object are different for each rendering band. In the example illustrated in FIG. 2, the rendering data creation unit 503 creates rendering data for each of the six rendering bands. The rendering unit 302 sequentially reads rendering data designated by an instruction from the control unit 301, and generates raster image data by performing rendering processing.

  The compressed data creation unit 504 reads compressed data compressed in various formats in accordance with a drawing command, and converts the compressed data 512 into a format that can be processed by the decoding unit 303 for each decoding band. Here, in the two-dimensional space in the image data held as compressed data, an image width in the horizontal direction and a region of 64 pixels in the vertical direction are set as decode bands. For the print page 200 shown in FIG. 2, the compressed data creation unit 504 divides each image object to create compressed data 512 of the decode bands a, b, c, d, and e.

  The schedule data creation unit 505 creates scheduling data for controlling the timing of rendering processing and decoding processing in accordance with a drawing command. The scheduling data includes a rendering schedule 513 for controlling processing timing in the rendering unit 303 and a decoding schedule 514 for controlling timing for decoding by the decoding unit 303. The schedule data creation unit 505 includes a decode buffer management unit 506, a dependency relationship determination unit 507, a drawing position calculation unit 508, a task creation unit 509, and a preceding possibility determination unit 510.

  The rendering schedule 513 is arranged in the order of rendering processing, and includes a task indicating rendering band identification information and a waiting ID indicating decoding band identification information associated with each task. The rendering task indicates identification information of a rendering band to be processed by the rendering unit 303. The waiting ID indicates the identification number of the last decoding band to be decoded by the decoding unit 304 before the rendering unit 303 starts processing for the rendering band to be processed. For example, in the rendering process shown in FIG. 2B, the rendering band 3 is rendered with the image data of the decoding bands b and c. Since the image object is decoded in the drawing order according to the drawing position, the decode band c to be decoded later is associated as a waiting ID corresponding to the task of the rendering band 3.

  FIG. 6A shows a rendering schedule for the rendering process shown in FIG. For a rendering task whose waiting ID is 0, it means that rendering for the rendering band can be executed immediately. The rendering schedule is sequentially read by the control unit 301 in the raster image data generation unit 106. When the control unit 301 refers to the rendering schedule 513 and confirms that the decoding process of the waiting ID corresponding to the processing target rendering band is completed, the control unit 301 instructs the rendering unit 302 to start the rendering processing for the processing target rendering band. .

  The drawing position calculation unit 508 first calculates the drawing position of the image object in the raster image data based on the drawing command obtained from the PDL interpreter 201. When an object to be drawn is held as compressed data, the task creation unit 509 determines a decode band to be drawn in each rendering band based on the calculated drawing position. The task creation unit 509 creates a task by associating the determined decode band as each waiting ID, and outputs a rendering schedule 513.

  On the other hand, the decode schedule 510 includes a decode task 510a indicating decode band identification information, and a wait ID 510b indicating rendering band identification information associated with each decode task a 510. When the waiting ID 510b indicates 0, it means that the corresponding decoding task 510a is immediately executed. When the waiting ID 510b indicates a value other than 0, it means that when the rendering task 509a of the rendering band indicated by the waiting ID is completed, the task is executed.

  The decoding schedule 510 is read in order from the top by the control unit 301. When the control unit detects that the rendering process of the rendering band indicated by the waiting ID corresponding to the read decode band has been completed, the control unit instructs to start the decode process of the read decode band.

  The dependency relationship determination unit 507 calculates the drawing end position of the image object in the raster image data based on the drawing command obtained from the PDL interpreter 201. Based on the calculated drawing end position, the dependency relationship determining unit 508 determines a rendering band in which each decode band is not referred to, and stores it as a dependency relationship between the decode band and the render band. The decode buffer management unit 506 holds in advance information indicating the number of decode bands that the decode buffer 304 can hold. The decode buffer management unit 506 can manage the use status (empty status) of the decode buffer 304. Based on the availability of the decode buffer 304, the task creation unit 509 creates a task by associating each task indicating the identification information of the decode band with a rendering band serving as a cue that can start the task.

  In the case of the print page shown in FIG. 2B, the correspondence (dependency relationship) between each decoding band and the rendering band in which the decoding band is not referred to is calculated as shown in FIG. 6B. Note that the decode bands are arranged in order from the top based on the drawing position. For example, the decode band a is a decode band that is decoded first, and when the rendering process proceeds to the render band 3, the area where the decode band a on the decode buffer 304 was stored can be overwritten. The task creation unit 509 determines the waiting ID of each decoding band based on the rendering band in which each decoding band is not referenced. The result is shown in FIG. In the first embodiment, since the decode buffer 304 can store three decode bands, the decode bands a, b, and c can store the decoded results without waiting for the decode buffer 304 to be free. . Therefore, the task creation unit 509 determines 0 as the wait ID for the decode bands a, b, and c. The decode band d can be stored in the decode buffer 304 when the decode band a can be released. Since the decoding band a can be overwritten when the rendering process of the rendering band 3 is performed, the task creation unit 509 determines the rendering band 2 as the wait ID of the decoding band d.

  As described above, the intermediate data creation unit 502 creates intermediate data. The created intermediate data is stored in the intermediate data buffer 507.

(When creating intermediate data for each divided area)
As described above, the intermediate data 506 includes rendering data, compressed data, and schedule data, and the amount of data may become enormous. Accordingly, a case will be described in which the intermediate data creation unit 502 creates intermediate data for each area for a print page in order to reduce the memory capacity of the intermediate data buffer 506. FIG. 7A shows a region 1 and a region 2 obtained by dividing the print page 200 in the horizontal direction.

  First, a case where intermediate data is created for each area by the same method as that when intermediate data is created without dividing a print page will be described with reference to FIG. The intermediate data creation unit 502 creates the intermediate data by interpreting the PDL data in the area 1 and stores it in the intermediate data buffer 507. For region 1, rendering data 511 corresponding to three rendering bands is created. Three compressed data 512 are created corresponding to three decoding bands a and b corresponding to the entire area of the image object 201 and a decoding band c in which the image object 202 is partially drawn. The raster image data generation unit 106 performs decoding and rendering processing on the rendering bands 1, 2, and 3 and the decoding bands a, b, and c constituting the area 1 based on the intermediate data of the area 1. When the rendering process of the rendering band 3, which is the last task, is started, the intermediate data buffer 506 can be overwritten.

  The intermediate data creation unit 502 creates the intermediate data by interpreting the PDL data in the area 2 and writes it in the intermediate data buffer 507. For the area 2, three compressed data 212 are created corresponding to the rendering data 511 corresponding to the three rendering bands and the decoding bands c, d, and e which are all areas of the image object 202. The raster image data generation unit 106 reads the intermediate data of the region 2 from the intermediate data buffer 506, and executes the rendering process and the decoding process for the rendering bands 4, 5, 6 and the decoding bands c, d, e.

  As described above, when intermediate data is created for each area, the rendering process for the area 2 must start from the decoding process of the decoding band necessary for the rendering band to be rendered first. As a result, if intermediate data is created for each print page for one page, the waiting time until an image object necessary for rendering is decoded is increased compared to the case where intermediate data is created without being divided. There is a case. The waiting time for the decoding process in this area 2 is longer than that in the case of not dividing as shown in FIG.

  Therefore, in the first embodiment, when intermediate data is created for each area for one print page, PDL data necessary for an area not included in the intermediate data is referred to according to the use state of the decode buffer. Create schedule data. That is, if an area in which intermediate data is to be created is an attention area, at least a part of the decoding band of an image object drawn in an area other than the attention area is decoded in advance. Therefore, the preceding possibility determination unit 510 refers to the PDL data of the area to be processed next, and determines whether or not the compressed data necessary for the rendering band rendered first in the area to be processed can be decoded in advance. To do. FIG. 8 shows an example of the result of the schedule data creation unit 505 creating intermediate data for each area.

  The task creation unit 509 creates a decoding schedule for precedingly decoding the compressed data to be decoded in the area to be processed next, according to the determination result by the preceding possibility determination unit 510. Further, the compressed data is generated as the preceding decoding band by compressing the decoding band to be decoded in advance. In other words, in the first embodiment, when intermediate data is created for each area, a preceding task that uses the decoding band of the area in which the intermediate data is created next and the decoding of the area in which the intermediate data is created next as identification information, It will be included in the intermediate data. The preceding decoding band included in the compressed data is compressed data of an image object that is not drawn in the attention area.

(Overall processing flow in the information processing apparatus)
Here, an overall processing flow by the PDL processing unit 102 and the raster image data generation unit 106 functioning as an information processing apparatus will be described. FIG. 9 is a flowchart of overall processing by the PDL processing unit 102 and the raster image data generation unit 106. The function of each processing unit is realized by the CPU 101 reading and controlling a program that can realize the flowchart shown in FIG.

  In step S <b> 901, PDL data to be printed is input to the PDL processing unit 102. In step S902, the PDL processing unit 102 creates and outputs intermediate data for each region based on PDL data for a predetermined region. First, the PDL interpreter 501 interprets PDL data in a part of the PDL data and converts it into a drawing command. The intermediate data creation unit 502 creates intermediate data in accordance with the rendering command interpreted by the PDL interpreter 501. Details of the intermediate data creation processing will be described later. The created intermediate data is stored in the intermediate data buffer 507 of the RAM 103. When the PDL processing unit 102 creates the intermediate data of the area, the PDL processing unit 102 sends a completion notification to the CPU 101.

  In step S <b> 903, the control unit 301 of the raster image data generation unit 106 reads intermediate data from the intermediate data buffer 507. In step S904, the control unit 301 refers to the rendering schedule included in the read intermediate data, reads a task to be processed, and determines a rendering band to be processed. The control unit 301 determines whether or not the rendering process of the rendering band to be processed can be started based on the task wait ID. If the wait ID is 0 or the decoding process of the decode band indicated by the wait ID has been completed, the control unit 301 proceeds to step S908. If the decoding process of the decoding band indicated by the waiting ID has not been completed, the control unit 301 proceeds to step S905.

  In step S905, the control unit 301 instructs the decoding unit 303 to start decoding processing up to the decoding band described in the waiting ID of the task to be processed. In step S906, the decoding unit 303 reads the compressed data included in the intermediate data in accordance with the instruction from the control unit 301, and sequentially decodes up to the designated decoding band. In step S907, the decoding unit 303 stores the image data obtained by decoding in the decoding buffer 304.

  When detecting that the decoding process of the decoding band indicated by the waiting ID of the processing target task is completed, the control unit 301 causes the rendering unit 302 to start the rendering process of the rendering band of the identification information indicated by the task in step S908. In step S909, the rendering unit 302 starts rendering the rendering band instructed by the control unit 301. When the decoded image data is necessary for the rendering band to be processed, it is read from the decode buffer 304. In step S910, the rendering unit 302 outputs raster image data generated by the rendering process.

  In step S908, when the control unit 301 instructs to start rendering, the control unit 301 proceeds to step S911 and determines whether the rendering process instructed to start is the last. In the last case, the decoding unit 303 means that the decoding of all the decoding bands has been completed. If the rendering unit 302 reads the rendering data of the last rendering band, the intermediate data buffer 507 can be overwritten. Therefore, when the rendering instructed to start is the last rendering band, the control unit 301 transmits a completion notification.

  In step S913, the PDL creation unit 102 determines whether intermediate data has been created for all areas of the print page. If there is an area for which intermediate data has not been created, the process returns to step S902, and the PDL processing unit 102 creates intermediate data for the next area.

(Processing flow in the intermediate data creation unit 502)
The intermediate data creation process executed by the intermediate data creation unit 502 in step S902 will be described in detail with reference to the flowchart of FIG. FIG. 11 further shows a flowchart of the preceding task creation process by the task creation unit 509 and the preceding decode band creation process by the compressed data creation unit 504.

  First, in step S1001, the intermediate data creation unit 502 starts creating rendering data and compressed image data under the control of the CPU 101. As described above, the intermediate data creation unit 502 divides the print page into region 1 and region 2 to create intermediate data. Hereinafter, it is assumed that intermediate data of region 1 is created. In step 1002, the rendering data creation unit 503 creates rendering data for each rendering band of a predetermined height.

  In step S1003, the compressed data creation unit 504 detects whether there is an object to be drawn on the raster image data. If there is no image object, only rendering data becomes intermediate data, and the process advances to step S1016. If there is an image object, the process proceeds to step S1004, and if it is the first area such as area 1, the process proceeds to S1006. The compressed data creation unit 504 converts the detected image object into compressed data for each decoding band for a predetermined height. By the processing so far, for the region 1, rendering data of three rendering bands and compressed data of three decoding bands drawn in the region 1 are created. If it is determined in step S1004 that processing is to be performed after the previous area as in area 2, the process proceeds to step S1005 to detect whether the decode buffer 304 has a decoded band that has been decoded in the previous area. By acquiring the decode buffer usage status stored in the decode buffer management unit 506, it is detected whether the detected image object is decoded in advance in the previous area. Image objects that have been decoded in advance are excluded from the target of creating compressed data, and those that have not been decoded are converted into compressed data in step S1006.

  If it is detected in step S1007 that the creation of rendering data and compressed data has been completed, the process advances to step S1008 to instruct the schedule data creation unit 505 to start creating schedule data.

  In step S1009, the drawing position calculation unit 508 first calculates the position where the object is drawn. In step S1010, the task creation unit 509 associates each rendering band with the decoding band that is rendered last as a waiting ID. For example, with respect to the rendering band 2 shown in FIG. 2B, the decoding band b is positioned in the raster order behind the decoding band a, and therefore, the rendering band 2 is associated with the decoding band b and is set as a waiting ID. Set. When the task creation unit 509 sets all the rendering bands as tasks and sets a waiting ID, the task creation unit 509 outputs the rendering schedule.

  In step S <b> 1011, the dependency relationship determination unit 815 determines the dependency relationship between the decode band and the rendering band. The dependency relationship means a correspondence relationship between a decoding band and a rendering band that does not refer to image data of the decoding band. The dependency relationship determination unit 507 refers to the position at which drawing of each decode band ends, and associates the rendering band that is rendered next to the rendering band at the end position.

  In step S1012, the task creation unit 509 selects a decode band in the drawing order, and sets identification information of the selected decode band as a task. In step S1013, the task creation unit 509 refers to the dependency between the decode band and the render band and the availability of the decode buffer 304 managed by the decode buffer management unit 506, and determines the waiting ID of the selected decode band. . If there is an empty area in the decode buffer 304, the selected decode band does not need to wait for the completion of rendering, so the wait ID becomes 0. Also, when there is no free space in the decode buffer 304, the dependency relationship is referred to, it is detected which rendering band is completed when the rendering process is completed, and the rendering band in which the free area is formed is determined as a waiting ID. . For example, when the decode band d is selected, the image data of the decode bands a, b, and c are stored in the decode buffer 304 and there is no free space. Referring to the dependency relationship, it can be seen that among the stored decoding bands, the decoding band a is not referred to when the processing proceeds to the rendering band 3. Therefore, the task creation unit 509 determines the rendering band 3 as a waiting ID for the task of the decode band d.

  In step S1014, the decode buffer management unit 506 updates the use status of the decode buffer 304 in accordance with the determined decode task and waiting ID. The decode buffer management unit 506 holds in advance information indicating the number of decode bands that can be stored in the decode buffer 304. If the wait ID of the decode task is determined to be 0 in step S1013, it is stored that 1 is decremented from the free space at the timing when the decode task is started. Also, in step S1013, the dependency relationship of the decoding task is referred to, and at the timing when the rendering band that is no longer referenced is completed, the free space is increased by the number of decoding bands that have a dependency relationship with the rendering band.

  In step S1015, the task creation unit 509 determines whether all decode bands have been selected as decode tasks. If not all decode band tasks have been created, the process returns to step S1012. If tasks for all the decode bands have been created, the process proceeds to step S1016.

  In step S1017, the task creation unit 509 creates a preceding task for precedingly decoding an image object to be drawn in the area where intermediate data is to be created next. Details of the preceding task creation process will be described later. As shown in FIG. 8, the predecessor task created here is arranged after the task created in step S1013 as part of the decode schedule.

  In step 1018, the intermediate data creation unit 502 transmits the intermediate data created by the above processing to the intermediate data buffer 507 and completes the creation of the intermediate data in the area 1.

  The flow of the preceding task creation process in step S1016 will be described with reference to FIG. First, in step S1102, the decode buffer management unit 506 updates the use status of the decode buffer at the timing when all the decode tasks in the area where the intermediate data is created are completed. Specifically, in the area 1, all the decoding tasks are completed when the decoding of the decoding c is completed and the task processing of the rendering band 2 is being performed. At this time, since the rendering band 2 requires the image data of the decode bands a and b, there is no area that can be overwritten. Therefore, the decode buffer management unit 508 updates 0 as the buffer free space when decoding of the decode c is completed.

  Next, in step S1103, the task creation unit 509 refers to the rendering command for the area where intermediate data is to be created next, and the image objects to be rendered next in the area where the intermediate data is created are processed in order from the first rendering band. Until it is detected. In the case of the present embodiment, the drawing command for the area 2 is referred to, and it is detected that the decode band c and the decode band d are drawn in the first band of the area 2.

  In step 1104, the drawing position calculation unit 508 calculates a rendering band in which the detected image object starts to be drawn and a rendering band in which drawing has ended. In the case of the decode band c, drawing starts from the rendering band 3 in the area 1 and drawing is completed in the rendering band 4 in the area 2. In the case of the decode band d, drawing is started from the rendering band 4 in the area 2 and drawing is completed in the rendering band 5 in the area 2.

  In step S1105, the task creation unit 509 detects whether the detected image object has already been decoded based on the use state of the decode buffer updated in step 1102. If the detected image object has already been decoded into the decode buffer, the preceding task creation process is skipped, and the process returns to step S1103 to repeat the detection of the next image object. In step S1105, if not decoded, the process proceeds to step S1106.

  In the case of the example shown in FIG. 7B, the decode band c drawn in the rendering band 4 in the region 2 is also drawn in the rendering band 3 in the region 1. Therefore, before the preceding task is executed, it has already been decoded and remains in the decoding buffer. Therefore, the decode band c is not the target of the preceding task. On the other hand, the decode band c is not drawn in the rendering band of the region 1, but is rendered up to the rendering band 4 in the region 2. Therefore, it is necessary that the decoding result of the decoding band c is not released in the decoding buffer 304 until the rendering processing of the rendering band 4 is completed. In step S <b> 1105, the decode buffer management unit 506 stores information on the decode band drawn in the subsequent area as in the decode band c. The information of the decode band drawn in the subsequent area is referred to in step S1105 when the intermediate data of area 2 is generated. If data to be referred to remains in the decode buffer, the process of creating compressed data for that decode band is skipped and the data to be referred to is not overwritten.

  In step S <b> 1106, the task creation unit 509 determines whether the decode band for which the preceding task is created can be decoded at the timing when the decode of the decode band in the region 1 is completed. In the case of this embodiment, when the decoding of the decoding band c is completed, there is no empty area in the decoding buffer 304, and therefore it is determined that decoding is not possible in S1106.

  If it is determined in step S1106 that decoding cannot be performed, the decode buffer management unit 506 checks the drawing end band of the image object that is using the buffer in step S1107. In step S1108, the task generation unit 509 detects the next timing at which the decode buffer 304 can be decoded. In the example shown in FIG. 7, when the task of the rendering band 2 in the region 1 is completed after the decoding of the decoding band c is completed, the image data of the decoding band a is not necessary, and the decoding buffer 304 has a free space.

  In step S1109, the preceding possibility determination unit 510 determines whether a preceding task can be created. Specifically, it is determined whether or not the timing at which the free space detected in S1108 is available is before the end of rendering of area 1. In the example of FIG. 7, it is detected that the free space is available before the completion of the rendering task in the area 1, and therefore the advance possibility determination unit 510 determines that the advance task can be created.

  If it is determined in step S1109 that the preceding task can be created, in step S1110, the compressed image creation unit 504 creates the compressed image data of the decoding band that is the target of the preceding task as the preceding decoding band of the region 2. In step S1111, the task creation unit 509 creates a task of the decode band that is the target of the preceding task. Here, since the decoding band d that is the target of the preceding task can be decoded when the processing of the rendering band 3 is started, the waiting ID 3 is associated with the preceding task d.

  In step S <b> 1112, the task creation unit 509 adds the preceding compressed data that is not drawn in the area 1 to the already created compressed data in the area 1. In addition, a preceding task is added to the decoding schedule of area 1.

  Finally, in step S1113, the information stored in the decode buffer management unit 506 is updated to the usage status of the decode buffer 304 at the timing when the added preceding task is completed.

  When the preceding task is added, the process returns to step 1103 and the detection of the image object is repeated. If it is determined in step S1108 that the detected object cannot be decoded in advance, or if no image object is detected, the process proceeds to step S1114 to complete the preceding task creation.

  As described above, in the present embodiment, intermediate data is generated including a decoding process that is not drawn in the area where the intermediate data is currently created so that the decoding process of the area where the intermediate data is created next can be preceded. . FIG. 12 shows a rendering process and a decoding process when intermediate data is created for each area by the above-described flow. Since the decoding band d is decoded in advance, the rendering unit 2 can start the rendering process of the rendering band 4 in the region 2 without waiting for the decoding process.

  As described above, the intermediate data buffer 507 can be reduced in cost by dividing one page and generating intermediate data for each region. Furthermore, when an image object straddles between areas, a decoding band drawn in the next area is detected and decoded in advance in consideration of the use status of the decoding buffer, thus reducing processing degradation due to waiting. be able to. Furthermore, by managing the empty state of the decoding buffer based on the dependency between rendering and decoding, a compressed image that cannot be decoded in advance and a task are not added. For this reason, the processing time for generating redundant intermediate data can be reduced, and the size of the intermediate data does not increase redundantly. In addition, since the raster image data generation unit can read the dependency relationship between rendering and decoding from the intermediate data, it can process the intermediate data with a simple configuration that does not require management of the decode buffer or analysis of the dependency. .

  In the first embodiment, an example in which the PDL processing unit 105 and the raster image data generation unit 106 that function as an information processing apparatus are built in the image forming apparatus 100 has been described. However, a part or all of the information processing apparatus may have a configuration independent of an apparatus having an output unit that executes printing. For example, the PDL processing unit 105 can be realized as software of an information terminal such as a personal computer (PC) or a tablet. In this case, when an image forming apparatus to be printed is specified, the PDL processing unit 105 executes PDL processing corresponding to the image forming apparatus to be printed.

Second Embodiment
In the first embodiment described above, after a decoding schedule necessary for an area is created, the preceding task is created by referring to the PDL data of the area where intermediate data is to be created next based on the usage status of the decoding buffer 304. In the second embodiment, a description will be given of a method for creating compressed data and a decoding task in advance by continuing to create compressed data to be decoded next regardless of an area to be drawn if there is a space in the decoding buffer 304. . FIG. 13 shows detailed blocks of the PDL processing unit 105 in the second embodiment. In the second embodiment, since the decoding task is created if there is free space in the decoding buffer 304, the advance possibility determination unit 510 is not required. In addition, about the structure similar to 1st Embodiment, the same number is attached | subjected and the description is abbreviate | omitted.

  FIG. 14 is a flowchart during the intermediate data creation process in the second embodiment. Steps S1401 to S1408 will be described.

  First, in step S1401, the task creation unit 509 determines whether the creation of a decoding task for an image object to be drawn in the attention area has been completed. If not all decode band tasks have been created, the process returns to step S1010. The task is created for all the decoding bands of the image object drawn in the attention area, but the process proceeds to step S1402.

  In step S1402, the task creation unit 509 checks the usage status of the decode buffer 304 when all the decode bands have been decoded. If there is no free space in the decode buffer 304, the dependency relationship of each decode band of the created task is further referred to. If there is a decoding band that has a free space when all the decoding bands have been decoded, but has a rendering band that is no longer referenced, the process proceeds to step S1402. If there is no free space when decoding of all the decoding bands is complete and there is no decoding band in the area that is not referenced, none of the decoding bands can be overwritten while rendering in the area. Means that. Accordingly, since the decoding band of the image object drawn in the next area cannot be decoded in advance, the creation of the schedule data is completed in step S1015.

  In step S1403, the compressed data creation unit 504 detects an image object in an area where intermediate data is created after the attention area. If there is no image object after that, the process advances to step S1015 to complete the process. If the image object can be detected, the decoding band is specified, and the process proceeds to step S1404.

  In step S1404, the task creation unit 509 selects the decode band detected in step S1403 as a preceding task. In step S1405, the task creation unit 509 sets, as a waiting ID, a timing at which an empty area is created in the decode buffer 304 during rendering of the attention area in step S1402.

  In step S1406, the compressed data creation unit 504 creates compressed data of the decode band specified in step S1403. In step S1407, the usage status of the decode buffer 304 is updated, the compressed data created in step S1406 is added to the compressed data in step S1408, and the task created in step S1405 is added to the decode schedule.

  According to the above processing, when the intermediate data creation unit 502 creates intermediate data for each area obtained by dividing the print page, the rendering data and the rendering schedule are targeted only within the area. On the other hand, the compression data and the decoding schedule of the drawing object are created including the image objects of other regions according to the use situation of the decoding buffer. When any one of the decoding bands can be overwritten in the decoding buffer, decoding of the compressed data of the image object other than the attention area is started in advance. As a result, the compressed data necessary for subsequent rendering is sequentially decoded at the earliest timing in the decode buffer. As a result, it is possible to reduce the decoding waiting time caused by creating intermediate data for each region.

<Third Embodiment>
In the first embodiment described above, the start of decoding is controlled in response to the process determination as to whether or not the rendering band to be processed can be started in step S904. In the third embodiment, a method for performing a decoding start instruction and a rendering start instruction in parallel will be described. In addition, about the structure similar to 1st Embodiment, the same number is attached | subjected and the description is abbreviate | omitted.

FIG. 15 is a flowchart of overall processing by the PDL processing unit 105 and the raster image data generation unit 106 in the third embodiment.
Since the processing from the step S1501 to the reading of the intermediate data in the step S1503 is the same as the processing in the first embodiment from the step S901 to the step S903, the description thereof is omitted.

  In step 1504, the control unit 301 refers to the decoding schedule included in the read intermediate data, reads the decoding task to be processed, and determines the decoding band to be processed. Based on the task wait ID, the control unit 301 determines whether the decoding process of the decoding band to be processed can be started. If the wait ID is 0 or the rendering process indicated by the wait ID has been completed, the control unit 301 proceeds to step S1505.

  In step S1505, when the control unit 301 instructs the decoding unit 303 to start decoding processing of the decoding band to be processed, the control unit 301 proceeds to step S1508 without waiting for completion notification. If the rendering process indicated by the waiting ID in step S1504 has not been completed, the process proceeds to step S1508 without instructing the start of the decoding process.

  In step S1506, the decoding unit 303 reads the compressed data included in the intermediate data in accordance with the instruction from the control unit 301, and performs decoding processing on the instructed decoding band. In step S1507, the decoding unit 303 stores the image data obtained by the decoding in the decoding buffer 304, and notifies the control unit 301 of the completion of decoding when the decoding process is completed.

  In step S1508, the control unit 301 refers to the rendering schedule included in the read intermediate data, reads a task to be processed, and determines a rendering band to be processed. The control unit 301 determines whether or not the rendering process of the rendering band to be processed can be started based on the task wait ID. If the wait ID is 0 or the decoding process of the decode band indicated by the wait ID has been completed, the control unit 301 proceeds to step S1509.

  In step S1509, when the control unit 301 instructs the rendering unit 302 to start rendering processing of the rendering band to be processed, the process proceeds to step S1512 without waiting for completion notification. If the decoding process indicated by the waiting ID in step S1508 has not been completed, the process proceeds to step S1512 without instructing the start of the rendering process.

  In step S1512, the control unit 301 waits for a notification of completion of the decoding process and the rendering process instructed in step S1505 or step S1509. When the completion notification of either the decoding process or the rendering process is detected, the process proceeds to step 1513, where it is determined whether or not the process of the last rendering band has been completed. If the rendering process is still in progress or there is an unprocessed rendering band, the process returns to step S1504, and the next decoding band or the next rendering band is processed. When it is detected that the processing of the last rendering band has been completed, the intermediate data buffer 507 can be overwritten, and a completion notification is transmitted.

  In step 1515, the PDL creation unit 102 determines whether intermediate data has been created for all areas of the print page. If there is an area for which intermediate data has not been created, the process returns to step S1502, and the PDL processing unit 102 creates intermediate data for the next area.

  As described above, the decoding process and the rendering process are controlled so as to execute the process if there is a process that can instruct the start of the process while waiting for the completion of the process having the dependency relationship. The start instruction and the rendering start instruction can be performed in parallel. As a result, the waiting time for rendering processing and the waiting time for decoding processing can be reduced.

  In the above-described embodiment, the control unit 301 instructs the rendering unit 302 and the decoding unit 303 to start processing, but two control units 301 may be configured independently. The rendering control unit that instructs the rendering unit 302 to start the rendering process and the decoding control unit that instructs the decoding unit 303 to start the decoding process are configured independently, thereby rendering the rendering process and the decoding process start instruction in parallel. It is good also as a structure performed to.

<Other embodiments>
In the above-described embodiment, there is no restriction on the area in which the compressed data is created in advance, but the restriction may be provided in consideration of the case where the image object to be drawn is not included in the area. For example, even if the subsequent area is processed up to two areas ahead, if the preceding compressed data is not created or if the decoding buffer is not empty, the creation of the compressed image data 212 may be finished.

105 PDL processing unit 105
106 Raster image data generation unit 502 Intermediate data creation unit 505 Schedule data creation unit 506 Decode buffer management unit 507 Dependency determination unit 508 Drawing position calculation unit 509 Task creation unit 510 Precedence determination unit

Claims (11)

An information processing apparatus that converts print data representing an input image to be printed into raster image data,
Decoding means for decoding compressed compressed data of an image object drawn on the image based on the print data;
A first holding means for holding the image data of the image object obtained as a result of the decoding means decoding the compressed data;
Rendering means for generating raster image data by rendering for each area of the image while referring to the image data of the image object held by the holding means;
The decoding means includes compressed data of an image object drawn in the attention area and an image object drawn in a subsequent area of the attention area while the rendering means generates raster image data of the attention area. An information processing apparatus that decodes at least a part of the compressed data. Furthermore, interpreting means for interpreting the print data and converting it into a drawing command;
In accordance with the drawing command, for each of the areas, intermediate data creating means for creating compressed data of an image object drawn on the image and intermediate data including rendering data of the image,
The decoding means decodes the compressed data included in the intermediate data, and the rendering means renders the rendering data,
The intermediate data creating means
Rendering data of the region of interest processed by the rendering means;
The compressed data of the image object drawn in the attention area and the compressed data of at least a part of the image object drawn in the area where intermediate data is created after the attention area without being drawn in the attention area. The information processing apparatus according to claim 1, wherein intermediate data including the intermediate data is created. The processing unit of the rendering unit is a rendering band, the decoding unit of the processing unit of the decoding unit,
The intermediate data creating means includes schedule data indicating the timing at which the rendering means can start rendering for each rendering band for the attention area;
3. The information processing apparatus according to claim 2, wherein schedule data indicating a timing at which the decoding unit can start decoding is created for each decoding band. The intermediate data creation means includes
Means for managing the usage status of the first holding means;
Calculating means for calculating a drawing position at which the image object is drawn in the print data;
Determining means for determining a correspondence relationship between each of the decoding bands and a rendering band in which image data of the decoding band is not referred to based on the drawing position;
Determination means for determining whether or not an image object drawn in an area other than the attention area can be decoded in advance based on the usage situation and the correspondence relationship;
Creating means for creating a task in which the identification information of the decoding band and the identification information of the rendering band to be waited for completion of rendering before starting the decoding band are associated as a waiting ID;
If it is determined by the determination unit that the task can be decoded in advance, based on the usage status, the task generation unit is not drawn in the attention area, but is an area in which intermediate data is generated after the attention area. 4. The information processing apparatus according to claim 3, further comprising: generating a decoding task for generating compressed data of at least a part of an image object to be drawn and controlling start of decoding the compressed data.   The task means creates a rendering task in which the identification number of a rendering band is associated with the identification number of the last decoding band to be decoded before rendering of the rendering band is started. The information processing apparatus described in 1.   The information processing apparatus according to claim 3, further comprising a control unit that reads the intermediate data and controls the rendering unit and the decoding unit according to the decoding task and the rendering task included in the intermediate data. .   The compressed data of the image object drawn in the area subsequent to the attention area is compressed data used for drawing only in the subsequent area. Information processing device. The intermediate data creating means determines whether or not there is compressed data already decoded in the compressed data of the image object drawn in the attention area,
3. The information processing apparatus according to claim 2, wherein if there is already decoded data, the intermediate data in the region of interest does not include the already decoded compressed data.   Furthermore, it has a 2nd holding means to hold | maintain the said intermediate data, The said 2nd holding means can hold | maintain only the intermediate data of one area | region among these several area | regions. The information processing apparatus described in 1.   A computer program that causes a computer to function as the information processing apparatus according to claim 1 by being read and executed by a computer. An information processing method for converting print data representing an input image to be printed into raster image data,
Decoding encoded compressed data of an image object drawn on the image based on the print data;
The process includes generating raster image data by rendering each area of the image while referring to the image data of the image object.
The decoding step includes the compressed data of the image object drawn in the attention area and the image drawn in the subsequent area of the attention area while the rendering step generates raster image data of the attention area. An information processing method characterized by decoding at least part of compressed data of an object.

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