JP4955582B2 - Image processing apparatus and image processing program - Google Patents

Description

  The present invention relates to an image processing apparatus such as a print processing apparatus that processes a print request for data composed of text, images, and path graphics, and an image processing program thereof.

  Normally, in a rendering process in an image processing apparatus, after inputting PDL (page description language), the PDL is interpreted and converted into a code that can be drawn by a printer. The converted code forms a page as a display list. When the display list of pages is created, they are scanned to create a page bitmap and output to the video engine.

  Also, with colorization, from the viewpoint of memory management, rendering processing inside the printer is generally performed for each band (page width divided in a horizontal direction at a page width) instead of one page. is there.

  For example, in an image forming apparatus having a printing function, such as a printer, a copier, a facsimile machine, or a multi-function machine of these, once a print job for one page is divided into a plurality of bands and then converted into an intermediate code and stored in memory. The memory area is saved by accumulating in the area, rasterizing the accumulated intermediate code into a bit image and printing the image in page units.

  Here, when large image data or the like is input, the memory resources of the printer system may be exhausted while creating the display list. In this case, the display list up to the middle of the page is rasterized, converted into a bitmap, and the display list is released (pre-rendering). The pre-rendering is executed when the real-time rendering cannot be performed in addition to the memory shortage. The pre-rendering handled here refers to pre-rendering from the viewpoint of memory management.

  For example, pre-rendering is performed to ensure that printer rendering is performed, and pre-rendering is performed to compress memory in order to avoid the occurrence of memory overflow or to solve the memory shortage during rendering. The intermediate data is released (see, for example, Patent Document 1).

  Here, FIG. 11 shows a state of pre-rendering that is triggered by a memory shortage.

  In the example shown in FIG. 11, when a display list is created by dividing one page into a plurality of bands as shown in (A), memory is insufficient while creating the display list for band 5 shown in (B). Therefore, as shown in (C), pre-rendering is performed in which the display lists of bands 1 to 4 created so far are rasterized, converted into bitmaps, and the display list is released.

JP-A-10-116160

  By the way, in the method of Patent Document 1, the memory shortage can be solved by pre-rendering, but since the timing for executing the pre-rendering is when the memory shortage occurs, it cannot be said that the pre-rendering is efficient with consideration of the processing speed. .

  Accordingly, an object of the present invention is to realize automatic optimization pre-rendering by determining the timing of execution of pre-rendering from the past data transmission method in view of the conventional problems as described above.

  Other objects of the present invention and specific advantages obtained by the present invention will become more apparent from the description of embodiments described below.

  In the present invention, whether to perform pre-rendering is determined by comparing the average size of the display list with the remaining number of display lists.

  That is, the present invention is an image processing apparatus, and includes a data analysis unit that analyzes received print data, and a predetermined band unit that extends a drawing image in one direction based on an analysis result of the print data by the data analysis unit. A display list creation means for creating a display list as an intermediate code by dividing the display list, a rendering means for executing a rendering process for converting the display list into bitmap data, and a display list created by the display list creation means Display list history information management means for storing and managing the size as history information, and the rendering means compares the cumulative size of the display list created by the display list creation means with the size indicated by the threshold, and Cumulative support When the display reaches the size indicated by the threshold value, the history information of the past display list size stored and managed by the display list history information management means when pre-rendering is executed to release the display list being created. When the difference between the average size of the past display list obtained based on the above and the accumulated size is less than a predetermined size smaller than the size indicated by the threshold, the pre-rendering is skipped and the accumulated size is Pre-rendering is performed when the average size of the past display list is reached.

  In the image processing apparatus according to the present invention, for example, the display list history information management unit determines whether or not the display list created by the display list creation unit is an image display list, and creates the display list. Is a display list of images, the size of the source image indicated by the display list is calculated and stored and managed as history information of the display list.

  The image processing apparatus according to the present invention further comprises information storage means for storing the history information of the display list, and the display list history information management means determines the size of the past display list from the information storage means when the system is started up. Read as history information and calculate the average size of past display lists.

  According to the present invention, the received print data is analyzed by the data analysis means, and based on the analysis result, the display list creation means divides the drawn image into predetermined band units extending in one direction and displays the intermediate code. An image processing program that is executed by a computer provided in an image processing apparatus that performs a rendering process for creating a list and converting the created display list into bitmap data by a rendering unit, the program being created by the display list creating unit The display list size is stored and managed by the display list history information management unit as history information, and the size indicated by the cumulative size and threshold value of the display list created by the display list creation unit by the rendering unit When the accumulated size reaches the size indicated by the threshold value, the pre-rendering is executed to release the display list being created. If the difference between the average size of the past display list obtained based on the history information of the display list and the cumulative size is less than a predetermined size smaller than the size indicated by the threshold value, pre-rendering is executed. The computer is controlled to execute pre-rendering when the accumulated size reaches the average size of the past display list.

  The image processing program according to the present invention, for example, determines whether or not the display list created by the display list creation means is an image display list by the display list history information management means, and creates the display list. Is a display list of images, the size of the source image indicated by the display list is calculated and stored and managed as history information of the display list.

  In addition, the image processing program according to the present invention, for example, reads the past display list size as history information from the information storage unit by the display list history information management unit when the system is started, and calculates the average size of the past display list. The computer is caused to perform a calculation process.

  According to the present invention, it is possible to effectively execute pre-rendering by storing the total size of display lists created on pages printed in the past and taking the average of those sizes.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Needless to say, the present invention is not limited to the following examples, and can be arbitrarily changed without departing from the gist of the present invention.

  The present invention is applied to the image processing apparatus 20 in the printing system 100 in which the host computer 10 and the image processing apparatus 20 are connected to each other via a network 15 such as a LAN, as shown in FIG. .

  In the printing system 100, the image processing apparatus 20 is a printer apparatus having a function of printing print data supplied from the host computer 10, and includes a computer (CPU) 21 that controls the entire apparatus and performs various arithmetic processes. A read only memory (ROM) 22 for storing programs and data, a random access memory (RAM) 23 for temporarily storing programs and data as a work area, a hard disk for storing various programs and data, etc. The information storage unit 24, the operation panel unit 25 used for displaying various information and inputting various instructions, and various image data on a recording medium such as paper using a known image forming process such as an electrophotographic process. Printing unit 26 for printing and LA for connecting to the network 15 A communication interface 27 such as a card is connected to each other via a bus 28.

  In the printing system 100, the CPU 21 provided in the image processing apparatus 20 executes image processing according to an image processing program read from the ROM 22, for example.

  As shown in the block diagram of FIG. 2, the image processing apparatus 20 receives a printable file sent from the host computer 10 via the communication interface 80 and buffers printable data. The print data reception storage unit 211 to perform, the PDL analysis unit 212 that branches the printable data received by the print data reception storage unit 211 to an appropriate process by analyzing an instruction by an emulator, and the drawing analyzed by the PDL analysis unit 212 A display list creation unit 213 that creates a display list divided into drawing primitives for efficient page rendering of data, a display list included in a page created by the display list creation unit 213 is rendered, and a video is rendered. The page rendering unit 214 that creates a bitmap on the AM, and the display list created by the display list creation unit 213 discriminates the type of image, path graphic, character, etc., and the corresponding identifier is used as the history of the display list. A display list history information management unit 215 managed as information, a display list history information storage unit 216 storing display list history information managed by the display list history information management unit 215, and the like are mounted as processing functions by the CPU 21. The printing unit 26 actually prints on the recording medium in accordance with the bitmap created by the page rendering unit 214.

  In the image processing apparatus 20 in the printing system 100, in order to use pre-rendering effectively, it is executed when the display list reaches a certain size. For example, when the display list has a capacity larger than the size of the band buffer. The threshold value at this time is [PR]. However, there are times when the predetermined size is not appropriate. Pre-rendering can create a free area of memory, but on the other hand, it takes time to execute rasterization processing and compression processing. For example, when there are only five display lists in band 8 as in the display lists of bands 1 to 8 shown in FIG. 3, the total performance is improved by not executing the second pre-rendering. That is, as shown in FIG. 4, the threshold value [PR] is reached at the time of the second pre-rendering, but since the average size of past page display lists is close to [110], the display list is accumulated up to that size. Wait until you do not pre-render. If the size of the display list reaches the average size [110], pre-rendering is executed at that time.

  That is, in the image processing apparatus 20 in the printing system 100, the type of the display list created by the display list creation unit 213 is stored and managed as history information.

  That is, in the printing system 100, the printable file transmitted from the host computer 10 to the image processing apparatus 20 is received by the print data reception storage unit 211 via the communication interface 27 of the image processing apparatus 20.

  In the image processing apparatus 20, for the printable file received by the print data reception storage unit 211, the PDL analysis unit 212 interprets the printable data, divides the interpreted printable data into drawing primitives, and a display list creation unit In 213, a display list that holds information such as a position and a size for drawing a drawing primitive is created.

  Then, after all the display lists for the corresponding page are created by the display list creation unit 213, the page rendering unit 214 converts the page into a bitmap.

  At the stage of creating the display list by the display list creation unit 213, the display list history information management unit 215 determines the type of the display list to be created, and according to the determination result, that is, what type of display list it is. The content of the display list history information stored in the display list history information storage unit 216 is updated.

  Here, the display list history information stored in the display list history information storage unit 216 is read from the information storage unit 24 when the system power is turned on, and is stored in the information storage unit 24 after the job processing is completed. To do.

  In this image processing apparatus 20, the PDL analysis unit 212 interprets the PDL received by the print data reception storage unit 211, and the display list creation unit 213 creates a page display list. It is saved as history information, and optimal pre-rendering is executed from the saved history information.

  The display list history information management unit 215 stores the history information of the display list created by the display list creation unit 213 in the information storage unit 24 by the display list history information storage unit 216, so that past received data Having an average display list size, the execution timing is determined in consideration of the size and the threshold PR for executing pre-rendering.

  Here, in the image processing apparatus 20, the history information of the display list is stored by adding the size of the display list itself. As shown in FIG. 5, the display list holds information such as the identifier of the display list, the position coordinates of the drawing destination, the width and height of the figure. The size of each display list itself is fixed. In the case of a display list indicating an image or a bit bullet image, the size of the source image or the bit bullet image is also calculated from the width / height of the image and added to the history information. As shown in FIG. 6, the history information size of the display list for one page is 2 bytes for the total number of pages, 4 bytes for the total size of the display list, and 6 bytes in total.

  Further, in this image processing apparatus 20, the average size of the page display list is calculated as follows.

  The contents of the history information saved in the information storage unit 24 at the time of system power-on, that is, the history information of the display list is copied to the memory of the display list history information storage unit 216. Then, the average size of the page display list using the history information and the average value of the size are calculated from the history information content copied on the memory. The execution timing is when the system power is turned on or when the job ends. Also, the file storage of the history information list in the information storage unit 24 is executed at the end of the job. Here, the upper limit of the history information size is specified by the number of pages. The upper limit is 10 million pages (60 Kbytes).

  The timing of execution of pre-rendering in the image processing apparatus 20 is shifted as follows.

  The pre-rendering is basically executed based on the threshold value [PR] size shown in FIG. 7A, and the display list size shown in FIG. When the threshold value [PR] shown in FIG. At this time, since the display list is released, the size of the display list immediately after pre-rendering becomes zero. However, as shown in FIG. 7C, the display list size of the entire page is stored as the cumulative size.

  When the pre-rendering size is reached by looking at the threshold value [PR] shown in FIG. 7A, the average size of the page display list is referred to as shown in FIG.

Then, the difference between the cumulative size of the page display list shown in FIG. 7C and the average size of the past page display list shown in FIG. 7D is the threshold [PR] shown in FIG. When it is less than 25% of the size, the pre-rendering is skipped, and the cumulative size of the page display list shown in FIG. 7C reaches the average size of the past page display list shown in FIG. When to do pre-rendering.
After pre-rendering is performed after waiting for the past page display list shown in FIG. 7D, the average size of the past page display list shown in FIG. The cumulative size of the page display list should not be used for pre-rendering activation determination. That is, when the cumulative size of the page display list shown in (C) of FIG. 7 exceeds the average size of the past page display list shown in (D) of FIG. 7, the threshold [PR] shown in (A) of FIG. This is determined only by the size of the display list shown in FIG.

  In this printing system 100, the image processing apparatus 20 creates a display list and stores history information in the printing process according to the procedure shown in the flowchart of FIG.

  That is, in the printing system 100, the printable file transmitted from the host computer 10 to the image processing apparatus 20 is received by the print data reception storage unit 211 via the communication interface 27 of the image processing apparatus 20 (step S501).

  In the image processing apparatus 20, the PDL analysis unit 212 interprets the printable data for the printable file received by the print data reception storage unit 211 in step S501 (step S502), and the PDL analysis unit 212 in step S502. The displayable data interpreted in accordance with the above is divided into drawing primitives, and the display list creation unit 213 creates a display list describing information for drawing an object such as the position and size for drawing the drawing primitive (S503).

  Next, in the display list creation by the display list creation unit 213, the memory size for storing necessary information is added to the display list history information by the display list history information management unit 215, and the display list history information storage unit 216 is added. (Step S504).

  Next, it is determined whether or not the display list created by the display list creation unit 213 in step S503 is a display list for drawing an image (step S505).

  If the determination result in step S505 is “NO”, that is, if the created display list is an image display list, the process moves to step S508 to determine whether or not a display list for one page has been created. If the determination result in step S505 is “YES”, that is, if the created display list is an image display list, the display list history information management unit 215 causes the display list to have a source image (an image before conversion such as enlargement / rotation). ) Is calculated from the width and height of the image and the bit depth (BPP) of the pixel of the image (step S506).

  Next, the size calculated in step S506 is added to the display list history information by the display list history information management unit 215 and stored in the display list history information storage unit 216 (step S507).

  Then, the display list creation unit 213 determines whether a display list for one page has been created (step S508).

  If the determination result in step S508 is “NO”, that is, if a display list for one page is not created, the process returns to step S501, and the determination result in step S508 is “YES”, that is, one page. When the display list is created, the page rendering unit 214 interprets the page display list and creates a bitmap image (step S509).

  Then, the page created by the page rendering unit 214 in step S509 is output by the printing unit 70 (step S510). That is, a print request is issued to the engine to output a page.

  Here, in the image processing apparatus 20 in the printing system 100, the past page display list size is copied to the memory of the display list history information storage unit 216 when the system power is turned on according to the procedure shown in the flowchart of FIG.

  That is, in the image processing apparatus 20, when the system is activated (step S601), the display list history information storage unit 216 reads the display list history information file stored in the information storage unit 24, and copies it to the memory. (Step S6021). The display list history information storage unit 216 scans the history information data read in step S602, calculates the sum and average of the recorded page display list sizes, and stores them in the average value A.

  In the image processing apparatus 20 in the printing system 100, the display list creation unit 213 performs pre-rendering according to the procedure shown in the flowchart of FIG.

  That is, the display list creation unit 213 in the image processing apparatus 20 creates a display list (step S701), and whether or not a flag indicating whether or not to pre-render using the cumulative page display list size is on. Is determined (step S702).

  When the determination result in step S702 is “YES”, that is, the flag indicating whether or not to pre-render is on, the display list creation unit 213 determines the size of the display list created in step S701. Is added to the display list size, and at the same time, the cumulative page display list size update process is added to the cumulative page display list size (step S703), and the display list size and threshold [ PR] is compared, and it is determined whether or not the display list size has reached the threshold value [PR] (step S704).

  The display list creation unit 213 determines the size of the display list created in step S701 when the determination result in step S702 is “NO”, that is, when the flag indicating whether to pre-render is off. Display list size update processing is performed (step S705), and the display list size updated in step S705 is compared with the threshold value [PR] to determine whether the display list size has reached the threshold value [PR]. Is determined (step S706).

  Next, if the determination result in step S704 is “NO”, that is, if the display list size is smaller than the threshold value PR, the display list creation unit 213 returns to step S701 to create the next display list. If the determination result in step S704 is “YES”, that is, if the display list size is larger than the threshold value PR, the difference between the cumulative page display list size and the past average page display list size is calculated and the variable It is stored in diff (step S707), and the value of the variable diff obtained in step S707 is compared with the threshold PR to determine whether the value of the variable diff is 25% or more of the threshold PR size (step S708). .

  Next, if the determination result in step S706 is “NO”, that is, if the display list size is smaller than the threshold value PR, the display list creation unit 213 returns to step S701 and proceeds to the next display list creation. If the determination result in step S706 is “YES”, that is, if the display list size is larger than the threshold value PR, pre-rendering is executed (step S710).

  The display list creation unit 213 returns to step S701 to move to the next display list creation if the determination result in step S708 is “NO”, that is, less than 25%, and the determination result in step S708. If “YES”, that is, 25% or more, the flag indicating whether or not to pre-render using the cumulative page display list size is turned off (step S709).

  Then, the display list creation unit 213 executes pre-rendering (step S710) and ends the process.

1 is a block diagram illustrating a printing system including an image processing apparatus to which the present invention is applied and a host computer. It is a block diagram which shows the functional structure of the said image processing apparatus. It is a figure which shows typically the example of execution of the pre-rendering by the conventional method in the said image processing apparatus. It is a figure which shows typically the example of execution of the pre-rendering by this invention in the said image processing apparatus. It is a figure which shows typically the content of the display list in the said image processing apparatus. It is a figure which shows typically the log | history information size of the said display list. It is a figure which shows typically the mode of execution of the pre-rendering in the said image processing apparatus. It is a flowchart which shows the procedure of the process which produces a display list in the case of the printing process performed by the said image processing apparatus, and memorize | stores the historical information. 5 is a flowchart showing a procedure of display list history information copy processing executed when the system power is turned on in the image processing apparatus. It is a flowchart which shows the execution procedure of the pre-rendering by the display list preparation part of the said image processing apparatus. It is a figure which shows typically the mode of the execution of the conventional pre-rendering process started with memory shortage as a trigger.

Explanation of symbols

10 host computer, 15 network, 20 image processing device, 21 CPU, 22 ROM, 23 RAM, 24 information storage unit, 25 operation panel unit, 26 printing unit, 27 communication interface, 211 print data reception storage unit, 212 PDL analysis unit 213 Display list creation unit, 214 page rendering unit, 215 display list history information management unit, 216 display list history information storage unit

Claims (6)

Data analysis means for analyzing the received print data;
Based on the analysis result of the print data by the data analysis unit, a display list creation unit that creates a display list that is an intermediate code by dividing a drawing image into predetermined band units extending in one direction;
Rendering means for executing a rendering process for converting the display list into bitmap data;
Display list history information management means for storing and managing the size of the display list created by the display list creation means as history information,
The rendering means compares the cumulative size of the display list created by the display list creating means with the size indicated by the threshold value, and executes pre-rendering when the cumulative size reaches the size indicated by the threshold value. When the display list being created is released, the average size of the past display list calculated based on the past display list size history information stored and managed by the display list history information management means and the cumulative size If the difference is less than a predetermined size smaller than the size indicated by the threshold, pre-rendering is skipped and pre-rendering is performed when the accumulated size reaches the average size of the past display list Image processing characterized by Location.   The display list history information management means determines whether or not the display list created by the display list creation means is an image display list, and when the created display list is an image display list, The image processing apparatus according to claim 1, wherein a size of a source image indicated by the display list is calculated and stored and managed as history information of the display list. Comprising information storage means for storing the history information of the display list,
The display list history information management means reads the size of the past display list from the information storage means as history information when the system is started, and calculates the average size of the past display list. 3. The image processing apparatus according to any one of 2 above. The data analysis means analyzes the received print data, and based on the analysis result, the display list creation means creates a display list as an intermediate code by dividing the drawing image into predetermined band units extending in one direction. An image processing program executed by a computer provided in an image processing apparatus that performs a rendering process for converting the created display list into bitmap data by a rendering unit,
The display list history information management means stores and manages the size of the display list created by the display list creation means as history information,
The rendering means compares the accumulated size of the display list created by the display list creating means with the size indicated by the threshold value, and executes pre-rendering when the accumulated size reaches the size indicated by the threshold value. When the display list being created is released, the average size of the past display list calculated based on the past display list size history information stored and managed by the display list history information management means and the cumulative size When the difference is less than a predetermined size smaller than the size indicated by the threshold, pre-rendering is skipped and pre-rendering is executed when the accumulated size reaches the average size of the past display list The above process The image processing program characterized by causing a Yuta.   The display list history information management means determines whether or not the display list created by the display list creation means is an image display list, and when the created display list is an image display list, 5. The image processing program according to claim 4, wherein the computer is caused to perform a process of calculating a size of a source image indicated by the display list and storing and managing it as history information of the display list.   When the system is started, the display list history information management means reads the past display list size from the information storage means as history information, and causes the computer to perform a process of calculating an average size of the past display list. The image processing program according to claim 4, wherein the image processing program is characterized by the following.

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