JP6786415B2 - Information processing equipment, information processing methods, programs, and image forming equipment - Google Patents

Description

The present invention relates to techniques for rendering and printing transparent objects.

There are the following two processing flows for printing a document on a printer from an application running on Microsoft's Windows operating system via a printer driver. That is, a GDI (Graphics Device Interface) print path and an XPS (XML Paper Specification) print path. In addition, to the application running on the Windows operating system, when a document print instruction is given, GDI format drawing data is output and XPS format drawing data is output as a drawing command of the document to be printed. There is something. In the present specification, an application that outputs GDI format drawing data when a document printing instruction is given is referred to as a GDI application, and an application that outputs XPS format drawing data is referred to as an XPS application.

In the GDI print path, the GDI printer driver (also called the V3 printer driver) creates PDL data (print job) that can be processed by the printer from the drawing data in the GDI format. On the other hand, in the XPS print path, PDL data (print job) for the printer is created from the drawing data in XPS format by the Version 4 printer driver (hereinafter referred to as "V4 printer driver") that is now supported by Windows 8. Will be done. When a print job of a document created by a GDI application is created by using this V4 printer driver, it is necessary to convert the drawing data in GDI format into drawing data in XPS format by MXDC. MXDC is an abbreviation for Microsoft XPS Document Converter.

When the print target document has a transparent object that has transmittance as color information, MXDC issues a RAP drawing command that synthesizes and draws a 3-channel RGB image and a mask image, and has a 4-channel alpha channel as color information. Converts to a drawing command for an RGBA image. Then, the V4 printer driver creates a print job by performing a rendering process of a 4-channel RGBA image having an alpha channel as color information.

By the way, when a print job including a transparent object is printed by a printer, composition (alpha blending) in consideration of the colors of other objects in the background of the transparent object is performed by the printer. This alpha blending has a problem that it uses a lot of memory and takes a long time to process. As a technique for solving this problem, Patent Document 1 discloses a technique for efficiently executing an alpha blending process using a table in which an alpha channel is described.

JP-A-2006-244248

However, when the number of transparent objects included in the print job is large, there is a problem that the method of Patent Document 1 also takes a long time to process. Therefore, an object of the present invention is to provide an information processing apparatus that reduces the amount of memory used for alpha blending processing in a printer and enables high-speed printing processing.

The present invention comprises an overlap determining means for determining whether the transparent object overlaps with another drawing object when the drawing object constituting the page data is a transparent object having an alpha channel as color information, and the transparent object. When it is determined by the overlap determination means that it does not overlap with the other drawing object, it has a conversion means for converting the drawing data of the transparent object into drawing data of a drawing object having no alpha channel as color information. It is an information processing device characterized by.

INDUSTRIAL APPLICABILITY According to the present invention, the amount of memory used for alpha blending processing in a printer can be reduced, and high-speed printing processing becomes possible.

The figure which shows the structure of the printing system in Example 1. Block diagram showing the hardware configuration of the PC in the first embodiment Block diagram showing the software configuration of the PC in the first embodiment A block diagram showing a configuration of a rendering filter according to the first embodiment. The figure which shows the transparent image object in Example 1. (A) Page data to which Example 1 is applied (b) Schematic diagram of page data decomposed for each drawing object Flow chart showing the flow of processing in the first embodiment Page data to which Example 2 is applied Schematic diagram of blocked page data Flow chart showing the flow of processing in the second embodiment Schematic diagram illustrating the alpha trimming process, the block blending process, and the block RAP processing in the second embodiment. (A) Page data to which Example 3 is applied (b) Schematic diagram of blocked page data Flowchart showing the flow of processing in Example 3 Flowchart showing the flow of processing in Example 4 A graph showing the relationship between the number of drawing objects O and the printing time t in the fourth embodiment. The figure explaining the effect by Example 4.

Hereinafter, preferred embodiments of the present invention will be exemplified with reference to the drawings. However, the relative arrangement of the components, the shape of the device, and the like described below are merely examples, and the scope of the present invention is not limited to them. It should be understood that, as long as it does not deviate from the purpose, those which have been appropriately modified or improved with respect to the embodiments described below based on the ordinary knowledge of those skilled in the art are also within the scope of the present invention. Is.

[Example 1]
<About the configuration of the printing system>
FIG. 1 is a diagram showing a configuration example of a printing system in this embodiment. As shown in the figure, the printing system is composed of an information processing device (hereinafter referred to as “PC”) 10 and an image forming device (hereinafter referred to as “printer”) 20. The PC 10 and the printer 20 are connected to each other via LAN 1, and data can be transmitted and received between the PC 10 and the printer 20. As LAN1, a wired LAN or a wireless LAN corresponding to the Ethernet communication method may be used. However, the form of connecting the PC 10 and the printer 20 is not limited to LAN, and other connection forms such as Bluetooth (registered trademark) and USB may be used.

<About the hardware configuration of the PC>
FIG. 2 is a block diagram showing a hardware configuration example of the PC 10 in this embodiment. The CPU 101 comprehensively controls each device connected to the system bus 104 according to the program stored in the RAM 102. The RAM 102 is a storage medium for temporarily storing data, and functions as a main memory, a work area, or the like of the CPU 101. The ROM 103 stores various programs and data, and is divided into a font ROM 103a for storing various fonts, a program ROM 103b for storing a boot program, a BIOS, and the like, and a data ROM 103c for storing various data. In this embodiment, the area of the ROM 103 is divided internally and used, but the font ROM 103a, the program ROM 103b, and the data ROM 103c may be configured as physically separate storage means. The network interface (hereinafter, “interface” is abbreviated as “I / F”) 105 is connected to LAN1 and controls data communication between the PC 10 and an external device. The input I / F 106 controls input by the user via a keyboard 109, a pointing device (for example, a mouse) (not shown), or the like. The output I / F 107 controls an output such as a display on the display 110. The external memory I / F 108 controls access to an external memory 111 such as a hard disk. The external memory 111 is a storage medium that stores an operating system (hereinafter abbreviated as “OS”) 112, various software 113 that bears the printing system of this embodiment, and various data 114 such as user files and edit files. is there. In this embodiment, Microsoft Windows (trademark) 10 is used as the OS 112, but the OS used is not limited to this.

<About PC software configuration>
FIG. 3 is a block diagram showing a software configuration example of the PC 10 in this embodiment, and is a diagram showing a software module related to the rendering process in the V4 printer driver among the software modules of the PC 10.

The GDI application 11 is software for a user to create a document and give a print instruction. When a print instruction is given by the user, the GDI application 11 uses the GDI API to output drawing data in GDI format to the MXDC 12 as a drawing command of the document to be printed. The MXDC 12 converts the GDI format drawing data received from the GDI application 11 into XPS format drawing data. Then, the converted XPS format drawing data is output to the V4 printer driver 13.

The V4 printer driver executes a series of processes for creating a print job according to a programming model called XPS print filter pipeline service. Specifically, the V4 printer driver 13 has a filter pipeline 14 composed of a plurality of connected filters, and processing by each of the connected filters is executed in order. That is, the output of a certain filter becomes the input of the next connected filter, and each filter sequentially executes processing to create a print job (PDL data) to be output to the printer 20.

In this embodiment, the filter pipeline 14 is composed of two filters, a layout filter 15 that performs layout processing and a rendering filter 16 that performs rendering processing. The layout filter 15 executes layout processing such as Nup that combines a plurality of pages into one sheet for the input XPS format drawing data, and the layoutd XPS format drawing data obtained by the execution is used in the rendering filter 16. Output. The rendering filter 16 converts the input layoutd XPS format drawing data into PDL data, and outputs the PDL data to the port monitor 17. The processing of the transparent object in this embodiment, which will be described later, is executed by the rendering filter 16.

Note that FIG. 3 shows the flow of data when printing from the GDI application, but the process of the present invention described later with reference to FIG. 7 is not limited to printing from the GDI application, and XPS. It can also be applied to printing from applications. However, in the case of the XPS application, when a print instruction is given by the user, the XPS application outputs XPS format drawing data to the V4 printer driver 13 as a drawing command of the document to be printed. The subsequent processing in the V4 printer driver 13 is the same as the printing processing from the GDI application.

<Rendering filter configuration>
FIG. 4 is a block diagram showing the configuration of the rendering filter 16. As shown in the figure, the rendering filter 16 is composed of three components, an XPS data analysis unit 161, an image processing unit 162, and a PDL data creation unit 163.

The XPS data analysis unit 161 analyzes the layoutd XPS format drawing data input from the layout filter 15 and sequentially outputs drawing data for drawing one or a plurality of drawing objects. Here, the drawing object is an internally set of data used for rendering the drawing target. Drawing targets in this embodiment include images (photographs, etc.), figures, and characters. Further, the drawing object may be a transparent object having an alpha channel as color information. Hereinafter, a drawing object for drawing an image is referred to as an "image object", and a drawing object for drawing a figure is referred to as a "figure object".

The image processing unit 162 executes image processing such as enlargement, reduction, and rotation on the drawing data of the drawing object input from the XPS data analysis unit 161 and outputs the drawing data in which the image processing is executed. The processing of the transparent object in this embodiment, which will be described later, is executed by the image processing unit 162.

The PDL data creation unit 163 creates PDL data based on the drawing data of one or a plurality of drawing objects input from the image processing unit 162. Regarding the layoutd XPS format drawing data handled by these components constituting the rendering filter 16, the drawing data of one or more drawing objects, and the PDL data, these are all a set of information to be drawn, and the drawing target is output. Indicates the order of For example, when there are two drawing targets having different output orders and these drawing targets are arranged at the same position, the drawing target having a smaller order (output first) has a larger order (later). The drawing target (output) is placed and rendered. In this case, the drawing targets overlap each other, and a part or all of the drawing targets output first is covered by the drawing targets output later.

<About transparent objects>
FIG. 5 shows a transparent image object (an image object having an alpha channel as color information) as an example of the transparent object in this embodiment. The transparent image object shown in FIG. 5 is a bitmap format image representing the letter "o" in the alphabet. This image is composed of black-painted pixels (black pixels) and unpainted pixels (white pixels), and has four channels of color information for each pixel. Here, the 4-channel color information is obtained by adding the color information of the alpha channel (A) for designating the transmittance to the color information of the RGB3 channel for expressing colors such as black and white. Regarding the pixel value of the alpha channel (hereinafter, transmittance), for example, the transmittance of the black pixel 51 in the figure is 0 (%), and the transmittance of the white pixel 52 is 100 (%). Regarding the transmittance, 0 (%) indicates complete opacity and 100 (%) indicates complete transmission. Such transparency is usually specified to make the background image visible in areas of high transparency of the foreground image when two drawing objects are placed and rendered overlapping. .. Alternatively, it may be specified to make the background image invisible in a region where the transmittance of the background image is low.

<About the page data of the print page>
FIG. 6A is a diagram schematically showing page data 60 of print pages constituting a print job to which this embodiment is applied. Further, FIG. 6B is a diagram for explaining the drawing objects constituting the page data 60, and the page data 60 is decomposed and shown for each drawing object corresponding to the drawing data sequentially input to the image processing unit 162. ing.

Reference numerals 601 and 603, 604, 605, 606, and 608 in FIG. 6B indicate transparent image objects, respectively. The transparent image object has four channels of color information as described above. Here, in the transparent image objects 601, 603, 604, 605, 606, and 608, as in the transparent image object shown in FIG. 5, the characters and the filled parts are composed of completely opaque black pixels, and the other parts are composed of completely opaque black pixels. It shall be composed of completely transparent white pixels.

Reference numerals 602 and 607 in FIG. 6B indicate graphic objects, respectively. As shown, the graphic object 602 that draws the graph does not overlap any drawing object, while the graphic object 607 that draws the colored figure overlaps the transparent image object 608. Here, a case where the drawing data of the graphic object 607 is input to the image processing unit 162 and processed before the drawing data of the transparent image object 608 will be examined. In this case, it is necessary to combine the graphic object and the transparent image object so that the colored graphic based on the graphic object 607 is the background and the transparent image based on the transparent image object 608 is the foreground. Such a composition process is a form of a process of synthesizing a transparent image object with another drawing object or a background based on the transmittance (alpha value) which is a pixel value of the transparent image object. Such a synthesis process is called an "alpha blending process".

On the other hand, for the transparent image objects 601, 603, 604, 605, and 606, they do not overlap with the other drawing objects, but each has an alpha channel. If the drawing data is converted into PDL data and transmitted to the printer 20 while these transparent image objects have an alpha channel, the printer 20 must perform an alpha blending process on a large number of transparent image objects. Therefore, it takes time to print. Therefore, in this embodiment, the alpha channel is removed from the color information of the non-overlapping transparent objects by executing the white blending process (see FIG. 7) described below in the image processing unit 162 of the PC 10. As a result, the total number of transparent objects that the printer 20 executes the alpha blending process is reduced, so that the processing load of the printer 20 can be reduced and high-speed printing can be realized.

<About white blending processing>
FIG. 7 is a flowchart showing the flow of processing in this embodiment.

First, in step S701, the image processing unit 162 determines whether or not there is an unprocessed drawing object among the drawing objects corresponding to the drawing data input from the XPS data analysis unit 151. If the result of the determination in step S701 is true, the process proceeds to step S702, while if the result of the determination is false, the series of processes ends.

In step S702, the image processing unit 162 pays attention to one drawing object from the unprocessed drawing objects, and acquires the information (number of channels of color information, circumscribing rectangular coordinates, etc.) of the focused drawing object. Hereinafter, the drawing object of interest is referred to as a "drawing object of interest".

In step S703, the image processing unit 162 determines whether the drawing object of interest is a transparent object. If the result of the determination in step S703 is true, the process proceeds to step S704, while if the result of the determination is false, the process proceeds to step S706. Whether or not the drawing object of interest is a transparent object is determined based on the number of channels of color information input as an attribute of the drawing object of interest. That is, when the number of channels of the color information of the attention drawing object is 4, the attention drawing object has RGBA color information, so that it is determined that the attention drawing object is a transparent object. On the other hand, when the number of channels of the color information of the attention drawing object is 3, the attention drawing object has RGB color information, so that it is determined that the attention drawing object is not a transparent object.

In step S704, the image processing unit 162 searches the drawing object management list and determines whether or not there is a drawing object in the drawing object management list that overlaps with the drawing object of interest. Here, the drawing object management list is a list created for each page to manage the drawing objects constituting the page data of the print page, temporarily stored in the RAM 102, and discarded. Information such as the identifier of the drawing object and the coordinates of the circumscribing rectangle is held in the drawing object management list. Hereinafter, the drawing object management list is abbreviated as "management list". Whether or not there is a drawing object that overlaps with the drawing object of interest is determined based on the circumscribing rectangular coordinates of the drawing object of interest and the circumscribing rectangular coordinates of the drawing object registered in the management list. That is, when the circumscribed rectangle of the attention drawing object and the circumscribed rectangle of the drawing object registered in the management list overlap, it is determined that the attention drawing object and the registered drawing object also overlap. Depending on the shape of the drawing object, even if the extrinsic rectangles of the drawing objects overlap, it cannot be said that the drawing objects overlap each other, but considering the calculation cost, the extrinsic rectangle coordinates are used for the overlap determination. It makes sense to use it. If the result of the determination in step S704 is true, the process proceeds to step S706, while if the result of the determination is false, the process proceeds to step S705.

When it is determined that there is no drawing object overlapping the attention drawing object in the management list (NO in step 704), there is no other drawing object on the background side of the attention drawing object which is a transparent object. In this case, in step S705, the image processing unit 162 executes an alpha blending process of the attention drawing object and the white background, that is, a process of synthesizing each pixel of the attention drawing object and the white pixel of the background. Hereinafter, the alpha blending process of the transparent object and the white background is referred to as "white blending process". By the white blending process in this step, the drawing object of interest is converted into a drawing object that does not have an alpha channel as color information, so that the number of color information channels of the drawing object is reduced from 4 to 3. Here, the RGB pixel values in the composite image having the color information of 3 channels obtained by the alpha blending process are expressed by the following equation (1).
Pixel value of composite image (R, G, B) = Pixel value of foreground image (R, G, B) x (100 [%] -Transmittance of foreground image [%]) + Pixel value of background (R, G) , B) × Transmittance of foreground image [%] ・ ・ ・ Equation (1)
As an example, consider the case where the white blending process is executed on the transparent image object 601 in this embodiment. As described above, the transparent image object 601 as the foreground is composed only of black pixels that are completely opaque (transmittance 0%) and white pixels that are completely transparent (transmittance 100%). Here, the pixel value (R, G, B, A) of the black pixel of the transparent image object 601 is set to (0,0,0,0), and the pixel value (R, G, B, A) of the white pixel is set to (255). , 255,255,100), and the background pixel values (R, G, B) are expressed as (255,255,255). In this case, according to the equation (1), the pixel value (R, G, B) of the black pixel of the composite image becomes (0,0,0), and the pixel value (R, G, B) of the white pixel of the composite image. Is (255,255,255). In this way, the pixel value of the black pixel with 0% transmittance (4 channels) and the pixel value of the white pixel with 100% transmittance (4 channels) in the transparent image object are converted into the pixel values of 3 channels, respectively. To.

On the other hand, when it is determined that there is a drawing object that overlaps with the attention drawing object in the management list (YES in step 704), another drawing object exists on the background side of the attention drawing object which is a transparent object. .. In this case, the white blending process is not executed. For example, when the drawing object of interest is the transparent image object 608, this case is applicable because the graphic object 607 exists on the background side of the transparent image object 608.

In step S706, the image processing unit 162 adds the drawing object of interest to the management list. Specifically, the identifier of the drawing object of interest and the circumscribing rectangular coordinates are newly described in the management list. As a result, the drawing object of interest is managed.

In step S707, the image processing unit 162 outputs the drawing data of the drawing object of interest to the PDL data creating unit 163. Then, the process returns to step S701.

The above is the image processing accompanied by the white blending process in this embodiment. The process of FIG. 7 is executed for each print page. The PDL data creation unit 163 creates PDL data based on the drawing data corresponding to each drawing object sequentially output from the image processing unit 162.

By the processing of the image processing unit 162 in this embodiment, the transparent objects that do not overlap with other drawing objects are converted into drawing objects without an alpha channel, so that the total number of transparent objects in the PDL data creation unit 163 is reduced. Become. Therefore, since the total number of transparent objects is also reduced in the PDL data created by the PDL data creation unit 163, the processing load and memory usage of the printer 20 when the PDL data is processed by the printer 20 can be reduced.

The process of converting the drawing data of the transparent object into the drawing data of the drawing object without the alpha channel has been described above when there is no other drawing object on the background side (behind) of the transparent object.

In the above description, the transparent object that is the foreground is a transparent image object that draws a transparent image. However, this embodiment is also applicable to other transparent objects having an alpha channel as color information, and is also applicable to, for example, transparent objects of figures and characters whose shapes are described by vector data.

Further, in the above description, a case where PDL data is created based on XPS format drawing data using a V4 printer driver is described, but this embodiment can be applied to a V3 printer driver in addition to the V4 printer driver. Is. Specifically, it is conceivable that the GDI application outputs a drawing command for a 4-channel (RGBA) object to the V3 printer driver, and this embodiment can be applied in such a case.

[Example 2]
In the first embodiment, as shown in FIG. 6B, the area of each transparent object as the foreground occupies only a part of the print page, and the area of each transparent object is smaller than that of the print page. However, there may be cases where the transparent object area in the foreground occupies most of the printed page (the area of the transparent object is large). FIG. 8 is a diagram showing an example of such a case.

Reference numerals 801 and 802 in the drawing indicate graphic objects, and reference numeral 803 indicates a transparent image object. That is, the page data 80 is composed of a graphic object 801 for drawing a graph, a graphic object 802 for drawing a colored figure, and a transparent image object 803. As shown in the figure, the graphic object 801 and the graphic object 802 are arranged in the background, and the transparent image object 803 having an area substantially the same as the entire page is arranged so as to cover the graphic object 801 and the graphic object 802. When Example 1 is applied to the page data shown in FIG. 8, white blending cannot be applied to the transparent image object 803 because another drawing object exists on the background side of the transparent image object 803. Therefore, in this embodiment, the transparent image object is divided into fine regions, it is determined whether or not the white blending process can be executed for each of the divided fine regions, and the white blending process is executed in the fine regions determined to be feasible. .. In the following description, the same contents as in the first embodiment will be omitted.

FIG. 9 is a schematic diagram of blocked page data. The blocking process in this embodiment refers to a process of dividing a transparent image object into fine regions (blocks) such as 256 × 256 pixels. As described above, this embodiment is different from the first embodiment in that the blocking process is executed.

<About block blending processing and block RAP processing>
FIG. 10 is a flowchart showing the flow of processing in this embodiment.

In step S1001, the image processing unit 162 determines whether or not there is an unprocessed drawing object among the drawing objects corresponding to the drawing data input from the XPS data analysis unit 151. If the result of the determination in step S1001 is true, the process proceeds to step S1002, while if the result of the determination is false, the series of processes ends.

In step S1002, the image processing unit 162 acquires the information of the drawing object of interest.

In step S1003, the image processing unit 162 determines whether the drawing object of interest is a transparent object. If the result of the determination in step S1003 is true, the process proceeds to step S1004, while if the result of the determination is false, the process proceeds to step S1016.

In step S1004, the image processing unit 162 searches the management list and determines whether or not there is a drawing object in the management list that overlaps with the drawing object of interest. If the result of the determination in step S1004 is true, the process proceeds to step S1006, while if the result of the determination is false, the process proceeds to step S1005.

In step S1005, the image processing unit 162 executes a compositing process (white blending process) of the drawing object of interest and the white background. As described above, the processing of steps S1001 to S1005 is the same as the processing of steps S701 to 705 shown in FIG.

In step S1006, the image processing unit 162 executes a blocking process for dividing the drawing object of interest into fine regions. An example of the blocking process is as shown in FIG.

In step S1007, the image processing unit 162 determines whether or not there is an unprocessed block. If the result of the determination in step S1007 is true, the process proceeds to step S1008, while if the result of the determination is false, the process returns to step S1001.

In step S1008, the image processing unit 162 acquires one of the unprocessed blocks (hereinafter, referred to as “attention block”), and executes alpha trimming processing on the attention block. The alpha trimming process is a process of cutting out a region composed of only pixels having a transmittance of 100% from a block of interest and cutting out a rectangular region including pixels having a transmittance of not 100%. FIG. 11 shows an alpha trimming process for the block 1110 as an example of the alpha trimming process. As shown in the figure, in the block 1110, the character image is arranged in the upper right, and the left and lower regions 1111 in which the character image is not arranged are composed of only white pixels having a transmittance of 100%. In the alpha trimming process, a rectangular region 1112 including pixels whose transmittance is not 100% is specified and cut out by scanning one line from each of the top, bottom, left, and right sides of the block 1110. This rectangular area is specified to have the smallest area. Hereinafter, the image of the rectangular area cut out from the block of interest is referred to as a "trimmed block". Trimmed blocks are part of transparent objects. In addition, the trimmed block information (coordinates, size, etc. of each point) is also acquired by this step.

In step S1009, the image processing unit 162 determines whether the area of the trimmed block is larger than zero. If the result of the determination in step S1009 is true, the process proceeds to step S1010, while if the result of the determination is false, the process returns to step S1007 to process the next block.

In step S1010, the image processing unit 162 searches the management list and determines whether there is a drawing object overlapping the trimmed block in the management list. If the result of the determination in step S1010 is false, the process proceeds to step S1011. If the result of the determination is true, the process proceeds to step S1012.

In step S1011, the image processing unit 162 executes a white blending process on the trimmed block. Hereinafter, the white blending process for the trimmed block is referred to as "block blending process".

In step S1012, does the image processing unit 162 include pixels other than completely transparent (transmittance 100%) pixels and completely opaque (transmittance 0%) pixels in the pixels constituting the trimmed block? To judge. If the result of the determination in step S1012 is true, the process proceeds to step S1013, while if the result of the determination is false, the process proceeds to step S1014.

In step S1013, the image processing unit 162 executes the block ROP (raster operation) processing on the trimmed block. Here, the block ROP processing will be described with reference to FIG. FIG. 11 shows a block ROP conversion process for the block 1120 as an example of the block ROP conversion process. Block blending cannot be applied to the trimmed block 1121 in which the block 1120 is subjected to the alpha trimming process because there is a graphic object that draws a colored graphic on the background side. However, all the alpha channel values of the pixels constituting the trimmed block 1121 are a value indicating complete transparency (transmittance 100%) and a value indicating complete opacity (transmittance 0) as in the examples seen so far. %) And either. Such a trimmed block (a part of a 4-channel transparent image object) drawing command is a ROP that combines and draws a 3-channel RGB image 1122 that does not include an alpha channel and a mask image 1123 that serves as auxiliary data. It can be replaced with a drawing command. That is, by creating a mask image in which the mask value 0 that uses the background is specified at the position of the pixel having the transmittance of 100% and the mask value 1 that uses the foreground is specified at the position of the transmittance of 0%, the original transparent image object is created. It becomes possible to obtain the same print result as the print result based on. Since the 3-channel RGB image created by the block ROP processing has better compression efficiency than the 4-channel RGBA image, the memory usage in the printer 20 can be reduced. Further, since the ROP drawing command can be processed at a higher speed than the drawing command of the trimmed block of 4 channels, high-speed printing processing can be realized.

In step S1014, the image processing unit 162 adds the trimmed block to the management list (the identifier of the trimmed block and the circumscribing rectangular coordinates are described in the management list).

In step S1015, the image processing unit 162 outputs the drawing data of the trimmed block to the PDL data creation unit 163. Then, the process returns to step S1007, and the processes of steps S1007 to S1015 are repeated until there are no unprocessed blocks.

In step S1016, the image processing unit 162 adds the drawing object of interest to the management list. In step S1017, the image processing unit 162 outputs the drawing data of the drawing object of interest to the PDL data creating unit 163. Then, the process returns to step S1001. The processing of steps S1016 to S1017 is the same as the processing of steps S706 to 707 shown in FIG.

The above is the image processing accompanied by the block blending process and the block ROP process in this embodiment. According to this embodiment, when the rendering process for page data having a transparent object having a large area and overlapping with other drawing objects is executed, the memory usage used in the alpha blending process is reduced and high-speed printing process is realized. Is possible.

[Example 3]
In the second embodiment, when the trimmed block is composed of only completely opaque black pixels, the block RAP processing for the trimmed block is executed (YES in step S1012 → step S1013). By this block ROP processing, the drawing command of the trimmed block of the RGBA 4 channel is converted into the ROP drawing command of combining the RGB image of the 3 channels and the mask image and drawing. However, regarding the drawing command of the trimmed block composed of only completely opaque black pixels, it is better to convert it into a drawing command of a 3-channel RGB image than to convert it into a ROP drawing command in the printer 20. Efficient in RIP processing.

FIG. 12A is a diagram showing page data of a print page to which this embodiment is applied, and the page data 1200 is composed of a graphic object 1201 and a transparent image object 1202 arranged on the graphic object 1201. As shown, the transparent image object 1202 is a gradation image that gradually becomes transparent from opaque. In the gradation image, the value of the alpha channel of each pixel changes gradually.

When Example 2 is applied to the page data shown in FIG. 12A, since the graphic object 1201 is on the background side (behind) of the transparent image object 1202, the transparent image object 1202 is blocked instead of white blending. Is executed. FIG. 12B is a schematic diagram of blocked page data. After the blocking process, the block blending process is executed for the blocks in the area that does not overlap with the graphic object 1201. On the other hand, the block blending process is not executed for the block in the area 1203 that overlaps with the graphic object 1201. Here, with respect to the region 1203, no gradation change in transparency is observed in this region, and it is assumed that all the blocks in this region are composed of only pixels that are completely opaque (transmittance 0%). In this case, in the second embodiment, the block ROP processing was executed instead of the block blending processing on the block in the area 1203. In this embodiment, the drawing command of the block composed of only completely opaque pixels is converted into a drawing command of a 3-channel RGB image capable of higher-speed processing instead of a ROP drawing command. This conversion is synonymous with the conversion from a 4-channel RGBA block to a 3-channel RGB block, and this process is called a "block RGB conversion process".

<About block RGB processing>
FIG. 13 is a flowchart showing the flow of processing in this embodiment. However, FIG. 13 shows an excerpt of the process added to the flow of the second embodiment.

As shown in the figure, in this embodiment, if YES is determined in step S1010, the process proceeds to step S1301. In step S1301, the image processing unit 162 determines whether the trimmed block is composed of only pixels that are completely opaque (transmittance 0%). In this step, it is determined whether the drawing command of the trimmed block, which is a part of the transparent image object of 4 channels, can be converted into the drawing command of the RGB image of 3 channels instead of the ROP drawing command. If the result of the determination in step S1301 is true, the process proceeds to step S1302, while if the result of the determination is false, the process proceeds to step S1012.

In step S1302, the image processing unit 162 converts the trimmed block, which is a part of the 4-channel transparent image object, into the 3-channel image object by deleting the alpha channel from the color information of the trimmed block. This conversion process is the block RGB conversion process described above. Then, the process proceeds to step S1014.

The above is the image processing accompanied by the block RGB conversion processing in this embodiment.

[Example 4]
In the first embodiment, a case where it is determined whether or not to execute the white blending process for all the drawing objects existing in the page data of the print page and the white blending process is executed according to the result of the determination will be described. did. As described above, when the white blending process is executed for a certain drawing object of interest, the overlap determination process with all the drawing objects registered in the management list is executed (step S704). Therefore, when a large number of drawing objects exist in the page data, the number of drawing objects registered in the management list increases, so that the overlap determination process may take a long time. In this embodiment, the white blending process is controlled so as not to be executed according to the number of objects (specifically, when the number of objects registered in the management list is equal to or greater than a predetermined threshold value).

FIG. 15 is a graph showing how the print time t changes as the number of drawing objects O existing in the page data changes. Here, the printing time t is the total time of the processing time of the V4 printer driver 13 and the processing time of the printer 20. Reference numeral 1501 in the figure indicates the relationship between the number of drawing objects in the page data and the printing time when the printing process is performed without performing the white blending process at all. Further, reference numeral 1502 indicates the relationship between the number of drawing objects in the page data and the printing time when the white blending process is performed on all the drawing objects. In the example shown in FIG. 15, when the number of drawing objects O is smaller than the threshold value o_th, the printing time is shorter when the white blending process is performed than when the white blending process is not performed. Further, when the number of drawing objects O is larger than the threshold value o_th, the printing time is shorter when the white blending process is not performed than when the white blending process is performed.

Further, FIG. 16A shows a breakdown image graph of the printing time by the V4 printer driver 13 and the printer 20 when O = o1 and FIG. 16B shows O = o2.

First, the case of O = o1 (FIG. 16A) will be examined. In this case, the printing time when the white blending process is executed (the total of the processing time of the V4 printer driver and the processing time of the printer) is shorter than the printing time when the white blending process is not executed (the processing time of the printer only). .. Therefore, in the case of O = o1, the printing time can be shorter when the white blending process is executed than when the white blending process is not executed.

Next, the case of O = o2 (FIG. 16 (b)) will be examined. In this case, the printing time when the white blending process is executed (the total of the processing time of the V4 printer driver and the processing time of the printer) is longer than the printing time when the white blending process is not executed (the processing time of the printer only). turn into. This is because the overlap determination process takes a lot of time. Therefore, in the case of O = o2, the printing time can be shorter when the white blending process is not executed than when the process is executed.

In this way, depending on the number of drawing objects for which overlap judgment is performed, the printing time, which is the total of the processing time of the V4 printer driver and the processing time of the printer, may be shorter if the white blending process is not executed than if it is executed. is there.

Hereinafter, a series of processes including a process of determining whether or not to execute the white blending process according to the number of drawing objects registered in the management list in this embodiment will be described with reference to FIG. Since FIG. 14 is created based on the flowchart of the first embodiment (FIG. 7), description of the same contents as that of the first embodiment will be omitted as appropriate.

In this embodiment, if it is determined in step S701 that there is an unprocessed drawing object (YES in step S701), the process proceeds to step S1401.

In step S1401, the image processing unit 162 functions as a drawing object number determination means, and determines whether the drawing object management list length, that is, the number of drawing objects already registered in the management list is less than the threshold value. If the result of the determination in step S1401 is true, the process proceeds to step S702 in the same manner as in the first embodiment, and thereafter, the same processing as in the first embodiment is executed from steps S702 to S707. On the other hand, if the result of the determination in step S1401 is false, it is determined that further overlap determination will prolong the printing time, and the process proceeds to step S1402. Then, in step S1402, the image processing unit 162 transmits the drawing data of the drawing object of interest to the PDL data creation unit 163 as it is. Similarly, for the unprocessed drawing objects other than the drawing object of interest, the drawing data of the drawing object is transmitted to the PDL data creation unit 163 as it is.

In this way, the printing time can be shortened by stopping the overlap determination according to the number of objects in the page data.

As the threshold value used in step S1401, the number of drawing objects in which the magnitude relationship between the print time when the white blending process such as the threshold value o_th described above is executed and the print time when the white blending process is not executed is reversed is derived. There is a need. In deriving such a threshold value, an optimum value may be calculated based on the relationship between the specifications of the printer or PC to be used and the number of drawing objects. Further, although the case of applying to the first embodiment has been described here, the present embodiment can also be applied to the second and third embodiments.

[Other Examples]
In Examples 1 to 4, the PC 10 is configured to reduce the processing load on the printer 20 by converting a part of the drawing data of the transparent object into the drawing data of the drawing object having no alpha channel. However, the process of converting a part of the drawing data of the transparent object into the drawing data of the drawing object having no alpha channel is configured to be executed as a preprocessing before executing the RIP process on the printer 20 instead of the PC 10. Is also good. With this configuration, the load during RIP processing in the printer 20 can be reduced. The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

10 ... PC
162 ... Image processing unit

Claims (15)

When the drawing object constituting the page data is a transparent object having an alpha channel as color information, an overlap determination means for determining whether the transparent object overlaps with another drawing object, and
When it is determined by the overlap determination means that the transparent object does not overlap with the other drawing object, the conversion means for converting the drawing data of the transparent object into the drawing data of the drawing object having no alpha channel as color information. ,
An information processing device characterized by having. Further, a generation means for generating PDL data to be output to the image forming apparatus based on the drawing data of the transparent object converted by the conversion means and the drawing data of the drawing object not converted by the conversion means. The information processing apparatus according to claim 1, wherein the information processing apparatus has. The information processing apparatus according to claim 1 or 2, further comprising a determination means for determining whether the drawing object is the transparent object. The conversion means is characterized in that by executing an alpha blending process between the transparent object and the white background, the drawing data of the transparent object is converted into drawing data of a drawing object having no alpha channel as color information. The information processing apparatus according to any one of claims 1 to 3. Further having a storage means for storing a list holding information of drawing objects constituting the page data.
The information processing apparatus according to any one of claims 1 to 4, wherein the overlap determining means determines whether or not the transparent object overlaps with the other drawing object by using the list. The information of the drawing object held in the list is the information of the circumscribing rectangular coordinates of the drawing object constituting the page data.
The overlap determining means is characterized in that it determines whether the transparent object overlaps with the other drawing object based on the circumscribing rectangular coordinates of the transparent object and the circumscribing rectangular coordinates of the drawing object held in the list. The information processing apparatus according to claim 5. When the overlap determination means determines that the transparent object overlaps with the other drawing object, the means for dividing the transparent object into a plurality of blocks and
A means for cutting out a trimmed block, which is the smallest rectangular area including pixels that are not completely transparent, by cutting out a region composed of only completely transparent pixels for each of the plurality of divided blocks.
A means for executing the block blending process, which is an alpha blending process between the trimmed block and the white background,
The information processing apparatus according to any one of claims 1 to 6, wherein the information processing apparatus has. When the trimmed block does not include pixels other than completely transparent pixels and completely opaque pixels, the drawing command of the trimmed block is used to combine an image having no alpha channel and a mask image as color information. The information processing apparatus according to claim 7, further comprising means for converting into a RAP drawing command for drawing. In the mask image, the mask value at the position corresponding to the completely transparent pixel of the trimmed block is a value indicating that the background is used, and the mask at the position corresponding to the completely opaque pixel of the trimmed block. The information processing apparatus according to claim 8, wherein the value is a value indicating that the foreground is used. The method according to any one of claims 7 to 9, wherein when the trimmed block is composed of only completely opaque pixels, the trimmed block further has a means for removing an alpha channel from the color information of the trimmed block. The information processing device described. Further, it has a drawing object number determination means for determining whether the number of drawing objects constituting the page data is less than the threshold value.
When the number of drawing objects determining means determines that the number of drawing objects constituting the page data is not less than the threshold value, the overlap determination process by the overlap determination means and the conversion process by the conversion means are not executed. The information processing apparatus according to claim 1. The information processing apparatus according to claim 11, wherein the threshold value is derived based on the specifications of the information processing apparatus and the specifications of the image forming apparatus. When the drawing object constituting the page data is a transparent object having an alpha channel as color information, an overlap determination step for determining whether the transparent object overlaps with another drawing object, and
When it is determined in the overlap determination step that the transparent object does not overlap with the other drawing object, the conversion step of converting the drawing data of the transparent object into the drawing data of the drawing object having no alpha channel as color information. When,
An information processing method characterized by having. A program for causing a computer to function as each means of the information processing apparatus according to any one of claims 1 to 12. An image forming apparatus that forms an image based on PDL data generated by the generation means of the information processing apparatus according to claim 2.