JP2009066926A - Image processing device and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing device capable of precisely drawing data depicted by a page depicting language capable of depicting a telescoping structure. <P>SOLUTION: The image processing device carries out image processing based on the depiction of the page depicting language. The image processing device stores the page depicting language in a recording device. Then, the depiction relating to the telescoping structure is analyzed from the recorded page depicting language. Further, a display list which is a list including the kind of the pattern being depicted and the depth information of the telescoping structure is made based on the analyzed telescoping structure. Furthermore, the sub rendering buffer is obtained based on the depth of the telescoping structure to carry out the rendering to the sub rendering buffer according to the display list. Furthermore, the rendering of each page is carried out using the content of the sub rendering buffer. In addition, the image forming system with the image processing device and a communication device is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and an image forming system, and more particularly to an image processing apparatus and an image forming system in which drawing failure does not occur in XPS.

  In recent years, with the spread of PCs (personal computers), printing apparatuses such as printers that print data from PCs and image forming systems such as multifunction peripherals including printers, scanners, and fax machines have become widespread.

  As this printer, a page printer that prints a high-quality image at high speed is used for business use such as an office. As a type of page printer, for example, a charge pattern corresponding to an image to be printed on a photoconductor is created using a laser, toner is attached to the photoconductor according to this pattern, and the toner is transferred to paper and fixed with heat and pressure. Therefore, laser printers that perform printing are widely used. Also, LED printers, which are page printers using LED arrays instead of lasers, are often used.

  In this page printer, data to be printed at the time of printing is often described in a computer language called a page description language (PDL).

  The page description language includes information such as vector information such as drawing a line from which coordinate on paper to which coordinate and font information that is a character shape.

  For this reason, the data described in the page description language can often reduce the data capacity compared to transmitting bitmap data, which is a collection of dots, directly to the printer.

  When data described in this page description language is transmitted to a page printer via, for example, a USB or LAN, a CPU (central processing unit) inside the page printer analyzes and creates an image to be actually printed. This image creation is called rendering (rendering) or rasterization.

  Inside the page printer, bitmap data having a resolution higher than that of a PC screen (usually 72 dpi), such as 1200 dpi (dot per inch) or 2400 dpi, is generated by rendering. The bitmap data can create a pattern that matches the characteristics of each page printer.

  For this reason, it is possible to perform higher quality printing than when bitmap data is created on a PC and directly transferred to the printer.

  However, a printer such as a page printer often has a smaller memory capacity of a main storage device or the like than a PC. For this reason, it is required to reduce the memory capacity when rendering data described in a page description language.

  Therefore, with reference to Patent Document 1, there is a printing apparatus that draws data described in a page description language while reducing the amount of memory used (hereinafter referred to as Prior Art 1).

  In the prior art 1, a host that transmits print data for a plurality of drawing primitives or drawing objects that need to be combined and rendered (for example, those that perform logical operations such as AND and OR between drawing primitives) It is specified on the PC side and header information is added.

The memory capacity used by the printing apparatus can be reduced by compressing the rendered image of the rendering primitive other than the header information added to a state where the memory usage is small, such as a dithering pattern called halftone. it can.
JP 2006-168051 A

  However, the printing apparatus of the prior art 1 has a problem that drawing may not be performed normally in the case of a page description language that can describe a plurality of nested structures.

  In particular, in recent years, Microsoft has fully adopted XPS, which is a high-performance page description language described in XML format in Windows (registered trademark) Vista OS (operating system). Since this XPS can describe a nested structure in layers, drawing failure has occurred in the printing apparatus of the prior art 1.

  This invention is made | formed in view of such a condition, and makes it a subject to eliminate the above-mentioned subject.

  An image processing apparatus according to the present invention is an image processing apparatus that performs image processing based on a description of a page description language, and includes a storage unit that stores data described in the page description language, and a page stored in the storage unit A page description language analyzing means for analyzing a description relating to a nested structure of the description language, and a list including information on the type of figure to be drawn and the depth level of the nested structure based on the nested structure analyzed by the page description language analyzing means Display list creation means for creating a display list, and in accordance with the display list, a sub-rendering buffer is acquired for each depth level of the nested structure, and rendering is performed on the sub-rendering buffer. Page rendering means to render each page using And wherein the Rukoto.

  The image processing apparatus of the present invention is characterized in that the page description language is a page description language based on XML including XPS.

  An image forming system according to the present invention includes the image processing device according to claim 1 or 2 and a communication device.

  According to the present invention, it is possible to provide an image processing apparatus and an image forming system that can accurately draw data described in a page description language that can describe a nested structure.

<First Embodiment>
(Control configuration of image processing apparatus X)
The image processing apparatus X according to the embodiment of the present invention is a part corresponding to an image processing unit of a page printer.

  Referring to FIG. 1, which is a control block diagram, an image processing apparatus X is a program to be executed using an XML processing co-processor in a CPU, a SIMD (Single Instruction / Multiple Data) arithmetic unit, a ROM, a RAM, and the like. Print data reception storage unit 201 (storage unit), PDL analysis unit 202 (page description language analysis unit), display list creation unit 203 (display list creation unit), and page rendering unit 204 (page rendering unit). It has the following components.

  In addition to the image processing apparatus X, the page printer according to the embodiment of the present invention includes a known CPU (central processing unit, MPU), laser, photoconductor (drum), polygon mirror, auxiliary storage device (RAM, ROM, HDD, flash memory, etc.), I / O, and the like.

  Furthermore, it is equipped with an interface (communication device) for a PC such as a USB (Universal Serial Bus) or LAN, and can be used as an image forming system. This image forming system can also be used as a multifunction machine having a scanner, a FAX function, and the like.

  Details of the control configuration of the image processing apparatus X according to the embodiment will be described below.

  The print data reception storage unit 201 is a RAM or auxiliary storage device that buffers data described in a page description language received by the USB or LAN of the image processing apparatus X.

  The PDL analysis unit 202 is a control unit that analyzes the buffered data according to a page description language instruction and branches to an appropriate process. The PDL analysis unit 202 can perform different analysis processing for each type of page description language. For example, in addition to Microsoft XPS, it can support Adobe PostScript (registered trademark) language, PRESCRIBE language, and the like. . In the case of PostScript, it can be handled by an emulator.

  The display list creation unit 203 creates a display list divided into drawing primitives, which are the minimum units of drawing to be rendered, in order to efficiently render data having a nested structure using the data of each page.

  Here, in the image processing apparatus X according to the embodiment of the present invention, a rendering buffer that is bitmap data actually used for printing and a separate buffer that is temporarily used are prepared and rendered. It can be performed.

  In the image processing apparatus X according to the embodiment of the present invention, this temporarily used another buffer is called a sub-rendering buffer.

  The display list creation unit 203 can also acquire this sub-rendering buffer.

  The page rendering unit 204 actually performs a rasterizing operation on the rendering buffer or the sub-rendering buffer according to the display list. As a result, each page is rendered. In addition, the page rendering unit 204 is equipped with a line drawing engine, a fill with a specific color, a blter that performs bilinear enlargement / reduction / rotation, an acceleration function for performing processing such as error diffusion, color space conversion, and the like at high speed. It is possible to perform high-speed rendering.

(Outline of blending process by XPS)
Here, with reference to FIG. 2 and FIG. 3, the outline at the time of performing blend processing (translucent rendering processing) using a rendering image based on the description of XPS in FIG. 2 will be described.

  First, an outline of XPS will be described.

  XPS is a high-function page description language that is used as a standard in Windows (registered trademark) Vista OS as described above. XPS is described in an XML format used as a standard in a database or the like, and is composed of elements having a plurality of nested structures. Each element is defined by describing necessary information in an inner side surrounded by tags such as <canvas> and </ canvas>.

  It is possible to describe another element inside each element. For this reason, in XPS, an image to be rendered often has a nested structure.

  The blending process is a typical example for performing another drawing using an image drawn in the nested structure as described above as an attribute value. Specifically, it is possible to draw an image and use the drawn image as transmission mask data describing the transparency of drawing another figure.

  Here, with reference to FIG. 2, description of blend processing in XPS will be briefly described. FIG. 2 is an excerpt of XPS for explaining the blending process.

  In the XPS description of FIG. 2, the <fixed page> element describes the contents drawn on a certain page. That is, the image processing apparatus X prints the contents of the elements described in the tags <fixed page> to </ fixed page> on one page.

  The <canvas> element is an element indicating a rendering area of an arbitrary range of figures. With this <canvas> element, a plurality of elements can be combined into one unit. That is, the content described between <canvas> to </ canvas> is translated into a drawing primitive that is one unit of an image to be drawn.

  Further, the attribute specified in the <canvas> element affects a child element that is an inner element.

  The <opacitymask> element is an element that explicitly indicates that it is transmission information. The <opacitymask> element is an element for handling an image drawn by an element inside this element as an image indicating an alpha value describing transparency. That is, the image processing apparatus X uses an image drawn with a description between <opacitymask> to </ opacitymask> as transmission mask data.

  The above-described transmission mask data defines the transmittance in units of, for example, 0 to 255 (8 bits) or 0 to 65535 (16 bits).

  In the case of 8 bits, 0 indicates completely transparent, and 255 indicates completely opaque. Similarly, in the case of 16 bits, 0 indicates completely transparent and 65535 indicates completely opaque.

  Note that the transmission mask data may be prepared for each color such as an RGB value or a CMYK value.

Further, it may be expressed as a fixed-point value or a floating-point value. In this case, it is desirable to determine values that define the maximum value and the minimum value.
(Drawing by Conventional Technology 1)
When the XPS of FIG. 2 is rendered, according to the prior art 1, the description contents in the <opacitymask> element are collected as a plurality of drawing primitives and header information is added. That is, in the case of XPS in FIG. 2, header information is added to the whole, and only the rendering buffer which is bitmap data for rendering, which is called a contone image buffer in the prior art 1, is used. become.

  The addition of this header is considered difficult because the prior art 1 does not provide a mechanism for processing the nested structure, but will be described as being rendered in an uncompressed state as a whole.

  Further, since the printing apparatus according to the related art 1 does not process the nested structure, translucency processing is immediately performed on the rendering buffer that is the background image immediately after the rendering of the <opacitymask> element.

  Therefore, the rendering of XPS in FIG. 2 is performed as follows with reference to FIG.

  First, it is assumed that a background character or the like is originally drawn in the rendering buffer image 100 which is an image of the rendering state of the rendering buffer in FIG.

  Here, the printing apparatus of the conventional technique 1 analyzes the PDL, and draws two rectangles of the graphic drawing (1) of FIG. 3 in the rendering buffer with the innermost <canvas> element. The rendering buffer at this point is an image like the rendering buffer image 101. Here, background characters and the like are filled.

  Since this graphic drawing (1) is inside the <opacitymask> element, this becomes transmission mask data.

  Next, the background image, which is transmission mask data, and the figure (2) figure (in this case, a 50% gray rectangle) in FIG. 3 are drawn in the rendering buffer. The rendering buffer at this point is an image like the rendering buffer 102.

  Here, since the image of the rendering buffer 102 is inside the <opacitymask> element, it is used as transmission mask data.

  Here, in practice, the prior art 1 does not support such a plurality of nested structures, so it seems appropriate to perform error processing. However, here, for the sake of explanation, what happens when the drawing is advanced using the information of the <opacitymask> element will be described.

  In this case, the printing apparatus of the related art 1 draws a color rectangle (blue component 100%) of the graphic drawing (3) in FIG. 3 and the background used for the graphic drawing 3 among the images generated at 102 at this time. An image blended with a rectangle to be drawn is drawn as part of the transmission mask data.

  That is, the final rendering buffer image is an image like the rendering buffer image 103.

  However, the drawing result as shown in FIG. 3 is far from the drawing result originally intended for the XPS description. In other words, it can be said that a drawing failure has occurred.

  Accordingly, the inventors of the present invention have made extensive research and development using actual print data, and have come to develop a method optimal for drawing in an advanced page description language such as XPS in a printing apparatus.

In the image processing apparatus X according to the embodiment of the present invention, when rendering is performed based on the description of the page description language having a nested structure as shown in FIG. By providing a mechanism for drawing on the other hand, it is possible to avoid drawing failures.
(Drawing by the image processing apparatus X according to the embodiment of the present invention)
An outline of processing in the case of performing blend processing in the image processing apparatus X according to the embodiment of the present invention using XPS in FIG. 2 will be described with reference to FIGS. 4 and 5.

  In the image processing apparatus X, the print data reception storage unit 201 receives the print data (step S701), and the PDL analysis unit 202 analyzes the PDL (step S702).

  Based on the analyzed data, when the <canvas> element is analyzed, the display list creation unit 203 determines that there is a nested structure (step S703).

  If there is a nested structure, the display list creation unit 203 increments the counter <canvas> (step S704).

  Then, the display list creation unit 203 creates a display list from the description content of the PDL in the subsequent line (step S705).

  Further, when it is determined that the sub-rendering buffer needs to be acquired inside the nested structure (step S706), the display list creating unit 203 acquires the sub-rendering buffer (2) separately from the rendering buffer (step S706). In step S707, the sub-rendering buffer count is increased (step S708).

  Further, the display list creation unit 203 determines that it is no longer inside the nested structure (step S709), and also performs processing such as decrementing the <canvas> counter (step S710).

Furthermore, if the display list creation unit 203 is inside the nested structure when the display list is created, the display list creating unit 203 selects a sub-rendering buffer corresponding to the nested structure hierarchy as the display list drawing destination (step S712). ) If it is outside the nested structure, a rendering buffer is selected (step S713).
The display list creation unit 203 determines whether or not the creation of the display list has been completed (step S7014), and when the creation of the display list for one page has not been completed yet, the above steps are repeated.

  When the display list creation unit 203 finishes creating the display list, the page rendering unit 204 interprets the display list and performs rendering (steps S715 to S716).

  Here, how the page rendering unit actually draws when the display list is created based on the above-described steps will be described.

  First, the rendering buffer image 110 in FIG. 4 is assumed to have the original background characters and the like drawn by the page rendering unit 204 as in the rendering buffer image 100 in FIG.

  First, when the page rendering unit 204 interprets the display list corresponding to the innermost <canvas> element, the page rendering unit 204 draws the rectangle of the graphic drawing (1) in FIG.

  This drawing is performed on the sub-rendering buffer (2) since the display list creating unit 203 acquires the sub-rendering buffer (2) separately from the rendering buffer when the display list is created as described above. The rendering buffer at this point is like the rendering buffer image 111 and does not change.

  Note that, since the figure drawing (1) is inside the <opacitymask> element, this becomes transmission mask data.

  The sub-rendering buffer is preferably acquired (reserved) according to the depth level of the <canvas> element. Details of this acquisition will be described later.

  Next, the page rendering unit 204 uses the drawing data of the sub-rendering buffer (2) as the transmission mask data, and converts the figure of the drawing (2) of FIG. 3 (in this case, a 50% gray rectangle) into the sub-rendering buffer ( Draw for 1). This is because the graphic of the graphic drawing (2) is in the nested structure one outer side than the innermost <canvas> element.

  Here, since the transparency mask data indicates transparency, the page rendering unit 204 renders an image blended with the sub-rendering buffer (2) in the sub-rendering buffer (1). In addition, the rendering buffer at this time has not yet changed as in the rendering buffer image 112.

  The drawing data of the sub-rendering buffer (1) is further used as transmission mask data by the outer <opacitymask> element.

  Finally, the page rendering unit 204 draws the color rectangle (blue component 100%) of the graphic drawing (3) of FIG. 3 in the rendering buffer using the drawing data of the sub-rendering buffer (1) as the transmission mask data. . This is because the figure of the figure drawing (3) is outside the nested structure.

  As a result, a rendering buffer image 113, which is a rendering buffer (bitmap data) that is finally used by the printer for printing, is created.

Such an image is what the original XPS description intended.
(Rendering example of page description language)
Next, referring to the flowchart of FIG. 5, referring to the XPS of FIG. 6, which is an XPS different from the above-described example, and the drawing example of FIG. 7, a page when actually drawing using the image processing apparatus X An example of interpreting and rendering the description language will be described in more detail.
(Step S701)
In step S701, the print data reception storage unit 201 of the image processing apparatus X receives and stores print data described in a page description language from a PC or the like connected via USB or LAN. .

  Note that the print data may be received as a whole in a unit of page data.

  When print data is received, as an initialization process before printing, the display list creation unit 203 sets CVcnt and SRcnt to 0 and releases the sub-rendering buffer if it remains.

It also initializes the pointers for the head position and the additional position for the display list. Furthermore, processing such as clearing by performing 0 fill or the like in the rendering buffer is performed.
(Step S702)
In step S702, the PDL analysis unit 202 interprets the print data in the page description language received in step S701 and stored in the print data reception storage unit 201 line by line.

The PDL analysis unit 202 stores a row counter as to what line is being interpreted.
(Step S703)
Next, in step S703, the PDL analysis unit 202 determines whether the data interpreted in step S702 is a <canvas> tag.

  In the case of Yes, the PDL analysis unit 202 advances the process to step S704.

In No, the PDL analysis part 202 advances a process to step S709.
(Step S704)
In step S704, if the element analyzed by the PDL analysis unit 202 in step S703 is a <canvas> tag, the display list creation unit 203 increments a counter that counts the depth of the nested structure of the <canvas> element.

Specifically, “CVcnt” described below is incremented.
(Count example of <canvas> element)
Here, the depth level count in the nested structure of the <canvas> element will be described in detail below with reference to FIG.

  For this counted number, the display list creation unit 203 stores a <canvas> counter (hereinafter referred to as CVcnt) and a sub-rendering buffer counter (hereinafter referred to as SRcnt) in a RAM or the like. Here, the number of CVcnt indicates the depth level of the <canvas> element, and SRcnt indicates the number of sub-rendering buffers actually acquired.

  The actual acquisition of the sub-rendering buffer is performed as follows using CVcnt and SRcnt.

  When the PDL analysis unit 202 reads the row 601, since the <canvas> tag has not been read yet, CVcnt and SRcnt are 0 which is a default value.

  When the PDL analysis unit 202 reads the line 602, the <canvas> tag is interpreted. As a result, the display list creation unit 203 increments CVcnt. Furthermore, since CVcnt is larger than SRcnt, the display list creation unit 203 secures a sub-rendering buffer and increments SRcnt.

  When the PDL analysis unit 202 reads the line 603, the <canvas> tag is interpreted. As a result, the display list creation unit 203 increments CVcnt. Further, since CVcnt is larger than SRcnt, a sub-rendering buffer is secured and SRcnt is incremented.

  When the PDL analysis unit 202 reads the line 604, </ canvas> is interpreted. As a result, the display list creation unit 203 decrements CVcnt. The sub-rendering buffer is not released.

  When the PDL analysis unit 202 reads the line 605, <canvas> is interpreted. As a result, the display list creation unit 203 increments CVcnt. Here, since CVcnt is not larger than SRcnt, it is not necessary to secure a new sub-rendering buffer.

  When the PDL analysis unit 202 reads the line 606, </ canvas> is interpreted. As a result, the display list creation unit 203 decrements CVcnt. However, the sub-rendering buffer is not released.

When the PDL analysis unit 202 reads the row 607, </ canvas> is interpreted. As a result, the display list creation unit 203 decrements CVcnt. However, the sub-rendering buffer is not released.
(Step S705)
Returning to the flowchart of FIG.

In step S705, an object designating a rendering buffer corresponding to the count number (CVcnt) of the <canvas> counter is created and added to the display list.
(Create display list)
Here, a display list used in the image processing apparatus X according to the embodiment of the present invention will be described in detail with reference to FIG.

  The display list is an attribute information and additional information describing the type of drawing primitive and how to proceed with drawing, information indicating the drawing destination, information specifying the drawing primitive, and an object that summarizes pointers to other objects, This is data having a list (link list) type data structure that is connected by a pointer.

  Each object of the display list stores the following components.

  First, in the image processing apparatus X according to the embodiment of the present invention, as drawing primitives that can be drawn, for example, points, lines (straight lines, Bezier curves, spline curves, etc.), circles, ellipses, quadrilateral fills, polygons Fill, font, bitmap data, etc. can be specified. These drawing primitive types are stored.

  In addition, since the drawing primitive can create a drawing of a translucent or transparent mask and a logical operation (AND, OR, XOR, etc.) between figures at the time of drawing, this attribute information can be stored.

  Furthermore, in addition to the colors and highlights of points, lines, polygons, etc., metal reflection coefficients, shading information, textures, shading methods, etc., additional information such as language, help text, coordinate transformation information, etc. can also be stored. .

  Information specifying the drawing destination is described based on the depth level of the nested structure. As data actually held, an address (pointer) on the storage device is described.

  Further, a pointer indicating the next object is described. This flag can be included when multiple objects are drawn together.

  Next, with reference to FIG. 10, an example of creating a display list in the case where the XPS drawing of FIG. 6 is performed will be described in more detail.

  When rendering the image 303 in FIG. 7 described above, it is necessary to first execute the rendering from 301 and 302. Therefore, when creating a display list as a small unit of rendering, the display list 301 is created first.

  First, the PDL analysis unit 202 interprets the <opacitymask> element and creates a display list 401 that is a display list that enables the transparent processing.

  Next, the PDL analysis unit 202 creates the display list 402 after interpreting the nested structure of the <canvas> element. As described above, since the nested structure of the <canvas> element is generated in the XPS of FIG. 6, the depth level count of the nested structure described later is increased, and rendering is performed in the sub-rendering buffer. Therefore, the display list 402 acquires this sub-rendering buffer and stores that it has this buffer address as a drawing destination.

  Next, the PDL analysis unit 202 creates a display list 403 indicating the drawing primitives of drawing (4) and drawing (5) in FIG.

  Finally, the PDL analysis unit 202 creates a display list 404 indicating a display list for drawing (6) in FIG. Since the display list 404 is outside the nested structure of the <canvas> element, it stores that the rendering buffer is the drawing destination.

  The display list creation unit 203 holds a pointer indicating the first object in the display list.

  In addition, a pointer (address) of a pointer indicating the next object in the terminal part object is held.

The pointer of this pointer is nil (empty) by default. As described above, when each object is added to the display list, after the memory of the object is secured, the address of the object to be added is stored in the pointer of this pointer.
(Step S706)
Returning to the flowchart of FIG.

  In step S706, the display list creation unit 203 determines whether the count number (CVcnt) of the <canvas> counter is larger than the count number (SRcnt) of the sub-rendering buffer (the number of <canvas> counters and the sub-rendering buffer). Compare the number of reserved counters).

  In the case of Yes, the PDL analysis unit 202 advances the process to step S707.

In No, the PDL analysis part 202 advances a process to step S709.
(Step S707)
In step S707, when the number of <canvas> counters is larger than the number of sub-rendering buffers acquired in step S706, the display list creation unit 203 acquires a new sub-rendering buffer.

(Get sub-rendering buffer)
Here, acquisition of the sub-rendering buffer according to the image processing apparatus X according to the embodiment of the present invention will be described.

  In the image processing apparatus X, the PDL analysis unit 202 analyzes the PDL as described above.

  In addition, as described above, when rendering is instructed hierarchically, the display list creation unit 203 uses the sub-rendering buffer that is a temporary rendering buffer depending on the level of the nested structure of <campus>. Is acquired (secured) in the RAM or the auxiliary storage device. A plurality of sub-rendering buffers can be prepared.

  Hereinafter, the procedure for actually acquiring the sub-rendering buffer will be described in more detail with reference to the XPS having the same level of nesting structure in FIG. 6 and FIG. 7 showing the rendering result.

  In FIG. 6, a rendering image is generated by interpreting a <canvas> element, that is, a command between <canvas> to </ canvas> tags as described above.

  In addition, as described above, the <opacitymask> element, that is, between the <opacitymask> to </ opacitymask> tags, defines the transmission mask data that is the transmittance.

  Referring to FIG. 6, an image 301 that is a rendering result of the graphic drawing (4) is used as transmission information in the rendering of the outer image 303.

  Specifically, the graphic drawing (4) is drawn as an image different from the actually printed page, like the image 301 in FIG. That is, drawing is performed in a sub-rendering buffer different from the rendering buffer. At this time, the background of the image 301 is black, and a 50% Gray rectangle is drawn. That is, the transmittance 1.0 is black and the transmittance 0.0 is white.

  Similarly, the image 302 that is the rendering result of the graphic drawing (5) is drawn in the same sub-rendering buffer as the image 301 as another image. Again, the background is black and a 25% Gray rectangle is drawn. The sub-rendering buffer to be written is determined by using the depth level count of the nested structure of <canvas>. This will be described later.

  Next, the rendered images of the images 301 and 302 are rendered as transparency mask data by blending with the background color in rendering of the image 303.

  Referring to FIG. 7, rendering of the image 303 is performed by blending with a blue rectangular image using the images 301 and 302 as transmission mask data.

  Here, a sub-rendering buffer is secured for data in which a <canvas> element is described as a child element between a <canvas> tag and a </ canvas> tag.

  That is, when the PDL analysis unit 202 interprets “<canvas>” and inputs “<canvas>” before interpreting “</ canvas>”, the display list creation unit 203 performs sub-rendering. Performs processing to secure the buffer.

  Specifically, the PDL analysis unit 202 interprets the <canvas> element of the child element, and calculates the minimum value (upper left) and the maximum value (lower right) of the coordinates to be rendered with the drawing primitive in the page. The display list creating unit 203 dynamically secures a buffer as a memory area in which data corresponding to the coordinates is zero-filled like calloc () in C language. The display list creation unit 203 releases the memory area for the sub-rendering buffer when drawing of the page is completed. This release process will also be described later.

In order to increase the processing speed, a sub-rendering buffer having the same capacity as the bitmap data of the rendering buffer may be secured or acquired in advance without interpreting the coordinates of the child elements as described above.
(How to use the buffer)
Next, a method of securing and using an actual sub-rendering buffer will be described with reference to XPS in FIG.

  When rendering based on the XPS of FIG. 11, two sub-rendering buffers are prepared. This is because the number of sub-rendering buffers to be prepared is determined according to the information on the depth level of <canvas>.

  That is, the PDL analysis unit 202 interprets the <canvas> tag at the line 502. In order to perform drawing inside the <canvas> element, the display list creation unit 203 acquires one sub-rendering buffer (this is assumed to be a sub-rendering buffer (3)).

  Next, the PDL analysis unit 202 interprets the <canvas> element inside the <canvas> element in line 503. As a result, the display list creation unit 203 prepares another sub-rendering buffer (this sub-rendering buffer (4)).

  Also, the PDL analysis unit 202 interprets the <canvas> element in the row 504 as well. However, since this is the same depth level of the nested structure as the <canvas> element in the row 503, drawing is performed in the same sub-rendering buffer as the sub-rendering buffer acquired in the row 503 without adding the sub-rendering buffer.

  In other words, drawing in a nested structure with the same depth level count is drawn in the same subband buffer.

  Here, drawing in the nested structure of <canvas> in FIG. 11 will be described in more detail.

  In the case of the XPS described in FIG. 11, first, the images of the nested <canvas> graphic drawing (4) and graphic drawing (5) are drawn in the sub-rendering buffer (4).

  Next, the image information of the sub-rendering buffer (4) is used for the sub-rendering buffer (3), and a transparency process is performed as a graphic drawing (6) to draw an image.

In fact, the rendering destination for each line is as follows:
The page-level rendering destination defined by the row 501 <fixedpage> element is a rendering buffer (image buffer and bitmap data output from the image processing apparatus X).

  Line 502 When <canvas> is read by the PDL analysis unit 202, the display list creation unit 203 reserves a new sub-rendering buffer (3).

  Line 503 Since a new <canvas> is read before reading </ canvas> in the PDL analysis unit, a sub-rendering buffer (4) is added and secured, and a figure is drawn.

Line 504 Since the sub-rendering buffer (4) of the same level is secured in line 502, drawing is performed on it.
(Step S708)
Here, returning to the flowchart of FIG.

In step S708, the display list creation unit 203 increments SRcnt which is the count number of the sub-rendering buffer.
(Step S709)
In step S708, the PDL analysis unit 202 determines whether the data interpreted in step S702 is a </ canvas> tag.

  In the case of Yes, the PDL analysis unit 202 advances the process to step S710.

In No, the PDL analysis part 202 advances a process to step S714.
(Step S710)
In step S710, if the data interpreted in step S709 is </ canvas>, the display list creation unit 203 decrements the <canvas> counter (CVcnt).
(Step S711)
In step S711, the display list creation unit 203 determines whether the decremented <canvas> counter (CVcnt) is not zero.

  If Yes, that is, if CVcnt is not 0, the PDL analysis unit 202 advances the process to step S712.

If No, that is, if CVcnt is 0, the PDL analysis unit 202 advances the process to step S713.
(Step S712)
In step S712, if CVcnt is not 0 in step S711, the display list creation unit 203 creates an object that designates the rendering destination as a sub-rendering buffer corresponding to the count number of CVcnt and adds it to the display list. Information about whether to release the rendering buffer can be added to the display list.
(Step S713)
In step S713, when CVcnt is 0 in step S711, the display list creation unit 203 creates an object that designates a rendering buffer to be directly printed as a drawing destination, and adds it to the display list.
(Step S714)
In step S714, the PDL analysis unit 202 determines whether a display list for the entire page has been created. That is, it is interpreted whether or not the </ fixedpage> tag or the </ fixeddocument> tag appears, or whether the print data read in step S701 has ended.

  In the case of Yes, the PDL analysis unit 202 advances the process to step S715.

In the case of No, the PDL analysis unit 202 advances the line counter so as to read the next line, and returns the process to step S702.
(Step S715)
In step S <b> 715, when the display list is created, the display list creation unit 203 passes the display list pointer to the page rendering unit 204.

As a result, the page rendering unit 204 renders the drawing primitive of the type designated by the object in the display list in the rendering buffer or the sub-rendering buffer, and performs various arithmetic processes.
(Step S716)
When rendering is completed, the display list creation unit 203 releases the secured sub-rendering buffer.

This sub-rendering buffer release process will be described in detail below.
(Sub-rendering buffer release processing)
The display list creating unit 203 basically releases the sub-rendering buffer when the creation of an image of one page in the rendering buffer is finished.

  However, it is actually possible to refer to the display list and release it when the nested structure is resolved. However, in this case, it is desirable to release the sub-rendering buffer when rendering of each page is completed so that a buffer that is not released does not remain even if there is an error in the description of the page description language. This makes it possible to use the memory efficiently. When the sub-rendering buffer is released, the display list is also released at the same time.

  If the sub-rendering buffer cannot be obtained (reserved) due to a memory shortage or the like, drawing failure can be minimized by performing drawing directly on the rendering buffer.

  When the sub-rendering buffer is released, drawing for one page is terminated.

  Here, the control device of the page printer including the image processing device X actually scans and exposes the bitmap data of the rendering buffer onto the photosensitive member, and creates a latent image electrostatically. Then, toner is attached and transferred to paper for printing. In the case of a color laser printer, this procedure is performed for each color of CMYK.

  By repeating this printing process, all pages in the document are printed.

  By configuring as described above, the image processing apparatus X according to the embodiment of the present invention can obtain the following effects.

  First, in the case of the printing apparatus of the prior art 1, when rendering includes a description of a page description language such as a color raster operation or alpha blending that may cause rendering fraud, only the portion that can be rendered is rendered. I was going. When this drawing fraud occurred, the parts that could not be drawn were rendered semi-transparently so that they would appear less broken.

  With the method of the prior art 1, it is difficult to realize rendering for a page description that can be defined hierarchically like XML.

  Actually, in the XPS described in the XML format, a rendering image can be defined to be drawn hierarchically, that is, in a nested structure. That is, there is a problem in that a final rendered image may be generated using data in the sub-rendering buffer as a rendering result for data described in XPS.

  For this reason, when rendering a page description by XPS, it is necessary to solve a rendering nesting structure.

  In the present invention, when a final rendered image is generated using an image of a drawing result, drawing can be performed without any problem by additionally securing a buffer according to a specified nested structure of a drawing target.

  As a result, it is possible to avoid the failure of drawing as occurs in the printing apparatus of the prior art 1.

  In the present invention, a counter for obtaining a sub-rendering buffer is prepared (for example, CVcnt and SRcnt) by paying attention to an element (a <canvas> element in the case of XPS) where the nesting structure is a problem. This makes it possible to easily draw data with a nested structure, and the effect of reducing the number of man-hours required by software can be obtained.

  Further, when installed in an actual printer as software for interpreting PDL, there is an effect that there is no problem in rendering.

  In addition, since the sub-rendering buffer is acquired according to the nesting structure, for example, the memory consumption can be minimized as compared with a method of acquiring all the buffers every time <canvas> appears.

  In the above-described embodiment, the acquisition of the sub-rendering buffer is described to be performed when the page description language is analyzed.

  However, it is naturally possible to configure such that it is acquired at the time of actual rendering. In this case, the number of <canvas> counter (CVcnt) can be described as information indicating the drawing destination of each object in the display list. When a sub-rendering buffer needs to be acquired, a flag indicating this is added. Then, at the time of actual page rendering, the page rendering unit 204 acquires the sub-rendering buffer and renders it.

  When drawing this nested structure, if sufficient memory capacity can be secured, the depth (depth) describing the depth of the nested structure for each bit of the rendering buffer (bitmap data) to be printed finally. It is also possible to perform processing using a buffer without using a sub-rendering buffer.

  In this case, when each drawing primitive is drawn, the process of determining whether the depth buffer is above or below the nested structure and writing to the bitmap data is sequentially performed. Thereby, it is possible to perform drawing without failure.

  However, when translucent drawing processing is performed, the drawing order may become a problem only with this depth buffer.

  In this case, a rendering failure can be avoided by redrawing after rendering (z-sorting) each rendering primitive in the display list related to the location where the failure occurs based on the depth of the <canvas> element.

  Furthermore, in the above-described depth count, a nested structure can be expressed in a tree shape such as a binary tree to draw a more complicated structure.

  In addition, in the embodiment of the present invention, a laser printer has been described. However, the image processing apparatus of the present invention can naturally be applied to other types of printers.

  Note that the configuration and operation of the above-described embodiment are examples, and it is needless to say that the configuration and operation can be appropriately changed and executed without departing from the gist of the present invention.

It is a control block diagram of the image processing apparatus X which concerns on embodiment of this invention. It is a figure which shows the description of XPS for demonstrating the outline | summary of the blend process which concerns on embodiment of this invention. It is a conceptual diagram of the rendering for demonstrating the outline | summary of the blend process which concerns on the prior art 1. FIG. It is a conceptual diagram of the rendering for demonstrating the outline | summary of the blend process which concerns on embodiment of this invention. It is a flowchart which shows the procedure of rendering of the image processing apparatus X which concerns on embodiment of this invention. It is a figure which shows the description of XPS for demonstrating reservation of the sub-rendering buffer which concerns on embodiment of this invention. It is a conceptual diagram for demonstrating securing of the sub-rendering buffer which concerns on embodiment of this invention. It is a conceptual diagram for demonstrating the count of the depth level of the nesting structure which concerns on embodiment of this invention. It is a conceptual diagram which shows the structure of the object of the display list which concerns on embodiment of this invention. It is a conceptual diagram which shows the display list which concerns on embodiment of this invention. It is a conceptual diagram for demonstrating the timing of sub-rendering buffer acquisition which concerns on embodiment of this invention.

Explanation of symbols

100 to 103, 110 to 113 Rendering buffer image 201 Print data reception storage unit 202 PDL analysis unit 203 Display list creation unit 204 Page rendering units 301 to 303 Images 401 to 404 Display list X Image processing apparatus

Claims (3)

An image processing apparatus that performs image processing based on a description of a page description language,
Storage means for storing data described in the page description language;
Page description language analyzing means for analyzing a description related to a nested structure of the page description language stored in the storage means;
Based on the nested structure analyzed by the page description language analyzing means, a display list creating means for creating a display list which is a list including information on the type of figure to be drawn and the depth level of the nested structure;
Page rendering means for acquiring a sub-rendering buffer for each depth level of the nested structure in accordance with the display list, rendering the sub-rendering buffer, and rendering each page using the contents of the sub-rendering buffer; An image processing apparatus comprising:   The image processing apparatus according to claim 1, wherein the page description language is a page description language based on XML including XPS. The image processing apparatus according to claim 1 or 2,
An image forming system comprising: a communication device.