JP2005099900A - Print system and host computer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve development efficiency while maintaining processing speed and image quality of a printer driver favorably in a print system of a host based printing system. <P>SOLUTION: As a print system configuration which is made up by connecting a host computer 1 and a printer 5 via a channel 10, a printer driver 8 of the host computer 1 has; a core printer driver section 81 which assigns unique identification information for each character associated with outline data which represent a character; and a rendering processing section 82 which receives data for rendering which include outline data and the identification information from the core printer driver section 81 and carrying out rendering processing, manages a font cache which stores temporarily image data of a character font generated by this rendering processing, and generates a cache key for registration process of the font cache, and searching processing using the identification information contained in the data for renderings. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printing system configured by connecting a host computer and a printer by communication means.

  There is a printing system that processes various drawing commands output from an image creation device such as a host computer, develops it into image data for printing represented by an array of pixels, and prints it on paper or the like with a printing device.

  FIG. 8 is a diagram illustrating a configuration example of a printing system. In this printing system, the host computer 51 includes an operating system 52, an application program 53, a printer driver 54, and hardware 55. A display device 56, an external storage device 57, and an input device 58 are connected to the host computer 51 through dedicated cables or the like. A printer 60 is connected to the host computer 51 via a communication path 59 such as a network.

  In the printing system configured as described above, the data created by the application program 53 on the host computer 51 is converted into data in the page description language (PDL) format (hereinafter referred to as PDL data) by the printer driver (printer control program) 54. The PDL data is transmitted to the printer 60 through the communication path 59. In this case, the PDL data includes graphic data, character data, image data generated by reading a photograph with a scanner or the like.

  Among these, the character data includes character typeface information and code information. When this character data is developed into image data expressed by an arrangement of pixels, a method is used in which data is acquired from font data stored in the printer 60 and bitmap data for printing is generated. . In addition, a user who creates data using the application program 53 on the host computer 51 may use various character fonts. Accordingly, there may be a case where the font of characters used for data creation is not stored in the printer 60. In such a case, the printer driver 54 may cope with this problem by acquiring character outline data or character bitmap data from the operating system 52 and then transmitting the data included in the PDL data.

  On the other hand, in addition to the data processing mode described above, graphic data and character data for which printing is instructed on the host computer 51 are expanded into image data for printing expressed in an array of pixels, and the image data is compressed. After that, there is a data processing form to be transmitted to the printer 60. (Hereinafter, a printing method adopting this data processing form is called a “host-based printing method”).

  As a prior art related to the host-based printing method, for example, in Patent Document 1 below, data to be printed is rendered in the form of image data on the host computer side and transmitted to the printer. It is described that, when all characters are sent as image data to the printer, the amount of data transfer increases, so that the character portion is sent to the printer using a character code.

Japanese Patent Laid-Open No. 10-293669

  The host-based printing method is one of the technologies attracting attention due to recent increases in the speed of host computers, improvement in processing efficiency, and improvement in data storage. In this host-based printing method, on the host computer 51, the printer driver 54 develops drawing data equivalent to PDL, such as characters, graphics, and photographs, into image data for printing expressed in an array of pixels ( After compression by rendering, the compressed image data for printing is transmitted to the printer 60 through the communication path 59. Therefore, in the printing system adopting the above-described data processing form of the PDL format, the print data transmitted through the communication path 59 is PDL data. However, in the printing system adopting the data processing form of the host-based printing method, The compressed image data obtained by rasterizing and compressing the page by the printer driver 54 is transmitted through the communication path 59. The host-based printing is characterized in that the throughput of the entire printing system is improved without replacing the printer driver (program) 54 as the processing speed of the host computer 51 is improved and the communication speed of the communication path 59 is improved. There is.

  Further, from the viewpoint of the internal configuration of the printer driver 54, as shown in FIG. 9, a processing part (hereinafter referred to as a core printer driver part) 541 that depends on the operating system 52 and data such as graphics and characters are expressed in an array of pixels. It is preferable to operate by dividing into a processing part (hereinafter referred to as a rendering processing unit) 542 that develops the image data. This is because even if the type or version of the operating system 52 changes, the rendering processing unit 542 can be used in common, or the core printer driver unit 541 can be developed without significantly changing from the conventional PDL printer driver. This occurs because the interface (calling function) between the core printer driver unit 541 and the rendering processing unit 542 is desired to be equivalent to the conventional PDL. Therefore, the development efficiency of the printer driver 54 can be improved by dividing the internal configuration of the printer driver 54 into the core printer driver unit 541 and the rendering processing unit 542.

  Here, if attention is paid to the process of expanding the font information of a character into image data expressed by an arrangement of pixels such as a character bitmap, the graphics provided by the operating system 52 are usually used in the host-based printing method. Bitmap data of characters is acquired through a data interface, copied to a final output buffer, and a page image for one page is generated and then compressed. In this case, since the cache processing for the character bitmap operates in the operating system 52, the printer driver 54 can perform high-speed processing without preparing a special font cache.

  However, the interface that calls the rendering processing unit 542 is preferably provided with data independent of the coordinate space of the printer serving as the output device, like the device-independent PDL, but the core printer driver unit 541 uses the character bit. In the case of acquiring a map, the enlargement / reduction processing in the rendering processing unit 542 causes image quality degradation such as jaggies, and processing speed decreases due to rotation processing.

  On the other hand, a configuration in which the rendering processing unit 542 performs character bitmap acquisition processing is also conceivable. When this configuration is adopted, the problem of image quality and speed reduction can be solved by acquiring the character bitmap after enlargement / reduction or rotation from the operating system 52. However, adopting such a configuration is not preferable from the viewpoint of improving the development efficiency of the printer driver 54 because the rendering processing unit 541 depends on the operating system 52.

  The present invention has been made to solve the above-described problems, and the object of the present invention is to perform the same processing as when a bitmap character is acquired from an operating system in a printing system employing a host-based printing method. The purpose is to increase the development efficiency by making the rendering processing unit inside the printer driver independent of the operating system while maintaining the speed and image quality.

  The printing system according to the present invention is configured by connecting a host computer and a printer by communication means, and develops data to be printed into image data for printing expressed in a pixel array by the host computer. In this printing system, the image data is transmitted to the printer for printing processing. The host computer has printer control means for controlling the printer, and the printer control means is associated with outline data representing characters. A first processing unit for assigning unique identification information for each character, rendering data including outline data and identification information received from the first processing unit, rendering processing, and a character font generated by the rendering processing Manage the font cache that temporarily stores image data, One, in which a second processing section for generating a cache key for registration and search processing font cache by using the identification information included in the data for rendering.

  In this printing system, when character data is processed by the printer control means of the host computer, unique identification information is assigned to each character by the first processing unit in association with the outline data of the character to be processed. At the same time, rendering data including the outline data and identification information is sent from the first processing unit to the second processing unit. In the second processing unit, the rendering data received from the first processing unit is subjected to rendering processing, and the font cache registration processing and search processing are performed using the identification information included in the rendering data. A cache key is generated.

  According to the present invention, when printing processing of data including characters is performed in a printing system adopting the host-based printing method, the printer control means of the host computer performs rendering processing using the outline data of characters. High image quality is achieved, and a cache key is generated using unique identification information for each character, and rendering processing is performed using the font cache by cache registration and cache search based on this, realizing high processing speed. be able to. Furthermore, since the host computer can perform rendering processing independent of the operating system, it is possible to simplify the internal configuration of the printer control means and increase the development efficiency.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration example of a printing system according to an embodiment of the present invention. The illustrated printing system mainly includes a host computer 1, a display device 2, an external storage device 3, an input device 4, and a printer 5 connected to the host computer 1. The host computer 1 includes an operating system 6, an application program 7, a printer driver 8, and hardware 9.

  The host computer 1 includes hardware 9 such as a CPU (Central Processing Unit) and a memory. The application program 7 can create data to be printed and can instruct the operating system 6 to print the created data. Connected to the host computer 1 are a display device 2 such as a CRT (cathode ray tube) or LCD (liquid crystal display), an external storage device 3 such as an HDD (hard disk drive), and an input device 4 such as a keyboard or a mouse. The hardware 9 and software built in the host computer 1 and various external devices connected to the host computer 1 operate under the control and management of the operating system 6. On the other hand, the printer 5 prints an image on a recording medium such as paper, and is connected to the host computer 1 via a communication path 10 such as a network serving as communication means and a printer cable.

  In this printing system, the compressed image data generated by the host computer 1 is transmitted to the printer 5 using the communication path 10, and the printer 5 prints out an image on a recording medium. At that time, on the host computer 1, the data (data to be printed) that the application program 7 instructs the operating system 6 to print is converted into image data for printing expressed by the pixel array by the printer driver 8. The image data is expanded and compressed to generate compressed image data for printing.

  FIG. 2 is a diagram showing a data processing flow of the printing system according to the embodiment of the present invention. First, in the host computer 1, the operating system 6 sends data created using the application program 7 to the printer driver 8 in accordance with a print instruction from the application program 7. The printer driver 8 corresponds to a printer control unit that controls the printer 5, and this is a print driver that expresses data (data to be printed) sent from the operating system 6 in a sequence of pixels. The data is expanded into image data, and the expanded image data is transmitted (returned) to the operating system 6. Then, the operating system 6 transmits the compressed image data received from the printer driver 8 to the printer 5 via the communication path 10. On the other hand, the printer 5 receives the compressed image data transmitted through the communication path 10, decompresses the received compressed image data, interprets the contents, and prints it as a visible image on a recording medium such as paper. Output.

  In the data processing flow described above, the data (print target data) sent from the operating system 6 to the printer driver 8 includes drawing data (graphic data, character data, image data, etc.) necessary for printing, This includes print control data such as the start and end of a page. In the printer driver 8, the print target data transmitted from the operating system 6 is received by the core printer driver unit (first processing unit) 81, and this received data is received as necessary by the rendering processing unit (second processing unit). The data is converted into a data format that can be interpreted by the processing unit 82, and then transmitted to the rendering processing unit 82. The rendering processing unit 82 receives the data (rendering data) transmitted from the core printer driver unit 81, and develops (renders) the data into printing image data (bitmap data or the like) represented by an array of pixels. The compressed image data is generated by compressing the expanded image data.

  When the rendering processing unit 82 generates compressed image data (image data for printing) for one page or several pages in this way, this compressed image data (processing result in the rendering processing unit 82) is used as the core printer driver unit 81. Send to. Then, the core printer driver unit 81 sends the compressed image data received from the rendering processing unit 82 to the operating system 6.

  Here, when the character data is included in the print target data (drawing data) transmitted from the operating system 6 and this character data is processed by the printer driver 8, the core printer driver unit 81 receives the character received from the operating system 6. A character is identified from the character code (JIS code) of the data, and an ID number serving as unique identification information is assigned to each character in association with outline data representing the character. Outline data is basically data representing the outline of one character. Since the core printer driver unit 81 assigns a unique ID number to each character, if the characters represented by the outline data are the same, the same ID number is assigned. At this time, the ID number may be generated and assigned by the core printer driver unit 81 itself, or the ID number generated by the operating system 6 may be acquired and assigned by the core printer driver unit 81. Further, the association between the outline data and the ID number may be performed by including the information (outline data, ID number) in the data for rendering one character, for example.

  Incidentally, in the case of a character that cannot generate an ID number (for example, a special character such as an external character) or a character that has a very large character size and presses the memory capacity of a later-described font cache, the core printer driver unit 81 In order to make characters that do not need to be registered in the font cache, a common ID number set in advance within the range of possible ID numbers is assigned to such characters. For example, if the ID number is assigned from 0, the value representing the ID number undetermined is determined as 0 in advance, and the core printer driver unit 81 determines that the ID number cannot be assigned to the target character ( If it is determined that the registration processing in the font cache is unnecessary, 0 is assigned as the ID number of the character. In addition, the core printer driver unit 81 distinguishes (identifies) each character based on font information such as a character font, character code value, and character modification status included in the character data. For example, the character is “Mincho”, and it is the character “A” in 0x82A0 (hexadecimal number) in the SJIS code expression, and the modification status of italic is determined to identify (determine) one character.

  On the other hand, the rendering processing unit 82 receives the outline data of characters included in the data for rendering and the ID number (identification information) assigned to the characters from the core driver unit 81 and performs rendering processing. At that time, the rendering processing unit 82 uses (manages) a font cache in order to efficiently draw characters. For example, the font cache is allocated to a part of the memory included in the host computer 1, and when the outline data of the character is rendered and expanded into a bitmap, the image data (bitmap image data) of the character font is used. It is secured as a memory area for temporary storage. In using the font cache, the rendering processing unit 82 generates a cache key for font cache registration processing and inspection processing using the ID number included in the rendering data received from the core printer driver unit 81. .

  When generating the cache key, the rendering processing unit 82 generates a cache key by combining the conversion matrix element applied when printing the compressed image data for printing with the printer 5 and the ID number described above. As a result, the core printer driver unit 81 can assign the same ID number to the same character and send it to the rendering processing unit 82 without being influenced by the conversion matrix into the coordinate space of the printer 5 serving as the image output device. it can.

  For example, even for the character “A”, the output result of the character bitmap that is actually printed differs depending on whether the print page direction (paper orientation) of the image output apparatus is vertical or horizontal. In another example, even when a processing method (an output method called N-UP or the like) that prints and outputs a plurality of pages (N pages) of image data in one page is specified, the character size and direction (Direction) is different. In such a case, even if the same ID number is assigned to the same character “a” by the core printer driver unit 81, the rendering processing unit 82 does not simply generate a cache key from the ID number but performs matrix conversion. Generate a cache key in combination with the element. As a result, even for characters assigned the same ID number in the core printer driver 81, the rendering processor 82 generates a different cache key for each matrix conversion element. Therefore, the core printer driver unit 81 can specify the same character using the same ID number without depending on the coordinate space of the printer 5.

  FIG. 3 shows an example of an interface (I / F) between the core printer driver unit 81 and the rendering processing unit 82 in the printer driver 8. The interface described here means a function (calling function) that specifies processing contents when rendering data input from the core printer driver unit 81 is subjected to rendering processing by the rendering processing unit 82. Is an interface that specifies the start / end of a page, the color of a figure or character, an interface that specifies a transformation matrix such as rotation or scaling of a drawing object, an interface that draws a figure in a path format, or a character drawing interface And raster image drawing interface.

  Note that FIG. 3 illustrates a typical interface between the core printer driver unit 81 and the rendering processing unit 82 inside the printer driver 8. Besides these interfaces, for example, a rectangle or an ellipse is used. An interface for directly specifying a graphic, an interface for specifying a line width / broken line shape of the graphic, and an interface for specifying a pattern such as hatching can also be included.

  FIG. 4 shows details of the character drawing interface (DrawFont () function in the figure) among the various interfaces shown in FIG. The illustrated character drawing interface includes a memory address indicating a storage destination of outline data representing one character, an X coordinate value and a Y coordinate value representing a drawing reference point when the character is drawn, and a character unique to each character. The ID numbers assigned as identification information are included as function call arguments (ID, FontData, X, Y), respectively.

  FIG. 5 is a diagram showing an example of a specific data format of character outline data represented by arguments of the character drawing interface of FIG. In the illustrated outline data format, the first field represents the data size. The second field represents the total number of control points, and the third field represents the total number of line types. The fourth and subsequent fields are fields for storing control points for expressing the outline of the character and the line type of the outline formed by the control points. That is, the fourth and subsequent fields represent the X coordinate value and the Y coordinate value of each control point constituting the outline, and the subsequent fields represent line type values.

  There are five types of line types such as MOVETO and LINETO based on the path drawing format drawing method. The number of control points used varies depending on the type of line type. For example, MOVETO uses only one control point, but CLOSE (command to close a path) does not use any control point. The coordinate value of the control point is expressed by a relative position from the X coordinate value or the Y coordinate value which is the character drawing reference point of the character drawing interface of FIG. Therefore, even if the X coordinate value or the Y coordinate value of the character drawing reference point of the character drawing interface is changed, the same outline data (address storing data) can be designated.

  FIG. 6 shows an example of outline data representing the character “A”. This outline data uses 116 bytes of data in total and consists of 11 control points (a0 to a10) and 16 line patterns (MOVETO × 2, LINETO × 11, CLOSE × 2, ENDCHAR × 1). Has been. These data are stored in a memory area managed by the core printer driver unit 81 in the memory of the host computer 1.

  FIG. 7 is a flowchart illustrating an example of a processing procedure related to the character processing of the rendering processing unit 82. First, data necessary for drawing a character, such as an ID number, outline data (address), X coordinate value, and Y coordinate value, is input by the character drawing interface called from the core printer driver unit 81 (step S1).

  Next, the value of the conversion matrix to the coordinate space depending on the printer (image output device) set when the character drawing interface is called is acquired (step S2). The value of the transformation matrix is set by scaling or rotating the image. The value of this transformation matrix is designated in advance by SetMatrix () included in the list of interfaces shown in FIG. The value of the transformation matrix is expressed in a 2 × 2 matrix format that expresses transformation such as enlargement / reduction or rotation of the image. Therefore, the value of the transformation matrix is four real values.

  Next, a cache key for font cache registration processing and search processing is generated from the ID number assigned to the outline data of the character and four real values representing the matrix conversion elements. When the cache key is generated in the simplest case, if one matrix transformation element is expressed by a fixed point of 4 bytes, a total of 4 bytes × 5 = 20 bytes including 4 bytes of the ID number. Is generated (step S3). At this time, if the font information such as the character type, typeface, size, and orientation is the same, the same cache key is generated.

  Subsequently, using the cache key generated earlier as a search key, whether or not there is image data registered with the same cache key as the search key in the font cache, that is, the character of the same font information is rendered. Whether the bitmap image data is stored is searched (step S4).

  If character image data (bitmap data) with the same font information is stored as a result of the search, an address in the font cache that is the storage destination is acquired (step S5).

  If the image data of the character in the same font is not stored as a result of the search, the outline data specified by the character drawing interface is referred to, and rendering processing is performed according to the outline data to character such as a bitmap. Image data (rendering result) is obtained (step S6). Next, the rendering result is registered (stored) in the font cache in association with the cache key, and an address in the font cache serving as the registration destination (storage destination) is acquired (step S7).

  After the font cache search process or registration process is performed in this way, characters are drawn in the output buffer based on the X coordinate value and Y coordinate value of the character drawing reference point input in step S1 (step S8).

  With the above processing, characters with the same font information are rendered once and registered in the font cache. After that, they are output using the registration information in the font cache without rendering each time. Speeding up of processing can be realized.

1 is a diagram illustrating a configuration example of a printing system according to an embodiment of the present invention. It is a figure which shows the data processing flow of the printing system which concerns on embodiment of this invention. FIG. 4 is an example diagram of an interface delivered inside a printer driver. It is a figure which shows the detail of the interface of a character drawing. It is a figure which shows an example of the specific data format of character outline data. It is a figure which shows the example of outline data. It is a flowchart which shows an example of the process sequence of a rendering process part. 1 is a diagram illustrating a configuration example of a printing system. It is a figure which shows the data processing flow of a printing system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Host computer, 5 ... Printer, 8 ... Printer driver, 10 ... Communication path, 81 ... Core printer driver part, 82 ... Rendering processing part

Claims (3)

The host computer and the printer are configured to be connected by communication means, and the data to be printed is expanded into image data for printing expressed in an array of pixels by the host computer. A printing system that transmits to a printer and performs printing processing.
The host computer has printer control means for controlling the printer,
A first processing unit that assigns unique identification information for each character in association with outline data representing the character; and the first data for rendering data including the outline data and the identification information. A font cache that temporarily stores image data of a character font generated by the rendering process, and uses the identification information included in the rendering data to perform the rendering process. And a second processing unit that generates a cache key for cache registration processing and search processing. The said 2nd process part produces | generates the said cache key combining the conversion matrix element applied when printing the said image data for printing with the said printer, and the said identification information. The printing system described. A host computer connected to the printer via communication means and having printer control means for controlling the printer,
A first processing unit that assigns unique identification information for each character in association with outline data representing the character; and the first data for rendering data including the outline data and the identification information. A font cache that temporarily stores image data of a character font generated by the rendering process, and uses the identification information included in the rendering data to perform the rendering process. And a second processing unit for generating a cache key for cache registration processing and search processing.

Images