Patent Publication Number: US-2007109322-A1

Title: Print control program product

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority from Japanese Patent Application No. 2005-329240, filed on Nov. 14, 2006, the entire subject matter of which is incorporated herein by reference.  
     TECHNICAL FIELD  
      Aspects of the present invention relate to a print control program product which displays a preview image that visualizes a printing result before printing on a printing apparatus, and more particularly to a print control program product which displays the preview image after editing promptly and correctly.  
     BACKGROUND  
      When print data created by a personal computer (hereinafter simply referred to as a “PC”) is to be printed using a printer, it is common that a print instruction is sent from the PC to the printer to produce a printing result. To meet the needs of grasping the printing result before printing, there is a preview function of displaying the printing result of the printer on a monitor of the PC, before outputting the print data (print instruction) to the printer. This preview function is provided in an application program or a printer driver.  
      The preview function of the application program involves generating and displaying the preview image using font information set in an operating system of the PC and an image formation program in the application program. The displayed preview image may be often different from the printing result on the printer. This is because the font information provided for the PC and the font information built in the printer may be different, or the processing contents of creating the image data in the print data may be different.  
      The printer driver intervenes between the application program and the printer and assists in sending or receiving data therebetween. The print data generated by the application program is converted into a data format according to the printer, which is an output destination, and outputted to the printer by the printer driver. Thereby, the print data outputted from the PC is printed by the printer. Since the printer driver is a program prepared for the printer, the preview image displayed with this preview function can accurately reflect the actual printing result.  
      In recent years, the preview function of such a printer driver is enabled to make an edit process for the preview image. In this printer driver, the displayed preview image can be edited based on an instruction on the display screen. The edit process to be performed involves changing (moving) the display position of a displayed object, scaling up or down and deleting the object (see JP-A-2001-282499).  
     SUMMARY  
      When the preview image is edited, it is necessary to redisplay the preview image after editing. Two redisplay methods have been proposed. The first method includes saving a rendering instruction of each object (constituting the preview image) displayed in the preview image, and rendering each object again in accordance with the saved rendering instruction, when the preview image after editing is displayed. The second method involves generating and storing the bitmapped data rendering each object displayed in the preview image and reconfiguring the preview image using the bitmapped data in making the redisplay.  
      With the first method, it is required to render each object in accordance with the rendering instruction every time of redisplay. Therefore, the display operation of the preview image is slow. Also, with the second method, since each object is stored in the bitmapped data, some portion of the earlier displayed object, which should be displayed, maybe hidden with the bitmapped data of the later displayed object, if the rendering areas of the objects overlap. The bitmapped data is formed in a rectangular range containing the object. If the object is not rectangular, a margin portion generated by the solid image is contained, in addition to the object. This results in the above-described phenomenon.  
      Aspects of the invention provide a print control program product that can display the preview image after editing promptly and correctly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a block diagram showing the electrical configuration of a personal computer mounting a printer driver according to an aspect of the present invention;  
       FIG. 2  is a view schematically showing the configuration of a rendering instruction;  
       FIGS. 3A and 3B  are views schematically showing the configuration of a preview management memory;  
       FIGS. 4A and 4B  are views showing bitmapped data created based on the rendering instruction;  
       FIGS. 5A  to  5 D are views showing a preview image firstly displayed on an LCD when the preview image is requested to display and its production process;  
       FIGS. 6A  to  6 C are views showing the image in generating the bit map of an object with a mask set;  
       FIG. 7  is a view showing the preview image after the preview image of  FIG. 5  is edited;  
       FIG. 8  is a flowchart of a preview process that is performed when the printer driver is started;  
       FIG. 9  is a flowchart of a bit map generation process that is performed in the preview process of  FIG. 8 ;  
       FIG. 10  is a flowchart of a mask generation process that is performed in the bit map generation process of  FIG. 9 ;  
       FIG. 11  is a flowchart of a preview screen generation process that is performed in the preview process of  FIG. 8 ; and  
       FIG. 12  is a flowchart of a rendering process that is performed in the preview screen generation process of  FIG. 11 . 
    
    
     DETAILED DESCRIPTION  
      &lt;General Overview&gt; 
      According to a first aspect of the invention, there is provided a print control program product comprising: software instructions which, when executed on a computer, enables the computer to perform predetermined operations; and a computer readable medium which stores the software instructions; the predetermined operations including: outputting a print data to a printing apparatus to enable the printing apparatus to print an image corresponding to the print data; displaying a preview image that visualizes the printing result on a display device before the outputted print data is printed; editing a rendering object displayed in the preview image based on a change instruction for the preview image displayed on the display device; and redisplaying the edited preview image, wherein, before the displaying step, the predetermined operations further include: storing the image data of the rendering object displayed in the preview image as a dot data in which a range containing at least the rendering object is represented in a dot arrangement; generating a tag information for distinguishing a portion corresponding to the rendering object within the dot data from the other portion, if the dot data contains a portion other than the rendering object; and storing the tag information in association with the dot data, and wherein the redisplaying step includes: displaying the rendering object after editing based on the dot data stored at the image data storing step; and extracting and displaying a portion of the rendering object from the dot data in accordance with the associated tag information, if the tag information corresponding to the dot data is stored at the tag information storing step.  
      According to a second aspect of the invention, the print control program product further comprises: acquiring a rendering information including at least one of an outside shape information indicating the outside shape of the rendering object, a representation information for representing a form of the rendering object, and a rendering area information indicating a rendering area, the rendering information being the information for defining the rendering object and set for each rendering object, wherein the displaying step includes rendering the rendering object in accordance with the representation information and the rendering area information of the rendering information acquired at the acquisition step, and wherein the image data storage step stores the dot data containing the rendering data of the rendering object rendered at the rendering step.  
      According to a third aspect of the invention, the print control program product further comprises: judging whether or not to generate the tag information corresponding to the rendering object, based on the rendering information of the rendering object, wherein the tag information generating step generates the tag information for the dot data, if the tag generation judgement step judges to generate the tag information for the dot data.  
      According to a fourth aspect of the invention, the image data storing step includes: storing the rectangular rendering data directly as the dot data, if the outside shape of the rendering object is rectangular in accordance with the outside shape information; and storing the dot data in a rectangular range including the rendering data of the rendering object rendered at the rendering step and additionally its peripheral portion, if the outside shape of the rendering object is not rectangular in accordance with the outside shape information, and the judging step judges to generate the tag information, if the outside shape of the rendering object is not rectangular.  
      According to a fifth aspect of the invention, the judging step judges not to generate the tag information, if the outside shape of the rendering object is rectangular.  
      According to a sixth aspect of the invention, the judging step judges to generate the tag information, if the rendering information acquired at the acquisition step is not a character rendering information, and the dot data storing step includes storing the character rendering data rendered at the rendering step directly as the dot data.  
      According to a seventh aspect of the invention, the judging step judges not to generate the tag information, if the rendering information is the character rendering information.  
      According to an eighth aspect of the invention, the print control program product further comprises: extracting a common area between the mask area information indicating a mask area contained in a mask information and the rendering area information, if the rendering information has the mask information indicating that at least part of the rendering object is masked, wherein, if the extracted common area is rectangular, the dot data storing step stores the rendering data of a portion corresponding to the common area as the dot data.  
      According to a ninth aspect of the invention, the print control program product further comprises: a specific information storage step of storing, for each the rendering object, the tag presence information indicating that the tag information corresponding to the dot data is stored, the dot specific information specifying the dot data, and the tag specific information specifying the tag information, wherein, when the rendering object is redisplayed, the redisplaying step specifies and displays one dot data corresponding to the rendering object with the stored dot specific information, when the rendering object is redisplayed, and wherein, if the tag presence information is stored corresponding to the dot specific information, the redisplaying step specifies one tag information with the corresponding tag specific information and extracts and displays a portion of the rendering object from the dot data based on the specified tag information.  
      According to a tenth aspect of the invention, a rendering order and a rendering area information of the rendering object are changeable based on a change instruction, the editing step includes editing the rendering object displayed in the preview image by updating the rendering order or the rendering area information based on the change instruction, the redisplay step includes displaying the corresponding rendering object in the dot data in accordance with the rendering order or the rendering area information after update, and the initial values of the dot data are held, irrespective of whether or not at least one of the corresponding rendering order and the corresponding rendering area information is updated.  
      With the print control program product according to the first aspect of the invention, at the dot data storing step, the image data of the rendering object displayed in the preview image is stored in the dot data in which a range containing at least the rendering object is represented in a dot arrangement. At the generating step, the tag information for distinguishing a portion corresponding to the rendering object of the dot data from the other portion is generated, if the dot data contains a portion other than the rendering object. And at the tag information storing step, the generated tag information is stored in association with the dot data. At the redisplaying step, the rendering object after editing is displayed based on the dot data stored at the dot data storing step. However, a portion of the rendering object is extracted and displayed from the dot data in accordance with the tag information, if the tag information corresponding to the dot data is stored.  
      Hence, the redisplayed preview image can be formed based on the stored dot data. That is, since the rendering object can be displayed by the dot data that is already stored, it is unnecessary to decode the rendering instruction of each rendering object to render (display) each rendering object, whereby there is the effect that the preview image can be redisplayed promptly.  
      Moreover, since a portion of the rendering object in the dot data is extracted from the dot data in accordance with the tag information and displayed, only the rendering object can be displayed, even if the dot data contains any other portion than the rendering object. In other words, even if the preview image is redisplayed based on the dot data, no other portion than the rendering object is displayed. Thereby, it is possible to avoid a situation where the earlier displayed rendering object (all or a part of rendering object) is hidden because any other portion than the rendering object in the dot data of the rendering object overlaps the earlier displayed rendering object, whereby there is the effect that each rendering object can be displayed accurately, even if each rendering object is displayed based on the dot data to form the preview image.  
      With the print control program product according to the second aspect of the invention, at the acquiring step, the rendering information having at least the outside shape information, the representation information and the rendering area information is acquired. At the rendering step, the rendering object is rendered in accordance with the rendering information (representation information and the rendering area information) acquired at the acquiring step. And at the dot data storing step, the dot data containing the rendering data of the rendering object rendered at the rendering step is stored.  
      When the preview image is displayed on the display device at the displaying step, it is necessary to generate the rendering data of the rendering object by making the dot expansion of the rendering information. That is, in displaying the preview image, the generation of the rendering data at the rendering step is requisite. Hence, by storing the dot data based on the rendering data generated at the rendering step, the dot data can be acquired as the image data of each rendering object before editing the preview image, whereby there is the effect that the redisplay of the preview image can be performed promptly and smoothly. Since it is unnecessary to create the dot data by making the dot expansion of the rendering information every time of redisplaying the preview image, it is possible to avoid the redundant process regarding the preview display as a whole.  
      With the print control program product according to the third aspect of the invention, at the judging step, it is judged whether or not it is unnecessary to generate the tag information corresponding to the rendering object, based on the rendering information of the rendering object, and the generation of the tag information at the generating step is not performed, if it is judged that it is unnecessary to generate the tag information for the dot data. Hence, there is the effect that it is possible to avoid a squeeze on the memory area due to storage of the unnecessary tag information by avoiding generating the tag information wastefully, and to speed up the redisplay process for the preview image than where the tag information is uniquely generated irrespective of the contents of the rendering object.  
      With the print control program product according to the forth and fifth aspects of the invention, at the dot data storing step, the rectangular rendering data rendered at the rendering step is stored directly as the dot data, if it is revealed that the outside shape of the rendering object is rectangular in accordance with the outside shape information acquired at the acquiring step. Also, at the dot data storing step, the dot data is stored in a rectangular range including the rendering data of the rendering object rendered at the rendering step and additionally its peripheral portion, if it is revealed that the outside shape of the rendering object is not rectangular in accordance with the outside shape information. And at the judging step, it is judged that it is unnecessary to generate the tag information, if the outside shape of the rendering object is rectangular. Therefore, the generation of the tag information at the generating step is performed if the outside shape of the rendering object is not rectangular. Hence, if the dot data of the stored range is coincident with the rendering data, the generation of the tag information may not be performed, because the dot data does not contain any other portion than the rendering object, whereas if not coincident, the tag information can be generated, because the dot data contains any other portion than the rendering object. That is, there is the effect that it is possible to accurately switch between the generation and the non-generation of the tag information depending on whether the tag information is necessary or not.  
      One of the typical dot data forms is the bitmap format. In this bitmap format, the dot data is generated in the rectangular range. Accordingly, the bitmapped data is composed of the rendering object only or contains the margin portion other than the rendering object, depending on whether or not the rendering object is rectangular. Therefore, there is the effect that in this program for creating the tag information depending on whether or not the shape is rectangular, the universal apparatus for generating the dot data in the bitmap format can be widely applied.  
      With the print control program product according to the sixth and seventh aspects of the invention, at the judging step, it is judged that it is unnecessary to generate the tag information, if the rendering information acquired at the acquiring step is the character rendering information, whereby the character rendering data rendered at the rendering step is stored directly as the dot data at the dot data storing step. Therefore, the generation of the tag information at the generating step is performed if the rendering information is not the character rendering information.  
      Hence, if the stored dot data corresponds to the character, the generation of the tag information is avoided, but if the dot data is not the character, the tag information can be generated. That is, there is the effect that it is possible to accurately switch between the generation and the non-generation of the tag information depending on whether or not the rendering object is the character.  
      The schematically generated character rendering information has the data indicating the formation of dot for the character image portion or the non-formation of dot for the margin portion other than the character image, separately from the color designation information for designating the color. Since the character of the rendering object is rendered based on this rendering information, it is possible to generate the dot data that can identify the portion corresponding to the rendering object (character image) and the other portion in the dot data. Accordingly, if it is revealed that the kind of rendering object is the character (the rendering information is the character rendering information), there is the effect that it is possible to avoid generating the unnecessary tag information by performing no generation of the tag information, and speed up the redisplay process for the preview image. Also, even if the character rendering object is superposed on the earlier displayed rendering object in the redisplayed preview image, it does not occur that the earlier displayed rendering object is covered with any other portion than the character in the dot data.  
      With the print control program product according to the eighth aspect of the invention, at the extracting step, a common area between the mask area information indicating a mask area contained in the mask information, and the rendering area information, if the rendering information acquired at the acquiring step has the mask information. If the extracted common area is rectangular, the rendering data of the portion corresponding to the common area is stored as the dot data at the dot data storing step.  
      Hence, it is possible that the portion of the rendering object not actually displayed as the image (portion other than the common area) is not stored as the dot data, and only the portion of the common area displayed (printed) as the image is stored as the dot data. The image data (dot data) of the rendering object tends to have an enormous amount of data capacity, but the dot data is not stored for the unnecessary portion not displayed as the image, whereby there is the effect that this program can be operated in an inexpensive system employing the cheap memory while the memory capacity required to store the dot data is suppressed. Also, in redisplaying the preview image, the process can be sped up because the processing amount of data is reduced.  
      With the print control program product according to the ninth aspect of the invention, at the specific information storing step, the tag presence information, the dot specific information and the tag specific information are stored for each rendering object. At the redisplaying step, one dot data corresponding to the rendering object is specified and displayed with the dot specific information stored at the specific information storing step, when the rendering object is redisplayed. Also, one tag information is specified with the corresponding tag specific information, and a portion of the rendering object is extracted and displayed from the dot data, based on the specified tag information, if the tag presence information is stored corresponding to the dot specific information.  
      Hence, in the apparatus in which this program is run, the correspondence between the dot specific information and the tag specific information can be accurately judged, whereby there is the effect that the throughput can be increased by shortening the processing time taken to retrieve (read) the dot data and the tag information corresponding to the rendering information. That is, since whether or not the tag information corresponding to the dot data is stored is indicated with the tag presence information, it is unnecessary to retrieve the storage area where the tag information is stored and confirm the presence or absence of the storage to check whether or not the tag information corresponding to the dot data is stored. The processing for retrieving the storage area where the tag information is stored and confirming the presence or absence of the storage is troublesome and takes a lot of time. Also, if the tag information is not stored, the wasteful processing results, and all the tag information must be confirmed, whereby the processing time is increased uselessly. However, this program can omit the processing for searching the storage area to investigate the presence or absence of this tag information by storing the tag presence information, whereby the processing speed can be increased.  
      With the print control program product according to the tenth aspect of the invention, the rendering order or the rendering area information of the rendering object is updated based on a change instruction at the editing step. At the redisplaying step, the corresponding rendering object is displayed in the dot data in accordance with the rendering order or the rendering area information after update. Herein, the initial values of the dot data stored at the dot data storing step are held, irrespective of whether or not the corresponding rendering order or the rendering area information is updated. That is, even if the edit is executed, the dot data of the first preview image is held.  
      Hence, there is the effect that the re-edit of the preview image can be made, and the initial preview image can be restored from the preview image after editing. For example, if a change instruction is issued from the apparatus mounting this program by a manipulation of the operator, the preview image generated based on this change instruction may be different from the operator&#39;s image. Also, as the operator edits the preview image greatly, the image may differ from the desired form of the operator. In such a case, it is often difficult to return to the original preview image by the edit operation. However, this program the dot data of the (first) preview image stored in the dot data storage means is not changed and holds the initial values even if the rendering order or the rendering area information of the rendering object is updated, whereby it is possible to return to the first preview image at any edit stage, so that the edit operation of the operator becomes more user-friendly.  
      [Illustrative Aspects] 
      Illustrative aspects of the present invention will be described below with reference to the accompanying drawings.  FIG. 1  is a block diagram showing the electrical configuration of a printing system  100  having a personal computer (hereinafter referred to as a “PC”)  10  mounting a printer driver  14   a  as a print control program product. As shown in  FIG. 1 , the printing system  100  comprises a PC  10  and a printer  20  connected to the PC  10 .  
      The PC  10  creates image data using a document creation application program or an image creation application program and outputs the image data via a printer driver  14   a  to the printer  20 , which is an output destination.  
      The printer driver  14   a  converts the image data from the application program into the print data (print instruction) corresponding to the printer  20 , and outputs it to the printer  20 . This printer driver  14   a  is provided with a preview function of displaying beforehand the printing result on an LCD  16  before outputting the print data to the printer  20 . Also, the printer driver  14   a  can edit a preview image displayed by the preview function, whereby the preview image is edited based on an edit operation by the operator, and the preview image after editing is redisplayed on the LCD  16 .  
      This PC  10  comprises a CPU  11 , a ROM  12 , a RAM  13 , an HDD  14 , an operation unit  15 , an LCD  16 , a printer interface (printer I/F)  18  for connecting the PC  10  to the printer  20 , and a universal serial bus interface (USB I/F)  19  for connecting the PC  10  to the peripheral devices, as shown in  FIG. 1 .  
      The CPU  11  is an operation unit that operates based on a program stored in the ROM  12 , an operating system (OS) and various application programs stored in the HDD  14 , to perform various kinds of information processing. The ROM  12  is an unrewritable memory for storing a basic program for operating the CPU  11 , and various kinds of data.  
      The RAM  13  is a rewritable memory for temporarily storing the data or program required for various kinds of processing performed by the CPU  11 , and comprises a preview management memory  13   a , a rendering file memory  13   b , a tag mask file memory  13   c , a preview image memory  13   d  and an object counter  13   e.    
      In the application program of the PC  10 , the information (object data) forming the image within the image data is created in the format of vector graphics. The vector graphics represents the image as a set of information such as coordinates of points, parameters for an equation of the line or plane connecting the points, and fill or special effects. Generally, since the screen display of the computer or the printing method of the printer is in the bitmap format to deal with all kinds of images, the image data of the vector graphics can not be directly treated, whereby it is required to perform a process for converting into the dot data (bitmapped data) or a so-called dot expansion. That is, since the object is formed in accordance with the image data created by the application program, the image data from the application program becomes a rendering instruction  30  for generating the bitmapped data. Referring to  FIG. 2 , this rendering instruction  30  will be described below.  
       FIG. 2  is a view schematically showing the configuration of the rendering instruction  30 . The rendering instructions  30  are acquired by the CPU  11  in the order sent out from the application program and recognized in succession. In  FIG. 2 , as one example of the rendering instruction  30 , four rendering instructions  30   a  to  30   d  generated to form four objects (in one page of image) are shown, and displayed in the order in which the rendering instructions  30   a  to  30   d  are acquired from the upper stage to the lower stage. In  FIG. 2 , a series of information displayed in the same row corresponds to one rendering instruction  30 .  
      As shown in  FIG. 2 , the rendering instruction  30  is a group of information in series formed in accordance with the kind of object to be rendered. The rendering instruction of different kind (mode) is created corresponding to the kind of object by the application program. More specifically, any one of a graphics rendering instruction (e.g., rendering instructions  30   a ,  30   c  and  30   d ) for generating the graphics with the path, a character rendering instruction (e.g., rendering instruction  30   b ) for generating the character with text data, and a bit map rendering instruction for generating the image with bitmapped data is created.  
      The CPU  11  performs the rendering in the order in which the rendering instructions  30  are acquired from the application program in generating the first preview image. In the example as shown in  FIG. 2 , the rendering is performed in the order of rendering instructions  30   a ,  30   b ,  30   c  and  30   d . Thereby, the objects A, B, C and D corresponding to the rendering instructions  30   a ,  30   b ,  30   c  and  30   d  are respectively generated (see  FIGS. 5A  to  5 C and  7 ). When a plurality of objects are overlaid in one page of the preview image, arranging a certain object on the rear side or the front side is determined by the order in which the rendering instructions are acquired.  
      Each rendering instruction  30  includes mode information  31 , object data  32 , color number information  33 , mask type information  34  and position coordinate  35 . The mode information  31  indicates the mode of the object rendered by the rendering instruction  30 . In the graphics rendering instruction for rendering the object with the path, the “path” is included as the mode information (rendering instructions  30   a ,  30   b  and  30   d ). Also, in the character rendering instruction for rendering the object with text data, the “character” is included as the mode information (rendering instruction  30   c ). In the bit map rendering instruction for rendering the object with bitmapped data, the “bit map” is included as the mode information.  
      The object data  32  is the information forming the image, namely, the representation information representing the mode of the object and defining the shape or color of the object. Since the application program forms the image in the format of vector graphics, the object data  32  is composed of a group of information in which the data such as coordinates of points, parameters for an equation of the line or plane connecting the points, and fill (set-solid), color or special effects are set forth. In  FIG. 2 , the object data  32  for the rendering instructions  30  are schematically displayed as the “star image”, “spherical image”, “ABC” and “house image”. Also, the rendering instruction  30   c  is designated as the non-solid image in which the fill (background color, set-solid) does not appear on the rear face of character.  
      The color number information  33  indicates the maximum number of colors representable in a color representation system that is applied to the object. In the case where the formed object is the graphics, the color number information  33  is “2”, if the color representation system of two colors, black and white, called as a monotone, is applied, for example. Also, in the color representation system of three or more colors, there are three forms in which the maximum number of representable colors is 16, 256 or 16777216 (full-color). The color number information  33  is “16” for the object employing the 16-color form, the color number information  33  is “256” for the object employing the 256-color form, and the color number information  33  is “full-color” for the object employing the 16777216-color form. When the color number information  33  is “2”, the data representing the color has one bit (binary data) for one pixel, because all the data representing the color can be covered in one bit. Also, when the color number information  33  is “16”, the data representing the color has four bits for one pixel, when the color number information  33  is “256”, the data representing the color has eight bits for one pixel, and when the color number information  33  is “full-color”, the data representing the color has 24 bits for one pixel.  
      In  FIG. 2 , the rendering instruction  30   a  has “2” as the color number information  33 , the rendering instruction  30   b  has “full-color” as the color number information  33 , and the rendering instruction  30   d  has “256” as the color number information  33 .  
      Also, the rendering instruction  30   c  has “1” as the color number information  33 . Herein, the rendering instruction  30   c  is the character rendering instruction. In the case where the formed object is the character, the color number information  33  is indicated by the number of colors actually employed for the object of character. Since the object of character formed by the rendering instruction  30   c  is monochrome, the color number information  33  is “1”. Generally, the object of character is generated in a rectangular (square or oblong) range (frame) surrounding the periphery of the character string. A non-character portion within this frame can be set with the background color. For example, when the background color (background color of 1) is set, the color number information  33  is “2”.  
      The mask type information  34  indicates whether or not a mask M 1  is set to the object. The mask M 1  is superposed on the image of the object, and generated corresponding to the object by the application program.  
      The mask M 1  serves to partition the object as defined by the object data  32  into a display portion and a non-display portion. The portion covered with the mask M 1  is displayed, and the portion not covered with the mask M 1  is not displayed.  
      The mask type information  34  is given depending on the outside shape of the object to be rendered. Each rendering instruction  30  includes any one of the “rectangular” information, “path” information and “no-mask” information as the mask type information  34 .  
      The “rectangular” information indicates that the mask M 1  is set to the object, and further the mask M 1  and the display portion of the object set by the mask M 1  are rectangular. The rendering instruction  30   a  as shown in  FIG. 2  includes this “rectangular” information as the mask type information  34 .  
      The “path” information and the “no-mask” information indicate that the mask M 1  is not provided for the rendering instruction  30 . Further, the “path” information indicates that the outside shape of the formed object is not rectangular, and is included in the rendering instruction  30  forming the object of curvilinear or indefinite shape. The rendering instruction  30   b  as shown in  FIG. 2  includes this “path” information as the mask type information  34 .  
      On the other hand, the “no-mask” information indicates that the outside shape of the object is rectangular. The rendering instructions  30   c  and  30   d  forming the rectangular object include this “no-mask” information. When the formed object is the character, the rectangular range containing the character string corresponds to one object, as described above. Therefore, the rendering instruction  30  of the character does not have the “path” information as the mask type information  34 .  
      The position coordinate  35  is the information indicating the position, including the rendering area information  35   a  indicating the position (rendering area) of the object and the mask area information  35   b  indicating the position (mask area) of the mask.  
      This position coordinate  35  is the information indicating the position in terms of the X coordinate indicating the position on the X axis and the Y coordinate indicating the position on the Y axis orthogonal to the X axis. The position coordinate  35  of pixel (dot) at the upper left end of the image is defined as the X coordinate ( 0 ) and the Y coordinate ( 0 ). When the image is composed of 960×680 pixels, for example, the last coordinate of the X coordinate is 959 and the last coordinate of the Y coordinate is 679.  
      The rendering area information  35   a  indicates the positions of the object in the image of one page, namely, the range where the object is rendered, and is designated by the minimum coordinate and the maximum coordinate in the rectangular (square or oblong) range surrounded by four sides passing through the coordinates at both ends of the object in the X axis direction and the y axis direction. The minimum coordinate and the maximum coordinate are two vertices of such rectangular range. Since the rectangular (square or oblong) range is defined by the position coordinates  35  (minimum coordinate and maximum coordinate) of two diagonally opposite vertices, the rectangular range where the object is rendered can be indicated by this rendering area information  35   a . Herein, when the object is rectangular, the range defined by the rendering area information  35   a  is coincident with the rendering area where the object is actually rendered.  
      For example, the rendering area information  35   a  for the rendering instruction  30   a  has the minimum coordinate ( 330 , 590 ) and the maximum coordinate ( 730 , 990 ) as shown in  FIG. 2 , whereby the rendering area is the rectangular range of which the vertices are the four coordinates ( 330 , 590 ), ( 730 , 590 ), ( 330 , 990 ) and ( 730 , 990 ).  
      The object formed based on the rendering instruction  30   c  or the rendering instruction  30   d  is the rectangular object, and the rendering area information  35   a  has the minimum coordinate ( 110 , 860 ) and the maximum coordinate ( 620 , 1040 ), and the minimum coordinate ( 360 , 140 ) and the maximum coordinate ( 760 , 440 ). Therefore, the rendering area of the actually rendered object is coincident with this rendering area information  35   a.    
      On the other hand, the rendering area information  35   a  for the rendering instruction  30   b  is represented by the minimum coordinate ( 80 , 280 ) and the maximum coordinate ( 480 , 700 ). The mask type information  34  for this rendering instruction  30   b  is the “path” information, and the formed object is not rectangular. Since the rendering area information  35   a  is designated by the minimum coordinate and the maximum coordinate in the rectangular (square or oblong) range surrounded by four sides passing through the coordinates at both ends of the object in the X axis direction and the Y axis direction, this rendering area information  35   a  is the information indicating the smallest rectangular range containing the object, if the object is not rectangular. That is, the rendering area of the object is not directly indicated, but the object is contained in the rectangular range surrounded by four position coordinates ( 80 , 280 ), ( 480 , 280 ), ( 80 , 700 ) and ( 480 , 700 ) as defined by the minimum coordinate and the maximum coordinate of the rendering area information  35   a.    
      The mask area information  35   b  is provided when the mask M 1  is set to the object, and indicates the range (mask area) where the mask M 1  is developed. The mask M 1  is rectangular, and the minimum coordinate and the maximum coordinate of the four coordinates indicating the four vertices of the rectangle are stored as the mask area information  35   b . If the mask M 1  is developed, the rectangular range surrounded by the lines in the X axis direction and Y axis direction passing through the minimum coordinate and the lines in the X axis direction and Y axis direction passing through the maximum coordinate is defined, based on this mask area information  35   b , whereby the mask M 1  is developed over the defined range (mask area).  
      The rendering instruction  30   a  has the minimum coordinate ( 0 , 0 ) and the maximum coordinate ( 530 , 1100 ) as such mask area information  35   b . This mask area is the range where the four coordinates (vertices of the rectangular shape) of ( 0 , 0 ), ( 530 , 0 ), ( 0 , 1100 ) and ( 530 , 1100 ) are connected by the line.  
      If printing the image data created by the application program of the PC  10  is requested, the printer driver  14   a  is started. Herein, if the output of the preview image is requested for the printer driver  14   a , the rendering instruction  30  having the above configuration is called from the application program (acquisition of the rendering instruction), each object is rendered based on the acquired rendering instruction  30 , whereby the bitmapped data is created (see  FIGS. 4 and 5 ).  
      Returning to  FIG. 1 , the explanation is made.  
      The preview management memory  13   a  manages the bitmapped data of each object (all the objects belonging to the image of one page) displayed in the preview image. The PC  10  generates the dot data by making the dot expansion of the rendering instruction  30  called from the application program with the preview function of the printer driver  14   a , and creates the bitmapped data of each object from the generated dot data. The preview management memory  13   a  stores the information regarding the bitmapped data corresponding to each rendering instruction (each object) to manage this created bitmapped data. Referring to  FIGS. 3A and 3B , this preview management memory  13   a  will be described below.  
       FIGS. 3A and 3B  are views schematically showing the configuration of the preview management memory  13   a . The information regarding the bitmapped data includes the position coordinate (rendering area information  45 ) of the bitmapped data (object), the rendering file name  46 , the mask type information  44  and the tag mask file name  47 . The preview management memory  13   a  is provided with the areas  13   a   1  to  13   a   4  for storing each information regarding such bitmapped data.  
       FIG. 3A  shows the contents of the preview management memory  13   a  where the first preview image is generated in accordance with a display request for the preview image, or in other words, shows the contents of this preview management memory  13   a  where the object is generated by the rendering instruction  30  as shown in  FIG. 2 .  
      Accordingly, the preview management memory  13   a  stores the information  30   a ′ to  30   d ′ regarding the bitmapped data of each object generated by the rendering instruction  30   a  to  30   d  in the generated order, namely, in the order in which the rendering instructions  30  are acquired from the application program. In  FIG. 3A , the information regarding the bitmapped data is displayed in the generated order, in which the information  30   a ′ regarding the bitmapped data corresponding to the rendering instruction  30   a  is displayed at the uppermost row, and at the succeeding rows, the information  30   b ′,  30   c ′ and  30   d ′ regarding the corresponding bitmapped data are displayed in the order of the rendering instructions  30   b ,  30   c  and  30   d.    
      The position coordinate area  13   a   1  stores the position coordinate (rendering area information  45 ). In  FIG. 3A , the position coordinate area  13   a   1  stores the rendering area information  45  for the first preview image. Herein, if the mask type information  34  for the rendering instruction  30  is the “rectangular” information, and the mask area information  35   b  is included in the rendering instruction  30 , a common area (actually displayed object portion) between the rendering area of the object and the mask area is extracted, and stored as the rendering area information  45  of the object in the position coordinate area  13   a   1 . Therefore, the rendering area information  45  is stored with the different values from the rendering area information  35   b  of the rendering instruction  30 .  
      For example, the rendering area information  35   a  of the rendering instruction  30   a  includes the minimum coordinate ( 330 , 590 ) and the maximum coordinate ( 730 , 990 ) (see  FIG. 2 ), as described above. The rendering area information  35   a  is the information indicating the rendering area of the original object formed by the object data  32 . Herein, the rendering instruction  30   a  is provided with the mask area information  35   b  having the minimum coordinate ( 0 , 0 ) and the maximum coordinate ( 530 , 1100 ). Therefore, the extraction of the common area is executed, the common area ( 330 , 590 ), ( 530 , 590 ), ( 330 , 990 ) and ( 530 , 990 ) is extracted, and the minimum coordinate ( 330 , 590 ) and the maximum coordinate ( 530 , 990 ) of such rectangular area are stored in the position coordinate area  13   a   1  as rendering area information  40 .  
      If the mask area information  35   b  is not included in the rendering instruction  30 , the rendering area information  35   a  for the rendering instruction  30  is directly stored as the rendering area information  45  in the position coordinate area  13   a   1 , in the case of the rendering instructions  30   b  to  30   d.    
      The rendering file name area  13   a   2  stores the rendering file name  46 . The rendering file name  46  is the information designating the file (rendering file) of the bitmapped data of the created object. The bitmapped data of the created object is stored as the rendering file in the bit map file format. The stored rendering file is given a unique file name not overlapping the other file names, and the given rendering file name  46  is written into the rendering file name area  13   a   2 .  
      The mask type area  13   a   3  stores the mask type information. The rendering instruction  30  has any one of the “rectangular” information, the “path” information and the “no-mask” information as the mask type information  34 , as described above. The mask type information  44  based on the mask type information  34  provided for such rendering instruction  30  is stored in this mask type area  13   a   3 .  
      More specifically, the mask type information  34  given by the rendering instruction  30  is the “path” information or the “no-mask” information, the “path” information or the “no-mask” information is directly stored as the mask type information  44  in this mask type area  13   a   3 . Also, if the mask type information  34  for the rendering instruction  30  is the “rectangular” information (rendering instruction  30   a ), the information of the mask area is unnecessary because the rendering area (rendering area information  45 ) of the object is changed to the values reflecting the mask M 1 , whereby the mask type information  44  stored in the mask type area  13   a   3  is the “no-mask” information.  
      Also, the mask type information  44  stored in this mask type area  13   a   3  is the information indicating the presence or absence of the tag mask M 2  corresponding to the object. If the mask type information  44  is the “no-mask” information, it is indicated that the tag mask M 2  does not exist, or if the mask type information  44  is the “path” information, it is indicated that the tag mask M 2  exists.  
      Moreover, in the case where the bitmapped data of the non-solid character is generated, the mask type area  13   a   3  stores the “character” information as the mask type information  44 . If the object is the set-solid character, it can be treated in the same manner as the rectangular graphics, whereby the mask type information  44  is stored as the “no mask” information in the mask type area  13   a   3  even though the generated bitmapped data is the character.  
      The tag mask file area  13   a   4  is the memory storing the file name (tag mask file name  47 ) of the tag mask M 2 . If the mask type information  34  of the rendering instruction  30  is the “path” information, the tag mask M 2  is generated together with the bitmapped data of the object, and stored as the tag mask file. Accordingly, if the mask type information  34  for the rendering instruction  30  is the “path” information (rendering instruction  30   b ), the tag mask file name  47  is stored in the corresponding tag mask file area  13   a   4 .  
      When the preview image is displayed, the CPU  11  selects the corresponding tag mask by referring to the tag mask file name  47  stored in this tag mask file area  13   a   4 , and superposes the bitmapped data on the object to be masked to display the object on the LCD  16 .  
      As described above, the preview management memory  13   a  stores the information regarding the bitmapped data of the object in the rendering order. Herein, each rendering instruction, the information regarding each bitmapped data and each object (e.g., the rendering instruction  30   a , the information  30   a ′ regarding the bitmapped data, and the object A) are associated with each other, in which the information  30   a ′ to  30   d ′ regarding the bitmapped data of each object are stored in the order of objects A, B, C and D in the preview management memory  13   a  as shown in  FIG. 3A . Accordingly, the objects are displayed in the order of objects A, B, C and D in this case.  
       FIG. 3B  shows the preview management memory  13   a  after editing the preview image displayed with the contents of the preview management memory  13   a  of  FIG. 3A . The printer driver  14   a  has an edit function of the preview image, enabling the movement, scale-up/scale-down or deletion of the object and the change of the rendering order to be made from the display screen of the preview image, based on an operation on the operation unit  15  (keyboard and mouse) by the operator. If the movement or scale-up/scale-down of the object is made, the rendering area information  45  is changed in accordance with the movement amount or scaling factor, whereby the rendering area information  45  of the position coordinate area  13   a   1  is updated with the values after change. Also, if the deletion of the object is performed, the information corresponding to the deleted object is deleted from the preview management memory  13   a . If the change of the rendering order is performed, the storage order (storage location, data list) of the information regarding the bitmapped data in the preview management memory  13   a  is changed.  
      In  FIG. 3B , the rendering order is changed by editing the preview image, where by the information  30   a ′ to  30   d ′ regarding the bitmapped data stored in the order of objects A, B, C and D is changed into the storage order corresponding to the objects C, A, D and B. Further, it is indicated that the edit of moving the object positions of the objects A, C and D is performed in the rendering area information  45  of the position coordinate area  13   a   1  corresponding to the information regarding the bitmapped data.  
      Returning to  FIG. 1 , the explanation is made.  
      The rendering file memory  13   b  stores the bitmapped data of each object displayed in the preview image. Each bitmapped data is given a filename as one rendering file, and individually managed as the rendering file. Also, the given rendering file name  46  is written into the preview management memory  13   a  as described above. The CPU  11  selects the corresponding rendering file (one bitmapped data) from the rendering file name  46  stored in the preview management memory  13   a  and displays the object based on the bitmapped data, in displaying (or redisplaying) the preview image.  
      The bitmapped data is created in the rectangular shape, and an aggregate of color points (dots or pixels), in which each pixel is indicated by the color values such as the RGB values. Therefore, if the object to be converted into the bitmapped data is not rectangular, the bitmapped data of its object is generated by containing the portion other than the object.  
      For the object portion of such bitmapped data, each pixel belonging to its object is formed with the color values (RGB values) according to the rendering instruction  30 . However, the margin portion other than the object has no original data, whereby some new data must be generated. Generally, each pixel in the margin portion of such bitmapped data is given the value of while color.  
      Herein, the character rendering instruction, unlike the graphics rendering instruction, is indicated by the data of character color (and background color), separately from the graphic data indicating the shape of character. In other words, the graphic data indicating whether or not the dot is formed within the rendering area is the independent data provided separately from the data of color.  
      If the object of character is non-solid, the character itself has no regular shape, like the irregular-shaped graphics, and further the portion other than the character within the rendering area is colorless. Such a mode is apparently the same as the image data is not rectangular, but the data structure itself is different, whereby it is clarified that the margin portion is blank (with the information designating it as the portion where the dot is not formed). Accordingly, the object (character) portion can be only indicated without creating the tag mask M 2 . Therefore, if the object is the character, the bitmapped data represented by the binary data indicating the display or non-display of each pixel is generated (based on the rendering instruction  30 ). If the background color (set-solid) is designated in the rendering instruction  30  of the character (character rendering instruction), the bitmapped data of the object of that character is generated as the usual bitmapped data (each pixel is represented by the color values), like the rectangular graphics, because it is unnecessary to discriminate whether the margin portion is white or colorless (non-display portion).  
      The tag mask file memory  13   c  stores the tag mask M 2 . The tag mask M 2  is created, if the mask type information  34  of the rendering instruction  30  is the “path” information, namely, if the outside shape of the generated object is not rectangular. The tag mask M 2  is given the file name as the one tag mask file, and managed individually as the tag mask file. Also, the given tag mask file name  47  is written into the preview management memory  13   a  as described above. In displaying the preview image, the CPU  11  selects the corresponding tag mask file from the tag mask file name  47  stored in the preview management memory  13   a  and displays the object on the LCD  16  based on the bitmapped data of the object and the tag mask M 2 .  
      The tag mask M 2  is the data formed with the portion corresponding to the object within the bitmapped data of the object as the value of black color and the other portion than the object as the value of white color to discriminate the actual object portion in the bitmapped data of the object. The tag mask M 2  is generated to discriminate the actual object portion in the bitmapped data of the object, and unnecessary if the object is rectangular or if the object is the character. Accordingly, in such a case, the tag mask M 2  is not generated. Thereby, the processing for creating the tag mask M 2  can be minimized if required, whereby the processing time for creating the preview image is shortened.  
      The bitmapped data of the non-rectangular (graphic) object is made rectangular by adding the white margin portion to the peripheral portion of the original object. Therefore, when it is directly displayed in the preview image, the white peripheral portion may overlap the other object, depending on the arrangement (position coordinate or rendering order) of the object. The other object (a part thereof) is not displayed by the portion that is not the image of the original object. In such a case, the role of the preview that the image of the printing result is presented to the operator by the preview image before printing is not only insufficiently fulfilled, but also the non-display portion is not printed and a part of the image to be displayed is lost, if the printing is directly performed, whereby the printing result as desired by the operator can not be obtained.  
      To solve this problem, if the pixel with the value of white color is simply not displayed, the image portion of white color to be displayed is also lost. Also, even if the value of other than white color is applied to the margin portion other than the object of the bitmapped data, the applied color must be made the color that can not be displayed, restricting the color representation. However, the tag mask M 2  is stored in the tag mask file memory  13   c , and the actual object portion in the bitmapped data of the object can be discriminated by referring to such tag mask M 2 , whereby the portion of the object can be selectively displayed. Hence, even if the preview image is displayed in the bitmapped data, there is no change to the display mode against the operator&#39;s intention due to the overlap of the bitmapped data, or no restriction on the color representation.  
      Even if the edit such as movement or scale-up/scale-down of the object is made, neither the contents of the rendering file stored in the rendering file memory  13   b  nor the contents of the tag mask M 2  stored in the tag mask file memory  13   c  are changed, whereby the initial values are held. Accordingly, if the edit such as movement or scale-up/scale-down is made, the rendering area information  45  in the preview management memory  13   a  is only updated. And the bitmapped data according to the rendering area information  45  after update is generated from the rendering file (bitmapped data of the object) or the tag mask read from the rendering file memory  13   b  or the tag mask file memory  13   c , and the object is displayed on the LCD  16 .  
      The preview image memory  13   d  stores the bitmapped data of the preview image actually displayed on the LCD  16 . Each object created based on the information regarding the bitmapped data stored in the preview management memory  13   a  is written into the preview image memory  13   d , and then outputted to the LCD  16 . Also, if a print request is made, the bitmapped data stored in the preview image memory  13   d  is converted into the print data and outputted to the printer  20 .  
      The object counter  13   e  counts the number of rendered objects (for judging whether or not the rendering for all the objects is ended), as well as designating the object to be rendered in a preview screen generation process (see  FIG. 11 ) for generating the preview image. The count value of the object counter  13   e  is set at “1” at the timing when the preview screen generation process is started, and incremented by one every time when the rendering of the object is ended, until its count value exceeds the number of information regarding the bitmapped data stored in the preview management memory  13   a , namely, the number of all the objects belonging to the image of one page.  
      The HDD  14  is a hard disk reading device containing a hard disk, and has the printer driver  14   a . This HDD  14  stores various kinds of control programs, such as the application program and the OS, not shown, in addition to the printer driver  14   a . The CPU  11  performs the process in accordance with the various kinds of control programs. Also, the HDD  14  stores a look-up table for converting the color representation system (RGB values) in the PC  10  into the color representation system (CMYK values) according to the printer  20 .  
      The printer driver  14   a  is the program for converting the document data or image data created by various kinds of application, such as a document creation application or an image creation application, into the print data that can be processed by the printer  20  and outputting the print data to the printer  20 . The programs as shown in the flowcharts of FIGS.  8  to  12  are stored as a part of this printer driver  14   a.    
      The PC  10  performs the rendering process for the rendering instruction  30  created by the application program in accordance with the printer driver  14   a , to generate the dot data (print image data) of the RGB values. Thereafter, the original image data is subjected to various kinds of processes such as a color conversion process for converting the RGB values into the CMYK values and a binarization process, and converted into the print data.  
      Also, the printer driver  14   a  has the preview function of displaying the printing result on the LCD  16  before outputting the print data to the printer  20 , as described above, and an edit function of editing the preview image displayed on the display screen. The details of the process regarding the preview function performed by this printer driver  14   a  will be described later with reference to the flowcharts of FIGS.  8  to  12 .  
      The operation unit  15  is used to input the data or command into the PC  10 , and comprises a keyboard and a mouse. The LCD  16  displays the character or the image to visually confirm the processing contents executed on the PC  10  or the input data. The preview image created by the printer driver  14   a  is displayed on this LCD  16 , as described above.  
      The I/F  18  connects the PC  10  to the printer  20 . The PC  10  sends the print command or print data to the printer  20  via this I/F  18 , and the printer  20  performs the printing on the recording sheet. The USB I/F  19  connects the peripheral device to the PC  10  in accordance with the USB standard. The sending or receiving of data is performed via this USB I/F  19  between the connected peripheral device and the PC  10 .  
      As shown in  FIG. 1 , the CPU  11 , the ROM  12 , the RAM  13 , the HDD  14 , the operation unit  15 , the LCD  16 , the I/F  18  and the USB I/F  19  are interconnected via the bus line  17 .  
      Also, the PC  10  is connected to the printer  20  as the output destination of the print data, as shown in  FIG. 1 . Such printer  20  comprises a motor for conveying the recording medium, a print head for discharging the ink onto the recording medium to form the image, a carriage motor for driving (moving) the print head, and an interface for connecting to the PC  10 , in addition to the CPU of an operation unit, the ROM that is an unrewritable non-volatile memory storing the control program executed by the CPU, the RAM that is a rewritable volatile memory temporarily storing various kinds of data when the control program is executed by the CPU. Such printer  20  is a typical ink jet printer for printing the print data received via the interface from the PC  10  on the recording medium.  
      The printer  20  is not necessarily the ink jet printer, but may be a laser printer that performs the printing with the toner. Also, the apparatus connected to the PC  10  is not limited to the printer, but may be a facsimile apparatus or copying machine having the printer function, or a combination thereof.  
      Referring to FIGS.  4  to  7 , a production process for the preview image performed by the printer driver  14   a  will be described below.  
       FIG. 4  is a view showing the bitmapped data created based on the rendering instruction  30  from the application program. More specifically,  FIG. 4A  shows the bitmapped data of the objects A to D generated based on the rendering instructions  30   a  to  30   d  as shown in  FIG. 2 . In  FIG. 4 , the bitmapped data corresponding to the objects A to D are designated with A′ to D′.  
      Each object rendered based on the rendering instruction  30  is partitioned like a rectangle, thereby generating a rendering file in which the dot data in its rectangular range is the bitmapped data of the object. Herein, the partitioned rectangular range is defined by the rendering area information  35   a  for the rendering instruction  30 . More particularly, if the rendered object is rectangular, and its rendering area is coincident with the rendering area as indicated by the rendering area information  35   a  included in the rendering instruction  30  (rendering instructions  30   c ,  30   d , namely, the objects C, D), the dot data expanded in the rendering area designated by the rendering area information  35   a  for the rendering instruction  30  is stored directly as the bitmapped data (C′, D′ in  FIG. 4 ) of the object in the rendering file memory  13   b . Since the character object is the rectangular object, the bitmapped data is necessarily generated in the rendering area as indicated by the rendering area information  35   a  included in the rendering instruction  30 , as described above.  
      Also, if the rendered object is rectangular and the mask area information  35   b  is included in the rendering instruction  30  (rendering instruction  30   a , object A), the bitmapped data (A′ in  FIG. 4 ) of only the portion belonging to the mask area is generated. That is, the bitmapped data is generated not in the rendering area designated by the rendering area information  35   a  included in the rendering instruction  30 , but in the range of the common area between the rendering area defined by the rendering area information  35   a  and the mask area defined by the mask area information  35   b.    
      Moreover, if the rendered object is not rectangular (rendering instruction  30   b , object B), the bitmapped data (B′ in  FIG. 4 ) is generated in the rectangular range including the periphery of the rendered object. This is because the bitmapped data is rectangular data. In such a case, the bitmapped data is generated in the rectangular (square or oblong) range (rectangular range as defined by the rendering area information) surrounded by four sides passing through the position coordinates at both ends in the X axis direction and the Y axis direction for the expanded dot data. Therefore, such bitmapped data (B′) contains the object and the margin portion other than the object.  
      Though the generated bitmapped data is stored in the value of color for each dot of the rendered object, and the bitmapped data of the margin portion is stored in the value of white color, the value of color for the margin portion is not limited to the value of white color but the other colors may be applied. Further, the bitmapped data may have the data of transparency for each dot together with the value of color.  
       FIG. 4B  shows the bitmapped data of the tag mask M 2  generated for the non-rectangular object in generating the preview image. In a case of the non-rectangular object, the tag mask M 2  for the bitmapped data (B′) of the object B is generated for the object B corresponding to the rendering instruction  30   b . The bitmapped data of the generated tag mask M 2  is stored as the tag mask file in the tag mask file memory  13   c.    
      In generating this tag mask M 2 , first of all, the dot data of the corresponding object rendered in accordance with the rendering instruction  30  is stored as the dot data with the value of black color. If the rendering is made in accordance with the rendering instruction  30 , only the object portion is rendered, whereby the dot data with the value of black color becomes the information for tagging the rendered portion of the object (displayed with black fill in  FIG. 4B ). Thereafter, the rectangular range of the bitmapped data is defined from the rendering area information  35   a  included in the rendering instruction  30  for the rendered object. Since the rectangular range as defined by the rendering area information  35   a  is coincident with the generation range of the bitmapped data, a portion where the value of black color is not given within such rectangular range is recorded as the dot data with the value of white color. That is, the dot data with the value of white color becomes the information for tagging the margin portion (non-object portion) of the object in the bitmapped data (as displayed by the diagonally shaded part in  FIG. 4B ) And the bitmapped data of the tag mask M 2  for distinguishing the object portion and the non-object portion in the bitmapped data are generated by synthesizing the value of black for tagging this rendered portion and the value of white for tagging the margin portion (non-object portion).  
       FIG. 5  is a view showing the preview image displayed on the LCD  16  when the display of the preview image is requested, namely, the preview image firstly displayed in accordance with a display request, and its generation process. In  FIG. 5 , the preview image generated based on the rendering instruction  30  of  FIG. 2  and the information regarding the bitmapped data of  FIG. 3  is illustrated. If a print process is requested from the application program to the printer driver  14   a , each of the objects (objects A to D) belonging to the preview image is generated in accordance with the rendering instruction  30  called from the application program.  
      If the data (object data  32 ) forming each object is in the vector graphics format, the bitmapped data of each object is created from the dot data after the data is converted into the dot data (dot expansion, rendering) by computation. Also, the generation of the tag mask M 2  corresponding to the bitmapped data and the write of the information regarding each bitmapped data into the preview management memory  13   a  are executed. After the generation of the bitmapped data is ended for all the rendering instructions  30  for the image of one page, each object is displayed successively at the rendering position (area) designated by the rendering area information  45  stored corresponding to each created bitmapped data by referring to the preview management memory  13   a.    
      Herein, if the information  30   a ′ to  30   d ′ regarding the four bitmapped data corresponding to the four objects A to D belonging to the image of one page are stored in the preview management memory  13   a  as shown in  FIG. 3 , the information  30   a ′ corresponding to the object A stored at the initial address of the preview management memory  13   a  (of the first rendering order) among such information is firstly read. Also, the information  30   b ′ to  30   d ′ stored in the preview management memory  13   a  are read successively.  
      Thereafter, firstly, the object A based on the bitmapped data (A′, see  FIG. 4 ) corresponding to the information  30   a ′ is displayed at the position as indicated by the rendering area information  45  on the LCD  16 . Since the rendering instruction  30   a  corresponding to the object A includes the information of the mask M 1 , a part of the original object A 0  is displayed as the object A ( FIG. 5A ). Referring to  FIG. 6 , the production process for the bitmapped data of the object where the information of the mask M 1  is included in the rendering instruction  30  will be described below.  
       FIG. 6  is a view showing the image in generating the bitmapped data of the object with the mask M 1  set. If the mask M 1  is set to the object, the original object as defined in the object data  32  is not directly displayed, but partly not displayed. Hence, it is required to exclude the non-display portion from the display image.  
      Therefore, if the rendering is performed in accordance with the object data  32  of the rendering instruction  30   a , the bitmapped data A 0 ′ corresponding to the original object A 0  is generated ( FIG. 6A ). And the common are a between this bitmapped data A 0 ′ and the mask M 1  is recognized as the display portion by the CPU  11 , while the non-common area between the bitmapped data A 0 ′ and the mask M 1  is recognized as the non-display portion where the display is not made by the CPU  11  ( FIG. 6B ). As a result, the bitmapped data (A′) corresponding to a part of the original object is stored as the bitmapped data formed by the rendering instruction  30   a  in the rendering file ( FIG. 6C ). Thereby, the object A that is a part of the original object A 0  is displayed on the LCD  16  by the bitmapped data (A′).  
      Returning to  FIG. 5 , the explanation is made. After the display of the object A is ended, the object B based on the bitmapped data (B′, see  FIG. 4 ) corresponding to the information  30   b ′ stored in the second rendering order in the preview management memory  13   a  is displayed at the position indicated by the rendering area information  45  on the LCD  16 . Because apart of the rendering area of the object B overlaps the rendering area of the object A, a part of the object A displayed ahead is covered with the object B and not displayed ( FIG. 5B ).  
      Next, the object C based on the bitmapped data (C′, see  FIG. 4 ) corresponding to the information  30   c ′ stored in the third rendering order in the preview management memory  13   a  is displayed at the position indicated by the rendering area information  45  on the LCD  16 . Because the rendering area of the object C is set under the rendering area of the object A, the object C is displayed under the object A and on the front face of the object A ( FIG. 5C ). Lastly, the object D based on the bitmapped data (D′, see  FIG. 4 ) corresponding to the information  30   d ′ stored in the fourth rendering order in the preview management memory  13   a  is displayed at the position indicated by the rendering area information  45  on the LCD  16 . The preview image is completed by displaying the object D ( FIG. 5D )  
      Herein, the object B is displayed for only a portion of the bitmapped data (B′) designated (tagged) as the object by the tag mask M 2 , whereby the object is displayed in the correct mode to be displayed in which the margin portion of the bitmapped data is not displayed.  
       FIG. 7  is a view showing the preview image after the preview image of  FIG. 5  is edited. If the edit is performed, the contents of the preview management memory  13   a  are updated, and the preview image is redisplayed on the LCD  16 , based on the updated contents. Since the edited contents are stored in the preview management memory  13   a , the preview image after editing is created in accordance with the contents of the preview management memory  13   a . Also, each object in the preview image is displayed based on the bitmapped data (A′, B′, C′ and D′) read from the rendering file stored in the rendering file memory  13   b . Therefore, the preview image is redisplayed promptly after editing. The redisplayed preview image of  FIG. 7  is generated in accordance with the contents of the preview management memory  13   a  as shown in  FIG. 3B .  
      More specifically, for the object A, the rendering area information  45  having the minimum coordinate ( 330 , 590 ) and the maximum coordinate ( 530 , 990 ) in the first preview image is changed to the minimum coordinate ( 130 , 590 ) and the maximum coordinate ( 330 , 990 ). Accordingly, the display position of the object A is shifted to the left on the screen after editing. For the object C, the rendering area information  45  having the minimum coordinate ( 110 , 860 ) and the maximum coordinate ( 620 , 1040 ) in the first preview image is changed to the minimum coordinate ( 210 , 160 ) and the maximum coordinate ( 720 , 340 ) after editing. Accordingly, the display position of the object C is shifted to the upper right on the screen. For the object D, the rendering area information  45  having the minimum coordinate ( 360 , 140 ) and the maximum coordinate ( 760 , 440 ) in the first preview image is changed to the minimum coordinate ( 360 , 340 ) and the maximum coordinate ( 760 , 640 ). Accordingly, the display position of the object D is shifted downward on the screen.  
      Also, at the initial time (when the first preview image is generated), the preview management memory  13   a  stores the information  30   a ′ to  30   d ′ regarding the bitmapped data in the order of objects A, B, C and D. However, since the storage order is changed to the order of objects C, A, D and B by editing, the objects are reallocated in the order in which the object C is on the rearmost face, and the objects A, D and B are on the front side (the object B on the foremost face).  
      Referring now to the flowcharts of FIGS.  8  to  12 , each process of the printer driver  14   a  performed by the PC  10  configured in the above manner will be described below.  FIG. 8  is a flowchart of the preview process involving the preview and print process of the image data. This preview process is executed when the printer driver  14   a  is started. The printer driver  14   a  is started upon a print request from the application program as a momentum.  
      In this preview process, first of all, a bit map generation process for generating the bitmapped data of the object and the bitmapped data of the tag mask M 2  from the rendering instruction  30  called from the application program is performed (S 101 ). A preview screen generation process for displaying the preview image with the generated bitmapped data is performed (S 102 ). Thereafter, an edit process for editing the preview image based on an operation of the operator is performed (S 103 ).  
      In this edit process, for each object of the displayed preview image, the movement, scale-up/scale-down or deletion of the designated object or the change of the rendering order is performed based on an operation of the operator on the operation unit (keyboard and mouse), whereby the rendering area information  45  of the position coordinate area  13   a   1  in the preview management memory  13   a  is updated in accordance with a change by the edit operation. Also, the rendering order (data order of the preview management memory  13   a ) is interchanged.  
      Thereafter, in the edit process (S 103 ), it is confirmed whether or not the edit of the preview image is performed (S 104 ). If the edit is not performed (S 104 : No), it is confirmed whether or not the end of edit is requested (S 105 ). This edit end request is recognized by the CPU  11  when an edit end command is inputted by the operation of the operator. As a result of confirmation, if the end of edit is requested (S 105 : Yes), the image data (bitmapped data) stored in the preview image memory  13   d  is converted into the print data (S 106 ), the print data is sent to the printer  20  (S 107 ), and this preview process is ended.  
      On the other hand, as a result of confirmation at step S 104 , if the edit is performed (S 104 : Yes), the preview image memory  13   d  is cleared (S 108 ) to be in a state for starting the rendering of the new bitmapped data, and the operation goes to step S 102 .  
      Also, as a result of confirmation at step S 105 , if the end of edit is not requested (S 105 : No), the operation goes to the edit process (S 103 ) to wait for the edit to be performed or ended.  
       FIG. 9  is a flowchart of the bit map generation process (S 101 ) that is performed in the preview process of  FIG. 8 . In this bit map generation process (S 101 ), first of all, the rendering instruction  30  sent from the application program is acquired (S 201 ). In this bit map generation process (S 101 ), the process following step S 202  is performed (for the acquired rendering instruction  30 ) every time of acquiring one rendering instruction  30 .  
      The object is rendered in accordance with the acquired rendering instruction  30 . That is, a bit map rendering process for making the dot expansion of the object data  32  in the rendering area (a part of the operative area of the RAM, where the dot expansion of the rendering instruction  30  is made) is performed (S 202 ). Then, it is confirmed whether or not the mask type information  34  included in the acquired rendering instruction  30  is the “rectangular” information (S 203 ). As a result, if the mask type information  34  of the rendering instruction  30  is the “rectangular” information (S 203 : Yes), the common area is extracted from the rendering area of the object and the mask area in the rendering instruction  30 , and the extracted common area is written as the rendering area information  45  in the position coordinate area  13   a   1  of the preview management memory  13   a  in association with the rendering instruction (corresponding to the rendering instruction) (S 204 ). On the other hand, if the mask type information  34  of the rendering instruction  30  is not the “rectangular” information (S 203 : No), the rendering area information  35   a  of the acquired rendering instruction  30  is directly written (as the rendering area information  45 ) in the corresponding position coordinate area  13   a   1  of the preview management memory  13   a  in association with the rendering instruction (corresponding to the rendering instruction) (S 205 ).  
      After the step S 204  or S 205 , the color number information included in the rendering instruction  30  is confirmed (S 206 ). The bitmapped data of the object formed by dot expansion from the rendering instruction  30  at step S 202  in the range of the rendering area designated by the rendering area information  45  stored in the preview management memory  13   a  is stored as the rendering file in the bit map file format corresponding to the confirmed color number information in the rendering file memory  13   b  (S 207 ). Thereby, the bitmapped data of the object is formed (see  FIG. 4 ).  
      The color number information indicates the maximum number of colors that can be represented in the color representation system applied to the object. The bitmapped data is generated with a different number of bits depending on the number of representable colors. Accordingly, the color number information is confirmed, and the bitmapped data can be stored with an exact number of bits according to the number of colors in the bitmap format corresponding to the confirmed color number information.  
      Thereafter, the new file name (unique file name) is acquired, and given to the rendering file stored in the rendering file memory  13   b  (S 208 ). Then, the acquired file name (rendering file name  46 ) is written into the preview management memory  13   a  in association with the rendering area information  45  stored at step S 204  or S 205  (S 209 ). Subsequently, a mask generation process for generating the tag mask M 2  is performed (S 210 ), and the entire rendering area (all the regions of the rendering area) is cleared (S 211 ). And it is confirmed whether or not the rendering instruction is ended, namely, the sending of the rendering instruction  30  from the application program is ended (S 212 ). If the sending is ended (S 212 : Yes), this bit map generation process (S 101 ) is ended. On the other hand, if the sending is not ended (S 212 : No), the operation goes to step S 201  to repeat the steps S 201  to S 212  until the rendering instruction  30  sent from the application program is ended.  
       FIG. 10  is a flowchart of the mask generation process (S 210 ) that is performed in the bitmap generation process (S 101 ) of  FIG. 9 . In this mask generation process (S 210 ), first of all, it is confirmed whether or not the rendering instruction  30  acquired at step S 201  is the character rendering instruction and designated as non-solid (S 301 ). If the rendering instruction is not the character rendering instruction or if the rendering instruction is the character rendering instruction but designated as set-solid (not designated as non-solid) (S 301 : No), it is confirmed whether or not the mask type information  34  included in the rendering instruction  30  is the “path” information (S 302 ).  
      If the mask type information is the “path” information (S 302 : Yes), the object rendered by the rendering instruction  30  is the object of non-rectangular graphics, whereby the entire rendering area is cleared (S 303 ) and the path area of the mask is filled in black (S 304 ). The tag mask M 2  is created through the mask rendering process at steps S 303  and S 304 .  
      And the created tag mask M 2  is stored as one tag mask file in the tag mask file memory  13   c  (S 305 ). Further, the file name is given to the tag mask file stored in the tag mask file memory  13   c  (S 306 ). This file name is the unique file name not overlapping the other file names. Thereafter, the given file name (tag mask file name  47 ) and the mask type information  44  (“path” information) are written into the preview management memory  13   a  in association with the rendering area information  45  stored in at step S 204  or S 205  (S 307 ), and this mask generation process (S 210 ) is ended.  
      Also, as a result of confirmation at step S 301 , if the rendering instruction is the character rendering instruction and designated as non-solid (S 301 : Yes), the mask type information  44  (“character” information) is written into the preview management memory  13   a  in association with the rendering area information  45  stored at step S 204  or S 205  (S 308 ), and this mask generation process (S 210 ) is ended.  
      Moreover, as a result of confirmation at step S 302 , if the mask type information  34  of the rendering instruction  30  is not the “path” information (S 302 : No), the object rendered in accordance with the rendering instruction  30  is the rectangular object, whereby the mask type information  44  (“no-mask” information) is written into the preview management memory  13   a  in association with the rendering area information  45  stored at step S 204  or S 205  (S 309 ), and this mask generation process (S 210 ) is ended.  
       FIG. 11  is a flowchart of the preview screen generation process (S 102 ) that is performed in the preview process of  FIG. 8 . Before performing this preview screen generation process (S 102 ), the bitmapped data of each object displayed in one preview image and its corresponding tag mask M 2  are already generated, and stored in the rendering file memory  13   b  and the tag mask file memory  13   c . Also, the preview management memory  13   a  stores the information regarding each bitmapped data for each object. Therefore, in the preview screen generation process (S 102 ), the bitmapped data of each object or the tag mask M 2  is precisely read from the corresponding rendering file or the tag mask file by referring to the preview management memory  13   a  to form the preview image. That is, since the preview image is formed based on the prestored bitmapped data, the preview image can be displayed promptly on the LCD  16 , especially after the edit process is performed.  
      In this preview screen generation process (S 102 ), first of all, the count value (i) of the object counter  13   e  is set at 1 (S 401 ). It is confirmed whether or not the count value (i) exceeds the number of objects stored in the preview management memory  13   a  (S 402 ). If the count value (i) of the object counter  13   e  exceeds the number of objects (S 402 : Yes), the rendering (writing into the preview image memory  13   d ) of all the objects is ended, whereby the image data stored in the preview image memory  13   e  is outputted to (displayed on) the LCD  16  (S 403 ), and this preview screen generation process (S 102 ) is ended.  
      Also, as a result of confirmation at step S 402 , if the count value (i) of the object counter  13   e  does not exceed the number of objects (S 402 : No), the rendering of all the objects is not ended, whereby the rendering process for the ith object in the rendering order is performed by referring to the preview management memory  13   a  (S 404 ). After the rendering process for the ith object is performed, the count value (i) of the object counter  13   e  is incremented by one (S 405 ), and the operation goes to step S 402 .  
       FIG. 12  is a flowchart of the rendering process (S 404 ) for the ith object that is performed in the preview screen generation process (S 102 ) of  FIG. 11 . This rendering process (S 404 ) involves rendering the bitmapped data of the rendering file by referring to the tag mask M 2  to generate the preview image to be actually displayed.  
      In this rendering process (S 404 ), first of all, it is confirmed whether or not the mask type information  44  stored in the ith rendering order in the preview management memory  13   a  is the “path” information (S 501 ) If the mask type information is not the “path” information (S 501 : No), the object is rectangular, whereby it is confirmed whether or not the mask type information  44  is the “character” information to confirm whether or not the rectangular object is the character or the graphics (S 502 ). As a result, if the mask type information  44  is the“character” information (S 502 : No), the object rendered in the ith order is the rectangular graphics but not the character. Hence, the bitmapped data of the corresponding rendering file stored in the rendering file memory  13   b  is written into the preview image memory  13   d  in association with the rendering area as defined by the corresponding rendering area information  45  stored in the preview management memory  13   a  (S 503 ), and this rendering process (S 404 ) is ended.  
      On the other hand, as a result of confirmation at step S 501 , if the mask type information  44  is the “path” information (S 501 : Yes), the object to be rendered is not rectangular, and the tag mask M 2  corresponding to the bitmapped data of the object is stored in the tag mask file memory  13   c . Accordingly, the bitmapped data of the corresponding rendering file and the tag mask M 2  are read from the rendering file memory  13   b  and the tag mask file memory  13   c , respectively (S 506 ).  
      And a part of the bitmapped data of the read rendering file, indicated as the object by the tag mask M 2 , is extracted, and written into the preview image memory  13   d  in association with the rendering area as defined by the corresponding rendering area information  45  stored in the preview management memory  13   a  (S 507 ). Thereby, the margin portion of the bitmapped data other than the object is not outputted to the LCD  16  and not displayed.  
      Also, as a result of confirmation at step S 502 , if the mask type information  44  is the “character” information (S 502 : Yes), the bitmapped data of the corresponding rendering file stored in the rendering file memory  13   b  is written into the preview image memory  13   d  in association with the rendering area as defined by the corresponding rendering area information  45  stored in the preview management memory  13   a  (S 505 ).  
      At step S 505 , the object is the character and therefore rectangular, but the character and the margin portion other than the character are mixed. However, since the bitmapped data formed of the binary data indicating the display dot and the non-display dot is stored in the rendering file in accordance with the rendering instruction  30 , the data is written according to such binary data in the preview image memory  13   d , whereby the margin portion other than the character is not displayed on the LCD  16 .  
      Also, if the character is designated as set-solid by the rendering instruction  30 , the other portion than the character is designated as fill, and in the generated bitmapped data, the character portion and the other portion than the character are directly represented in the usual bitmapped data, whereby the object can be treated like the rectangular graphics. Therefore, the mask type information  44  is stored as the “no-mask” information in the preview management memory  13   a , whereby the operation branches to Yes at step S 501 .  
      In the above rendering process (S 404 ), a series of information regarding the dot data stored in the preview management memory  13   a  are specified by designating the rendering order. Accordingly, the rendering file name  46  of one object is recognized and the corresponding rendering file is selected, and the tag mask M 2  is also selected from the tag mask file name  47 . Also, the corresponding rendering area information  45  is selected.  
      If the object is scaled up or down by editing, the rendering area information  45  is changed to define the rendering area scaled up or down from the prestored data. Therefore, the bitmapped data read from the rendering file memory  13   b  and the tag mask file memory  13   c  is decompressed or compressed so that the data may be developed in the range as indicated by the rendering area information  45 . And the bitmapped data after decompression or compression is written into the preview image memory  13   d.    
      As described above, the printer driver  14   a  mounted on the PC  10  can generate the bitmapped data of each object to form the preview image, and display the preview image using the generated bitmapped data. Also, if the object is not rectangular, the tag mask M 2  for identifying the object portion within the bitmapped data is generated, and only the portion of the object within the bitmapped data can be displayed based on that tag mask M 2 . Therefore, the preview image after editing can be displayed promptly, and the object can be correctly displayed in the mode to be displayed in which the other object is not made in non-display by the margin portion of the bitmapped data against the operator&#39;s intention.  
      While the invention has been described above based on the aspects, the invention is not limited thereto. Various variations or modifications may be made thereto without departing from the spirit or scope of the invention.  
      For example, the printer driver  14   a  generates the bitmapped data by making the rendering based on the rendering instruction  30 , but the bitmapped data may be generated by an operation program, and the printer driver  14   a  may store the bitmapped data already generated by the operation program as the rendering file in the rendering file memory  13   b , and generate the tag mask M 2  from the bitmapped data stored in the rendering file memory  13   b.    
      While the dot data of each object for the preview image is generated in the bitmapped data format (bitmap format), the generated dot data may be in the other raster graphics format such as a GIF format or a JPEG format.  
      While the mask M 1  is limited to the rectangle and the shape of the object masked by the mask M 1  is limited to the rectangle, the mask M 1  may take various shapes and the masked object may take various shapes. If the shape of the masked object is not rectangular, the mask type information  34 ,  44  is set as the “path” information.  
      If the object is the character or rectangular, the tag mask M 2  is not generated, or otherwise the tag mask M 2  is generated. Instead, or in addition, the operator may select whether or not to generate the tag mask M 2 , in which the tag mask M 2  is generated for the object designated by the operator. Further, the tag mask M 2  is not limited to the bitmapped data, but may be formed in the dot data other than the bitmapped data, or in the data of vector graphics.  
      While the preview screen generation process (S 102 ) is configured to render all the objects again, if the new edit is made, instead, the rendering process may be performed for only the portion corresponding to the edited object if the new edit is made. In such a case, if the edit is recognized in the preview process (S 104 : Yes), the preview process is configured to delete only the portion corresponding to the edited object among the data stored in the preview image memory  13   d . Thereby, the preview image after editing can be displayed promptly.  
      The bitmapped data is generated when the first preview image is displayed in the preview process and the preview image is displayed by the bitmapped data. Instead, the preview process maybe configured such that at least for the first preview image, the rendering data rendered from the rendering instruction  30  is written into the preview image memory  13   d , and the image generated from the rendering instruction  30  is displayed on the LCD  16  (without generating the bitmapped data).  
      Since the edit is made by the operation of the operator at will, the edit may not be often performed. The display of the preview image with the bitmapped data is intended to shorten the time taken to redisplay the preview image by avoiding rendering the preview image from the rendering instruction  30  every time when displaying the preview image repeatedly. On the other hand, if the edit is not executed, the preview image can be displayed promptly by simply displaying the rendering data rendered from the rendering instruction  30  on the LCD  16 . This is because the process for generating the bitmapped data of the object or the tag mask M 2  from the rendered dot data can be omitted. Thus, when the edit is made, the bitmapped data of the object or the tag mask M 2  is generated from the rendering data. For the first preview image displayed before the edit is made, the rendering data is outputted to the LCD  16 , whereby the entire process for displaying the preview image is made more efficient.