PATENT ABSTRACT
An image processor includes an input device which inputs coded recording data, and a table generator generates a table which stores, by a scan line unit, memory addresses at each of which a function is stored for developing an image for one line into a memory, the function being generated based on the input coded recording data. The image processor also includes a developing unit which develops the input coded recording data into the memory in accordance with functions stored in the generated table.

PATENT DESCRIPTION
This application is a continuation of application Ser. No. 08/098,053 filed Jul. 28, 1993, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an image processing method and apparatus and, more particularly, to an image processing method and apparatus, which can color-output a character, figure, raster image, and the like on the basis of print data, a command, and the like sent from a host computer. 
     2. Related Background Art 
     FIG. 1 shows a coordinate system serving as a reference for, e.g., coordinate points designated when a figure or character is drawn using a PDL (Page Description Language) or a page description command (this coordinate system will be referred to as a user coordinate system hereinafter). 
     A hatched rectangular portion in FIG. 1 indicates an effective print area (a possible draw area in a print sheet). As shown in FIG. 1, the length of the effective print area will be referred to as an effective print area height hereinafter, and the width will be referred to as an effective print area width hereinafter. 
     The coordinate system shown in FIG. 1 is a two-dimensional x-y orthogonal coordinate system, and has an origin at the lower left corner of the effective print area, as shown in FIG.  1 . 
     The coordinate unit of this coordinate system can be desirably set (e.g., 0.01 mm, {fraction (1/72)} inch, and the like). 
     Description elements of the PDL for figure drawing and page description commands, which are set based on the above-mentioned user coordinate system, are analyzed in an image processing apparatus in the order of reception, and are converted into information to be developed on a memory. 
     FIG. 2 shows a coordinate system serving as a reference for creating the above-mentioned memory development information (this coordinate system will be referred to as a printer coordinate system hereinafter). 
     The coordinate unit of this coordinate system is determined by the resolution of an image processing apparatus used (for example, when the resolution is 300 dpi, the coordinate unit is {fraction (1/300)} inch). 
     A hatched rectangular portion in FIG. 2 is the same as the effective print area in FIG.  1 . 
     This coordinate system is a two-dimensional x-y orthogonal coordinate system, and has an origin at the upper left corner of the effective print area. 
     FIG. 3 shows a memory map in an internal RAM area of a conventional image processing apparatus for performing color recording on the basis of the PDL or the page description command. 
     The RAM area is constituted by a system work memory, a vacant area, and page development memories (each corresponding to the size of the effective print area shown in FIG. 2) for Y (Yellow), M (Magenta), C (Cyan), and Bk (Black). 
     The system work memory is used as a storage area for information (variables, and the like) used in internal control of the image processing apparatus, a fixed work area, and the like. 
     The vacant area is used as an area for storing memory development information, a character cache memory, and the like. 
     FIG. 4 shows a paint color designation command of drawing attribute designation commands. 
     This command is used for designating a color for painting a portion inside a closed figure. 
     A command No. varies depending on drawing attribute designation, and is used for identifying command functions. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     For example, the content of a number-of-data parameter of a line color designation command is 4. 
     Y, M, C, and Bk values indicate density data values of Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) as primary colors of coloring materials. 
     FIG. 5 shows an example of a polygon drawing command of drawing commands. 
     A command No. varies depending on drawing attribute designation, and is used for identifying command functions. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     Note that X and Y values of coordinates  1  to n are coordinates on the user coordinate system. 
     FIG. 6 shows an example of memory development information generated by analyzing the paint color designation command shown in FIG.  4 . 
     A command table No. is used for identifying each memory development information. 
     The contents of other parameters are the same as those in FIG.  4 . 
     FIG. 7 shows an example of memory development information generated by analyzing the polygon drawing command shown in FIG.  5 . 
     A command table No. is used for identifying each memory development information. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     X 1 , Y 1 , . . . , Xn, and Yn are coordinates converted into those on the printer coordinate system on the basis of the resolution of the image processing apparatus. 
     FIG. 8 shows a case wherein drawing of a polygon defined by four coordinates (100, 200), (200, 200), (200, 100), and (100, 100) is set on the user coordinate system shown in FIG. 1 to have a coordinate unit of 1 mm. 
     FIG. 9 shows an example of a command issued when the polygon drawing shown in FIG. 8 is set. 
     FIG. 10 shows a case wherein polygon drawing on the user coordinate system shown in FIG. 8 is converted into polygon drawing on the printer coordinate system having a coordinate unit of {fraction (1/300)} inch (about {fraction (1/11.8)} mm). 
     As shown in FIG. 10, the effective print area height in this case is set to be 400 mm. 
     The four coordinates are (1,180, 2,360), (2,360, 2,360), (2,360, 3,540), and (1,180, 3,540). 
     FIG. 11 shows an example of memory development information of polygon drawing shown in FIG. 10, which information is generated by analyzing the polygon drawing command shown in FIG.  9 . 
     FIG. 12 shows an example of memory development information set for paint color designation shown in FIG.  6 . 
     In this case, each of Y, M, C, and Bk values ranges from 0 to 255. The Y value is set to be 255, and other values are set to be 0. 
     FIG. 13 shows an example of memory development information set for paint color designation shown in FIG. 6 in a monochrome mode. 
     In the monochrome mode, a gray scale process using the coloring material Bk is performed in place of a color process using Y, M, C, and Bk. 
     The gray scale density value ranges from 0 to 255. In this example, a value “51” indicates a density “20” [(51/255)%]. 
     FIG. 14 shows a state wherein the polygon shown in FIG. 10 is divided using the coordinate unit of the printer coordinate system. 
     The minimum value of the Y-coordinate of this polygon is Y PMIN , and the maximum value of the Y-coordinate is Y PMAX . 
     In order to paint a portion inside this polygon, a paint pattern is developed on a development memory corresponding to a value between LEFTX and RIGHTX shown in FIG.  14 . 
     FIG. 15 is a flow chart showing an example of a process for painting a portion inside the polygon shown in FIG.  14 . 
     A drawing logic for the development memory of this example is “overwrite”. 
     In step S 300 , it is checked if a color mode is selected. 
     If YES in step S 300 , the flow advances to step S 301 , and a paint process in the color mode is performed, thus ending the process. 
     If NO in step S 300 , the flow advances to step S 302 , and a paint process in the monochrome mode is performed, thus ending the process. 
     FIGS. 16 to  21  are flow charts showing a summary of the paint process in the color mode in step S 301  in FIG.  15 . 
     In step S 310 , memory development information for paint color designation shown in FIG. 6 is taken, and the flow advances to step S 311 . 
     In step S 311 , Y, M, C, and Bk values of paint colors are taken from the taken memory development information for paint color designation, and are respectively set in P_Y, P_M, P_C, and P_Bk. Thereafter, the flow advances to step S 312 . 
     In step S 312 , Y PMIN  in FIG. 14 is set in β, and the flow advances to step S 313 . 
     In step S 313 , LEFTX and RIGHTX defining a range of X to be painted are computed, and the flow advances to step S 314 . 
     In step S 314 , addresses and bits on a Y-page memory in FIG. 3 corresponding to LEFTX and RIGHTX are computed, and the flow advances to step S 315 . 
     In step S 315 , the address and bit corresponding to LEFTX computed in step S 314  are respectively set in Y LAD  and Y LBIT , and the address and bit corresponding to RIGHTX are respectively set in Y RAD  and Y RBIT . Thereafter, the flow advances to step S 316 . 
     In step S 316 , P_Y is compared with 0. 
     If it is determined in step S 316  that P_Y=0, the flow advances to step S 317 , and a memory area (Y LAD , Y LBIT , Y RAD , Y RBIT ) is cleared. The flow then advances to step S 321 . 
     If it is determined in step S 316  that P_Y≠0, the flow advances to step S 318 , and the storage address of a dither pattern corresponding to the value P_Y is taken. The flow then advances to step S 319 . 
     In step S 319 , the dither pattern is taken from the storage address, and the flow advances to step S 320 . 
     In step S 320 , the dither pattern taken in step S 318  is developed on the memory area (Y LAD , Y LBIT , Y RAD , Y RBIT ), and the flow advances to step S 321 . 
     In step S 321 , the addresses and bits on an M-page memory in FIG. 3 corresponding to LEFTX and RIGHTX are computed, and the flow advances to step S 322 . 
     In step S 322 , the address and bit corresponding to LEFTX computed in step S 321  are respectively set in M LAD  and M LBIT , and the address and bit corresponding to RIGHTX are respectively set in M RAD  and M RBIT . Thereafter, the flow advances to step S 323 . 
     In step S 323 , P_M is compared with 0. 
     If it is determined in step S 323  that P_M=0, the flow advances to step S 324 , and a memory area (M LAD , M LBIT , M RAD , M RBIT ) is cleared. The flow then advances to step S 328 . 
     If it is determined in step S 323  that P_M≠0, the flow advances to step S 325 , and the storage address of a dither pattern corresponding to the value P_M is taken. Thereafter, the flow advances to step S 326 . 
     In step S 326 , the dither pattern is taken from the storage address, and the flow advances to step S 327 . 
     In step S 327 , the dither pattern taken in step S 326  is developed on the memory area (M LAD , M LBIT , M RAD , M RBIT ), and the flow advances to step S 328 . 
     In step S 328 , the addresses and bits on a C-page memory in FIG. 3 corresponding to LEFTX and RIGHTX are computed, and the flow advances to step S 329 . 
     In step S 329 , the address and bit corresponding to LEFTX computed in step S 328  are respectively set in C LAD  and C LBIT , and the address and bit corresponding to RIGHTX are respectively set in C RAD  and C RBIT . Thereafter, the flow advances to step S 330 . 
     In step S 330 , P_C is compared with 0. 
     If it is determined in step S 330  that P_C=0, the flow advances to step S 331  to clear a memory area (C LAD , C LBIT , C RAD , C RBIT ), and the flow advances to step S 335 . 
     If it is determined in step S 330  that P_C≠0, the flow advances to step S 332  to take the storage address of a dither pattern corresponding to the value P_C, and the flow advances to step S 333 . 
     In step S 333 , the dither pattern is taken from the storage address, and the flow advances to step S 334 . 
     In step S 334 , the dither pattern taken in step S 333  is developed on the memory area (C LAD , C LBIT , C RAD , C RBIT ), and the flow advances to step S 335 . 
     In step S 335 , the addresses and bits on a Bk-page memory in FIG. 3 corresponding to LEFTX and RIGHTX are computed, and the flow advances to step S 336 . 
     In step S 336 , the address and bit corresponding to LEFTX computed in step S 335  are respectively set in K LAD  and K LBIT , and the address and bit corresponding to RIGHTX are respectively set in K RAD and K RBIT . The flow then advances to step S 337 . 
     In step S 337 , P_Bk is compared with 0. 
     If it is determined in step S 337  that P_Bk=0, the flow advances to step S 338  to clear a memory area (K LAD , K LBIT , K RAD , K RBIT ), and the flow advances to step S 342 . 
     If it is determined in step S 337  that P_Bk≠0, the flow advances to step S 339  to take the storage address of a dither pattern corresponding to the value P_Bk, and the flow advances to step S 340 . 
     In step S 340 , the dither pattern is taken from the storage address, and the flow advances to step S 341 . 
     In step S 341 , the dither pattern taken in step S 340  is developed on the memory area (K LAD , K LBIT , K RAD , K RBIT ), and the flow advances to step S 342 . 
     In step S 342 , it is checked if β=Y PMAX , in FIG.  14 . 
     If it is determined in step S 342  that β=Y PMAX , the process is ended. 
     If it is determined in step S 342  that β≠Y PMAX , the flow advances to step S 343  to increment β by one, and the flow returns to step S 313 . 
     FIGS. 22 and 23 are flow charts showing a summary of the paint process in the monochrome mode in step S 302  in FIG.  15 . 
     In step S 350 , memory development information for paint color designation shown in FIG. 13 is taken, and the flow advances to step S 351 . 
     In step S 351 , a gray scale density value of a paint color is taken from the taken memory development information for paint color designation, and is set in P_G. The flow then advances to step S 352 . 
     In step S 352 , β is set in Y PMIN  in FIG. 14, and the flow advances to step S 353 . 
     In step S 353 , the storage address of a dither pattern corresponding to the value P_G is taken, and the flow advances to step S 354 . 
     In step S 354 , the dither pattern is taken from the storage address, and the flow advances to step S 355 . 
     In step S 355 , LEFTX and RIGHTX as a range of X to be painted are computed, and the flow advances to step S 356 . 
     In step S 356 , the addresses and bits on the Bk-page memory in FIG. 3 corresponding to LEFTX and RIGHTX are computed, and the flow advances to step S 357 . 
     In step S 357 , the address and bit corresponding to LEFTX computed in step S 356  are respectively set in K LAD  and K LBIT , and the address and bit corresponding to RIGHTX are respectively set in K RAD  and K RBIT . The flow then advances to step S 358 . 
     In step S 358 , the dither pattern taken in step S 354  is developed on a memory area (K LAD , K LBIT , K RAD , K RBIT ), and the flow advances to step S 359 . 
     In step S 359 , it is checked if β=Y MAX  in FIG.  14 . 
     If it is determined in step S 359  that β=Y PMAX , the processing is ended. 
     If it is determined in step S 359  that β≠Y PMAX , the flow advances to step S 360  to increment β by one, and the flow returns to step S 353 . 
     As described above, in the control of the conventional image processing apparatus for performing color recording on the basis of the PDL or page description commands, a drawing pattern of each of Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) as coloring materials of toners or inks is developed based on memory development information obtained by analyzing commands on a development memory having a size corresponding to the effective print area of a print sheet. 
     A portion inside the polygon shown in FIG. 14 is painted by the processes shown in FIGS. 15 to  23 . 
     However, the prior art suffers from the following drawbacks. 
     (1) In the paint process for each scan line, each of the Y, M, C, and Bk density values is detected, and the paint process of a figure drawing on each of the Y-, M-, C-, and Bk-page memories is controlled based on the detected value, resulting in a long drawing time. 
     (2) In the paint process for each scan line, each of Y, M, C, and Bk dither patterns corresponding to the Y, M, C, and Bk density values is taken from the storage area, and the paint process of a figure drawing on each page memory is controlled, resulting in a long drawing time. 
     (3) Since paint processes of figure drawings with different drawing logics are performed in units of drawing logics, the program amount or hardware scale necessary for control increases as the number of types of corresponding drawing logics is increased. 
     (4) When the color mode and the monochrome mode (a mode for outputting color data as gray scale data) can be switched, paint processes of figure drawings are performed in units of modes, and the program amount or hardware scale necessary for control increases. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to shorten the development process time onto a memory by improving paint process efficiency of, e.g., a figure for bit map memories in units of coloring materials, i.e., Y, M, C, and Bk, in a development process of data onto the bit map memories so as to output color data, and to reduce cost of an apparatus by executing switching of drawing logics or switching between a color mode and a monochrome mode under identical control as much as possible. 
     The present invention has a table for storing addresses of functions for developing a drawing such as a figure, a character, and the like in units of scan lines with respect to bit map memories in units of coloring materials or elements, and performs a development process using this table. Therefore, computation control need not be performed in units of scan lines, and the process time can be shortened. 
     When each function indicated by the address stored in the table is set in correspondence with the presence/absence of a value of a coloring material or element, the process time can be further shortened. 
     According to the present invention, the storage address of a binary pattern, corresponding to the density value of each coloring material or element, of data to be developed on bit map memories in units of coloring materials or elements, is computed and stored. Thus, a binary pattern used when the data is developed on the bit map memory can be easily obtained, and the drawing time can be shortened. 
     According to the present invention, a plurality of tables each for storing addresses of functions for developing a drawing such as a figure, a character, and the like are prepared in correspondence with the number of designatable drawing logics. Thus, programs or hardware arrangements corresponding to the drawing logics need not be prepared. 
     According to the present invention, a table for storing addresses of functions for developing a drawing such as a figure, a character, and the like is set in correspondence with both the color output mode and the gray scale mode. Thus, programs or hardware arrangements in units of modes need not be prepared. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view of an example of a user coordinate system; 
     FIG. 2 is a view of an example of a printer coordinate system; 
     FIG. 3 is a view of an example of a memory map of a RAM area in a color image processing apparatus when each of Y, M, C, and Bk has a memory area corresponding to the size of an effective print area of a print sheet; 
     FIG. 4 is a view of an example of a paint color designation command of drawing attribute commands; 
     FIG. 5 is a view of an example of a polygon drawing command of drawing commands; 
     FIG. 6 is a view of an example of memory development information for paint color designation of those for drawing attribute functions; 
     FIG. 7 is a view of memory development information for polygon drawing of those for drawing attribute functions; 
     FIG. 8 is a view of an example of polygon drawing on the user coordinate system; 
     FIG. 9 is a view of an example of a polygon drawing command issued when polygon drawing shown in FIG. 8 is set; 
     FIG. 10 is a view of an example of conversion of polygon drawing shown in FIG. 8 onto the printer coordinate system; 
     FIG. 11 is a view of an example of memory development information of polygon drawing shown in FIGS. 8 and 10; 
     FIG. 12 is a view of an example of memory development information used when a portion inside the polygon shown in FIG. 8 is painted in yellow (coloring material Yellow=100%); 
     FIG. 13 is a view of an example of memory development information used when a portion inside the polygon shown in FIG. 8 is painted in a gray scale color (coloring material Black=20%); 
     FIG. 14 is a view of the polygon shown in FIG. 10 divided in coordinate units of the printer coordinate system; 
     FIG. 15 is a flow chart showing an example of a process for painting a portion inside the polygon shown in FIG. 14; 
     FIG. 16 is a flow chart showing a process in step S 301  in FIG. 15; 
     FIG. 17 is a flow chart showing the process in step S 301  in FIG. 15; 
     FIG. 18 is a flow chart showing the process in step S 301  in FIG. 15; 
     FIG. 19 is a flow chart showing the process in step S 301  in FIG. 15; 
     FIG. 20 is a flow chart showing the process in step S 301  in FIG. 15; 
     FIG. 21 is a flow chart showing the process in step S 301  in FIG. 15; 
     FIG. 22 is a flow chart showing a process in step S 302  in FIG. 15; 
     FIG. 23 is a flow chart showing the process in step S 302  in FIG. 15; 
     FIG. 24 is comprised of FIGS. 24A and 24B block diagrams showing a circuit arrangement of an image processing apparatus according to an embodiment of the present invention; 
     FIG. 25 is a perspective view showing the details of an arrangement around a head unit of an ink jet type image processing apparatus; 
     FIG. 26 is a view showing the details of a head unit  101  shown in FIG. 25; 
     FIG. 27 is a view of an example of a band structure; 
     FIG. 28 is a view of an example when an effective print area of a print sheet is divided into eight bands each having a band height of 512 scan lines; 
     FIG. 29 is a view of an example of a memory map of a RAM area in a color mode; 
     FIG. 30 is a view of an example of a memory map of a RAM area in a monochrome mode; 
     FIG. 31 is a view of an example of an attribute information storage area for storing drawing attribute information used when data is developed on a memory; 
     FIG. 32 is a flow chart when color recording is performed using a memory for one band for each of Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) in a color image processing apparatus for receiving page description command data in units of pages, and performing recording control in units of pages; 
     FIG. 33 is a flow chart when color recording is performed using a memory for one band for each of Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) in a color image processing apparatus for receiving page description command data in units of pages, and performing recording control in units of pages; 
     FIG. 34 is a flow chart when color recording is performed using a memory for one band for each of Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) in a color image processing apparatus for receiving page description command data in units of pages, and performing recording control in units of pages; 
     FIGS. 35A to  35 C are views of examples of a color designation command of drawing attribute designation commands; 
     FIGS. 36A to  36 D are views respectively showing examples of a line width designation command, a clip area designation command, a paint definition designation command, and a drawing logic designation command of drawing attribute designation commands; 
     FIG. 37 is a view of an example of a straight line drawing command/polygon drawing command of drawing commands; 
     FIG. 38 is a view of an example of a character drawing command of drawing commands; 
     FIG. 39 shows a command analysis jump table  4  in FIGS. 24A and 24B, which stores jump addresses to functions for analyzing drawing commands and drawing attribute commands; 
     FIG. 40 is a flow chart showing the details of a command data analysis process in step S 3  in FIG. 32; 
     FIG. 41 is a flow chart showing the details of a process upon execution of a color designation command analysis function in step S 34  in FIG. 40; 
     FIG. 42 is a flow chart showing the details of the process upon execution of the color designation command analysis function in step S 34  in FIG. 40; 
     FIG. 43 is a flow chart showing the details of the process upon execution of the color designation command analysis function in step S 34  in FIG. 40; 
     FIG. 44 is a flow chart showing the details of the process upon execution of the color designation command analysis function in step S 34  in FIG. 40; 
     FIG. 45 is a flow chart showing the details of a process upon execution of a line width designation command analysis function in step S 34  in FIG. 40; 
     FIG. 46 is a flow chart showing the details of a process upon execution of a clip area designation command analysis function in step S 34  in FIG. 40; 
     FIG. 47 is a flow chart showing the details of a process upon execution of a paint definition designation command analysis function in step S 34  in FIG. 40; 
     FIG. 48 is a flow chart showing the details of a process upon execution of a drawing logic definition designation command analysis function in step S 34  in FIG. 40; 
     FIG. 49 is a flow chart showing the details of a process for setting MIN band No. and MAX band No. in a memory development information area in steps S 40 , S 60 , S 70 , S 80 , and S 100  in FIGS. 41,  45 ,  46 ,  47 , and  48 ; 
     FIG. 50 is a diagram of an example of a color reproduction process shown in steps S 701  and S 705  in FIG. 43; 
     FIG. 51 shows equations as an example of a color conversion process shown in step S 703  in FIG.  43  and step S 713  in FIG. 44; 
     FIG. 52 shows an equation as an example of a color conversion process shown in step S 704  in FIG.  43  and step S 714  in FIG. 44; 
     FIG. 53 is a flow chart showing an example of a color conversion process shown in steps S 711  and S 715  in FIG. 44; 
     FIG. 54 is a flow chart showing a process upon execution of a straight line drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 55 is a flow chart showing the process upon execution of the straight line drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 56 is a flow chart showing the process upon execution of the straight line drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 57 is a flow chart showing the process upon execution of a polygon drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 58 is a flow chart showing the process upon execution of the polygon drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 59 is a flow chart showing the process upon execution of the polygon drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 60 is a flow chart showing a process for setting data in a work area, and setting X MIN , Y MIN , X MAX , and Y MAX  in step S 600  in FIG.  54  and step S 120  in FIG. 57; 
     FIG. 61 is a flow chart showing the process for setting data in a work area, and setting X MIN , Y MIN , X MAX , and Y MAX  in step S 600  in FIG.  54  and step S 120  in FIG. 57; 
     FIG. 62 is a flow chart showing the process for setting data in a work area, and setting X MIN , Y MIN , X MAX , and Y MAX  in step S 600  in FIG.  54  and step S 120  in FIG. 57; 
     FIG. 63 is a flow chart showing a process upon execution of a character drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 64 is a flow chart showing the process upon execution of the character drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 65 is a flow chart showing the process upon execution of the character drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 66 is a flow chart showing the process upon execution of the character drawing command analysis function in step S 34  in FIG. 40; 
     FIG. 67 is a flow chart showing a computation process of a drawing range in step S 601  in FIG.  54  and step S 121  in FIG. 57; 
     FIG. 68 is a view of a drawing range of a polygon designated by four points (x 1 , y 1 ) to (x 4 , y 4 ); 
     FIG. 69 is a flow chart showing a computation process of a character drawing range in step S 220  in FIG. 64; 
     FIG. 70 is a view of a character drawing range; 
     FIG. 71 is a flow chart showing a clip check process of a drawing range in step S 602  in FIG. 54, step S 122  in FIG. 57, and step S 220  in FIG. 64; 
     FIG. 72 is a flow chart showing the clip check process of a drawing range in step S 602  in FIG. 54, step S 122  in FIG. 57, and step S 220  in FIG. 64; 
     FIG. 73 is a view showing a case wherein a clip area of a rectangular area surrounded by (C XMIN , C YMIN ) and (C XMAX , C YMAX ) is set in a drawing range of a rectangular area surrounded by (P XIN , P YMIN ) and (P XMAX , P YMAX ); 
     FIG. 74 is a flow chart showing a process for computing MIN band No. and MAX band No. in step S 604  in FIG. 55, step S 124  in FIG. 58, and step S 222  in FIG. 65; 
     FIGS. 75A and 75B are views of examples of memory development information for color designation generated by analyzing the color designation command in FIGS. 35A to  35 C on the basis of the flow charts of FIGS. 41 to  44 , in which FIG. 75A shows an example in a color mode, and FIG. 75B shows an example in a monochrome mode; 
     FIG. 76A is a view of an example of memory development information generated by analyzing the line width designation command in FIG. 36A on the basis of the flow chart of FIG. 45, 
     FIG. 76B is a view of an example of memory development information generated by analyzing the clip area designation command in FIG. 36B on the basis of the flow chart of FIG. 46, 
     FIG. 76C is a view of an example of memory development information generated by analyzing the paint definition designation command in FIG. 36C on the basis of the flow chart of FIG. 47, and 
     FIG. 76D is a view of an example of memory development information generated by analyzing the drawing logic designation command in FIG. 36D on the basis of the flow chart of FIG. 48; 
     FIG. 77A is a view of an example of memory development information generated by analyzing the straight line drawing command in FIG. 37 on the basis of the flow charts of FIGS. 54 to  56 , and 
     FIG. 77B is a view of an example of memory development information generated by analyzing the polygon drawing command in FIG. 37 on the basis of the flow charts of FIGS. 57 to  59 ; 
     FIG. 78 is a view of an example of memory development information generated by analyzing the character drawing command in FIG. 38 on the basis of the flow charts of FIGS. 63 to  66 ; 
     FIG. 79 is a view showing a case wherein one page is divided into four bands, and drawing is performed using Y, M, C, and Bk band memories each having a size corresponding to one band, and some drawing attribute commands and some drawing commands shown in FIGS. 27 to  30 ; 
     FIG. 80 is a view of memory development information used in drawing in FIG. 79; 
     FIG. 81 is a view of memory development information used in drawing in FIG. 79; 
     FIG. 82 is a view showing a case wherein one page is divided into four bands, and drawing is performed using Y, M, C, and Bk band memories each having a size corresponding to one band while setting clip area designation for a straight line drawing; 
     FIG. 83 is a view of memory development information used in drawing in FIG. 82; 
     FIG. 84 shows a command execution jump table  1 , which stores jump addresses to functions for practically performing pattern development of a drawing onto a memory, and jump addresses to functions for designating drawing attributes (setting attributes in internal variables, and the like); 
     FIG. 85 shows a command execution jump table  2  in which all jump addresses to functions for performing pattern development of a drawing onto a memory are replaced with jump addresses to skip functions in FIG. 84; 
     FIG. 86 is a flow chart showing the details of a process in step S 12  in FIG. 33; 
     FIG. 87 is a flow chart showing the details of a process in step S 390  in FIG. 86; 
     FIG. 88 is a view of a printer coordinate system set when a band height=512 dots; 
     FIG. 89 is a view showing a case wherein a clip area satisfying D SPYMI &lt;M INY  and M AXY &lt;D SPYMX  for a range where a figure, a character, or the like can be drawn when band No.=i; 
     FIG. 90 is a flow chart showing the details of a process in step S 391  in FIG. 86; 
     FIG. 91 is a view showing header addresses of Y, M, C, and Bk virtual page memories in a color mode when a drawing is developed on the fifth band (band No.=4) in FIG. 28; 
     FIG. 92 is a view showing header addresses of a Bk virtual page memory in a monochrome mode when a drawing is developed on the fifth band (band No.=4) in FIG. 28; 
     FIG. 93 is a flow chart showing a process upon execution of a line width designation function in step S 399  in FIG. 86; 
     FIG. 94 is a flow chart showing a process upon execution of a line color designation function in step S 399  in FIG. 86; 
     FIG. 95 is a flow chart showing a process upon execution of a paint color designation function in step S 399  in FIG. 86; 
     FIG. 96 is a flow chart showing a process upon execution of a character color designation function in step S 399  in FIG. 86; 
     FIG. 97 is a flow chart showing a process upon execution of a clip area designation function in step S 399  in FIG. 86; 
     FIG. 98 is a flow chart showing a process upon execution of a paint definition designation function in step S 399  in FIG. 86; 
     FIG. 99 is a flow chart showing a process upon execution of a drawing logic designation function in step S 399  in FIG. 86; 
     FIG. 100 is a flow chart showing a process upon execution of a straight line drawing function in step S 399  in FIG. 86; 
     FIG. 101 is a flow chart showing the process upon execution of the straight line drawing function in step S 399  in FIG. 86; 
     FIG. 102 is a flow chart showing a process upon execution of a polygon drawing function in step S 399  in FIG. 86; 
     FIG. 103 is a flow chart showing the process upon execution of the polygon drawing function in step S 399  in FIG. 86; 
     FIG. 104 is a flow chart showing the process upon execution of the polygon drawing function in step S 399  in FIG. 86; 
     FIG. 105 is a flow chart showing the process upon execution of the polygon drawing function in step S 399  in FIG. 86; 
     FIG. 106 is a flow chart showing a process upon execution of a character drawing function in step S 399  in FIG. 86; 
     FIG. 107 is a flow chart showing the process upon execution of the character drawing function in step S 399  in FIG. 86; 
     FIG. 108 is a flow chart showing a process upon execution of a skip function in step S 399  in FIG. 86; 
     FIG. 109 shows an example of a dither pattern address table  21 ; 
     FIGS. 110A and 110B are views of examples of a dither pattern; 
     FIG. 111 is a flow chart showing a process in step S 474  in FIG. 100, step S 500  in FIG. 103, step S 506  in FIG. 104, and step S 527  in FIG. 107; 
     FIG. 112 is a flow chart showing a process in step S 474  in FIG. 100, step S 500  in FIG. 103, step S 506  in FIG. 104, and step S 527  in FIG. 107; 
     FIG. 113 shows an example of a paint function address storage table for drawing logic designation=overwrite; 
     FIG. 114 shows an example of a paint function address storage table for drawing logic designation=transparent; 
     FIG. 115 shows an example of a drawing logic table address storage table  24 ; 
     FIGS. 116A and 116B are views of examples of a BITSET flag; 
     FIG. 117 is a flow chart showing a process in step S 475  in FIG. 100, step S 501  in FIG. 103, step S 507  in FIG. 104, and step S 528  in FIG. 107; 
     FIG. 118 is a flow chart showing the process in step S 475  in FIG. 100, step S 501  in FIG. 103, step S 507  in FIG. 104, and step S 528  in FIG. 107; 
     FIG. 119 is a flow chart showing the process in step S 475  in FIG. 100, step S 501  in FIG. 103, step S 507  in FIG. 104, and step S 528  in FIG. 107; 
     FIG. 120 is a view of an example of a straight line connecting two points on the printer coordinate system; 
     FIG. 121 is a flow chart showing a process in step S 479  in FIG.  101  and step S 511  in FIG. 105; 
     FIG. 122 is a flow chart showing the process in step S 479  in FIG.  101  and step S 511  in FIG. 105; 
     FIG. 123 is a flow chart showing the process in step S 479  in FIG.  101  and step S 511  in FIG. 105; 
     FIG. 124 is a view of an example of a polygon defined by five points on the printer coordinate system; 
     FIG. 125 is a view of an example of a character “E” defined by 12 outline points on the printer coordinate system; 
     FIG. 126 is a flow chart showing a process in step S 502  in FIG.  103  and step S 529  in FIG. 107; 
     FIG. 127 is a flow chart showing a process in step S 860  in FIG.  122  and step S 871  in FIG. 126; 
     FIG. 128 is a flow chart showing the process in step S 860  in FIG.  122  and step S 871  in FIG. 126; 
     FIG. 129 is a flow chart showing a process in step S 862  in FIG.  123  and step S 873  in FIG. 126; 
     FIG. 130 is a flow chart showing the process in step S 862  in FIG.  123  and step S 873  in FIG. 126; 
     FIG. 131 is a flow chart showing the process in step S 862  in FIG.  123  and step S 873  in FIG. 126; 
     FIG. 132 is a flow chart showing the process in step S 862  in FIG.  123  and step S 873  in FIG. 126; 
     FIG. 133 is a view showing information necessary for explaining drawing of the straight line shown in FIG. 120; 
     FIG. 134 is a view showing information necessary for explaining a process for painting a portion inside the polygon in FIG. 124; 
     FIG. 135 is a view showing information necessary for explaining a process for painting a portion inside the character in FIG. 125; 
     FIG. 136 is a flow chart showing an example of a clear paint process in the process in step S 922  in FIG. 132; 
     FIG. 137 is a flow chart showing an example of the clear paint process in the process in step S 922  in FIG. 132; 
     FIG. 138 is a flow chart showing an example of an overwrite paint process of the process in step S 922  in FIG. 132; 
     FIG. 139 is a flow chart showing an example of the overwrite paint process of the process in step S 922  in FIG. 132; 
     FIG. 140 is a flow chart showing an example of a reverse paint process of the process in step S 922  in FIG. 132; 
     FIG. 141 is a flow chart showing an example of the reverse paint process of the process in step S 922  in FIG. 132; 
     FIG. 142 is a flow chart showing an example of a transparent paint process of the process in step S 922  in FIG. 132; 
     FIG. 143 is a flow chart showing an example of the transparent paint process of the process in step S 922  in FIG. 132; 
     FIG. 144 is a view showing an example of the paint processes shown in FIGS. 136 to  143 ; 
     FIG. 145 is a view showing another embodiment of FIG. 133; 
     FIGS. 146A and 146B are views showing other embodiments of FIGS. 116A and 116B; and 
     FIG. 147 is a view showing a polygon including two portions to be painted with respect to one scan line of a Y coordinate. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of the present invention will be described in detail hereinafter with reference to the accompanying drawings. 
     FIG. 24 is comprised of FIGS. 24A and 25B block diagrams showing a circuit arrangement of an image processing apparatus according to an embodiment of the present invention. 
     As shown in FIGS. 24A and 24B, an image processing apparatus according to this embodiment is constituted by a host computer  1  and an image processing apparatus main body  1000 . 
     The host computer  1  supplies print data, a print command, and the like to the image processing apparatus, and causes the image processing apparatus to perform a recording process. The image processing apparatus has a microprocessor system including a CPU, a ROM, and a RAM. More specifically, the image processing apparatus main body comprises: an interface  2  for exchanging data with the host computer  1 ; a command analyzer  3  which includes a command analysis table  4  storing jump addresses to analysis programs corresponding to command Nos. of commands sent from the host computer  1 , and which analyzes print data or a command sent from the host computer  1 , and generates information for one page, which can be developed on a development memory; a band information storage  5  which includes a band height information table  6  storing a band height and information (memory capacity) of a development memory for a corresponding coloring material, and which stores information of band heights, and the like; a color reproduction information storage  7  storing information required in a color reproduction process; a color reproduction processor  8  for performing the color reproduction process; a character information storage  9  storing information for drawing a character; a controller  10  for controlling the apparatus; a memory development information storage  11  including an attribute information storage area  12  for storing attribute information, and a memory development information storage area  13  for storing information to be developed on a memory; a memory development information analyzer  14  which includes a command execution jump table  1  (15) and a command execution jump table  2  (16), and analyzes memory development information; a pattern developer  17  for developing analyzed memory development information on a development memory  18  consisting of four memories, i.e., Y, M, C, and Bk memories; an output unit  19  for outputting developed data onto a print sheet as a permanently visual image; a dither pattern storage  20  which includes a dither pattern address table  21  storing header addresses of dither pattern storage areas corresponding to Y, M, C, and Bk values used in development onto Y, M, C, and Bk development memories, and which stores Y, M, C, and Bk dither patterns; a memory development table storage  22  including paint function address storage tables  23  in units of drawing logics, which tables store jump addresses to paint functions used in development onto the Y, M, C, and Bk development memories, and a drawing logic address table address storage table  24  which stores header addresses of the paint function address storage tables in units of drawing logics; an operation panel  25  capable of changing and setting parameters of a print environment; and a data bus  26 . 
     FIG. 25 is a perspective view showing details of an arrangement around a head unit of an ink jet type image processing apparatus. 
     Head units  101  consist of Y, M, C, and Bk head units each including a large number of ink jet heads arranged in the sub-scan direction for one coloring material. 
     Ink tanks  102  for the head units  101 , and signal lines  103  are connected to the head units  101 . A carriage drive motor  104  moves a carriage, which mounts the head units, along a rail in cooperation with a conveyor belt. 
     A recording sheet  107  fed from a recording sheet roll  111  is wound around a platen  108  via a guide roller  112 , and is fed by recording sheet convey rollers  109  and  110 . 
     Each head unit  101  consists of a plurality of ink jet heads utilizing heat generation elements, as shown in FIG.  26 . For example, ink jet heads using electro-mechanical conversion means such as piezo elements may be used instead. 
     FIG. 26 shows the details of the head units  101  shown in FIG.  25 . 
     Referring to FIG. 26, each head unit has Y, M, C, or Bk nozzles corresponding in number to each head height. 
     More specifically, the head units  101  respectively have yellow ink ejection nozzles, magenta ink ejection nozzles, cyan ink ejection nozzles, and black ink ejection nozzles. 
     FIG. 27 shows an example of a band structure. 
     As shown in FIG. 27, a rectangular area having an effective print area width of a print sheet as a horizontal length, and a head height as a vertical length is defined as a segment. 
     One band is an area obtained by vertically arranging the segments, as shown in FIG. 27, and has a size corresponding to an integer multiple of the segment size. 
     Therefore, the band height (the height of the band) corresponds to an integer multiple of the head height. 
     In this example, one band is constituted by four segments. 
     FIG. 28 shows a case wherein the effective print area of a print sheet is divided into eight bands each having a band height of 512 scan lines. 
     As shown in FIG. 28, band Nos.  0  to  7  are assigned to the eight bands. 
     If the number of bands is n, the band No. ranges from 0 to (n−1). 
     Points such as (0, 512) on the printer coordinate system shown in FIG. 28 indicate points at the upper left corners of the bands, and are computed by (0, (n−1)×512). 
     The effective print area height is not always equal to an integer multiple of the band height, and the height of the final band (band  7  in FIG. 28) may often become equal to or smaller than the band height. 
     FIG. 29 shows an example of a memory map of an internal RAM area of the color image processing apparatus in a color mode. 
     The RAM area in the color mode is constituted by a system work memory, a vacant area, and 1-band memories for Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) as coloring materials (toners or inks) (memories each having a size corresponding to one band area in FIG.  28 ). 
     FIG. 30 shows an example of a memory map of the internal RAM area of the color image processing apparatus in a monochrome mode. 
     In the monochrome mode, since a print operation is performed using a coloring material Bk (Black) alone, the RAM area in the monochrome mode is constituted by a system work memory, a vacant area, and a 1-band memory for Bk (Black) as a coloring material (toner or ink) (a memory having a size corresponding to one band area in FIG.  28 ). 
     More specifically, the 1-band memories for Y (Yellow), M (Magenta), and C (Cyan) can be effectively utilized as a vacant area. 
     The system work memory is used as a storage area of information (e.g., variables) used in internal control of the image processing apparatus, a permanent work area, and the like. 
     The vacant area is used as an area for storing memory development information, a character cache memory, and the like. 
     FIG. 31 shows the attribute information storage area (RAM)  12  shown in FIGS. 24A and 24B. 
     The attribute information storage area is constituted by areas for temporarily retreating drawing attribute information used upon development data onto a memory, and variable areas set with the drawing attribute information. 
     As shown in FIG. 31, retreat areas are determined in correspondence with drawing attributes, and m pieces of information can be retreated. 
     L WIDTH , L YMCK , and the like represent variables in each of which the drawing attribute information is set. 
     FIGS. 32,  33 , and  34  are flow charts for performing color recording using only the 1-band memories for Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) in the color image processing apparatus for receiving page description command data in units of pages, and performing recording control in units of pages. 
     In step S 1 , the attribute information storage area shown in FIG. 31 is assured on a RAM, and the flow advances to step S 2 . 
     In step S 2 , a set of command data (a drawing command, a drawing attribute command, and the like) are read, and the flow advances to step S 3 . 
     In step S 3 , the command analyzer  3  analyzes the command data, and the flow advances to step S 4 . 
     If it is determined in step S 4  that command data for one page remain, the flow returns to step S 2 ; otherwise, the flow advances to step S 5 . 
     In step S 5 , drawing attribute information required for data development onto the memories at this time is temporarily retreated on the retreat area in the attribute information storage area  12  assured in step S 1 , and the flow advances to step S 10 . 
     In step S 10 , “0” is set in a constant i, and the flow advances to step S 11 . 
     In step S 11 , a pointer is placed at the head of the first set of memory development information stored in the memory development information area  13 , and the flow advances to step S 12 . 
     In step S 12 , the memory development information read in step S 11  is analyzed by the memory development information analyzer  14 , and is developed on the development memories corresponding to a band i portion (i.e., the Y, M, C, and Bk band memories). Thereafter, the flow advances to step S 13 . 
     If it is determined in step S 13  that memory development information remains, the flow advances to step S 14 , and the pointer is placed at the head of the next set of memory development information. The flow then returns to step S 12 . 
     If it is determined in step S 13  that no memory development information remains, the flow advances to step S 15 . 
     In step S 15 , the contents of the memories developed in step S 12  are color-recorded by the output unit  19 , and the flow advances to step S 16 . 
     In step S 16 , i is incremented by one, and the flow advances to step S 17 . 
     In step S 17 , the Y, M, C, and Bk band memories are cleared, and the flow advances to step S 18 . 
     In step S 18 , the number of bands is compared with i. If the number of bands is equal to i, the process ends. 
     If the number of bands is not equal to i, the flow advances to step S 19 . In step S 19 , the drawing attributes temporarily retreated in the retreat areas in the attribute information storage area  12  in step S 5  are loaded, and are set in the variable areas of the attribute information storage area  12 . Thereafter, the flow returns to step S 11 . 
     With the above-mentioned process, color recording can be performed using only the 1-band memories for Y (Yellow), M (Magenta), C (Cyan), and Bk (Black). 
     FIGS. 35A,  35 B, and  35 C show examples of color designation commands (line color designation, paint color designation, and character color designation) of the drawing attribute designation commands. 
     A line color designation command is used for designating a color of a straight line or an outline of a figure. 
     A paint color designation command is used for designating a color for painting a portion inside a closed figure. 
     A character color designation command is used for designating a color of a character. 
     A command No. varies depending on color designation commands, and is used for identifying a command. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     The content of a type flag parameter indicates the type of color designation data. 
     FIG. 35A shows a case wherein a type flag value=0, and represents that color designation data are brightness data values of R (Red), G (Green), and B (Blue) as primaries of light. 
     FIG. 35B shows a case wherein a type flag value=1, and represents that color designation data are L*, a*, and b* data values of the uniform perceptual space determined by the CIE (Commission Internationale de l&#39;Eclairage) in 1976. 
     FIG. 35C shows a case wherein a type flag value=2, and represents that color designation data are density data values of Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) as primary colors of coloring materials (toners or inks). 
     FIGS. 36A to  36 D show examples of a line width designation command, a clip area designation command, a paint definition designation command, and a drawing logic designation command of the drawing attribute designation commands. 
     A command No. varies depending on drawing attribute designation commands, and is used for identifying a command. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     A line width designation command shown in FIG. 36A is used for designating a line width of a straight line or an outline of a figure. 
     The line width value also uses the coordinate unit of the user coordinate system as a unit. 
     A clip area designation command shown in FIG. 36B is used for designating a drawable range of a figure, a character, or the like. 
     In FIG. 36B, X and Y MIN and MAX values use the coordinate unit of the user coordinate system as a unit. 
     A paint definition designation command shown in FIG. 36C is used for designating a paint pattern inside an outline of a closed figure, and the presence/absence of an outline. 
     In FIG. 36C, a paint pattern No. is used for identifying a paint pattern. When the pattern No.=0, it indicates the absence (blank) of a paint pattern; when the pattern No. is other than 0, it indicates a corresponding paint pattern such as a hatch pattern. 
     An outline flag indicates the absence of an outline when it is “0”, and indicates the presence of an outline when it is “1”. 
     A drawing logic designation command shown in FIG. 36D is used for designating a drawing logic of a figure, a character, or the like, i.e., a drawing logic (overwrite, transparent, or the like) for a memory upon development of a pattern on a development memory. 
     For example, when a drawing logic is “overwrite”, a drawing logic value “0” is designated; when a drawing logic is “transparent”, a drawing logic value “1” is designated. 
     FIG. 37 shows an example of a straight line drawing command or a polygon drawing command of the drawing commands. 
     A command No. varies depending on drawing functions, and is used for identifying a command. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     A straight line drawing command is used for drawing a straight line. 
     A polygon drawing command is used for drawing a polygon. 
     In FIG. 37, X and Y values in coordinates 1 to n are coordinate values on the user coordinate system. 
     FIG. 38 shows an example of a character drawing command of the drawing commands. 
     A command No. varies depending on drawing functions, and is used for identifying a command. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     A character drawing command is used for drawing a character. 
     In FIG. 38, X and Y coordinates of a drawing position are coordinates on the user coordinate system, which indicate a start reference position of character drawing. 
     Character data represents a character string (e.g., ABC) to be printed. 
     FIG. 39 shows the command analysis jump table (ROM)  4  (FIGS.  24 A and  24 B), which stores jump addresses to functions for analyzing drawing commands and drawing attribute commands. 
     The table  4  stores jump addresses to command analysis functions in correspondence with command Nos. (0 to n). 
     FIG. 40 is a flow chart showing the details of the command data analysis process in step S 3  in FIG.  32 . 
     In step S 30 , a command No. is taken out of a set of command data, and the flow advances to step S 31 . 
     In step S 31 , a pointer is placed at the head of the command analysis jump table shown in FIG. 39, and the flow advances to step S 32 . 
     In step S 32 , the pointer is advanced by an amount corresponding to the command No., and the flow advances to step S 33 . 
     In step S 33 , the content (jump address) indicated by the pointer is taken, and the flow advances to step S 34 . 
     In step S 34 , a function indicated by the taken jump address is executed, and the process ends. 
     FIGS. 41 and 42 are flow charts showing the details of a process upon execution of a color designation command analysis function in step S 34  in FIG.  40 . 
     In step S 40 , MIN and MAX band Nos. are set in the memory development information storage area  13 , and the flow advances to step S 41 . 
     In step S 41 , a command No. is read from a command, and is set in the memory development information storage area  13  to advance a pointer. Thereafter, the flow advances to step S 42 . 
     In step S 42 , the number of data is read from the command, and (the number of data−1) is set in a constant n. The flow then advances to step S 43 . 
     In step S 43 , “4” is set as the number of data in the memory development information storage area  13  to advance a pointer, and the flow advances to step S 44 . 
     In step S 44 , a type parameter is read from the command and is set in a type flag C SMFLG . The flow then advances to step S 45 . 
     In step S 45 , color designation data corresponding in number to the constant n are read, and the flow advances to step S 46 . 
     It is checked in step S 46  if the value of the type flag C SMFLG  is one of 0, 1, and 2. 
     If NO in step S 46 , the process ends. 
     If YES in step S 46 , the flow advances to step S 47  to check if the color mode is set. 
     If YES in step S 47 , the flow advances to step S 48  to execute a color conversion process in the color mode, and the flow then advances to step S 50 . 
     However, if NO in step S 47 , the flow advances to step S 49  to execute a color conversion process in the monochrome mode, and the flow then advances to step S 50 . 
     In step S 50 , Y, M, C, and Bk density data are set in the memory development information storage area  13 , and a pointer is advanced, thus ending the process. 
     In this manner, the color designation command is analyzed, and memory development information for color designation is generated. 
     FIG. 43 is a flow chart showing the details of a process upon execution of the color conversion process in the color mode in step S 48  in FIG.  42 . 
     In step S 700 , the value of the type flag C SMFLG  is compared with 0. 
     If C SMFLG =0, since it indicates that color designation data read in step S 45  are R, G, and B brightness data, the flow advances to step S 701 , and the R, G, and B brightness data are converted into Y, M, C, and Bk density data, thus ending the process. 
     If C SMFLG ≠0, the flow directly advances to step S 702 . 
     In step S 702 , the value of the type flag C SMFLG  is compared with 1. 
     If C SMFLG =1, since it indicates that color designation data read in step S 45  are L*, a*, and b* data of the uniform perceptual space determined by the CIE (Commission Internationale de l&#39;Eclairage) in 1976, the flow advances to step S 703 , and the CIE L*, a*, and b* data are converted into CIE XYZ data (the XYZ colorimetric system determined by the CIE in 1931). The flow then advances to step S 704 . 
     In step S 704 , the CIE XYZ data are converted into R, G, and B brightness data, and the flow advances to step S 705 . 
     In step S 705 , the R, G, and B brightness data are converted into Y, M, C, and Bk density data, and the process ends. 
     If it is determined in step S 702  that the type flag C SMFLG ≠1, the process ends. 
     If C SMFLG ≠2, the process ends. 
     In this manner, in the color mode, color designation data are converted into Y, M, C, and Bk density data. 
     FIG. 44 is a flow chart showing the details of a process upon execution of the color conversion process in the monochrome mode in step S 49  in FIG.  42 . 
     In step S 710 , the value of the type flag C SMFLG  is compared with 0. 
     If C SMFLG =0, since it indicates that color designation data read in step S 45  are R, G, and B brightness data, the flow advances to step S 711 , and the R, G, and B brightness data are converted into gray scale density data. The flow then advances to step S 716 . 
     If C SMFLG ≠0, the flow advances to step S 712 , and the value of the type flag C SMFLG  is compared with 1. 
     If C SMFLG =1, since it indicates that color designation data read in step S 45  are L*, a*, and b* data of the uniform perceptual space determined by the CIE (Commission Internationale de l&#39;Eclairage) in 1976, the flow advances to step S 713 , and the CIE L*, a*, and b* data are converted into CIE XYZ data (the XYZ colorimetric system determined by the CIE in 1931). The flow then advances to step S 714 . 
     In step S 714 , the CIE XYZ data are converted into R, G, and B brightness data, and the flow advances to step S 715 . 
     In step S 715 , the R, G, and B brightness data are converted into gray scale density data, and the flow advances to step S 716 . 
     In step S 716 , gray scale density data Gray is set in Y density data, and 0 is set in M, C, and Bk density data, thus ending the process. 
     More specifically, gray scale density data, 0, 0, 0, are stored in a color information portion of the memory development information of the gray scale density data. 
     In this manner, in the monochrome mode, color designation data are converted into gray scale density data. 
     FIG. 45 is a flow chart showing the details of a process upon execution of a line width designation command analysis function in step S 34  in FIG.  40 . 
     In step S 60 , MIN and MAX band Nos. are set in the memory development information storage area  13 , and the flow advances to step S 61 . 
     In step S 61 , a command No. is read from a command, and is set in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 62 . 
     In step S 62 , the number of data is read from the command, and is set as the number of data in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 63 . 
     In step S 63 , a line value parameter is read from the command, and the flow advances to step S 64 . 
     In step S 64 , the read line width value is converted into a pixel (dot) value on the basis of the resolution of the image processing apparatus, and the flow advances to step S 65 . 
     In step S 65 , the converted line width value is set in an internal variable L WIDTH , and the flow advances to step S 66 . 
     In step S 66 , the converted line width value is set in the memory development information storage area  13  to advance a pointer, and the process ends. 
     In this manner, the line width designation command is analyzed, and memory development information for line width designation is generated. 
     FIG. 46 is a flow chart showing the details of a process upon execution of a clip area designation command analysis function in step S 34  in FIG.  40 . 
     In step S 70 , MIN and MAX band Nos. are set in the memory development information storage area  13 , and the flow advances to step S 71 . 
     In step S 71 , a command No. is read from a command, and is set in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 72 . 
     In step S 72 , the number of data is read from the command, and is set as the number of data in the memory development information storage area  13  to advance a pointer. The flow advances to step S 73 . 
     In step S 73 , X and Y MIN and MAX value parameters of a clip area are read from the command, and the flow advances to step S 74 . 
     In step S 74 , the read X and Y MIN and MAX values are converted into values X MIN , Y MIN , X MAX  and Y MAX  on the printer coordinate system on the basis of the resolution of the image processing apparatus, and the flow advances to step S 75 . 
     In step S 75 , the values X MIN , Y MIN , X MAX , and Y MAX  are respectively set in C XMIN , C YMIN , C XMAX , and C YMAX , and the flow advances to step S 76 . 
     In step S 76 , the value s X MIN , Y MIN , X MAX , and Y MAX  are set in the memory development information storage area  13  to advance a pointer, and the process ends. 
     In this manner, the clip area designation command is analyzed, and memory development information for clip area designation is generated. 
     FIG. 47 is a flow chart showing the details of a process upon execution of a paint definition designation command analysis function in step S 34  in FIG.  40 . 
     In step S 80 , MIN and MAX band Nos. are set in the memory development information storage area  13 , and the flow advances to step S 81 . 
     In step S 81 , a command No. is read from a command, and is set in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 82 . 
     In step S 82 , the number of data is read from the command, and is set as the number of data in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 83 . 
     In step S 83 , a paint pattern No. is read from the command, and is set in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 84 . 
     In step S 84 , an outline flag is read from the command, and is set in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 85 . 
     In step S 85 , the paint pattern No. is set in an internal variable F PAT , and the flow advances to step S 86 . 
     In step S 86 , the content of the outline flag is set in an internal variable F PERMT , and the process ends. 
     In this manner, the paint definition designation command is analyzed, and memory development information for paint definition designation is generated. 
     FIG. 48 is a flow chart showing the details of a process upon execution of a drawing logic designation command analysis function in step S 34  in FIG.  40 . 
     In step S 100 , MIN and MAX band Nos. are set in the memory development information storage area  13 , and the flow advances to step S 101 . 
     In step S 101 , a command No. is read from a command, and is set in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 102 . 
     In step S 102 , the number of data is read from the command, and is set as the number of data in the memory development information storage area  13  to advance a pointer. The flow then advances to step S 103 . 
     In step S 103 , a drawing logic parameter is read from the command, and the flow advances to step S 104 . 
     In step S 104 , the drawing logic is set in the memory development information storage area  13  to advance a pointer, and the process ends. 
     In this manner, the drawing logic designation command is analyzed, and memory development information for drawing logic designation is generated. 
     FIG. 49 is a flow chart showing the details of the process for setting the MIN and MAX band Nos. in the memory development information storage area in steps S 40 , S 60 , S 70 , S 80 , and S 100  in FIGS. 41 to  48 . 
     In step S 90 , “0” is set in the MIN band No., and the flow advances to step S 91 . 
     In step S 91 , the MIN band No. is set in the memory development information storage area  13  to advance a pointer, and the flow advances to step S 92 . 
     In step S 92 , information of the present number of bands is taken out of the band information storage  5 , and the flow advances to step S 93 . 
     In step S 93 , a value (the number of bands−1) is set in the MAX band No., and the flow advances to step S 94 . 
     In step S 94 , the MAX band No. is set in the memory development information storage area  13  to advance a pointer, and the process ends. 
     In this manner, in memory development information for a drawing attribute, “0” is set in the MIN band No., and the value (the number of bands−1) is set in the MAX band No., so that memory development information is analyzed in a process of each band. 
     FIG. 50 is a diagram showing an example of a color reproduction process in steps S 701  and S 705  in FIG.  43 . 
     In process  1 , a density conversion process for LOG-converting R, B, and B values as brightness information into C, M, and Y as density information is performed. 
     In process  2 , a Bk extraction process for extracting a value Bk from the C, M, and Y values is performed. 
     In process  3 , a masking process for correcting unnecessary absorption characteristics of C, M, and Y toners or inks to achieve proper color reproduction is performed. 
     In process  4 , a γ conversion process is performed so as to adjust the contrast and brightness in correspondence with an image. 
     The above-mentioned processes are performed in the color reproduction processor  8  using information from the color reproduction information storage  7 . 
     Assume that the mutual conversion method of the above-mentioned R, G, and B data with CIE XYZ data is predetermined in advance. 
     FIG. 51 shows an example of the color conversion process in steps S 703  and S 713  in FIGS. 43 and 44. 
     CIE L*, a*, and b* data can be converted into CIE XYZ data by equations (a) to (d). 
     In FIG. 51, Xn, Yn, and Zn are values determined depending on a CIE standard source. 
     FIG. 52 shows an example of the color conversion process in steps S 704  and S 714  in FIGS. 43 and 44. 
     CIE XYZ data can be converted into R, G, and B brightness data by a matrix conversion formula shown in FIG.  52 . 
     In FIG. 52, parameter values of the matrix are determined depending on a CIE standard source, and the values of this embodiment are those obtained when the CIE standard source D 65  is used. 
     FIG. 53 is a flow chart showing the details of the color conversion process in steps S 711  and S 715  in FIG.  44 . 
     In step S 720 , an R brightness data value is multiplied with 0.289659, and the product is set in R′. The flow then advances to step S 721 . 
     In step S 721 , a G brightness data value is multiplied with 0.605936, and the product is set in G′. The flow advances to step S 722 . 
     In step S 722 , a B brightness data value is multiplied with 0.104665, and the product is set in B′. The flow then advances to step S 723 . 
     In step S 723 , a sum of R′+G′+B′ is set in gray, and the flow advances to step S 724 . 
     In step S 724 , gray is converted by the same density conversion as in process  1  in FIG. 50, and the converted value is set in Gray, thus ending the process. 
     FIGS. 54 to  56  are flow charts showing a process upon execution of a straight line drawing command analysis function in step S 34  in FIG.  40 . 
     In step S 600 , data is set in a work area, and X MIN , Y MIN , X MAX , and Y MAX  are set. The flow advances to step S 601 . 
     In step S 601 , a drawing range is computed (straight line and polygon), and the flow advances to step S 602 . 
     In step S 602 , a clip check process of a drawing range is performed, and the flow advances to step S 603 . 
     In step S 603 , a drawing range flag set in the clip check process of the drawing range is checked. 
     If the drawing range flag is ERROR, the process ends. 
     However, if the drawing range flag is not ERROR, the flow advances to step S 604  to compute MIN and MAX band Nos., and the flow then advances to step S 605 . 
     In step S 605 , pointer  1  is placed in the memory development information storage area  13 , and the flow advances to step S 606 . 
     In step S 606 , the MIN and MAX band Nos. are set in the memory development information storage area  13  to advance pointer  1 , and the flow advances to step S 607 . 
     In step S 607 , pointer  2  is placed at the first position of a work area, and the flow advances to step S 608 . 
     In step S 608 , a command No. is taken out of the work area, and is set in the memory development information storage area  13 . The flow then advances to step S 609 . 
     In step S 609 , pointer  1  and pointer  2  are advanced, and the flow advances to step S 610 . 
     In step S 610 , the number of data is taken out of the work area, and is set in the memory development information storage area  13 . Thereafter, the flow advances to step S 611 . 
     In step S 611 , “1” is set in m, and the flow advances to step S 612 . 
     In step S 612 , X m  and Y m  are taken out of the work area, and are set in the memory development information storage area  13 . The flow then advances to step S 613 . 
     In step S 613 , m and n (the number of coordinates) are compared with each other. 
     If m≧n, the process ends. 
     If n&gt;m, the flow advances to step S 614 , and m is incremented by 1. The flow then advances to step S 615 . 
     In step S 615 , pointer  1  and pointer  2  are advanced, and the flow returns to step S 612 . 
     In this manner, the straight line drawing command is analyzed, and memory development information for straight line drawing is generated. 
     FIGS. 57 to  59  are flow charts showing a process upon execution of a polygon drawing command analysis function in step S 34  in FIG.  40 . 
     In step S 120 , data is set in a work area, and X MIN , Y MIN , X MAX , and Y MAX  are set. The flow advances to step S 121 . 
     In step S 121 , a drawing range is computed (straight line and polygon), and the flow advances to step S 122 . 
     In step S 122 , a clip check process of the drawing range is performed, and the flow advances to step S 123 . 
     In step S 123 , a drawing range flag set in the clip check process of the drawing range is checked. 
     If the drawing range flag is ERROR, the process ends. 
     If the drawing range flag is not ERROR, the flow advances to step S 124  to compute MIN and MAX band Nos., and the flow advances to step S 125 . 
     In step S 125 , pointer  1  is placed in the memory development information storage area  13 , and the flow advances to step S 126 . 
     In step S 126 , the MIN and MAX band Nos. are set in the memory development information storage area  13  to advance pointer  1 , and the flow advances to step S 127 . 
     In step S 127 , pointer  2  is placed at the first position of the work area, and the flow advances to step S 128 . 
     In step S 128 , a command No. is taken out of the work area, and is set in the memory development information storage area  13 . Thereafter, the flow advances to step S 129 . 
     In step S 129 , pointer  1  and pointer  2  are advanced, and the flow advances to step S 130 . 
     In step S 130 , the number of data is taken out of the work area, and (the number of data+2) is set in the memory development information storage area  13 . The flow then advances to step S 131 . 
     In step S 131 , “1” is set in m, and the flow advances to step S 132 . 
     In step S 132 , X m  and Y m  are taken out of the work area, and are set in the memory development information storage area  13 . The flow then advances to step S 133 . 
     In step S 133 , m and n (the number of coordinates) are compared with each other. 
     If n&gt;m, the flow advances to step S 134 , and m is incremented by 1. Thereafter, the flow advances to step S 135 . 
     In step S 135 , pointer  1  and pointer  2  are advanced, and the flow returns to step S 132 . 
     If m≧n, the flow advances to step S 136 . 
     In step S 136 , pointer  2  is placed at the first position of the work area, and the flow advances to step S 137 . 
     In step S 137 , pointer  2  is advanced by two, and is set in X 1 . The flow then advances to step S 138 . 
     In step S 138 , X 1  and Y 1  are taken out of the work area, and are set in the memory development information storage area  13 , thus ending the process. 
     In this manner, the polygon drawing command is analyzed, and memory development information for polygon drawing is generated. 
     FIGS. 60 to  62  are flow charts showing the details of the process for setting data in the work area, and setting X MIN , Y MIN , X MAX , and Y MAX  in step S 600  in FIG. 54, and step S 120  in FIG.  57 . 
     In step S 150 , a pointer is placed at the first position of the work area, and the flow advances to step S 151 . 
     In step S 151 , a command No. is read, and is set in the work area to advance the pointer. The flow then advances to step S 152 . 
     In step S 152 , the number of data is read, and is set in the work area to advance the pointer. The flow then advances to step S 153 . 
     In step S 153 , (the number of data)/2 (the number of coordinate points of a straight line) is set in a constant n, and the flow advances to step S 154 . 
     In step S 154 , X and Y coordinates of coordinate  1  are read, and the flow advances to step S 155 . 
     In step S 155 , the X and Y coordinates of coordinate  1  are converted into printer coordinates, and are respectively set in X 1  and Y 1 . Thereafter, the flow advances to step S 156 . 
     In step S 156 , X 1  is set in X MIN  and X MAX , and Y 1  is set in Y MIN  and Y MAX . The flow then advances to step S 157 . 
     In step S 157 , X 1  and Y 1  are set in the work area to advance the pointer, and the flow advances to step S 158 . 
     In step S 158 , “1” is set in m, and the flow advances to step S 159 . 
     In step S 159 , m and n (the number of coordinates) are compared with each other. 
     If m≧n, the process ends. 
     If n&gt;m, the flow advances to step S 160  to increment m by 1, and the flow advances to step S 161 . 
     In step S 161 , X and Y coordinates of coordinate m are read, and the flow advances to step S 162 . 
     In step S 162 , the X and Y coordinates of coordinate m are converted into printer coordinates, and are set in X m  and Y m . The flow then advances to step S 163 . 
     In step S 163 , the values X m  and X MIN  are compared with each other. 
     If X m ≧X MIN , the flow advances to step S 165 . 
     If X MIN &gt;X m , the flow advances to step S 164  to set the value X m  in X MIN , and the flow advances to step S 165 . 
     In step S 165 , the values X m  and X MAX  are compared with each other. 
     If X MAX ≧X m , the flow advances to step S 167 . 
     If X m &gt;X MAX , the flow advances to step S 166  to set the value X m  in X MAX , and the flow advances to step S 167 . 
     In step S 167 , the values Y m  and Y MIN  are compared with each other. 
     If Y m ≧Y MIN , the flow advances to step S 169 . 
     If Y MIN &gt;Y m , the flow advances to step S 168  to set the value Y m  in Y MIN , and the flow advances to step S 169 . 
     In step S 169 , the values Y m  and Y MAX  are compared with each other. 
     If Y MAX ≧Y m , the flow advances to step S 171 . 
     If Y m &gt;Y MAX , the flow advances to step S 170  to set the value Y m  in Y MAX , and the flow advances to step S 171 . 
     In step S 171 , X m  and Y m  are set in the work area to advance the pointer, and the flow returns to step S 159 . 
     In this manner, data can be set in the work area, and X MIN , Y MIN , X MAX , and Y MAX  can be set. 
     FIGS. 63 to  66  are flow charts showing a process upon execution of a character drawing command analysis function in step S 34  in FIG.  40 . 
     In step S 210 , a pointer is placed at the first position of the work area, and the flow advances to step S 211 . 
     In step S 211 , a command No. is read, and is set in the work area to advance the pointer. The flow then advances to step S 212 . 
     In step S 212 , the number of data is read, and the flow advances to step S 213 . 
     In step S 213 , X and Y coordinates of a drawing position are read, and the flow advances to step S 214 . 
     In step S 214 , the X and Y coordinates of the drawing position are converted into printer coordinates, and are set in X r  and Y r . Thereafter, the flow advances to step S 215 . 
     In step S 215 , character data is read from the command, and is converted into an internal code. The flow then advances to step S 216 . 
     In step S 216 , (the number of data of the internal code)+2 is set as the number of data in the work area to advance the pointer, and the flow advances to step S 217 . 
     In step S 217 , X r  and Y r  are set in the work area to advance the pointer, and the flow advances to step S 218 . 
     In step S 218 , the internal code is set in the work area, and the flow advances to step S 219 . 
     In step S 219 , a drawing range of a character is computed, and the flow advances to step S 220 . 
     In step S 220 , a clip check process of the drawing range is performed, and the flow advances to step S 221 . 
     In step S 221 , a drawing range flag set in the clip check process of the drawing range is checked. 
     If the drawing range flag is ERROR, the process ends. 
     If the drawing range flag is not ERROR, the flow advances to step S 222  to compute MIN and MAX band Nos., and the flow then advances to step S 223 . 
     In step S 223 , pointer  1  is placed in the memory development information storage area  13 , and the flow advances to step S 224 . 
     In step S 224 , the MIN and MAX band Nos. are set in the memory development information storage area  13  to advance pointer  1 , and the flow advances to step S 225 . 
     In step S 225 , pointer  2  is placed at the first position of the work area, and the flow advances to step S 226 . 
     In step S 226 , a command No. is taken out of the work area, and is set in the memory development information storage area  13 . The flow then advances to step S 227 . 
     In step S 227 , pointer  1  and pointer  2  are advanced, and the flow advances to step S 228 . 
     In step S 228 , the number of data is taken out of the work area, and is set in the memory development information storage area  13 . Thereafter, the flow advances to step S 229 . 
     In step S 229 , pointer  1  and pointer  2  are advanced, and the flow advances to step S 230 . 
     In step S 230 , X r  and Y r  are taken out of the work area, and are set in the memory development information storage area  13 . The flow then advances to step S 231 . 
     In step S 231 , pointer  1  and pointer  2  are advanced, and the flow advances to step S 232 . 
     In step S 232 , the internal code is taken out of the work area, and is set in the memory development information storage area  13 , thus ending the process. 
     In this manner, the character drawing command is analyzed, and memory development information for character drawing is generated. 
     FIG. 67 is a flow chart showing the details of the process for computing the drawing range (straight line and polygon) in step S 601  in FIG.  54  and step S 121  in FIG.  57 . 
     In step S 240 , X MIN  is set in P XMIN , and X MAX  is set in P XMAX . The flow then advances to step S 241 . 
     In step S 241 , Y MIN  is set in P YMIN , and Y MAX  is set in P YMAX . The flow then advances to step S 242 . 
     In step S 242 , α (a constant equal to or larger than 0) is added to L WIDTH /2, and the sum is set in β. The flow then advances to step S 243 . 
     In step S 243 , P XMIN −β is set in P XMIN , and P XMAX +β is set in P XMAX . Thereafter, the flow advances to step S 244 . 
     In step S 244 , P YMIN −β is set in P YMIN , and P YMAX +β is set in P YMAX , thus ending the process. 
     In this manner, the drawing range of a straight line or a polygon can be computed. 
     FIG. 68 shows a drawing range of a polygon designated by four points (x 1 , y 1 ) to (x 4 , y 4 ). 
     This range is a rectangular area surrounded by (P XMIN , P YMIN ) and (P XMAX , P YMAX ), and corresponds to a computation result obtained when the value α is set to be “0” in the process shown in FIG.  67 . 
     FIG. 69 is a flow chart showing the details of the process for computing the character drawing range in step S 219  in FIG.  64 . 
     In step S 260 , left and top offset values are taken out from the character information storage  9  (FIG.  24 A and  24 B), and the flow advances to step S 261 . 
     In step S 261 , the left offset value is set in α 1 , and the top offset value is set in α 2 . The flow then advances to step S 262 . 
     In step S 262 , X r +α 1  is set in P XMIN , and Y r −α 2  is set in P YMIN . The flow then advances to step S 263 . 
     In step S 263 , a pattern width and a pattern height are taken out of the character information storage  9 , and the flow advances to step S 264 . 
     In step S 264 , the pattern width is set in β 1 , and the pattern height is set in β 2 . The flow advances to step S 265 . 
     In step S 265 , P XMIN +β 1  is set in P XMAX , and P YMIN +β 2  is set in P YMAX , thus ending the process. 
     In this manner, a drawing range of a character can be computed. 
     FIG. 70 shows a character drawing range. 
     This range is a rectangular area surrounded by (P XMIN , P YMIN ) and (P XMAX , P YMAX ) 
     FIGS. 71 and 72 are flow charts showing the details of the clip check process of the drawing range in step S 602  in FIG. 54, S 122  in FIG. 57, and step S 220  in FIG.  64 . 
     In step S 270 , values P XMAX  and C XMIN  are compared with each other. 
     If C XMIN &gt;P XMAX , the flow advances to step S 274 , and ERROR is set in the drawing range flag, thus ending the process. 
     Otherwise, the flow advances to step S 271 . 
     In step S 271 , values P XMIN  and C XMAX  are compared with each other. 
     If P XMIN &gt;C XMIX , the flow advances to step S 274 , and ERROR is set in the drawing range flag, thus ending the process. 
     Otherwise, the flow advances to step S 272 . 
     In step S 272 , values P YMAX  and C YMIN  are compared with each other. 
     If C YMIN &gt;P YMAX , the flow advances to step S 274 , and ERROR is set in the drawing range flag, thus ending the process. 
     Otherwise, the flow advances to step S 273 . 
     In step S 273 , values P YMIN  and C YMAX  are compared with each other. 
     If P YMIN &gt;C YMAX , the flow advances to step S 274 , and ERROR is set in the drawing range flag, thus ending the process. 
     Otherwise, the flow advances to step S 275 . 
     In step S 275 , values P XMIN  and C XMIN  are compared with each other. 
     If C XMIN &gt;P XMIN , the flow advances to step S 276  to set the value C XMIN  in P XMIN , and the flow advances to step S 277 . 
     Otherwise, the flow advances to step S 277 . 
     In step S 277 , values P YMIN  and C YMIN  are compared with each other. 
     If C YMIN &gt;P YMIN , the flow advances to step S 278  to set the value C YMIN  in P YMIN , and the flow advances to step S 279 . 
     Otherwise, the flow advances to step S 279 . 
     In step S 279 , values P XMAX  and C XMAX  are compared with each other. 
     If P XMAX &gt;C XMAX , the flow advances to step S 280  to set the value C XMAX  in P XMAX , and the flow advances to step S 281 . 
     Otherwise, the flow advances to step S 281 . 
     In step S 281 , values P YMAX  and C YMAX  are compared with each other. 
     If P YMAX &gt;C YMAX , the flow advances to step S 282  to set the value C YMAX  in P YMAX , and the flow advances to step S 283 . 
     Otherwise, the flow advances to step S 283 . 
     In step S 283 , OK is set in the drawing range flag, thus ending the process. 
     In this manner, a common range between the drawing range and a clip area can be obtained. 
     FIG. 73 shows a case wherein a clip area of a rectangular area surrounded by (C XMIN , C YMIN ) and (C XMAX , C YMAX ) is set for a drawing range of a rectangular area surrounded by (P XMIN , P YMIN ) and (P XMAX , P YMAX ). 
     With the processes in FIGS. 71 and 72, the drawing range shown in FIG. 68 becomes a rectangular area surrounded by (C XMIN , C YMIN ) and (C XMAX , C YMAX ). 
     FIG. 74 is a flow chart showing the details of the process for computing the MIN and MAX band Nos. in step S 604  in FIG. 55, step S 124  in FIG. 58, and step S 222  in FIG.  65 . 
     In step S 380 , a band height (the height of one band) is taken out of the band information storage  5 , and the flow advances to step S 381 . 
     In step S 381 , the band height is set in h, and the flow advances to step S 382 . 
     In step S 382 , P YMIN  and P YMAX  are taken out of drawing range information, and the flow advances to step S 383 . 
     In step S 383 , a quotient of (P YMIN /h) is set in the MIN band No., and the flow advances to step S 384 . 
     In step S 384 , a quotient of (P YMAX /h) is set in the MAX band No., and the process ends. 
     In this manner, the MIN and MAX band Nos. can be computed from the drawing range information. 
     FIGS. 75A and 75B show examples of memory development information for color designation (line, paint, character) generated by analyzing the color designation command shown in FIG. 35 on the basis of the flow charts shown in FIGS. 41 and 42. 
     FIG. 75A shows an example of memory development information for color designation in the color mode, and FIG. 75B shows an example of memory development information for color designation in the monochrome mode. 
     In FIGS. 75A and 75B, a command table No. varies depending on color designation memory development information, and is used for identifying each command. 
     In FIGS. 75A and 75B, the content of a number-of-data parameter is  4 . 
     In FIG. 75A, Y, M, C, and Bk values are density data values of Y (Yellow), M (Magenta), C (Cyan), and Bk (Black) as primary colors of coloring materials (toners or inks). As can be seen from FIG. 75A, even when a color designation command includes color designation data values of a different type, the color designation data values are converted into Y, M, C, and Bk density values upon generation of memory development information after analysis. 
     In FIG. 75B, a gray scale density value is a Bk (Black) density data value. As can be seen from FIG. 75B, even when a color designation command includes a color designation data value of a different type, the color designation data value is converted into the Bk density data value, and is set at the storage position of the Y density data value. In addition, “0” is set at the storage positions of the M, C, and Bk density data values. 
     FIG. 76A shows an example of memory development information generated by analyzing the line width designation command shown in FIG. 36A on the basis of the flow chart of FIG. 45, FIG. 76B shows an example of memory development information generated by analyzing the clip area designation command shown in FIG. 36B on the basis of the flow chart of FIG. 46, FIG. 76C shows an example of memory development information generated by analyzing the paint definition designation command shown in FIG. 36C on the basis of the flow chart of FIG. 47, and FIG. 76D shows an example of memory development information generated by analyzing the drawing logic designation command shown in FIG. 36D on the basis of the flow chart of FIG.  48 . 
     In FIGS. 76A to  76 D, a command table No. varies depending on memory development information, and is used for identifying each command. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     FIG. 77A shows an example of memory development information generated by analyzing the straight line drawing command shown in FIG. 37 on the basis of the flow charts of FIGS. 54 to  56 , and FIG. 77B shows an example of memory development information generated by analyzing the polygon drawing command shown in FIG. 37 on the basis of the flow charts of FIGS. 57 to  59 . 
     In FIGS. 77A and 77B, a command table No. varies depending on memory development information, and is used for identifying each command. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     Since the last parameters in the memory development information for polygon drawing represent a start point (a polygon is closed by returning to the start point), X 1  and Y 1  are set, as shown in FIG.  77 B. 
     FIG. 78 shows an example of memory development information generated by analyzing the character drawing command shown in FIG. 38 on the basis of the flow charts of FIGS. 63 to  66 . 
     In FIG. 78, a command table No. varies depending on memory development information, and is used for identifying each command. 
     The content of a number-of-data parameter indicates the number of data following the number-of-data parameter. 
     FIG. 79 shows a case wherein one page is divided into four bands, and drawing is performed using Y, M, C, and Bk band memories each having a size corresponding to one band, and using some drawing attribute commands and some drawing commands shown in FIGS. 35A to  38 . 
     Assume that drawing is performed in the order of a polygon and a character. 
     Assume that a polygon is set with an inside paint attribute, is not set with an outline attribute, and the paint color is magenta. 
     Assume that the inside paint color of a character is yellow. 
     FIGS. 80 and 81 show memory development information used in drawing shown in FIG.  79 . 
     In FIGS. 80 and 81, a required number of information are arranged in an order to be analyzed, which order is the same as a reception order of commands. 
     Note that a drawing logic designation value “0” in memory development information for drawing logic designation indicates that a drawing logic is “overwrite”. 
     As shown in FIGS. 80 and 81, as for memory development information for drawing attributes, “0” is set in the MIN band No., and “3” is set in the MAX band No., so that the drawing attributes are analyzed in all bands. 
     If this is not done, drawing attribute information must be added to memory development information of each drawing command, resulting in a large data amount of memory development information. 
     In memory development information of each drawing command, a minimum band No. where a drawing range is present is set in the MIN band No., and a maximum band No. where the drawing range is present is set in the MAX band No. 
     For example, “0” is set in the MIN band No. in memory development information of a polygon drawing command, and “1” is set in its MAX band No. 
     FIG. 82 shows a case wherein one page is divided into four bands, and drawing is performed using Y, M, C, and Bk band memories each having a size corresponding to one band, while setting clip area designation to straight line drawing. 
     Assume that a line color of a straight line is red (M=100%, Y=100%). 
     FIG. 83 shows memory development information used in drawing shown in FIG.  82 . 
     In FIG. 83, a required number of information are arranged in an order to be analyzed, which order is the same as a reception order of commands. 
     A drawing range for straight line drawing extends from band  0  to band  3  with the process in FIG. 67 if the clip area is not taken into consideration. 
     If the clip area is taken into consideration, the drawing range extends from band  1  to band  2  with the processes in FIGS. 71 and 72. 
     Therefore, in memory development information of the straight line drawing command, “1” is set in the MIN band No., and “2” is set in the MAX band No. 
     FIG. 84 shows a command execution jump table  1  (ROM), which stores jump addresses to functions for actually performing pattern development of a drawing on a memory, and jump addresses to functions for designating drawing attributes (setting attributes in internal variables). 
     Jump addresses are stored in correspondence with command Nos. (0 to n). 
     FIG. 85 shows a command execution jump table  2  (ROM) in which all jump addresses to functions for performing pattern development of a drawing onto a memory are replaced with jump addresses to skip functions in FIG.  84 . 
     Like in FIG. 84, jump addresses are stored in correspondence with command Nos. (0 to n). 
     FIG. 86 is a flow chart showing the details of the process in step S 12  in FIG.  33 . 
     In step S 390 , a drawable range is set in consideration of a clip range (a rectangular area for setting a drawable range of a figure, a character, or the like), and the flow advances to step S 391 . 
     In step S 391 , the header addresses of Y, M, C, and Bk virtual page memories are computed and set, and the flow advances to step S 392 . 
     In step S 392 , MIN and MAX band No. values in memory development information are read, and a pointer is advanced to the next data. Thereafter, the flow advances to step S 393 . 
     In step S 393 , a command No. is read, and the flow advances to step S 394 . 
     In step S 394 , it is checked if MIN band No.≦(present band No.)≦MAX band No. is satisfied. 
     If YES in step S 394 , the flow advances to step S 395 , and a pointer is placed at the first position of the command execution jump table shown in FIG.  84 . The flow then advances to step S 397 . 
     If NO in step S 394 , the flow advances to step S 396 , and a pointer is placed at the first position of the command jump table  2  shown in FIG.  85 . The flow then advances to step S 397 . 
     In step S 397 , the pointer in the table is advanced by an amount corresponding to the command No., and the flow advances to step S 398 . 
     In step S 398 , the content (jump address) indicated by the pointer is taken, and the flow advances to step S 399 . 
     In step S 399 , a function indicated by the jump address is executed, thus ending the process. 
     FIG. 87 is a flow chart showing the details of the process in step S 390  in FIG.  86 . 
     In the following description, assume that the Y value of a drawing range, and the value of a clip area are values on the printer coordinate system. 
     In step S 400 , band height information [the height (the number of dots or the number of scan lines) of one band] is taken out of the band information storage  5 , and the flow advances to step S 401 . 
     In step S 401 , a value (the band height)×i (present band No.) is set in a minimum Y value MINY of a drawable range, and the flow advances to step S 402 . 
     In step S 402 , a value (i+1) is compared with the number of bands. 
     If the number of bands is larger than the value (i+1), the flow advances to step S 403 , and a value (the band height)×(i+1)−1 is set in a maximum Y value MAXY of the drawable range. Thereafter, the flow advances to step S 405 . 
     Otherwise, the flow advances to step S 404 , and a maximum Y value of an effective print area of a print sheet is set in the maximum Y value MAXY of the drawable range. Thereafter, the flow advances to step S 405 . 
     In step S 405 , a minimum Y value D SPYMI  and a maximum Y value D SPYMX  are taken out of information of a clip area (a rectangular area for setting a drawable range of a figure, a character, or the like), and the flow advances to step S 406 . 
     In step S 406 , MINY and D SPYMI  are compared with each other. 
     If MINY&gt;D SPYMI , the flow advances to step S 407 , and the value MINY is set in D SPYMI . The flow then advances to step S 408 . 
     Otherwise, the flow directly advances to step S 408 . 
     In step S 408 , MAXY and D SPYMX  are compared with each other. 
     If D SPYMX &gt;MAXY, the flow advances to step S 409 , an d the value MAXY is set in D SPYMX , thus ending the process. 
     Otherwise, the process ends. 
     An actual drawable range of a figure, a character, or the like used upon band memory development uses D SPYMI  and D SPYMX  set in this flow. 
     FIG. 88 shows printer coordinates set when the band height=512 dots. 
     In this case, as shown in FIG. 88, the value MINY of band 0 is “0”, and its value MAXY is “511”. The value MINY of band 1 is “512”, and its value MAXY is “1,023”. 
     FIG. 89 shows a case wherein a clip area satisfying D SPYMI &lt;MINY and MAXY&lt;D SPYMX  is set for a drawable range of a figure, a character, or the like when band No.=i. 
     In this case, an actual drawable range of a figure, a character, or the like used in development on each band memory whose band No. corresponds to i is a hatched portion in FIG. 89 according to the above-mentioned process. 
     In FIG. 89, D SPXMI  and D SPXMX  are minimum and maximum X values of a clip area. 
     FIG. 90 is a flow chart showing the details of the process in step S 391  in FIG.  86 . 
     In step S 740 , it is checked if the color mode is set. 
     If YES in step S 740 , the flow advances to step S 741  to take information X_BANDADR (X=Y, M, C, K) of header addresses of Y, M, C, and Bk band memories out of the band information storage  5 , and the flow then advances to step S 742 . 
     In step S 742 , information of a band memory capacity (bytes) is taken out of the band information storage  5 , and the flow advances to step S 743 . 
     In step S 743 , header addresses X_TOPADR (X=Y, M, C, K) of Y, M, C, and Bk virtual page memories are calculated by computing X_BANDADR (X=Y, M, C, K)−(band memory capacity)×i (present band No.), thus ending the process. 
     If it is determined in step S 740  that the color mode is not set, the flow advances to step S 744  to take information K_BANDADR of a header address of a Bk band memory out of the band information storage  5 , and the flow then advances to step S 745 . 
     In step S 745 , information of a band memory capacity (bytes) is taken out of the band information storage  5 , and the flow advances to step S 746 . 
     In step S 746 , the header address of each Bk virtual page memory is obtained by computing K_BANDADR−(band memory capacity)×i (present band No.), and is set in Y_TOPADR, thus ending the process. 
     FIG. 91 shows the header addresses of Y, M, C, and Bk virtual page memories when a drawing is developed on the fifth band (band No.=4) in FIG. 28 in the color mode. 
     The addresses shown in FIG. 91 are obtained by the process shown in FIG.  90 . 
     FIG. 92 shows the header address of each Bk virtual page memory when a drawing is developed on the fifth band (band No.=4) in FIG. 28 in the monochrome mode. 
     The addresses shown in FIG. 92 are obtained by the process shown in FIG.  90 . 
     FIG. 93 is a flow chart showing a process upon execution of a line width designation function in step S 399  in FIG.  86 . 
     In step S 410 , a line width value is read from memory development information for line width designation, and the flow advances to step S 411 . 
     In step S 411 , the line width value is set in a variable L WIDTH  as line width information used in development of a drawing pattern on a memory upon execution of a drawing function, thus ending the process. 
     FIG. 94 is a flow chart showing a process upon execution of a line color designation function in step S 399  in FIG.  86 . 
     In step S 420 , Y, M, C, and Bk values of a line color are read from memory development information for line color designation, and the flow advances to step S 421 . 
     In step S 421 , the Y, M, C, and Bk values are set in a variable L YMCK  as line color information used in development of a drawing pattern on a memory upon execution of a drawing function, thus ending the process. 
     FIG. 95 is a flow chart showing a process upon execution of a paint color designation function in step S 399  in FIG.  86 . 
     In step S 430 , Y, M, C, and Bk values of a paint color are read from memory development information for paint color designation, and the flow advances to step S 431 . 
     In step S 431 , the Y, M, C, and Bk values are set in a variable F YMCK  as paint color information used in development of a drawing pattern on a memory upon execution of a drawing function, thus ending the process. 
     FIG. 96 is a flow chart showing a process upon execution of a character color designation function in step S 399  in FIG.  86 . 
     In step S 440 , Y, M, C, and Bk values of a character color are read from memory development information for character color designation, and the flow advances to step S 441 . 
     In step S 441 , the Y, M, C, and Bk values are set in a variable T YMCK  as character color information used in development of a character pattern on a memory upon execution of a character drawing function, thus ending the process. 
     FIG. 97 is a flow chart showing a process upon execution of a clip area color designation function in step S 399  in FIG.  86 . 
     In step S 450 , values X MIN , Y MIN , X MAX , and Y MAX  of a clip area are read from memory development information for clip area designation, and the flow advances to step S 451 . 
     In step S 451 , the values X MIN , Y MIN , X MAX , and Y MAX  are respectively set in variables D SPXMI , D SPYMI , D SPXMX , and D SPYMX  as clip area information used in development of a drawing pattern on a memory upon execution of a drawing function, and the flow then advances to step S 452 . 
     In step S 452 , values MINY and MAXY (on the printer coordinate system) of a drawing range of a band corresponding to band No. i are taken out of the band information storage  5 , and the flow advances to step S 453 . 
     In step S 453 , MINY is compared with D SPYMI . 
     If MINY&gt;D SPYMI , the flow advances to step S 454  to set the value MINY in D SPYMI , and the flow advances to step S 455 . 
     Otherwise, the flow advances to step S 455 . 
     In step S 455 , MAXY is compared with D SPYMX . If D SPYMX &gt;MAXY, the flow advances to step S 456  to set the value MAXY in D SPYMX , thus ending the process. 
     Otherwise, the process ends directly. 
     FIG. 98 is a flow chart showing the process upon execution of a paint definition designation function in step S 399  in FIG.  86 . 
     In step S 460 , a paint pattern No. is read from memory development information for paint definition designation, and the flow advances to step S 461 . 
     In step S 461 , the paint pattern No. is set in a variable F PAT  as paint pattern information used in development of a drawing pattern onto a memory upon execution of a drawing function, and the flow then advances to step S 462 . 
     In step S 462 , an outline presence/absence flag value is read from the memory development information for paint definition designation, and the flow advances to step S 463 . 
     In step S 463 , the outline presence/absence flag value is set in a variable F PERMT  as outline presence/absence information used in development of a drawing pattern onto a memory upon execution of a drawing function, thus ending the process. 
     FIG. 99 is a flow chart showing the process upon execution of a drawing logic designation function in step S 399  in FIG.  86 . 
     In step S 730 , a drawing logic value is read from memory development information for drawing logic designation, and the flow advances to step S 731 . 
     In step S 731 , the drawing logic value is set in a variable L OGSTYL  as drawing logic information used in development of a drawing pattern onto a memory upon execution of a drawing function, thus ending the process. 
     FIGS. 100 and 101 are flow charts showing the process upon execution of a straight line drawing function in step S 399  in FIG.  86 . 
     In step S 470 , the number of data is read from memory development information for straight line drawing, and the flow advances to step S 471 . 
     In step S 471 , (the number of data)/2 (the number of coordinate points of a straight line) is set in a constant n, and the flow advances to step S 472 . 
     In step S 472 , the values of line color information L YMCK  are taken, and the flow advances to step S 473 . 
     In step S 473 , the Y value of L YMCK  is set in P_Y, the M value of L YMCK  is set in P_M, the C value of L YMCK  is set in P_C, and the Bk value of L YMCK  is set in P_Bk. Thereafter, the flow advances to step S 474 . 
     In step S 474 , dither patterns corresponding to the values P_Y, P_M, P_C, and P_Bk obtained in step S 473  are set, and the flow advances to step S 475 . 
     In step S 475 , a pointer for accessing a paint function is set at P GJMPTBL , and the flow advances to step S 476 . 
     In step S 476 , “1” is set in a constant m, and the flow advances to step S 477 . 
     In step S 477 , a point (X m , Y m ) on the printer coordinate system is read from the memory development information for straight line drawing, and the flow advances to step S 478 . 
     In step S 478 , a point (X m+1 , Y m+1 ) on the printer coordinate system is read from the memory development information for straight line drawing, and the flow advances to step S 479 . 
     In step S 479 , a straight line pattern between the two points (X m , Y m ) and (X m+1 , Y m+1 ) on the printer coordinate system is developed on each band memory, and the flow advances to step S 480 . 
     In step S 480 , n is compared with the value (m+1). 
     If n&gt;(m+1), the flow advances to step S 481  to increment m by 1, and the flow returns to step S 478 . 
     Otherwise, the process ends. 
     In this manner, a straight line drawing pattern can be developed on each band memory on the basis of the memory development information for straight line drawing, line color designation, line width designation, and drawing logic designation. 
     FIGS. 102 to  105  are flow charts showing the process upon execution of a polygon drawing function in step S 399  in FIG.  86 . 
     In step S 490 , the number of data is read from memory development information for polygon drawing, and the flow advances to step S 491 . 
     In step S 491 , (the number of data)/2 (the number of coordinate points of a polygon) is set in a constant n, and the flow advances to step S 492 . 
     In step S 492 , “1” is set in a constant m, and the flow advances to step S 493 . 
     In step S 493 , a point (X m , Y m ) on the printer coordinate system is read from the memory development information for polygon drawing, and the flow advances to step S 494 . 
     In step S 494 , the values X m  and Y m  are set in a storage area in the system work memory, and the flow advances to step S 495 . 
     In step S 495 , the values n and m are compared with each other. 
     If n&gt;m, the flow advances to step S 496  to increment m by 1, and the flow returns to step S 493 . 
     Otherwise, the flow advances to step S 497 . 
     In step S 497 , the value of paint pattern information F PAT  is compared with “0”. 
     If F PAT =0 the flow advances to step S 503 . 
     If F PAT ≠0, the flow advances to step S 498  to take values of paint color information F YMCK , and the flow then advances to step S 499 . 
     In step S 499 , the Y value of F YMCK  is set in P_Y, the M value of F YMCK  is set in P_M, the C value of F YMCK  is set in P_C, and the Bk value of F YMCK  is set in P_Bk. Thereafter, the flow advances to step S 500 . 
     In step S 500 , a pointer for accessing a paint function is set at P GJMPTBL , and the flow advances to step S 501 . 
     In step S 501 , dither patterns corresponding to the values P_Y, P_M, P_C, and P_Bk obtained in step S 499  are set, and the flow advances to step S 502 . 
     In step S 502 , a paint pattern of a polygon is developed on an area surrounded by outline points (X 1 , Y 1 ), . . . , (X n , Y n ), which are set in the storage area in the system work memory with the processes in steps S 492  to S 496 , on each band memory, and thereafter, the flow advances to step S 503 . 
     In step S 503 , a value of outline presence/absence information F PERMT  is compared with “0”. 
     If F PERMT =0, the process ends. 
     If F PERMT ≠0, the flow advances to step S 504  to take values of line color information L YMCK , and the flow advances to step S 505 . 
     In step S 505 , the Y value of L YMCK , is set in P_Y, the M value of L YMCK  is set in P_M, the C value of L YMCK  is set in P_C, and the Bk value of L YMCK  is set in P_Bk. Thereafter, the flow advances to step S 506 . 
     In step S 506 , dither patterns corresponding to the values P_Y, P_M, P_C, and P_Bk obtained in step S 505  are set, and the flow advances to step S 507 . 
     In step S 507 , a pointer for accessing a paint function is set at P GJMPTBL , and the flow advances to step S 508 . 
     In step S 508 , “1” is set in a constant m, and the flow advances to step S 509 . 
     In step S 509 , coordinates X m  and Y m  of an outline point of a polygon are taken out of the storage area in the system work memory, and the flow advances to step S 510 . 
     In step S 510 , coordinates X m+1  and Y m+1  of an outline point of the polygon are taken out of the storage area in the system work memory, and the flow advances to step S 511 . 
     In step S 511 , a straight line pattern between the two points (X m , Y m ) and (X m+1 , Y m+1 ) on the printer coordinate system is developed on each band memory, and the flow advances to step S 512 . 
     In step S 512 , n is compared with (m+1). 
     If n&gt;(m+1), the flow advances to step S 513  to increment m by 1, and the flow returns to step S 510 . 
     Otherwise, the process ends. 
     In this manner, a drawing pattern of a polygon can be developed on each band memory on the basis of memory development information for polygon drawing, paint definition designation, line color designation, paint color designation, and drawing logic designation. 
     FIGS. 106 and 107 are flow charts showing the process upon execution of a character drawing function in step S 399  in FIG.  86 . 
     In step S 520 , the number of data is read from memory development information for character drawing, and the flow advances to step S 521 . 
     In step S 521 , X and Y coordinates X r  and Y r  of a drawing position are read from the memory development information for character drawing, and the flow advances to step S 522 . In step S 522 , an internal code of a character is read from the memory development information for character drawing, and the flow advances to step S 523 . 
     In step S 523 , outline information (coordinate points) of the character to be printed is computed on the basis of values of X r , Y r , and the internal code, and the flow advances to step S 524 . 
     In step S 524 , the outline information including (X 1 , Y 1 ), . . . , (X n , Y n ) of the character computed in step S 523  is set in the storage area in the system work memory, and the flow advances to step S 525 . 
     In step S 525 , values of character color information T YMCK  are taken, and the flow advances to step S 526 . 
     In step S 526 , the Y value of T YMCK  is set in P_Y, the M value of T YMCK  is set in P_M, the C value of T YMCK  is set in P_C, and the Bk value of T YMCK  is set in P_Bk. Thereafter, the flow advances to step S 527 . 
     In step S 527 , dither patterns corresponding to the values P_Y, P_M, P_C, and P_Bk obtained in step S 526  are set, and the flow advances to step S 528 . 
     In step S 528 , a pointer for accessing a paint function is set at P GJMPTBL , and the flow advances to step S 529 . 
     In step S 529 , a character pattern is developed on each band memory on the basis of the outline information (X 1 , Y 1 ), . . . , (X n , Y n ) of the character in the storage area in the system work memory, thus ending the process. 
     In this manner, a character pattern can be developed on each band memory on the basis of memory development information for character drawing, character color designation, and drawing logic designation. 
     FIG. 108 is a flow chart showing the process upon execution of a skip function in step S 399  in FIG.  86 . 
     In step S 540 , the number of data is read from memory development information, and the flow advances to step S 541 . 
     In step S 541 , the number of data is set in a constant n, and the flow advances to step S 542 . 
     In step S 542 , “0” is set in a constant j, and the flow advances to step S 543 . 
     In step S 543 , a pointer is placed at data next to the number-of-data parameter, and the flow advances to step S 544 . 
     In step S 544 , data indicated by the pointer is read, and the flow advances to step S 545 . 
     In step S 545 , the constant j is incremented by 1, and the flow advances to step S 546 . 
     In step S 546 , the pointer is advanced to the next data, and the flow then advances to step S 547 . 
     In step S 547 , the constant j is compared with the number n of data. If the two values are not equal to each other, the flow returns to step S 544 . 
     If the two values are equal to each other, the process ends. 
     In this manner, memory development information for drawing can be skipped. 
     FIG. 109 shows an example of the dither pattern address table  21  in the dither pattern storage  20  shown in FIGS. 24A and 24B. 
     The dither pattern address table stores header addresses of areas which store dither patterns corresponding to Y, M, C, and Bk density values. 
     In this embodiment, each of the Y, M, C, and Bk density values ranges from 0 to 255. 
     The dither pattern address table includes four tables corresponding to Y, M, C, and Bk, respectively, and this means that different dither patterns may be used even when the Y, M, C, and Bk density values have the same value. 
     FIGS. 110A and 110B show an example of a dither pattern stored in the dither pattern storage  20  shown in FIGS. 24A and 24B. 
     FIG. 110A shows that a dither pattern has a size of 32 dots×32 dots, and has a memory capacity of 128 bytes. 
     FIG. 110B shows an example of a dither pattern when the Y, M, C, and Bk density values are 51 (dot portions=20%). 
     FIGS. 111 and 112 are flow charts showing the process in step S 474  in FIG. 100, step S 500  in FIG. 103, step S 506  in FIG. 104, and step S 527  in FIG.  107 . 
     It is checked in step S 800  if the color mode is set. 
     If NO in step S 800 , the flow advances to step S 801 , and a pointer is placed at the first position of an M dither pattern address table (FIG.  109 ). The flow then advances to step S 802 . 
     In step S 802 , the pointer is advanced by an amount corresponding to the value P_Y, and the flow advances to step S 803 . 
     In step S 803 , the content indicated by the pointer is set in Y DTOPAD , and the process ends. 
     If it is determined in step S 800  that the color mode is set, the flow advances to step S 804 , and a pointer is placed at the first position of a Y dither pattern address table (FIG.  109 ). Thereafter, the flow advances to step S 805 . 
     In step S 805 , the pointer is advanced by an amount corresponding to the value P_Y, and the flow advances to step S 806 . 
     In step S 806 , the content indicated by the pointer is set in Y DTOPAD , and the flow advances to step S 807 . 
     In step S 807 , a pointer is placed at the first position of an M dither pattern address table (FIG.  109 ). Thereafter, the flow advances to step S 808 . 
     In step S 808 , the pointer is advanced by an amount corresponding to the value P_M, and the flow advances to step S 809 . 
     In step S 809 , the content indicated by the pointer is set in M DTOPAD , and the flow advances to step S 810 . 
     In step S 810 , a pointer is placed at the first position of a C dither pattern address table (FIG.  109 ). Thereafter, the flow advances to step S 811 . 
     In step S 811 , the pointer is advanced by an amount corresponding to the value P_C, and the flow advances to step S 812 . 
     In step S 812 , the content indicated by the pointer is set in C DTOPAD , and the flow advances to step S 813 . 
     In step S 813 , a pointer is placed at the first position of a Bk dither pattern address table (FIG.  109 ). Thereafter, the flow advances to step S 814 . 
     In step S 814 , the pointer is advanced by an amount corresponding to the value P_Bk, and the flow advances to step S 815 . 
     In step S 815 , the content indicated by the pointer is set in K DTOPAD , and the process ends. 
     In this manner, the header addresses of the areas for storing dither patterns used in the paint process can be obtained in correspondence with the Y, M, C, and Bk density values, and can be set in variables. 
     In this embodiment, an M dither pattern is used as one used in the monochrome mode, and the header address of the storage area is set in the storage variable Y DTOPAD  of a Y dither pattern. 
     FIG. 113 shows an example of a table with a drawing logic of “overwrite” of the paint function address storage table  23  in the memory development table storage  22  shown in FIGS. 24A and 24B. 
     As shown in FIG. 113, this table stores jump addresses to paint functions onto development memories in units of Y, M, C, and Bk. 
     Note that the paint function is used for executing a paint process on a memory for one scan line. ◯, □, Δ, and ⋄ indicate jump addresses to clear paint functions onto development memories, and are respectively those for development onto Y, M, C, and Bk band memories. 
       ◯ ,  □ ,  Δ , and  ⋄  indicate jump addresses to overwrite paint functions onto development memories, and are respectively those for development onto Y, M, C, and Bk band memories. 
      indicates a jump address to an overwrite paint function onto a development memory in the monochrome mode. 
      indicates a jump address to a dummy process function. 
     The dummy process function is a function for executing no process. 
     In an overwrite process, if Y and C values of Y, M, C, and Bk density values are not “0”, and M and Bk values are “0”, portions to be painted by M and Bk must be cleared. 
     This is because the contents of the Y, M, C, and Bk memories are logically ORed, and the OR is printed on a print sheet. 
     FIG. 114 shows an example of a table with a drawing logic of “transparent” of the paint function address storage table  23  in the memory development table storage  22  shown in FIGS. 24A and 24B. 
     As shown in FIG. 114, this table stores jump addresses to paint functions onto development memories in units of Y, M, C, and Bk. 
     Note that the paint function is used for executing a paint process on a memory for one scan line. 
     V, W, X, and Z indicate jump addresses to reverse paint functions onto development memories, and are respectively those for development onto Y, M, C, and Bk band memories. 
       V ,  W ,  X , and  Z  indicate jump addresses to transparent paint functions onto development memories, and are respectively those for development onto Y, M, C, and Bk band memories. 
      indicates a jump address to a transparent paint function onto a development memory in the monochrome mode. 
      indicates a jump address to a dummy process function. 
     The dummy process function is a function for executing no process. 
     In a transparent process, if Y and C values of Y, M, C, and Bk density values are not “0”, and M and Bk values are “0”, paint processes of M and Bk must be performed by ANDing reverse patterns of paint patterns on the memories. 
     This is because the contents of the Y, M, C, and Bk memories are logically ORed, and the OR is printed on a print sheet. 
     FIG. 115 shows an example of the drawing logic table address storage table  24  in the memory development table storage  22  shown in FIGS. 24A and 24B. 
     This table stores header addresses of the paint function address storage tables  23  corresponding to drawing logics shown in, e.g., FIGS. 113 and 114. 
     The table stores addresses in correspondence with the values of drawing logic information L OGSTYL . When the value L OGSTYL  is “0”, the drawing logic is “overwrite”, and the content indicated by a pointer at the first position of the table is the header address of FIG.  113 . 
     When the value L OGSTYL  is “1”, the drawing logic is “transparent”, and the content indicated by a pointer at the first position of the table is the header address of FIG.  114 . 
     The table can store addresses corresponding to n types of drawing logics. 
     FIGS. 116A and 116B show an example of the BITSET flag used in the process in step S 475  in FIG. 100, step S 501  in FIG. 103, step S 507  in FIG. 104, and step S 528  in FIG.  107 . 
     As shown in FIG. 116A, the BITSET flag consists of 8 bits, and information indicating whether or not a Bk, C, M, or Y density value is “0” is set in each of bits 0, 1, 2, and 3. 
     More specifically, if the density value is “0”, the corresponding bit is OFF; if it is not “0”, the corresponding bit is ON. 
     For example, if Y and C values of Y, M, C, and Bk density values are not “0”, and M and Bk values are “0”, the flag value becomes “10”. 
     Bit  4  is ON in the monochrome mode, as shown in FIG.  116 B. 
     In the monochrome mode, bits other than bit  4  are set to be “0”, and the flag value becomes “16”. 
     FIGS. 117 to  119  are flow charts showing the process in step S 475  in FIG. 100, step S 501  in FIG. 103, step S 507  in FIG. 104, and step S 528  in FIG.  107 . 
     In step S 820 , the content of the BITSET flag is cleared, and the flow advances to step S 821 . 
     In step S 821 , it is checked if the color mode is set. 
     If NO in step S 821 , the flow advances to step S 822 , and “0x 1000” is set in the BITSET flag, i.e., bit 4 alone is set ON. The flow then advances to step S831.    
     If YES in step S 821 , the flow advances to step S 823 , and the value P_Y is compared with “0”. 
     If P_Y=0, the flow advances to step S 825 . 
     If P_Y≠0, the flow advances to step S 824 , and a Y bit (bit  3 ) of the BITSET flag is set ON. The flow then advances to step S 825 . 
     In step S 825 , the value P_M is compared with “0”. 
     If P_M=0, the flow advances to step S 827 . 
     If P_M×0, the flow advances to step S 826 , and an M bit (bit  2 ) of the BITSET flag is set ON. The flow then advances to step S 827 . 
     In step S 827 , the value P_C is compared with “0”. 
     If P_C=0, the flow advances to step S 829 . 
     If P_C≠0, the flow advances to step S 828 , and a C bit (bit  1 ) of the BITSET flag is set ON. The flow then advances to step S 829 . 
     In step S 827 , the value P_Bk is compared with “0”. 
     If P_Bk=0, the flow advances to step S 831 . 
     If P_Bk≠0, the flow advances to step S 830 , and a Bk bit (bit  0 ) of the BITSET flag is set ON. The flow then advances to step S 831 . 
     In step S 831 , a pointer is placed at the first position of the drawing logic table address storage table  24 , and the flow advances to step S 832 . 
     In step S 832 , drawing logic information L OGSTYL  is taken, and the flow advances to step S 833 . 
     In step S 833 , the pointer is advanced by an amount corresponding to the value L OGSTYL , and the flow advances to step S 834 . 
     In step S 834 , the content indicated by the pointer (the header address of the paint function address storage table  23 ) is set in T ABLETOP , and the flow advances to step S 835 . 
     In step S 835 , a pointer is placed in T ABLETOP , and the flow advances to step S 836 . 
     In step S 836 , the value of the BITSET flag is taken, and the flow advances to step S 837 . 
     In step S 837 , the pointer is advanced by an amount corresponding to the taken value, and the flow advances to step S 838 . 
     In step S 838 , the address indicated by the pointer is set in P GJMPTBL , thus ending the process. 
     In this manner, the jump address to a paint function in the paint function address storage table  23  corresponding to the drawing logic shown in, e.g., FIGS. 113 and 114 can be accessed on the basis of drawing logic information in correspondence with the Y, M, C, and Bk density values (0 or not 0) according to the value of the BITSET flag. 
     Also, the jump address to a paint function in the monochrome mode can be accessed. 
     FIG. 120 shows an example of a straight line connecting two points (X m , Y m ) and (X m+1 , Y m+1 ) on the printer coordinate system. 
     In consideration of a line width L WIDTH , drawing of a straight line can be regarded as a paint process of an area surrounded by four points (X 1 , Y 1 ), (X 2 , Y 2 ), (X 3 , Y 3 ), and (X 4 , Y 4 ). An angle e indicates the inclination of a straight line from the horizontal right direction. 
     FIGS. 121 to  123  are flow charts showing the process in step S 479  in FIG.  101  and step S 511  in FIG. 105 on the basis of FIG.  120 . 
     In step S 850 , line width information L WIDTH  is taken, and the flow advances to step S 851 . 
     In step S 851 , a quotient of L WIDTH /2 is set in α, and the flow advances to step S 852 . 
     In step S 852 , {(X m+1 −X m ) 2 +(Y m+1 −Y m ) 2 } ½  is set in l, and the flow advances to step S 853 . 
     In step S 853 , a quotient of (X m+1 −X m )/l is set in cos θ, and a quotient of (Y m+1 −Y m )/l is set in sin θ. Thereafter, the flow advances to step S 854 . 
     In step S 854 , a sum of X m+1 +α sin θ is set in X 1 , and a difference of Y m+1 −α cos θ is set in Y 1 . The flow then advances to step S 855 . 
     In step S 855 , a difference of X m+1 −α sin θ is set in X 2 , and a sum of Y m+1 +α cos θ is set in Y 2 . The flow then advances to step S 856 . 
     In step S 856 , a difference of X m −α sin θ is set in X 3 , and a sum of Y m +α cos θ is set in Y 3 . The flow then advances to step S 857 . 
     In step S 857 , the sum of X m +α sin θ is set in X 4 , and the sum of Y m +α cos θ is set in Y 4 . The flow then advances to step S 858 . 
     In step S 858 , (X 1 , Y 1 ), (X 2 , Y 2 ), (X 3 , Y 3 ), and (X 4 , Y 4 ) are set in the storage area of the system work memory in the order named, and the flow advances to step S 859 . 
     In step S 859 , “4” (the number of coordinate points in step S 858 ) is set in a constant p, and the flow advances to step S 860 . 
     In step S 860 , the minimum and maximum values of Y coordinates set in the storage area of the system work memory in step S 858  are detected, and are respectively set in Y PMIN  and Y PMAX . The flow then advances to step S 861 . 
     In step S 861 , the value Y PMIN  is set in a variable β, and the flow advances to step S 862 . 
     In step S 862 , a paint process for one scan line corresponding to the Y coordinate value β is performed, and the flow advances to step S 863 . 
     In step S 863 , the values β and Y PMAX  are compared with each other. 
     If β=Y PMAX , the process ends. 
     If β≠Y PMAX , the flow advances to step S 864  to increment the value β by 1, and the flow returns to step S 862 . 
     In this manner, a straight line connecting two points (X m , Y m ) and (X m+1 , Y m+1 ) on the printer coordinate system can be developed on each band memory. 
     FIG. 124 shows a polygon defined by five points (X 1 , Y 1 ) to (X 5 , Y 5 ) on the printer coordinate system. 
     A paint process of a portion inside this polygon is realized by a paint process of an area surrounded by five points (X 1 , Y 1 ) to (X 5 , Y 5 ). 
     FIG. 125 shows a character “E” constituted by outline points (X 1 , Y 1 ) to (X 12 , Y 12 ) on the printer coordinate system. 
     A paint process of a portion inside this character is realized by a paint process of an area surrounded by 12 points (X 1 , Y 1 ) to (X 12 , Y 12 ). 
     FIG. 126 is a flow chart showing the process in step S 502  in FIG.  103  and step S 529  in FIG. 107 in the paint process of a portion inside the polygon or character shown in FIG. 124 or  125 . 
     In step S 870 , n (the number of outline points) is set in a constant p, and the flow advances to step S 871 . 
     In step S 871 , the minimum and maximum values of Y coordinates set in the storage area in the system work memory in step S 494  in FIG. 102 or step S 524  in FIG. 106 are detected, and are respectively set in Y PMIN  and Y PMAX . Thereafter, the flow advances to step S 872 . 
     In step S 872 , the value Y PMIN  is set in a variable β, and the flow advances to step S 873 . 
     In step S 873 , a paint process for one scan line corresponding to the Y coordinate value β is performed, and the flow advances to step S 874 . 
     In step S 874 , the values β and Y PMAX  are compared with each other. 
     If β=Y PMAX , the process ends. 
     If β≠Y PMAX , the flow advances to step S 875  to increment the value β by 1, and the flow returns to step S 873 . 
     In this manner, a paint pattern of a region surrounded by n outline points (X 1 , Y 1 ) to (X n , Y n ) on the printer coordinate system can be developed on each band memory. 
     FIGS. 127 and 128 are flow charts showing the process in step S 860  in FIG.  122  and step S 871  in FIG.  126 . 
     In step S 880 , a pointer is placed at the first position of the outline point storage area of the system work memory, and the flow advances to step S 881 . 
     In step S 881 , the Y value of a coordinate indicated by the pointer is set in Y 1 , and the flow advances to step S 882 . 
     In step S 882 , the value Y 1  is set in Y PMIN  and Y PMAX  and the flow advances to step S 883 . 
     In step S 883 , “1” is set in a variable i, and the flow advances to step S 884 . 
     In step S 884 , i is compared with a constant p. 
     If i=p, the process ends. 
     If i≠p, the flow advances to step S 885  to advance the pointer by 1, and the flow then advances to step S 886 . 
     In step S 886 , the value i is incremented by 1, and the flow advances to step S 887 . 
     In step S 887 , the Y value of a coordinate indicated by the pointer is set in Y i , and the flow advances to step S 888 . 
     In step S 888 , the values Y i  and Y PMAX  are compared with each other. 
     If Y i &gt;Y PMAX  the flow advances to step S 889 , and Y i  is set in Y PMAX . The flow then advances to step S 890 . 
     Otherwise, the flow advances to step S 890 . 
     In step S 890 , the values Y i  and Y PMIN  are compared with each other. 
     If Y PMIN &gt;Y i , the flow advances to step S 891 , and Y i  is set in Y PMIN . The flow then returns to step S 884 . 
     Otherwise, the flow returns to step S 884 . 
     In this manner, the minimum and maximum values of the Y coordinates set in the storage area in the system work memory are detected, and can be respectively set in Y PMIN  and Y PMAX . 
     FIGS. 129 to  132  are flow charts showing the process in step S 862  in FIG.  123  and step S 873  in FIG.  126 . 
     In step S 900 , an X range on one scan line to be painted is computed, and the flow advances to step S 901 . 
     In step S 901 , the X coordinate on the printer coordinate system corresponding to the paint start point of the range computed in step S 900  is set in LEFTX, and the X coordinate on the printer coordinate system corresponding to the paint end point is set in RIGHTX. The flow then advances to step S 902 . 
     In step S 902 , D ISPXMI  as clip area information is compared with the value RIGHTX. 
     If D ISPXMI &gt;RIGHTX, since the paint range falls outside the range of the clip area, the process ends. 
     Otherwise, the flow advances to step S 903 , and D SPXMX  as clip area information is compared with the value LEFTX. 
     If LEFTX&gt;D SPXMX , since the paint range falls outside the range of the clip area, the process ends. 
     Otherwise, the flow advances to step S 904 , and D SPXMI  as clip area information is compared with the value LEFTX. 
     If D SPXMI &gt;LEFTX, the flow advances to step S 905 , and the value D SPXMI  is set in LEFTX. The flow then advances to step S 906 . 
     Otherwise, the flow advances to step S 906 . 
     In step S 906 , D SPXMX  as clip area information is compared with the value RIGHTX. 
     If RIGHTX&gt;D SPXMX , the flow advances to step S 907 , and the value D SPXMX  is set in RIGHTX. The flow then advances to step S 908 . 
     Otherwise, the flow advances to step S 908 . 
     In step S 908 , the origin (0, 0) of the printer coordinate system is assumed as address  0  of a page memory, and the flow advances to step S 909 . 
     In step S 909 , the addresses and bits of LEFTX and RIGHTX on the page memory are computed under the assumption in step S 908 , and the flow advances to step S 910 . 
     In this case, an address is based on a 4-byte boundary. 
     More specifically, an address is updated every 4 bytes, and a bit assumes a value ranging from 0 to 31. 
     This is because a dither pattern has a 4-byte width, as shown in FIG. 110A, and the reference position of the pattern (the start position of development of the pattern on a memory) is the origin (0, 0) of the printer coordinate system. 
     In step S 910 , the address and bit of LEFTX computed in step S 909  are respectively set in L XAD  and L XBIT , and the address and bit of RIGHTX are respectively set in R XAD  and R XBIT . Thereafter, the flow advances to step S 911 . 
     In step S 911 , a residue of the Y coordinate value β/32 is set in δ 1 , and the flow advances to step S 912 . 
     The process in step S 911  indicates that a dither pattern shown in FIG. 110A has a height of 32 scan lines (dots), and a dither pattern used when the Y coordinate=β is the (δ 1 )-th pattern from the uppermost scan line. 
     In step S 912 , a product of the value δ 1 ×4 is set in δ 2 , and the flow advances to step S 913 . 
     Note that δ 2  indicates a moving amount (the number of bytes) from the header address of a dither pattern to an address where a dither pattern used when the Y coordinate=β is stored. 
     In step S 913 , it is checked if the color mode is set. 
     If NO in step S 913 , the flow advances to step S 914 , and a sum of Y DTOPAD , where the header address of a dither pattern has already been stored, and δ 2  is set in Y DAD , The flow then advances to step S 915 . 
     Note that Y DAD  is set with the storage address of a dither pattern used when the Y coordinate value=β. 
     In step S 915 , a pointer is set in P GJMPTBL , and the flow advances to step S 916 . 
     In step S 916 , the content indicated by the pointer (the jump address to a paint function) is taken, and the flow advances to step S 917 . 
     Note that the content indicated by the pointer is, Ie.g.,  in FIG. 113 or  in FIG.  114 . 
     In step S 917 , a function indicated by the jump address is executed, and the process ends. 
     If it is determined in step S 913  that the color mode is set, the flow advances to step S 918 , sums of δ 2  and Y DTOPAD , M DTOPAD , C DTOPAD , and K DTOPAD , where the header address of dither patterns have already been stored, are respectively set in Y DAD , M DAD , C DAD , and K DAD . The flow then advances to step S 919 . 
     Note that Y DAD , M DAD , C DAD , and K DAD  are set with the storage addresses of Y, M, C, and Bk dither patterns used when the Y coordinate value=β. 
     In step S 919 , a pointer is placed in P GJMPTBL , and the flow advances to step S 920 . 
     In step S 920 , “1” is set in a variable s, and the flow advances to step S 921 . 
     In step S 921 , the content indicated by the pointer (the jump address to a paint function) is taken, and the flow advances to step S 922 . 
     In step S 922 , a function indicated by the jump address is executed, and the flow advances to step S 923 . 
     In step S 923 , the pointer is incremented by 4 bytes, and the flow advances to step S 924 . 
     In step S 924 , the value s is compared with 4. 
     If s=4, the process ends. 
     If s≠4, the flow advances to step S 924  to increment s by 1, and the flow returns to step S 921 . 
     In this manner, dither patterns used in the paint process are taken out of storage addresses of dither patterns corresponding to the Y, M, C, and Bk density values in advance, and the paint process of a scan line corresponding to the Y coordinate value β can be performed by accessing the paint function address storage table in the memory development table storage  22  shown in FIGS. 24A and 24B. 
     FIG. 133 shows the arrangement of LEFTX (◯) and RIGHTX (□) and the positions of Y PMIN  and Y PMAX  when the straight line shown in FIG. 120 is drawn by the process shown in FIGS. 121 to  123 . 
     FIG. 134 shows the arrangement of LEFTX (◯) and RIGHTX (□) and the positions of Y PMIN  and Y PMAX  when a portion inside the polygon shown in FIG. 124 is painted by the process shown in FIG.  126 . 
     FIG. 135 shows the arrangement of LEFTX (◯) and RIGHTX (□) and the positions of Y PMIN  and Y PMAX  when a portion inside the character shown in FIG. 125 is painted by the process shown in FIG.  126 . 
     FIGS. 136 and 137 are flow charts showing a process for executing a clear paint function indicated by ◯ in the paint function address storage table  23  shown in FIG. 113, of the process in step S 922  in FIG.  132 . 
     In step S 930 , the Y virtual page memory address Y_T OPADR  obtained by the process in FIG. 90 is taken, a sum of Y_T OPADR +L XAD  is set in L XAD , and a sum of Y_T OPADR +R XAD  is set in R XAD . The flow then advances to step S 931 . 
     Note that L XAD  and R XAD  obtained in step S 930  are the addresses of a memory on which a pattern is actually developed. 
     In step S 931 , L XAD  and R XAD  are compared with each other. 
     If L XAD =R XAD , the flow advances to step S 932  to clear bits between L XBIT  of the address L XAD  and R XBIT , thus ending the process. 
     If L LAD≠R   XAD , the flow advances to step S 933  to clear bits between L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow advances to step S 934 . 
     In step S 934 , a sum of L XAD +4 (bytes) is set in L XAD , and the flow advances to step S 935 . 
     In step S 935 , L XAD  and R XAD  are compared with each other. 
     If L XAD =R XAD  the flow advances to step S 932  to clear bits between L XBIT  of the address L XAD  and R XBIT , thus ending the process. 
     If L XAD ≠R XAD , the flow advances to step S 936  to clear bits between L XAD  and L XAD +4 (bytes), and the flow advances to step S 937 . 
     In step S 937 , a sum of L XAD +4 (bytes) is set in L XAD  and the flow returns to step S 935 . 
     In this manner, the clear paint function indicated by ◯ in the paint function address storage table  23  in FIG. 113 can be executed. 
     Similarly, clear paint functions indicated by □, Δ, and ⋄ can be executed by changing the virtual page memory address. 
     FIGS. 138 and 139 are flow charts showing a process for executing an overwrite paint function indicated by  ◯  in the paint function address storage table  23  shown in FIG. 113, of the process in step S 922  in FIG.  132 . 
     In step S 940 , the Y virtual page memory address Y_T OPADR  obtained by the process in FIG. 90 is taken, a sum of Y_T OPADR +L XAD  is set in L XAD , and a sum of Y_T OPADR +R XAD  is set in R XAD . The flow then advances to step S 941 . 
     Note that L XAD  and R XAD  obtained in step S 940  are the addresses of a memory on which a pattern is actually developed. 
     In step S 941 , the content (4 bytes) at the address Y DAD  is taken, and is set as a dither pattern to be developed in Y DTPATN . The flow then advances to step S 942 . 
     In step S 942 , L XAD  and R XAD  are compared with each other. 
     If L XAD =R XAD  the flow advances to step S 950  to clear bits between L XBIT  of the address L XAD  and R XBIT , and the flow advances to step S 951 . 
     In step S 951 , the pattern in the Y DPATN  is logically ORed on a memory between the L XBIT  of the address L XAD  and R XBIT , thus ending the process. 
     If it is determined in step S 942  that L XAD ≠R XAD , the flow advances to step S 943  to clear bits between L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow advances to step S 944 . 
     In step S 944 , the pattern in the Y DPATN  is logically ORed on a memory between the L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow advances to step S 945 . 
     In step S 945 , a sum of L XAD +4 (bytes) is set in L XAD , and the flow advances to step S 946 . 
     In step S 946 , L XAD  is compared with R XAD . 
     If L XAD =R XED , the flow advances to step S 950  to clear bits between L XBIT  of the address L XAD  and R XBIT , and the flow advances to step S 951 . 
     In step S 951 , the pattern in the Y DPATN  is logically ORed on a memory between the L XBIT  of the address L XAD  and R XBIT , thus ending the process. 
     If L XAD ≠R XAD , the flow advances to step S 947  to clear bits between L XAD  and L XAD +4 (bytes), and the flow advances to step S 948 . 
     In step S 948 , the pattern in the Y DPATN  is logically ORed on a memory between the L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow advances to step S 949 . 
     In step S 949 , a sum of L XAD +4 (bytes) is set in L XAD , and the flow returns to step S 946 . 
     In this manner, an overwrite paint function indicated by  ◯  in the paint function address storage table  23  in FIG. 113 can be executed. 
     With the same process, an overwrite paint function indicated by  in the paint function address storage table  23  in FIG. 113, of the process in step S 917  in FIG. 131 can be executed. 
     Similarly, overwrite paint functions indicated by  □  and  ⋄  can be executed by changing the virtual page memory address. 
     FIGS. 140 and 141 are flow charts showing a process for executing a reverse paint function indicated by W in the paint function address storage table  23  shown in FIG. 114, of the process in step S 922  in FIG.  132 . 
     In step S 960 , the Y virtual page memory address Y_T OPADR  obtained by the process in FIG. 90 is taken, a sum of Y_T OPADR +L XAD  is set in L XAD , and a sum of Y — T OPADR +R XAD  is set in R XAD . The flow then advances to step S 961 . 
     Note that L XAD  and R XAD  obtained in step S 960  are the addresses of a memory on which a pattern is actually developed. 
     In step S 961 , the content (4 bytes) at the address YDAD is taken, and is set as a dither pattern to be developed in Y DTPATN . The flow then advances to step S 962 . 
     In step S 962 , a pattern obtained by inverting the bits of Y DTPATN  is set in Y RPATN , and the flow advances to step S 963 . 
     In step S 963 , L XAD  and R XAD  are compared with each other. 
     If L XAD =R XAD  the flow advances to step S 969  to logically AND the pattern in Y RPATN  on a memory between L XBIT  of the address L XAD  and R XBIT , thus ending the process. 
     If L XAD ≠R XAD  in step S 963 , the flow advances to step S 964  to logically AND the pattern in Y RPATN  on a memory between L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow advances to step S 965 . 
     In step S 965 , a sum of L XAD +4 (bytes) is set in L XAD , and the flow advances to step S 966 . 
     In step S 966 , L XAD  and R XAD  are compared with each other. 
     If L XAD =R XAD , the flow advances to step S 969  to logically AND the pattern in Y RPATN  on a memory between L XBIT  of the address L XAD  and R XBIT , thus ending the process. 
     If L XAD ≠R XAD  the flow advances to step S 967  to logically AND the pattern in Y RPATN  on a memory between L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow advances to step S 968 . 
     In step S 968 , a sum of L XAD +4 (bytes) is set in L XAD , and the flow returns to step S 966 . 
     In this manner, the reverse paint function indicated by W in the paint function address storage table  23  in FIG. 114 can be executed. 
     Similarly, reverse paint functions indicated by V, X, and Z can be executed by changing the virtual page memory address. 
     FIGS. 142 and 143 are flow charts showing a process for executing a transparent paint function indicated by  W  in the paint function address storage table  23  shown in FIG. 114, of the process in step S 922  in FIG.  132 . 
     In step S 970 , the Y virtual page memory address Y_T OPADR  obtained by the process in FIG. 90 is taken, a sum of Y_T OPADR +L XAD  is set in L XAD , and a sum of Y_T OPADR +R XAD  is set in R XAD . The flow then advances to step S 971 . 
     Note that L XAD  and R XAD  obtained in step S 970  are the addresses of a memory on which a pattern is actually developed. 
     In step S 971 , the content (4 bytes) at the address Y DAD  is taken, and is set as a dither pattern to be developed in Y DTPATN . The flow then advances to step S 972 . 
     In step S 972 , a pattern obtained by inverting the bits of Y DTPATN  is set in Y RPATN , and the flow advances to step S 973 . 
     In step S 973 , L XAD  and R XAD  are compared with each other. 
     If L XAD =R XAD , the flow advances to step S 981  to logically AND the pattern in Y RPATN  on a memory between L XBIT  of the address L XAD  and R XBIT , and the flow then advances to step S 982 . 
     In step S 982 , the pattern in Y DTPATN  is logically ORed on a memory between L XBIT  of the address L XAD  and R XBIT , thus ending the process. 
     If L XAD ≠R XAD  in step S 973 , the flow advances to step S 974  to logically AND the pattern in Y RPATN  on a memory between L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow then advances to step S 975 . 
     In step S 975 , the pattern in Y DTPATN  is logically ORed on a memory between L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow then advances to step S 976 . 
     In step S 976 , a sum of L XAD +4 (bytes) is set in L XAD , and the flow advances to step S 977 . 
     In step S 977 , L XAD  and R XAD  are compared with each other. 
     If L XAD =R XAD , the flow advances to step S 981  to logically AND the pattern in Y RPATN  on a memory between L XBIT  of the address L XAD  and R XBIT , and the flow then advances to step S 982 . 
     In step S 982 , the pattern in Y DTPATN  is logically ORed on a memory between L XBIT  of the address L XAD  and R XBIT , thus ending the process. 
     If L XAD ≠R XAD , the flow advances to step S 978  to logically AND the pattern in Y RPATN  on a memory between L XAD  and L XAD +4 (bytes), and the flow advances to step S 979 . 
     In step S 979 , the pattern in Y DPATN  is logically ORed on a memory between L XBIT  of the address L XAD  and L XAD +4 (bytes), and the flow advances to step S 980 . 
     In step S 980 , a sum of L XAD +4 (bytes) is set in L XAD , and the flow returns to step S 977 . 
     In this manner, the transparent paint function indicated by  W  in the paint function address storage table  23  in FIG. 114 can be executed. 
     With the same process, a transparent paint function indicated by  in the paint function address storage table  23  in FIG. 114, of the process in step S 917  in FIG. 131 can be executed. 
     Similarly, transparent paint functions indicated by  V ,  X , and  Z  can be executed by changing the virtual page memory address. 
     FIG. 144 shows examples of paint results using the paint functions of the processes shown in FIGS. 136 to  143 . 
     Y DTPATN  and Y RPATN  are 32-bit patterns. In these patterns, a black portion indicates a bit ON state, and a white portion indicates a bit OFF state. 
     FIG. 144 shows paint results using the pattern Y DTPATN  between L XBIT  of the address L XAD  and R XBIT  of the address R XAD  on a memory after the process. 
     After a clear &amp; paint process, all bits in a painted portion are OFF. 
     After an overwriting &amp; paint process, the content of a memory before the process is cleared, and the pattern Y DTPATN  is developed. 
     After a reverse &amp; paint process, the pattern Y RPATN  is logically ANDed with the memory content before the process. 
     After a transparent paint process, the pattern Y RPATN  is logically ANDed with the memory content before the process, and the pattern Y DTPATN  is logically ORed with the AND result. 
     In this embodiment, Y, M, C, and Bk development memories are used. However, the present invention can be applied to other cases, e.g., R, G, and B development memories. 
     In this case, the paint function address storage table shown in FIG. 113 is rewritten, as shown in FIG.  145 . 
     As shown in FIG. 145, jump addresses to paint functions on development memories are stored in units of R, G, and B. 
     Note that a paint function is one for executing a paint process on a memory for one scan line. 
     ◯, □, and Δ indicate jump addresses to clear paint functions onto development memories, and are respectively those for development onto R, G, and B band memories. 
       ◯ ,  □ , and  Δ  indicate jump addresses to overwrite paint functions onto development memories, and are respectively those for development onto R, G, and B band memories. 
      indicates a jump address to an overwrite paint function onto a development memory in the monochrome mode. 
      indicates a jump address to a dummy process function. 
     The dummy process function is a function for executing no process. 
     In the above-mentioned case, the BITSET flag shown in FIGS. 116A and 116B is replaced, as shown in FIGS. 146A and 146B. 
     As shown in FIG. 146A, the BITSET flag consists of 8 bits, and information indicating whether or not a B, G, or R density or brightness value is “0” is set in each of bits  0 ,  1 , and  2 . 
     More specifically, if the density or brightness value is “0”, the corresponding bit is OFF; if it not “0”, the corresponding bit is ON. 
     For example, when an R value of R, G, and B density or brightness value is not “0”, and G and B values are “0”, the flag value becomes “4”. 
     Bit  3  is ON in the monochrome mode, as shown in FIG.  146 B. 
     In the monochrome mode, bits other than bit  3  are “0”, and the flag value becomes “8”. 
     FIG. 147 shows an example wherein one scan line of a certain Y coordinate includes two portions to be painted in a polygon. 
     In this case, as shown in FIG. 147, the X ranges of the two paint portions are defined as LEFTX1 to RIGHTX1, and LEFTX2 to RIGHTX2, and can be coped with by adopting the above-mentioned process. 
     Of course, the same applies to three or more portions to be painted. 
     The processes in step S 913  and steps S 914  to S 917  in FIG. 131 can be omitted. 
     This is because jump addresses to the dummy process function are stored at the end of the tables shown in FIGS. 113 and 114. 
     More specifically, a paint process for one scan line can be performed regardless of the color or monochrome mode.