referring first to fig1 there is shown the presently preferred embodiment of the invention , in the form of an apparatus adapted to prepare image reproduction data used for a laser printer . the apparatus has an interface 10 through which the apparatus is connected to a personal computer , a word processor , or any other external data supply device from which original image data in the form of printing data are received . the interface 10 is connected to a central processing unit 12 ( cpu ), a random - access memory 14 ( ram ) and a read - only memory 16 ( rom ). the ram 14 includes an image data register 17 , a working area 18 , a winding counter 19 , a page memory 20 and a print buffer 22 . the rom 16 stores various control programs such as the programs indicated by the flow charts of fig2 and 3 and the program indicated by the flow chart of fig1 . the cpu 12 , which operates according to these control programs , receives from the external data supply device the printing data , and stores original image data of the received data into the image data memory 17 . the original image data represent figures to be reproduced . the cpu 12 sequentially processes the original image data stored in the image data memory 17 , for preparing the corresponding image reproduction data in the form of solid - imaging data , while utilizing the temporary data storage function of the working area 18 . the prepared solid - imaging data are stored in the page memory 20 . the page memory 20 has memory locations in which are stored data bits corresponding to picture elements , which are minimum printing spots at which the corresponding image dots are selectively formed by the laser printer . the solid - imaging data take the form of dot data which indicate whether the image dots are formed at the appropriate printing spots , or not . upon printing , sets of the dot data are read out from the page memory 20 one after another , and temporarily stored in the print buffer 22 , from which the dot data are supplied to the laser printing head of the printer , so that the lines of images are printed one after another according to the dot data . there will be described an operation of the present data preparing apparatus , by reference to the flow charts of fig2 and 11 and the illustrations in fig4 through 6 . for each figure whose outline is defined by the appropriate batch of original image data stored in the image data register 17 , a control routine illustrated in the flow chart of fig2 is executed . initially , step s1 is implemented to determine whether it is apparent or not that the relevant figure has only one maximal value . the figure is defined by code data representative of the kind of the figure , and code data representative of the size and printing position of the figure . if the appropriate code data representative of the kind of the figure indicates that the figure defined by the image data is a simple figure such as a circle and a rectangle , an affirmative decision ( yes ) is obtained in step s1 . in this case , the control flow goes to step s2 in which a processing operation which does not include determination on the winding count for each scanning line will be executed as described below by reference to fig3 . if the image data include vector data representative of a plurality of vectors indicative of straight line segments representing the outline of the figure , on the other hand , a negative decision ( no ) is obtained in step s1 , and the control flow goes to step s3 in which the number of maximal values of the vectorial outline of the figure is calculated . in this respect , it is noted that a maximal value appears at each point of the vectorial outline at which the direction of the relevant vector changes from the upward direction to the downward direction as viewed in the direction perpendicular to the scanning lines , as indicated in fig7 for example . accordingly , the number of the maximal points is calculated by counting those points of the vectorial outline . where the outline includes a curved segment , the curved segment is approximated by a plurality of straight line segments , and the number of the maximal values is obtained based on the vectors representative of these straight line segments . step s3 is followed by step s4 to determine whether the calculated number of maximal values is equal to &# 34 ; 1 &# 34 ; or not . if an affirmative decision ( yes ) is obtained , that is , if the relevant figure has only one maximal value and is therefore a simple figure , step s4 is followed by step s2 to effect the processing without the determination on the winding count . if the calculated number obtained in step s3 is larger than &# 34 ; 1 &# 34 ;, that is , the relevant figure has two or more maximal values , the control flow goes to step s5 in which a data processing operation involving the determination on the winding count will be executed as described below by reference to fig1 . it is noted that step s3 is adapted such that there exists only one maximal value where a maximal value appears on a straight line segment of the vectorial outline of the figure parallel to the scanning lines . the data processing operation in step s2 which is effected without the determination on the winding count is illustrated in the flow chart of fig3 . an example of the data processing for preparing solid - imaging data without the determination of the winding count will be described with respect to a fig3 as illustrated in fig4 . the fig3 is superimposed on horizontal scanning lines 32 . a control routine of the flow chart of fig3 is implemented for each scanning line 32 . when the fig3 is scanned along the scanning line 32 which extends from point x1 to point y1 , for example , step s11 is initially executed to calculate coordinates of a first intersection point q1 between the scanning line 32 and a vector 34 . then , step s12 is executed to prepare start - point data , based on the calculated coordinates of the intersection point ql , such that the start - point data represent the start point of an enclosed solid - imaging area , which start point is located at the coordinates of a picture element whose center is nearest to the intersection point q1 and inside the vectorial outline of the fig3 . the prepared start - point data are stored in the working area 18 of the ram 14 of the apparatus . similarly , end - point data for the same scanning line 32 is prepared in steps s13 and s14 such that the end - point data represent the end point of the solid - imaging area , which end point is located at the coordinates of a picture element which is nearest to a second intersection point q2 between the scanning line and the vectorial outline of the fig3 and is inside the vectorial outline . the prepared end - point data is also stored in the working area 18 . based on the start - point data and end - point data stored in the working area 18 , the solid - imaging data for the relevant scanning line 32 is prepared in step s15 , so that image dots are formed at all the picture element positions ( printing spots ) between the start and end points represented by the start - point and end - point data . more specifically , the bits of the dot data at the memory locations of the page memory 20 which correspond to those picture element positions are set to &# 34 ; 1 &# 34 ;, which indicates the presence of the image dot . thus , the solid - imaging dot data as the image reproduction data used by the laser printer is prepared for each scanning line . no further description of the preparation of the solid - imaging data or dot data is deemed necessary for understanding the principle of the present invention . details of the manner of preparing the dot data are described in copending u . s . patent application no . 425 , 604 . the control routine of the flow chart of fig3 is executed for all the scanning lines which intersect the fig3 , the preparation of the solid - imaging data ( dot data ) for the fig3 is completed . referring to the flow chart of fig1 , there will be described the control routine for the data processing in step s5 which involves the determination on the winding count for each scanning line . initially , step s101 is implemented to clear the winding counter 19 . then , step s102 is implemented to determine whether there exists any intersection between the current scanning line and the vectorial outline of a figure to be reproduced . for example , there are four intersections p1 , p2 , p3 and p4 between a scanning line 40 extending from point x2 to point y2 , and the vectorial outline of a fig3 shown in fig5 . in this example , therefore , an affirmative decision ( yes ) is obtained in step s102 . accordingly , the control flow goes to step s103 to determine whether the outline intersects the relevant scanning line 40 in the upward direction , or not , namely , whether vectors 42 , 44 , 46 and 48 corresponding to the intersections p1 , p2 , p3 and p4 intersect the scanning line 40 in the upward direction , or in the downward direction . when step s103 is implemented for the first and third intersections p1 and p3 , an affirmative decision ( yes ) is obtained since the vectors 42 and 46 intersect the scanning line 40 in the upward direction . in this case , step s103 is followed by step s104 in which the winding counter 19 is incremented . when step s103 is implemented for the second and fourth intersections p2 and p4 , a negative decision ( no ) is obtained since the vectors 44 and 48 intersect the scanning line 40 in the downward direction . in this latter case , step s103 is followed by step s105 in which the winding counter 19 is decremented . steps s104 and s105 are followed by step s106 to determine whether the current count of the winding counter 19 is an odd number or not . for the first intersection p1 , an affirmative decision ( yes ) is obtained in step s106 , and step s107 is executed to prepare start - point data such that the start - point data represent a start - point of an enclosed solid - imaging area , which is located at the coordinates of a picture element whose center is nearest to the intersection point p1 and inside the vectorial outline of the fig3 . the prepared start - point data is stored in the working area 18 of the ram 14 . for the intersection p2 , a negative decision ( no ) is obtained in step s106 , and step s108 is executed to prepare end - point data , such that the end point data represent an end point of the solid - imaging area , which is located at the coordinates of a picture element whose center is nearest to the intersection p1 and inside the outline of the fig3 . the prepared end - point data is stored in the working area 18 . similarly , start - point data and end - point data representing a second start - point and a second end - point of the solid - imaging area are prepared for the third and fourth intersections p3 and p4 . when a negative decision ( no ) is eventually obtained in step s102 , and the control flow goes to step s109 in which solid - imaging dot data for the enclosed solid - imaging area of the fig3 are prepared for the relevant scanning line 40 and are stored in the page memory 20 . after the solid - imaging dot data for the fig3 are prepared for all the scanning lines 40 , a laser print operation is performed according to the prepared image reproduction data in the form of the solid - imaging dot data , whereby the fig3 is reproduced on a recording medium . the data processing with the determination on the winding count is effected for a fig5 indicated in fig6 . for this fig5 , solid - imaging dot data may be prepared in the same manner as described above , when the control routine of the flow chart of fig1 is executed . for instance , solid - imaging dot data is prepared for a scanning line 52 extending from point x3 to point y3 , such that the dot data represents image dots between first and second intersections a1 and a2 , image dots between third and fourth intersections a3 and a4 , and image dots between fifth and sixth intersections a5 and a6 . namely , dot data bits at the memory locations of the page memory 20 are set to &# 34 ; 1 &# 34 ; for the picture elements which are located within two enclosed solid - imaging areas , whose winding count is an odd number as indicated at ( 1 ) and ( 3 ) in fig6 . when printing is performed according to the solid - imaging dot data , the solid - imaging areas ( 1 ) and ( 3 ) are solid - imaged with a suitable inking material , for example . it will be understood from the above description that the image data register 17 constitutes memory means for storing original image data representative of the outline of a figure , and portions of the cpu 12 and rom 16 assigned to execute steps s1 , s3 and s4 of fig2 constitute selector means for selecting an adequate one of the two different modes of data processing operations in steps s2 and s5 , as described above . further , the winding counter 19 , page memory 20 and portions of the cpu 12 and rom 16 assigned to execute step s5 constitute first data preparing means for preparing solid - imaging dot data according to the control routine of fig1 . further , the page memory 20 and portions of the cpu 12 and rom 16 assigned to execute step s2 constitute second data preparing means for preparing solid - imaging dot data according to the control routine of fig3 . while the present invention has been described in the presently preferred embodiment , it is to be understood that the invention is not limited to the details of the illustrated embodiments , but may be otherwise embodied , with various changes , modifications and improvements , which may occur to those skilled in the art , without departing from the spirit and scope of the invention defined in the following claims .