Abstract:
The present invention provides a snap function that can move an object smoothly, without deteriorating the user operability. According to the present invention, there is provided an object editing system, including: an arrangement system for arranging an object and a snap target in a given display area; a moving system for moving the object in the display area; a snap system for causing the object to snap the snap target on a basis of a distance between the object and the snap target; and a restriction system for inhibiting the object from snapping the snap target on a basis of a direction in which the object is moving. According to the object editing system of the invention, the snap system causes the object to snap the snap target once the distance between the object and the snap target has become smaller than a predetermined threshold value.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a technique for using a computer to edit electronic documents. Particularly, the present invention relates to a system for editing objects in electronic documents, an object editing method and an object editing program product. 
     BACKGROUND OF THE INVENTION 
     When computers are employed for the layout editing of electronic documents, object snap functions are frequently used by electronic document layout editing tools to position objects at desired locations. When, for example, an object is continuously selected by means of a mouse and is moved (dragged) to a desired grid, the snap function aids in the object&#39;s being automatically arranged on a grid in a work area or on another object. 
     An electronic document layout editing screen is shown in  FIG. 8 . A plurality of vertical grids  101   a  to  101   e  and horizontal grids  102   a  to  102   c  are arranged on a screen  103 . In the state shown in  FIG. 8 , a snap function has been used to move a selected object  100  to a position indicated by an object  100 ′. It can be seen that the object  100 ′ has been snapped to the vertical grid  101   b  and the horizontal grid  102   b.    
     This snap function is an important function for the efficient arrangement of objects relative to grids and other objects, and is very frequently employed by users. When the interval between grids used as references is short, or when many other objects are present, the snap function must perform more work than necessary to move a specific object to a desired location, and therefore moving the object smoothly may be difficult. 
     This problem will be explained while referring to  FIG. 9 .  FIG. 9  is a diagram, showing a screen  103 , for explaining the operating frequency of a conventional snap function whereby an object  100  has been moved to a location indicated by an object  100 ′. Assume that reference numeral  104  denotes a mouse (a mouse pointer), and  100   a,    100   b,    100   c  and  100   d  respectively denote the right, left, upper and lower sides of the object  100 . A total of eight snaps (Snap  1  to Snap  8 ) occurred before the object  100  was moved to the location indicated by the object  100 ′, i.e., until the right side  100   a  snapped a vertical grid  101   f . In this example, the left side  100   b  snapped a vertical grid  101   b,  the lower side  100   d  snapped a horizontal grid  102   c,  the right side  100   a  snapped a vertical grid  101   d,  the upper side  100   c  snapped a horizontal grid  102   b,  the left side  100   b  snapped a vertical grid  101   c,  the right side  100   a  snapped a vertical grid  101   e,  the left side  100   b  snapped a vertical grid  101   d,  and thereafter, the right side  100   a  snapped the vertical grid  101   f.    
     As described above, when the conventional snap function is employed, the function must perform more work than necessary to move a specific object to a desired location, and this hinders the smooth movement of the object. 
     A technique for improving the above described conventional snap function is disclosed in Japanese Patent Laid-Open Publication No. 2001-281835. According to the technique disclosed in this reference, of four snap points for an object selected by a mouse, only the snap point closest to the mouse cursor is set to a snappable condition, and is snapped as a snap candidate point. 
     According to the technology disclosed in Japanese Patent Laid-Open Publication No. 2001-281835, while it is possible to suppress unnecessary snaps caused when moving an object to some extent, only a snap point closest to a mouse cursor is in a snappable condition out of four snap points of the object and therefore there is a limit in the number of snap points in the snappable condition, thereby deteriorating the operationality problematically. 
     Moreover, in the conventional snap function, there has also been known a technology of inhibiting the snap function from being operated unnecessarily by temporarily invalidating the snap function with a combination of a drag-and-drop operation with a mouse and a keyboard operation, in other words, with a depression of a shift key or the like on a keyboard at the time of the drag-and-drop operation. 
     By using these conventional snap functions, it is possible to move the object relatively smoothly. These functions, however, require simultaneous processing of a plurality of operations such as the combination of the drag-and-drop operation and the keyboard operation, which necessarily requires operations with both hands and thereby deteriorates the operationality. Furthermore, it has been hard for a user to find the operation method of the combined plurality of operations and to learn the operation method. 
     Due to these circumstances, the foregoing conventional snap functions cannot move the object smoothly without deteriorating the operationality, thereby hindering an improvement in usability in object editing of an electronic document. 
     SUMMARY OF THE INVENTION 
     Therefore, in view of these problems, the present invention has been provided. It is an object of the present invention to provide a snap function for realizing a smooth movement of an object without deteriorating the operationality, to increase an editing efficiency of the object, and to improve usability. 
     According to the present invention, there is provided an object editing system that includes: arrangement means for arranging an object and a snap target in a given display area; moving means for moving the object in the display area; snap means for causing the object to snap the snap target on a basis of a distance between the object and the snap target; and restriction means for inhibiting the object from snapping the snap target on a basis of a direction in which the object is moving. 
     The snap means causes the object to snap the snap target if the distance between the object and the snap target has become smaller than a predetermined threshold value. 
     A plurality of snap targets may be present on a path along which the object moves. 
     The restriction means may inhibit the object from snapping the snap target present on the side opposite to the direction in which the object is moving. 
     The object may have a plurality of snap references, and the snap means may cause a snap reference to snap a snap target based on a distance between the snap reference and the snap target, and the restriction means may inhibit the snap references that are present on the side opposite to the direction in which the object is moving from snapping a snap target. 
     The restriction means may cause the snap references that are present on the same side as the direction in which the object is moving to snap the snap target. 
     The display area is a two-dimensional display area defined by a vertical axis and a horizontal axis. The restriction means may inhibit the snap references that are present on the side opposite to a vertical component of the direction in which the object is moving from snapping the snap target, or inhibit the snap references that are present on the side opposite to a horizontal component of the direction in which the object is moving from snapping the snap target. 
     The display area is a two-dimensional display area defined by a vertical axis and a horizontal axis. The restriction means may inhibit the snap references that are present on the side opposite to a vertical component of the direction in which the object is moving from snapping the snap target, and inhibit the snap references that are present on the side opposite to a horizontal component of the direction in which the object is moving from snapping the snap target. 
     The display area is a two-dimensional display area, the form of the object is a rectangle, and the snap targets are a plurality of vertical grid lines and a plurality of horizontal grid lines. The snap means may cause a side of the object to snap a vertical grid line or a horizontal grid line on the basis of a distance between the side of the object and the vertical grid line or the horizontal grid line. The restriction means may inhibit the sides of the object that are present on the side opposite to the direction in which the object is moving from snapping the vertical grid lines or the horizontal grid lines. 
     Of the plurality of horizontal grid lines, the snap means may select a horizontal grid line closest to the side of the rectangle that is present along the vertical component of the direction in which the object is moving, and may cause the side to snap the selected horizontal grid line if the distance between the side and the horizontal grid line has been become smaller than a first threshold value. Further, of the plurality of vertical grid lines, the snap means may select a vertical grid line closest to the side of the rectangle that is present along the horizontal component of the direction in which the object is moving, and may cause the side to snap the selected vertical grid line if the distance between the side and the vertical grid line has become smaller than a second threshold value. 
     The restriction means may inhibit the sides of the rectangle on the side opposite to the vertical component of the direction in which the object is moving from snapping the horizontal grid lines, and may inhibit the sides of the rectangle on the side opposite to the horizontal component of the direction in which the object is moving from snapping the vertical grid lines. 
     The moving means may have a pointing device for displaying a pointer in the display area. 
     As a user manipulates the pointing device, the moving means may move the object designated by the pointer. 
     The pointing device may be a mouse. 
     In the display area, the direction in which the object is moving matches the direction in which the pointer is moving. 
     The display area is a two-dimensional display area defined by a vertical axis and a horizontal axis, and the direction in which the object is moving is either up rightward, directly rightward, down rightward, directly upward, directly downward, up leftward, directly leftward or down leftward. 
     According to the present invention, there is provided an object editing method that includes the steps of: arranging an object and a snap target in a given display area; and in response to a movement of the object in the display area, causing the object to snap the snap target on a basis of a distance between the object and the snap target while inhibiting the object from snapping the snap target on a basis of a direction in which the object is moving. 
     According to the invention, provided is an object editing method that includes the steps of: arranging an object and a snap target in a predetermined two-dimensional display area defined by a vertical axis and a horizontal axis; constituting the object as a rectangle; preparing a plurality of vertical grid lines and a plurality of horizontal grid lines as the snap target; in response to a movement of the object in the display area, causing a side of the rectangle to snap a horizontal grid line or a vertical grid line on a basis of a distance between the side and the horizontal grid line or the vertical grid line while inhibiting sides of the rectangle on a side opposite to the moving direction of the object from snapping the horizontal and vertical grid lines 
     According to the invention, provided is an object editing method that includes the steps of: inhibiting the sides of the rectangle that are on the side opposite to a vertical component of the direction in which the object is moving from snapping the horizontal grid lines, and inhibiting the sides of the rectangle that are on the side opposite to a horizontal component of the direction in which the object is moving from snapping the vertical grid lines. 
     According to the present invention, there is provided an object editing program product for enabling a computer to execute the steps of: arranging an object and a snap target in a given display area; and in response to a movement of the object in the display area, causing the object to snap the snap target on a basis of a distance between the object and the snap target while inhibiting the object from snapping the snap target on a basis of a direction in which the object is moving. 
     According to the invention, provided is an object editing program product that permits a computer to perform the steps of: arranging an object and a snap target in a predetermined two-dimensional display area defined by a vertical axis and a horizontal axis; constituting the object as a rectangle; preparing a plurality of vertical grid lines and a plurality of horizontal grid lines as the snap target; in response to a movement of the object in the display area, causing a side of the rectangle to snap a horizontal grid line or a vertical grid line on a basis of a distance between the side and the horizontal grid line or the vertical grid line while inhibiting sides of the rectangle on the side opposite to the moving direction of the object from snapping the horizontal and vertical grid lines. 
     According to the invention, provided is an object editing program product that permits a computer to perform the steps of: inhibiting the sides of the rectangle that are on the side opposite to a vertical component of the direction in which the object is moving from snapping the horizontal grid lines, and inhibiting the sides of the rectangle that are on the side opposite to a horizontal component of the direction in which the object is moving from snapping the vertical grid lines. 
     According to the present invention, the number of snap function operations that must be performed to move an object can be reduced, and the smooth movement of the object can be achieved without deteriorating user operability. As a result, the efficiency of object editing is increased, and usability is improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing the configuration of an object editing system according to one embodiment of the present invention; 
         FIG. 2  is a diagram showing an example of display on the screen of a display device when an object editing program according to an embodiment of the invention is executed; 
         FIG. 3  is a flowchart showing an object editing method according to an embodiment of the present invention; 
         FIG. 4  is a flowchart showing the processing performed by the object editing method according to an embodiment of the invention to calculate a direction in which a mouse is moving; 
         FIG. 5A  is a diagram showing the state of an object before an event occurs; 
         FIG. 5B  is a diagram showing the state of the object after an event has occurred and a snap function has been employed; 
         FIG. 6  is a flowchart showing the processing for an object editing method according to an embodiment of the present invention; 
         FIG. 7  is a diagram for explaining the frequency of the performance of a snap function for moving an object using the object editing method according to an embodiment of the present invention; 
         FIG. 8  is a diagram showing a conventional object editing screen for an electronic document; and 
         FIG. 9  is a diagram showing the frequency of the performance, for an electronic document, of a snap function for moving an object on a conventional object editing screen. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the present invention will now be specifically described while referring to  FIG. 1 .  FIG. 1  is a schematic diagram showing the configuration of an object editing system according to an embodiment of the invention. The object editing system in this embodiment includes a central processing unit (CPU)  1 , a memory  2 , an object editing program  3 , a hard disk  4 , a display device  5 , a mouse  6 , a keyboard  7  and a CD-ROM drive  8 . 
     The CPU  1  is a device for executing the object editing program  3 . The memory  2  is a storage device into which the object editing program  3 , which is stored on the hard disk  4 , is temporarily loaded for execution. The mouse  6  and the keyboard  7  are data input devices a user employs when inputting commands to be executed by the CPU  1 , or when using the object editing program  3 . The CD-ROM drive  8  is a device used, in accordance with a command issued by the CPU  1 , to transfer the object editing program  3 , stored on a CD-ROM, to the hard disk  4 . 
     The CPU  1  and the object editing program  3 , when it has been loaded into the memory  2 , cooperate in the execution of the object editing method of the present invention. 
     An explanation will be given while referring to  FIG. 2 .  FIG. 2  is a diagram showing an example of display on a screen  5   a  of the display device  5 , when the object editing program of this invention is executed. There are a plurality of vertical grids  11   a  to  11   g  and a plurality of horizontal grids  12   a  to  12   c  on the screen  5   a,  arranged within a predesignated two-dimensional display area by grid arrangement means. The grids serve as reference lines when an object in the display area is being edited and are used as snap targets for an object. Note that, although in  FIG. 2  the grids are displayed, under other circumstances they may not be visible. It is also noted, when the object editing program of the invention is executed, the available grids are not limited to the vertical grids  11   a  to  11   g  and the horizontal grids  12   a  to  12   c,  which are merely a set of grids. A mouse (a pointer for a mouse) denoted by reference numeral  13  is employed in this embodiment as a pointing device for moving the pointer. However, another pointing device may be employed. 
     An object  10  is also displayed on the screen  5   a . The form of the object  10  is a rectangle, and in this embodiment, the right side, the left side, the upper side and the lower side of the rectangle are respectively denoted by  10   a,    10   b,    10   c  and  10   d . In this invention, the right side, the left side, the upper side or the lower side of the rectangle, which is an edge line of the object  10 , is used as a snap reference relative to a grid that is a snap target for the object  10 . 
     As the feature of the object editing method of the invention, when the object  10  is to be moved to a desired location, the snap function is automatically enabled only for a side of the rectangle of the object  10  in the direction in which the object  10  moves. That is, the snap function is automatically disabled for a side of the rectangle located opposite to the direction in which the object  10  moves. 
     According to the object editing method of the invention, there are eight patterns, shown in Table 1 below, that reflect the relationship between the direction in which the object  10  moves, i.e., the direction in which the mouse  13  moves, and the side (the right side  10   a,  the left side  10   b,  the upper side  10   c  or the lower side  10   d ) of the rectangle of the object  10  for which the snap function is enabled. 
     
       
         
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Pattern of a direction 
                 Side of a rectangle of an object for which a 
               
               
                 in which a 
                 snap function is enabled 
               
             
          
           
               
                 a mouse moves 
                 Upper side 
                 Lower side 
                 Right side 
                 Left side 
               
               
                   
               
               
                 1 Up rightward 
                 ∘ 
                   
                 ∘ 
                   
               
               
                 2 Directly rightward 
                   
                   
                 ∘ 
                   
               
               
                 3 Down rightward 
                   
                 ∘ 
                 ∘ 
                   
               
               
                 4 Directly up 
                 ∘ 
                   
                   
                   
               
               
                 5 Directly down 
                   
                 ∘ 
                   
                   
               
               
                 6 Up left 
                 ∘ 
                   
                   
                 ∘ 
               
               
                 7 Directly left 
                   
                   
                   
                 ∘ 
               
               
                 8 Down leftward 
                   
                 ∘ 
                   
                 ∘ 
               
               
                   
               
               
                 ∘: Enabled 
               
             
          
         
       
     
     According to the object editing method of the invention, the side of the rectangle for which the snap function is enabled and the side of the rectangle for which the snap function is disabled are determined based on the eight patterns in Table 1 on the basis of the direction in which the mouse  13  moves, so that the number of snap operations can be reduced and the object  10  can be moved smoothly. 
     An explanation will be given while referring to  FIG. 3 .  FIG. 3  is a flowchart showing the object editing method of the invention. In this embodiment, an “event” means a phenomenon that, through the manipulation of the mouse  13  by a user (e.g., by keeping depressing the left button of the mouse  13 ), the object  10  is selected and held, and thereafter the position of the mouse  13  (the position of the mouse pointer) is changed. 
     First, through manipulation of the mouse  13  by the user, a moving means is operated, the object  10  is selected and held, and the position of the mouse  13  is changed, i.e., an event occurs (step S 1 ). 
     Next, the vertical direction and the horizontal direction in which the mouse  13  moves (the vertical component and the horizontal component of the direction in which the mouse  13  moves) are calculated (step S 2 ). specifically, the process at step S 2  is performed by three steps, as shown in  FIG. 4  (steps S 2   a,  S 2   b  and S 2   c ). At step S 2 , the preceding position coordinates of the mouse  13  (the position coordinates before the event occurred) (Xp, Yp) are obtained (step S 2   a ). Then, the current position coordinates of the mouse  13  (the position coordinates following the occurrence of the event) (Xc, Yc) are obtained (step S 2   b ). Thereafter, a difference between the preceding position coordinates and the current position coordinates, i.e., (ΔX, ΔY)=(Xc−Xp, Yc−Yp), is calculated. In accordance with the difference (ΔX, ΔY), the direction in which the mouse  13  moves is determined. The relationship between the difference (ΔX, ΔY) and the direction in which the mouse  13  moves is as shown in Table 2. 
     
       
         
               
               
             
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                   
                 Side of a rectangle for which a 
               
               
                   
                 candidate grid is calculated 
               
             
          
           
               
                 Pattern of direction 
                 (S4) 
                 (S5) 
                 (S6) 
                 (S7) 
               
               
                 in which a mouse moves 
                 Upper side 
                 Lower side 
                 Right side 
                 Left side 
               
               
                   
               
             
          
           
               
                 1 
                 Δx &gt; 0, Δy &gt; 0 
                 Up rightward 
                 ∘ 
                   
                 ∘ 
                   
               
               
                 2 
                 Δx &gt; 0, Δy = 0 
                 Directly rightward 
                   
                   
                 ∘ 
                   
               
               
                 3 
                 Δx &gt; 0, Δy &lt; 0 
                 Down rightward 
                   
                 ∘ 
                 ∘ 
                   
               
               
                 4 
                 Δx = 0, Δy &gt; 0 
                 Directly up 
                 ∘ 
                   
                   
                   
               
               
                 5 
                 Δx = 0, Δy &lt; 0 
                 Directly down 
                   
                 ∘ 
                   
                   
               
               
                 6 
                 Δx &lt; 0, Δy &gt; 0 
                 Up leftward 
                 ∘ 
                   
                   
                 ∘ 
               
               
                 7 
                 Δx &lt; 0, Δy = 0 
                 Directly left 
                   
                   
                   
                 ∘ 
               
               
                 8 
                 Δx &lt; 0, Δy &lt; 0 
                 Down leftward 
                   
                 ∘ 
                   
                 ∘ 
               
               
                   
               
               
                 ∘: Selected 
               
             
          
         
       
     
     Sequentially, the side of the rectangular object  10  for which the snap function is enabled, i.e., the side of the rectangle for which a grid (a snapping candidate grid) which the object  10  is to snap is to be calculated, is calculated based on the direction in which the mouse  13  moves, which is obtained at step S 2  (step S 3 ). The process at step S 3  is performed based on the eight patterns shown in Table 2 for the direction in which the mouse  13  moves, and the corresponding sides of the rectangle for which the snapping candidate grids are calculated. As shown in Table 2, the upper side and the right side of the rectangle are the sides that correspond to a difference (ΔX&gt;0, ΔY&gt;0), and for which snapping candidate grids are to be calculated. And the right side of the rectangle is the side that corresponds to a difference (ΔX&gt;0, ΔY=0), and for which a snapping candidate grid is to be calculated. In this manner, based on the calculation results obtained for the difference (ΔX, ΔY), at most two sides or at least one side of the rectangle is obtained. As shown in  FIG. 2 , when two sides of the rectangle are obtained, because of the properties of this invention, these should be the upper side or the lower side and the right side or the left side. Further, (S 4 ), (S 5 ), (S 6 ) and (S 7 ) in Table 2 correspond to the step numbers in  FIG. 3 . 
     Based on the calculation results obtained at step S 3 , at most two steps or at least one step of steps S 4  to S 7  is performed. For example, when the upper side and the right side have been calculated at step S 3 , the upper side (step S 4 ) and the right side (step S 6 ) are selected. When the lower side and the left side have been calculated at step S 3 , the lower side (step S 5 ) and the left side (step S 7 ) are selected. 
     When step S 4  is selected, step S 8  is performed; when step S 5  is selected, step S 9  is performed; when step S 6  is selected, step S 10  is performed; and when step S 7  is selected, step S 11  is performed. 
     At steps S 8  and S 9 , the nearest neighbor snapping candidate grid (horizontal grid) of the selected side of the rectangle is calculated. At steps S 10  and S 11 , the nearest neighbor snapping candidate grid (vertical grid) for the selected side of the rectangle is calculated. For example, at step S 8 , the nearest neighbor snapping candidate grid for the upper side of the rectangle is calculated, and at step S 10 , the nearest neighbor snapping candidate grid for the right side is calculated. As a result, at most two or at least one snapping candidate grid is calculated in accordance with the direction in which the mouse  13  moves. 
     Then, a check is performed to determine whether the distances between the snapping candidate grids obtained at steps S 8  to S 11  and the target sides of the rectangle are smaller than predesignated threshold values (a threshold value Xth in the X direction and a threshold value Yth in the Y direction) (step S 12 ). When the distances are smaller than the threshold values, the target sides of the rectangle are caused to snap the corresponding snapping candidate grids (step S 13 ), and the processing is thereafter terminated (END). When the distances are equal to or greater than the threshold values, the sides of the rectangle are inhibited from snapping the snapping candidate grids (step S 14 ), and the processing is terminated (END). For example, assume that the direction in which the mouse  13  moves is down rightward, and that, in accordance with the results obtained at steps S 9  and S 10 , a horizontal grid that is upper adjacent is obtained as the nearest neighboring snapping candidate grid for the lower side of the rectangle, and a vertical grid that is left adjacent is obtained as the nearest neighboring snapping candidate grid for the right side of the rectangle. When the distance between the lower side of the rectangle and the obtained horizontal grid is smaller than the threshold value Yth, and when the distance between the right side of the rectangle and the obtained vertical grid is smaller than the threshold value Xth, the lower side and the right side of the rectangle are caused to snap the horizontal grid and the vertical grid, respectively. On the other hand, when the distance between the lower side of the rectangle and the obtained horizontal grid is smaller than the threshold value Yth, and when the distance between the right side of the rectangle and the obtained vertical grid is equal to or greater than the threshold value Xth, the lower side of the rectangle is caused to snap the horizontal grid, but the right side of the rectangle is inhibited from snapping the vertical grid. It should be noted that the same value may be set for the vertical threshold value Yth and the horizontal threshold value Xth, or that different values may be set. 
     Alternatively, when the distances between the sides of the rectangle of the object that are snap references and grids that are snap targets are equal to or smaller than threshold values (Xth, Yth), the side may be caused to snap the grid. 
     By repeating the above described processing shown in  FIG. 3 , the snap function can be enabled only for the sides of the rectangle that are on the side in the direction in which the object  10  moves, and can be disabled for the sides of the rectangle that are on the side opposite to the direction in which the object  10  moves. Therefore, the number of snap operations can be reduced and the object  10  can be moved smoothly using the mouse  13 , so that the object drag-and-drop operation and the usability can be improved. 
     Furthermore, according to the object editing method of the invention, compared with the conventional complicated snap function such as the method whereby the snap function is temporarily disabled by simultaneously using the shift key, the object editing operation can be performed automatically, using a single hand, without any need to learn complicated snap function, and the frequency at which the snap function occurs can be reduced. 
     According to the object editing method of the invention, the object  10  can be caused to snap only a grid located in the direction in which the object  10  is moving. When in  FIG. 2 , for example, the left side  10   b  of the rectangle object  10 , is to be snapped the vertical grid  11   c,  the left side  10   b  is first moved to the right of the vertical grid  11   c,  and then the object  10  is moved to the left. Thus, the left side  10   b  of the rectangle object  10 , can be caused to snap the vertical grid  11   c.    
     While referring to  FIGS. 5A and 5B , an explanation will be given for example processing, performed by the object editing system that employs the object editing method in the above described embodiment, for moving the object  10  in a direction (upper right) indicated by arrows in  FIG. 5B . 
       FIG. 5A  is a diagram showing the state of the object  10  before an event occurs.  FIG. 5B  is a diagram showing the state of an object  10 ′ after the event has occurred and the snap function has been employed. 
     In this embodiment, as shown in  FIG. 5B , it is assumed the distance between the right side of the object  10 ′ and the vertical grid lid after the event occurred is smaller than the threshold value Xth, and the distance between the upper side of the object  10 ′ and the horizontal grid  12   b  is smaller than the threshold value Yth. It is understood that the right side and the upper side of the object  10 ′ are caused to snap the vertical grid  11   d  and the horizontal grid  12   b.    
     The processing, performed using the object editing method of this embodiment, will now be described while referring to  FIG. 6 . 
     First, through user manipulation of the mouse  13 , the object  10  is selected and held, and the position of the mouse  13  (the pointer of the mouse  13 ) is changed, i.e., an event occurs (step S 1 ). In this embodiment, it is assumed that the position of the mouse  13  is changed to the upper right position. 
     Next, the direction in which the mouse  13  is moving is calculated (step S 2 ). As described above, the process at step S 2  is performed in three steps in  FIG. 4  (steps S 2   a,  S 2   b  and S 2   c ). At step S 2 , the preceding position coordinates of the mouse  13  (the position coordinates before the event occurred) (Xp, Yp) are obtained (step S 2   a ). Then, the current position coordinates of the mouse  13  (the position coordinates after the event occurred, i.e., the position coordinates for a mouse  13 ′) (Xc, Yc) are obtained (step S 2   b ). Thereafter, a difference between the preceding position coordinates and the current position coordinates, i.e., (ΔX, ΔY)=(Xc−Xp, Yc−Yp), is calculated. In this embodiment, a difference (ΔX&gt;0, ΔY&gt;0) is obtained. 
     Sequentially, the sides of the rectangle, for which possible grids (snapping candidate grids) the object  10  is to snap are to be calculated, are calculated based on the direction in which the mouse  13  moves. The result is obtained at step S 2  (step S 3 ). In this embodiment, by referring to Table 2, the upper side and the right side of the rectangle are the sides that correspond to the difference (ΔX&gt;0, ΔY&gt;0), and that are targets for which the snapping candidate grids are to be calculated. 
     Since the upper side and the right side are obtained at step S 3 , the upper side (step S 4 ) and the right side (S 6 ) are selected. 
     Following this, steps S 8  and S 10  are preformed. At step S 8 , the nearest neighbor snapping candidate grid of the selected upper side of the rectangle is calculated, and at step S 10 , the nearest neighbor snapping candidate grid of the selected right side is calculated. 
     As shown in  FIG. 5B , in this embodiment, the horizontal grid  12   b  is obtained as the result at step S 8 , and the vertical grid lid is obtained as the result at step S 10 . 
     Thereafter, a check is performed to determine whether the distances between the snapping candidate grids obtained at steps S 8  and S 10  and the respective target sides of the rectangle are smaller than the predesignated threshold values (the threshold value Xth in the X direction and the threshold value Yth in the Y direction) (step S 12 ). When the distances are smaller than the threshold values, the target sides of the rectangle are caused to snap the corresponding snapping candidate grids (step S 13 ) and the processing is thereafter terminated (END). When the distances are equal to or greater than the threshold values, the sides of the rectangle are inhibited from snapping the snapping candidate grids (step S 14 ), and the processing is terminated (END). In this embodiment, since the distance between the upper side of the rectangle and the horizontal grid  12   b  is smaller than the threshold value Xth and the distance between the right side of the triangle and the vertical grid lid is smaller than the threshold value Yth, the upper side and the right side of the rectangle are caused to snap the horizontal grid  12   b  and the vertical grid lid, respectively. 
     When the event that, using the mouse  13 , the object  10  is held and moved up rightward occurs repetitively, the processing shown in  FIG. 6  is repeated. As a result, the snap function is enabled only for the upper side and right side of the rectangle in the direction in which the object  10  is moving, and is disabled for the lower side and left side that are on the side opposite to the direction in which the object  10  is moving. As a result, the number of snaps can be reduced, and the movement of the object  10  by using the mouse  13  can be performed smoothly. Further, the drag-and-drop operation for the object  10  and the usability can be improved. 
       FIG. 7  is a diagram for explaining the frequency of the operation of the snap function when the event occurs repetitively, and the object  10  is moved to the position indicated by the object  10 ′. Until the object  10  is moved to the position indicated by the object  10 ′, i.e., until the right side  10   a  is caused to snap the vertical grid  11   f,  a total eight snaps will occur when the conventional snap function is used, while only a total of four snaps (Snap 1  to Snap 4 ) will occur when the object editing method of this embodiment is employed. That is, the right side  10   a  is caused to snap the vertical grid  11   d,  the upper side  10   c  is caused to snap the horizontal grid  12   b,  the right side  10   a  is caused to snap the vertical grid lie, and thereafter, the right side  10   a  is caused to snap the vertical grid  11   f.    
     As described above, it has been found that, by employing the object editing method of this invention, the number of snapping operations can be reduced to about half, that the movement of the object  10  by using the mouse  13  can be performed smoothly, and that the drag-and-drop operation of the object  10  and the usability can be improved. 
     The specific mode and the embodiment of the present invention have been explained. The present invention, however, is not limited to the mode and the embodiment explained herein, and the design of the present invention can be variously modified without departing from the disclosed technical scope of the invention. 
     According to the object editing system and the object editing method of the invention, the snap function is enabled only for the sides of the rectangle in the direction in which the object moves, and is disabled for the sides of the rectangle opposite to the direction in which the object moves. Thus, the number of performances of snap operations can be reduced, and the movement of the object by using the mouse can be smoothly performed. As a result, the drag-and-drop operation for the object and the usability can be improved. 
     Further, according to the object editing system and the object editing method of the invention, when compared with the conventional complicated snap function, i.e., the method whereby the snap function is temporarily disabled by using the shift key together, the object editing process can be automatically performed using a single hand without having to learn any complicated snap function, and the frequency at which the snap function occurs can be reduced. 
     Therefore, the present invention can be applied to various types of software, such as word processor software that includes an object editing function, CAD software and WEB design software, and the computer systems that employ them.