Abstract:
An image-display control system including: a display having a display area; a touch panel; a processor; and a memory storing instructions that, when executed by the processor, cause the system to: display object images arranged in a first direction in the display area; determine a touch and a position of the touch; define, in the display area, first and second operation regions arranged in a second direction orthogonal to the first direction, the first operation region being not defined in the identical position to the second operation region, at least a part of each object image being displayed in the two operation regions; when determined the touch in the first operation region, execute a unique process assigned for one of the object images displayed at a position of the touch; and when determined the touch in the second operation region and when determined that a position of the touch is moving in the first direction while keeping the touch, scroll the object images in the first direction.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The present application claims priority from Japanese Patent Application No. 2012-200501, which was filed on Sep. 12, 2012, the disclosure of which is herein incorporated by reference in its entirety. 
       BACKGROUND 
       [0002]    The present invention relates to an image-display control system for controlling an image to be displayed on a display. The invention further relates to an image-display control method and a non-transitory computer-readable storage medium in which an image-display control program is stored. 
         [0003]    A display equipped with a touch panel is commonly used as a user interface (hereinafter abbreviated as “UI” where appropriate) for permitting a user to visually recognize or select a plurality of functions, setting items, and so on, in various information processing apparatus such as a multifunction peripheral and a mobile information terminal (e.g., PDA). One of the most typical examples of such a UI is the following structure. A screen including a plurality of object images indicative of various setting items and the like are displayed on a display in the form of a list. The display is configured to accept a user&#39;s operation for selecting a certain one of the object images and a user&#39;s another operation for scrolling the screen. 
         [0004]    In such a UI, when the user touches a desired position on the display by a pointer (pointing tool) such as a finger, a stylus, or the like, the object image that is being displayed at the touched position is selected and process corresponding to the selected object image is executed. On the other hand, when the user moves (drags) the pointer in an arrangement direction in which the object images are arranged in the list, with the display kept touched by the pointer, the list of the object images displayed on the display is scrolled in a direction in which the user moved the pointer. In other words, both of a tap operation and a drag operation can be accepted for the same one object image. In general, the tap operation and the drag operation are distinguished from each other on the basis of whether an amount of the movement of a touch point on the display by the pointer is equal to or greater than a prescribed threshold. In this respect, throughout the present specification, a touch operation that does not involve any movement of a position of a touch on the display is referred to as a tap operation where appropriate, for the sake of convenience. 
       SUMMARY 
       [0005]    Although both the tap operation and the drag operation are available in the UI, a process not intended by the user may be executed depending upon a user&#39;s operation condition. For instance, despite the user has touched, with his/her finger, a certain object image for selection, the finger may unintentionally move with the finger kept touched the display when the object image is touched, thereby causing the list to be scrolled contrary to the user&#39;s intention. 
         [0006]    To prevent the tap operation from being erroneously judged as the drag operation as described above, it may be determined whether it is the drag operation based on the greater threshold of the movement amount of the touch point. However, the greater the threshold is, the worse the scrolling operability is. In this case, the drag operation may be erroneously judged as the tap operation due to a shortage in the amount of the movement even though the user intended to do the drag operation for scrolling. 
         [0007]    The description of the present application may enable a user to easily obtain an intended operation result without suffering from deterioration in operability for the user, in a UI configured to accept both the tap operation and the drag operation. 
         [0008]    The object indicated above may be attained according to a first aspect of the present invention, which provides, an image-display control system comprising: a display including a display area; a touch panel disposed over the display; a processor coupled with the display and the touch panel; and a memory storing instructions that, when executed by the processor, cause the image-display control system to: display a plurality of object images arranged in a first direction in the display area of the display, each of the plurality of object images having a unique process assigned; determine a touch and a position of the touch while the pointer touches the display area; define a first operation region and a second operation region in the display area, wherein the first operation region and the second operation region are arranged in a second direction orthogonal to the first direction, wherein the first operation region is not defined in the identical position to the second operation region and wherein at least a part of each of the plurality of object images is displayed in the first operation region and the second operation region; when determined the touch in the first operation region, execute the unique process assigned for one of the plurality of object images displayed at a position of the touch; and when determined the touch in the second operation region and when determined that a position of the touch is moving in the first direction while keeping the touch, scroll the plurality of object images in the first direction. 
         [0009]    The object indicated above may be attained according to a second aspect of the present invention, which provides, a method of controlling an image to be displayed on a display including a display area, comprising the steps of: displaying a plurality of object images arranged in a first direction in the display area of the display, each of the plurality of object images having a unique process assigned; defining a first operation region and a second operation region in the display area, wherein the first operation region and the second operation region are arranged in a second direction orthogonal to the first direction, wherein the first operation region is not defined in the identical position to the second operation region; executing the unique process assigned for one of the plurality of object images displayed at a position of the touch, when determined the touch in the first operation region; and scrolling the plurality of object images in the first direction, when determined the touch in the second operation region and when determined that a position of the touch is moving in the first direction while keeping the touch. 
         [0010]    The object indicated above may be attained according to a third aspect of the present invention, which provides, a non-transitory computer-readable storage medium in which is stored an image-display control program to be executed by a computer of an image-control system comprising: a display including a display area; a touch panel disposed over the display; a processor provided in the computer and coupled with the display and the touch panel; and a memory storing instructions included in the image-display control program that, when executed by the processor, cause the image-display control system to: display a plurality of object images arranged in a first direction in the display area of the display, each of the plurality of object images having a unique process assigned; determine a touch and a position of the touch while the pointer touches the display area; define a first operation region and a second operation region in the display area wherein the first operation region and the second operation region are arranged in a second direction orthogonal to the first direction, wherein the first operation region in not defined in the identical position to the second operation region and wherein at least of part of such that each of the plurality of object images is displayed in the first operation region and the second operation region; when determined the touch in the first operation region, execute the unique process assigned for one of the plurality of object images displayed at a position of the touch; and when determined the touch in the second operation region and when determined that a position of the touch is moving in the first direction while keeping the touch, scroll the plurality of object images in the first direction. 
         [0011]    The image-display control system indicated above is realized by permitting the instructions described above to be executed by the processor according to a prescribed program. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above and other objects, features, advantages and technical and industrial significance of the present invention will be better understood by reading the following detailed description of embodiments of the invention, when considered in connection with the accompanying drawings, in which: 
           [0013]      FIG. 1A  is a view schematically showing a structure of an MFP according to one embodiment of the invention and  FIG. 1B  is a plan view of an operation panel portion; 
           [0014]      FIGS. 2A-2C  are views for explaining screen examples of a liquid crystal display (LCD), and more specifically,  FIG. 2A  is an initial screen example,  FIG. 2B  is a screen example when a tap region is tapped by a pointer, and  FIG. 2C  is a screen example when a scroll region is dragged in a scroll direction by the pointer; 
           [0015]      FIGS. 3A-3C  are views for explaining screen examples of the LCD, and more specifically,  FIG. 3A  shows a screen example in which a width of each region is changed,  FIG. 3B  shows a screen example in which the two regions are switched with each other, and  FIG. 3C  is an initial screen example in which the tap region and the scroll region partially overlap; 
           [0016]      FIG. 4  is a flow chart of touch-state detecting process executed by a CPU of the MFP; 
           [0017]      FIG. 5  is a flow chart of main process executed by the CPU of the MFP; 
           [0018]      FIG. 6  is a flow chart showing details of touch start process of S 135  in  FIG. 5 ; 
           [0019]      FIG. 7  is a flow chart showing details of drag process of S 145  in  FIG. 5 ; 
           [0020]      FIG. 8  is a flow chart showing details of vertical-direction process of S 350  in  FIG. 7 ; 
           [0021]      FIG. 9  is a flow chart showing details of lateral-direction process of S 355  in  FIG. 7 ; 
           [0022]      FIG. 10  is a flow chart showing details of release process of S 155  in  FIG. 5 ; 
           [0023]      FIGS. 11A-11C  are views for explaining a method for initial setting of respective widths of the tap region and the scroll region, i.e., for initial setting of a boundary between the tap region and the scroll region, in accordance with a number of characters in one of list-item images; 
           [0024]      FIG. 12  is a flow chart of automatic-region-determining process executed by the CPU of the MFP to realize the method for initial setting of the respective widths of the two regions, i.e., for initial setting of the boundary therebetween, in accordance with the number of characters; and 
           [0025]      FIGS. 13A and 13B  are views for explaining screen examples of the LCD according to other embodiments. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0026]    There will be hereinafter explained embodiments of the present invention while giving concrete examples. 
         [0027]    As shown in  FIG. 1A , a multifunction peripheral (MFP)  1  according to the present embodiment includes a CPU  11 , a ROM  12 , a RAM  13 , an image reading portion  14 , an image forming portion  15 , an operation panel portion  16 , a network communication portion  17 , and a telephone communication portion  18 . 
         [0028]    The CPU  11  is configured to execute a control of various portions in the MFP  1  and various calculation according to various control programs stored in the ROM  12 . The RAM  13  is configured to be directly accessible from the CPU  11 . The RAM  13  is also a temporal storage area for temporarily storing various coordinates and various process states to be set when various process (that will be later explained) is executed, various processing directions, various events to be issued, and so on. 
         [0029]    The image reading portion  14  is configured to read an image of a document by an image sensor and to generate image data indicative of the image. The image forming portion  15  is configured to record an image on a sheet-like recording medium such as a recording sheet. An example of the network communication portion  17  is a network interface card. An example of the telephone communication portion  18  is a modem. The modem is used in telephone communication and facsimile communication through a telephone network. 
         [0030]    The operation panel portion  16  includes a liquid crystal display (LCD)  21 , a touch panel  22 , and an internally illuminated display  23  that are disposed as described below. 
         [0031]    The LCD  21  includes an LCD module capable of displaying an arbitrary image in full color. There are displayed, on the LCD  21 , various sorts of information such as various functions and an operating status of the MFP  1 . For instance, there is displayed, on the LCD  21 , a menu-list image  31  including a plurality of list-item images  41 ,  42 , . . . , as shown in  FIGS. 2 and 3 . Each of the list-item images  41 ,  42 , . . . is indicative of a certain setting item or function. In a state in which the menu-list image  31  is displayed, a user is allowed to select any one of the list-item images  41 , etc., by performing a particular tap operation and to cause the menu-list image  31  to be scrolled by performing a particular drag operation in a particular arrangement direction in which the list-item images  41 ,  42 , . . . are arranged. Each of the list-item images  41 ,  42 , . . . is one example of an object image in the present invention. 
         [0032]    As shown in  FIG. 1B , the touch panel  22  is a transparent film-like input device, such as capacitive touch screen, that can detect a touch operation by a pointer such as a finger or a stylus, in a well-known capacitive sensing technology. The touch panel  22  is disposed so as to be superposed on display surfaces of the LCD  21  and the internally illuminated display  23 . As shown in  FIG. 1B , the internally illuminated display  23  displays thereon images indicative of a numeric keypad and some operation buttons. 
         [0033]    In the present embodiment, when a touch by the pointer is detected by the touch panel  22 , a touch detection signal indicative of coordinates of a position of the touch is outputted from the touch panel  22  to the CPU  11 . The CPU  11  is configured to execute various process that will be later explained, on the basis of the touch detection signal. 
         [0034]    Next, there will be explained in detail what is displayed when the menu-list image  31  is shown on the LCD  21  and how a user&#39;s operation is accepted by the MFP  1 , with reference to screen examples shown in  FIGS. 2 and 3 . 
         [0035]    In the MFP  1  of the present embodiment, an initial screen (shown in  FIG. 2A ) of the menu-list image  31  including the plurality of list-item images  41 ,  42 ,  43 ,  44 ,  45 , . . . is displayed in a display area  30  of the LCD  21  in various situations such as a situation in which a certain function is selected and a situation in which various setting items are set in image reading by the image reading portion  14 . 
         [0036]    More specifically, the menu-list image  31  includes the plurality of list-item images  41 , etc., that are arranged in the particular arrangement direction. In the screen example of  FIG. 2A , the arrangement direction is an up-down direction in  FIG. 2A . Hereinafter, the arrangement direction is referred to as a “scroll direction” where appropriate. In the present embodiment, more than six list-item images are arranged although a particular number of the list-item images (e.g., five list-item images in the present embodiment) among the plurality of list-item images are displayed in the display area  30 . A user can understand, by a scroll-position indication bar  32  that is displayed at a right end of the display area  30 , where the five list-item images that are currently being displayed are located among all of the list-item images that can be displayed. 
         [0037]    Each of the list-item images  41 , etc., contains a character string that indicates setting details or a function corresponding to the associated list-item image. In each character string, characters are arranged from a leftmost end toward a right end in a left-right direction of the screen (i.e., an orthogonal direction to the arrangement direction). The user can recognize, when looking at the character strings, what function is implemented by tapping a certain list-item image. In the display area  30 , x-y coordinates are set. That is, an x-axis is set in the left-right direction of the screen while a y-axis is set in the up-down direction of the screen. The scroll direction is identical to the up-down direction. An origin of the x-y coordinates may be suitably determined. 
         [0038]    In a state in which the initial screen is displayed, when the user taps a desired list-item image with the pointer such as a finger, a function corresponding to the tapped list-item image can be implemented. Further, when the user drags the pointer in the display area  30  in the arrangement direction, the menu-list image  31  can be scrolled in the dragged direction. In detail, various touch operations such as the tap operation and the drag operation by the pointer are realized via a touch on the touch panel  22 . Accordingly, in the following explanation, each of “tap (operation)”, “drag (operation)”, and “flick (operation)” means an operation on the touch panel  22 . 
         [0039]    In the present embodiment, not every tap operation performed by tapping any portion in the list-item image is accepted, namely, a function corresponding to the list-item image is not always realized by a tap operation on any portion in the list-item image. Similarly, not every drag operation performed by dragging any portion in the display area  30  causes the menu-list image  31  to be scrolled. In the present embodiment, there are individually set, in the display area  30 , a region in which the tap operation is accepted and a region in which the drag operation is accepted. 
         [0040]    More specifically, the entirety of the menu-list image  31  in the display area  30  is divided in two regions in the left-right direction, i.e., a tap region  51  on the left side and a scroll region  52  on the right side. The tap region  51  is one example of a first operation region in the present invention. The scroll region  52  is one example of a second operation region in the present invention. In each of the list-item images  41 , etc., a left-side portion thereof is disposed in the tap region  51  while a right-side portion thereof is disposed in the scroll region  52 . These two regions  51 ,  52  are set within the menu-list image  31  without extending beyond the menu-list image  31  and there is no clearance between the two regions  51 ,  52 . In the example shown in  FIG. 2 , however, for clarifying distinction between the two regions  51 ,  52 , the broken line showing each region  51 ,  52  is illustrated so as to extend beyond the menu-list image  31 , and the two regions  51 ,  52  are illustrated so as to be slightly spaced apart from each other. However, it is not essential that the two regions  51 ,  52  be set within the menu-list image  31  or be adjacent to each other with no clearance therebetween. 
         [0041]    In the present embodiment, the tap region  51  and the scroll region  52  are displayed in mutually different colors in a particular operation state, such that the two regions  51 ,  52  can be visually distinguished from each other and a boundary therebetween is easily recognized. A situation in which the two regions are displayed in mutually different colors will be described later. The two regions  51 ,  52  may be continuously displayed in mutually different colors regardless of the operation state as long as the menu-list image  31  is being displayed. On the contrary, the two regions  51 ,  52  may be displayed in the same color. 
         [0042]    Widths of the respective regions  51 ,  52  in the initial screen may be determined in various ways. For instance, the widths may be set to respective default values or may be set such that the last state when a preceding menu-list image  31  was being displayed is reproduced. The width of each of the regions  51 ,  52  is a dimension thereof in the orthogonal direction that is orthogonal to the arrangement direction. 
         [0043]    In the screen examples shown in  FIG. 2 ,  FIGS. 3A and 3B , the two regions  51 ,  52  are adjacent to each other in the left-right direction (in the orthogonal direction that is orthogonal to the scroll direction) without overlapping each other. The tap region and the scroll region may partially overlap each other, as shown in  FIG. 3C . In the example shown in  FIG. 3C , there is also set a common region  63  in which each of the tap operation and the drag operation is acceptable. 
         [0044]    In the screen example of the display area  30  shown in  FIG. 2A , where the user taps a desired position in the tap region  51  with a pointer such as his/her finger, it is determined that the tap operation has been performed and there is executed process predetermined for the list-item image that is being displayed at the tapped position. The process will be hereinafter referred to as the “corresponding process” where appropriate. In the present embodiment, timing at which the corresponding process is actually executed is not the exact time when the desired position is touched, but the time when the pointer is separated from the touch panel  22  after the desired position has been touched. It is, however, not essential that the corresponding process be executed at timing when the pointer is separated from the touch panel  22 . For instance, the corresponding process may be executed at timing when the pointer has come into contact with the touch panel  22  or at certain timing between when the pointer has come into contact with the touch panel  22  and when the pointer is separated therefrom. 
         [0045]      FIG. 2B  shows an example of the display region  30  that displays a screen in which the pointer has tapped the list-item image  44  that is the fourth list-item image from the top in the tap region  51 . In this instance, the CPU  11  determines that the list-item image  44  has been tapped on the basis of a tap detection signal indicative of coordinates of a position tapped by the pointer (i.e., tap position) and executes the corresponding process predetermined for the list-item image  44 . Where the pointer taps a certain position in the tap region  51 , the list-item image that is being displayed at the position tapped by the pointer may be highlighted in such a way that the list-item image is displayed in a different color from the other list-item images. 
         [0046]    In the screen example of the display area  30  shown in  FIG. 2A , when the user touches any position in the scroll region  52  with the pointer such as his/her finger, keeps the touch and subsequently moves the pointer in the scroll direction, it is determined that the drag operation has been performed. In this instance, the menu-list image  31  is scrolled by a certain amount, which is determined in accordance with an amount of the movement of the pointer in the scroll direction. In other words, the certain amount is determined in accordance with a distance of the movement of the pointer in the y-axis direction. 
         [0047]      FIG. 2C  is a screen example showing a state in which the menu-list image  31  is scrolled by an amount corresponding to a height of two list-item images due to the user&#39;s drag operation in the scroll region  52  with the pointer. In this instance, the CPU  11  determines that the drag operation has been performed on the basis of a continuous change of the coordinates of the touch position of the pointer. And then, the menu-list image  31  is scrolled by an amount in accordance with an amount of the drag operation (i.e., the movement distance of the pointer in the y-axis direction) in a direction of the drag operation (e.g., in the upward direction in  FIG. 2C ). 
         [0048]    In the initial screen shown in  FIG. 2A , the user can enlarge or reduce the width of each of the two regions  51 ,  52 , (i.e., the width thereof in the orthogonal direction). To be more specific, when the user drags the pointer in one of the two regions  51 ,  52  in the width direction thereof (i.e., in the orthogonal direction), the width of the one of the two regions  51 ,  52  on which the drag operation has been performed changes in a direction in which the drag operation has been performed. For instance, where the user drags the pointer in the scroll region  52  in a leftward direction, the width of the scroll region  52  is enlarged in the leftward direction, as shown in  FIG. 3A . In this instance, the width of the tap region  51  is reduced in the leftward direction by an amount corresponding to the enlargement amount of the scroll region  52 . The enlargement amount and the reduction amount of the regions  51 ,  52  correspond to the movement amount of the pointer in the drag operation, more specifically, the movement distance of the pointer in the x-axis direction. In other words, the width of each region  51 ,  52  is changed by an amount corresponding to the movement distance in the x-axis direction. 
         [0049]    Contrary to the example shown in  FIG. 3A , when the user drags the pointer in the scroll region  52  in a rightward direction, the width of the scroll region  52  is reduced in the rightward direction and the width of the tap region  51  is enlarged in the rightward direction by an amount corresponding to the reduction amount. 
         [0050]    The width of each region  51 ,  52  may be enlarged or reduced also by dragging the pointer in the press region  51 . For instance, when the user drags the pointer in the press region  51  in the rightward direction, the width of the press region  51  is enlarged in the rightward direction and the width of the scroll region  52  is reduced in the rightward direction by an amount corresponding to the enlargement amount. In this respect, each of the two regions  51 ,  52  is one example of a range-variable operation region. 
         [0051]    In the initial screen shown in  FIG. 2A , the user can switch the position of the tap region  51  and the position of the scroll region  52  with each other. When the user flicks one of the two regions  51 ,  52  toward the other of the two regions  51 ,  52 , the two regions  51 ,  52  switch each other. The screen example shown in  FIG. 3B  shows a state in which the scroll region  52  and the tap region  51  have switched each other, namely, the scroll region  52  has been moved to the left side while the press region  51  has been moved to the right side, after the user has performed a flick operation on the initial screen shown in  FIG. 2A  so as to flick the scroll region  52  with the pointer in the leftward direction toward the press region  51 . 
         [0052]    In the present embodiment, it is determined that the flick operation has been performed when a position of a touch by the pointer has moved, while keeping the touch, at a high speed by a certain distance beyond a distance of 30 dots within a particular short period, which is a touch-state detecting period described later. Here, 30 dots may vary depending on resolution of the LCD  21 . 
         [0053]    In each of the screen examples shown in  FIGS. 2A-2C  and  FIGS. 3A and 3B , the press region  51  and the scroll region  52  are adjacent to each other without overlapping. The regions  51 ,  52  may partially overlap each other. 
         [0054]      FIG. 3C  shows a screen example in which a common region  63  is defined. In the common region  63 , both of the tap operation and the drag operation are acceptable. In the screen example shown in  FIG. 3C , there are set, in the display area  30 , a tap-only region  61 , a scroll-only region  62 , the common region  63 , a tap-region-size change region  64 , and a scroll-region-size change region  65 . 
         [0055]    In the tap-only region  61 , the tap operation is acceptable whereas the drag operation in the scroll direction is not acceptable. In the scroll-only region  62 , the drag operation in the scroll direction is acceptable whereas the press operation is not acceptable. In the common region  63 , both of the drag operation in the scroll direction and the press operation are acceptable. All of the tap-only region  61 , the scroll-only region  62 , and the common region  63  are defined in the menu-list image  31 . In other words, the entirety of the menu-list image  31  is divided into these three regions  61 ,  62 ,  63 . 
         [0056]    In both of the press-only region  61  and the common region  63 , the tap operation is acceptable. Accordingly, the tap-only region  61  and the common region  63  as a whole are equivalent to the tap region  51  in the screen example shown in  FIG. 2 . Therefore, in the following explanation, with regard to the screen example shown in  FIG. 3C , the tap-only region  61  and the common region  63  may be collectively referred to as the tap region (as one example of a first operation region in the present invention). Similarly, in both of the scroll-only region  62  and the common region  63 , the drag operation in the scroll direction is acceptable. Accordingly, the scroll-only region  62  and the common region  63  as a whole are equivalent to the scroll region  52  in the screen example shown in  FIG. 2 . Therefore, in the following explanation, with regard to the screen example shown in  FIG. 3C , the scroll-only region  62  and the common region  63  may be collectively referred to as the scroll region (as one example of a second operation region in the present invention). 
         [0057]    The tap-region-size change region  64  and the scroll-region-size change region  65  are independently defined in the display area  30  so as to be different from the region of the menu-list image  31 . In the present embodiment, it may be available that combination of the tap-only region  61 , the common region  63 , and the tap-region-size change region  64  is equivalent to the tap region, which is the first operation region. It may also be available that combination of the scroll-only region  62 , the common region  63 , and the scroll-region-size change region  65  is equivalent to the scroll region, which is the second operation region. 
         [0058]    The tap-region-size change region  64  is defined so as to be adjacent to a lower portion of the tap region at a lower left side of the menu-list image  31 . In the tap-region-size change region  64 , the drag operation for enlarging or reducing the width of only the tap region is accepted. When the user performs, in the tap-region-size change region  64 , the drag operation in the rightward direction, the width of the tap region is enlarged in the rightward direction. In this instance, however, the width of the scroll region does not change. Accordingly, in actuality, the width of the tap-only region  61  does not change, and the width of the common region  63  is enlarged in the rightward direction. As a result, the width of the scroll-only region  62  is reduced in the rightward direction by an amount corresponding to the enlargement amount of the common region  63 . 
         [0059]    The scroll-region-size change region  65  is defined so as to be adjacent to an upper portion of the scroll region at an upper right side of the menu-list image  31 . In the scroll-region-size change region  65 , the drag operation for enlarging or reducing the width of only the scroll region is accepted. When the user performs, in the scroll-region-size change region  65 , the drag operation in the leftward direction, the width of the scroll region is enlarged in the leftward direction. In this instance, however, the width of the press region does not change. Accordingly, in actuality, the width of the scroll-only region  62  does not change, and the width of the common region  63  is enlarged in the leftward direction. As a result, the width of the press-only region  61  is reduced in the leftward direction by an amount corresponding to the enlargement amount of the common region  63 . 
         [0060]    Where the drag operation is performed in the common region  63  in one of the leftward direction and the rightward direction, both of the width of the tap region and the width of the scroll region change in the one of the leftward direction and the rightward direction in which the drag operation is performed. That is, when the drag operation is performed in the common region  63  in the leftward direction, the press region is reduced in the leftward direction while the scroll region is enlarged in the leftward direction. The change in the width of the press region and the change in the width of the scroll region is mutually the same. Accordingly, as a result, the common region  63  moves, while keeping the width of the common region  33 , in the leftward direction, and the scroll-only region  62  is enlarged in the leftward direction while the tap-only region  61  is reduced in the leftward direction, by an amount corresponding to the movement amount of the common region  63 . In this respect, each of the above-indicated tap region and scroll region may be one example of a range-variable operation region in the present invention. 
         [0061]    The tap region and the scroll region can be switched by the flick operation in a lateral direction in the screen example shown in  FIG. 3C  as well. When the flick operation is performed in the scroll-only region  62  or in the common region  63  in the leftward direction, the tap region and the scroll region are switched with each other. In this instance, the tap-region-size change region  64  moves rightward in association with the rightward movement of the tap region, and the scroll-region-size change region  65  moves leftward in association with the leftward movement of the scroll region. 
         [0062]    Referring next to  FIGS. 4-10 , there will be explained various control process executed by the CPU  11  when the menu-list image  31  is displayed. The process of  FIGS. 4-10  shows process executed in a case in which five regions  61 - 65  including the common region  63  are defined in the display area  30  as shown in  FIG. 3C . 
         [0063]    When the initial screen of the menu-list image  31  shown in  FIG. 3C  is displayed, after a startup of the MFP  1 , in the course of various operations by the user, the CPU  11  executes touch-state detecting process shown in  FIG. 4  and main process shown in  FIG. 5  in parallel. 
         [0064]    In the touch-state detecting process, the CPU  11  repeatedly executes the touch-state detecting process at particular time intervals, namely, at the particular touch-state detecting period. When the CPU  11  starts the touch-state detecting process, the CPU  11  initially confirms at S 5  presence or absence of a touch detection signal sent from the touch panel  22 . If the touch detection signal has been inputted from the touch panel  22 , the CPU  11  obtains, as designated coordinates (x1, y1), coordinates of a touch position indicative of the touch detection signal. 
         [0065]    On the basis of the result at S 5 , the CPU  11  determines at S 10  whether or not a start of a touch by the pointer has been detected. More specifically, the CPU  11  determines the start of the touch is detected and causes the process to proceed to S 15  in a case where the touch detection signal was not inputted at S 5  in the preceding touch-state detecting process and the touch detection signal is inputted at S 5  in the current touch-state detecting process. 
         [0066]    At S 15 , the designated coordinates (x1, y1) detected at S 5  are stored in the RAM  13  as preceding designated coordinates (x0, y0). Further, at S 20 , the designated coordinates (x1, y1) are stored in the RAM  13  as event coordinates (xe, ye). Subsequently, at S 25 , “touch” as an event type is stored in the RAM  13 , an event “touch” is issued, and the touch-state detecting process ends. The issuance of the event “touch” means a state in which the pointer has started a touch on the touch panel  22 . 
         [0067]    In the determination at S 10 , in a case where the touch detection signal was inputted at S 5  in the preceding execution of the touch-state detecting process and the touch detection signal is inputted at S 5  also in the current execution of the process, the process proceeds to S 30 . This means that, although the pointer is touching on the touch panel  22 , the touch is not currently started one but the touch is maintained from the preceding process. Further, if the touch detection signal is not inputted at S 5 , namely, if the pointer is not touching on the touch panel  22 , the process proceeds from S 10  to S 30 . 
         [0068]    At S 30 , it is determined whether or not the designated coordinates (x1, y1) detected at S 5  is different from the preceding designated coordinates (x0, y0). If it is determined that the designated coordinates (x1, y1) are different from the preceding designated coordinates (x0, y0), the designated coordinates (x1, y1) are stored in the RAM  13  at S 35  as the event coordinates (xe, ye). Further, at S 40 , the designated coordinates (x1, y1) are stored in the RAM  13  as the preceding designated coordinates (x0, y0). Subsequently, at S 45 , “drag” as an event type is stored in the RAM  13 , an event “drag” is issued. Then the touch-state detecting process ends. The issuance of the event “drag” means that the drag operation on the touch panel  22  by the pointer has been performed. In other words, the touch position has moved. 
         [0069]    When the event “touch” was issued as a result of detection of the start of the touch in the preceding touch-state detecting process and the event “drag” is issued at S 45  as a result of detection of a movement of the coordinates of the touch position in the current touch-state detecting process, there is also stored information representing that the drag operation is the first one performed after the start of the touch. The information is utilized at S 320  in  FIG. 7  that will be later explained. 
         [0070]    At S 30 , if the designated coordinates (x1, y1) do not differ from the preceding designated coordinates (x0, y0), the process proceeds to S 50 . Also if the touch detection signal is not inputted at S 5 , the process proceeds from S 30  to S 50 . At S 50 , it is determined whether or not the pointer has been released from the touch panel  22 . In a case where the touch detection signal is inputted at S 5 , the pointer is still touching on the touch panel  22 . In this instance, the touch-state detecting process ends. On the other hand, if the touch detection signal was inputted at S 5  in the preceding touch-state detecting process, whereas the touch detection signal is not inputted at S 5  in the current touch-state detecting process, it is determined that the pointer has been released from the touch panel  22 , and the process proceeds to S 55 . 
         [0071]    At S 55 , the preceding designated coordinates (x0, y0) are stored in the RAM  13  as the event coordinates (xe, ye). Subsequently, at S 60 , “release” as the event type is stored in the RAM  13 , an event “release” is issued, and then the touch-state detecting process ends. The issuance of the event “release” means that the pointer has been released from the touch panel  22 . 
         [0072]    The touch-state detecting process explained above is repeatedly executed at an interval of the touch-state detecting period. Thus, every time the touch-state detecting process is executed, any one of the following (1)-(5) is determined: (1) whether the touch by the pointer on the touch panel  22  has been started; (2) whether the touched state is being maintained at the same position; (3) whether the drag operation is being performed: (4) whether the pointer has been released; and (5) a state in which the pointer is not in touch with the touch panel  22  is being maintained. 
         [0073]    The main process of  FIG. 5  will be next explained. When the CPU  11  starts the main process, the CPU  11  initially executes list display process at S 110 . More specifically, the CPU  11  causes the menu-list image  31  as shown in  FIG. 3C  to be displayed, as the initial screen, in the display area  30  of the LCD  21 . In this instance, the regions  61 - 65  are initialized as shown in  FIG. 3C . 
         [0074]    At S 115 , the CPU  11  waits for any event. That is, the CPU  11  waits a predetermined time (e.g., 5 msec.) for issuance of any event. When an event is issued, the CPU  11  obtains the event. At S 120 , it is determined whether or not any event is obtained. If no event is obtained, the process returns to S 115 . If any event is obtained, the process proceeds to S 125 . At S 125 , the event coordinates (xe, ye) stored in the RAM  13  are stored as designated coordinates (XN, YN) in the RAM  13 . 
         [0075]    At S 130 , it is determined whether or not the event type is “touch”. If the event type is “touch”, the process proceeds to S 135  to execute touch start process. If the event type is not “touch”, it is determined at S 140  whether or not the event type is “drag”. If the event type is “drag”, the process proceeds to S 145  to execute drag process. If the event type is not “drag”, it is determined at S 150  whether or not the event type is “release”. If the event type is not “release”, the process returns to S 115 . If the event type is “release”, the process proceeds to S 155  to execute release process. The touch start process of S 135 , the drag process of S 145 , and the release process of S 155  will be explained in order. 
         [0076]    The touch start process of S 135  will be explained with reference to  FIG. 6 . When the CPU  11  starts the touch start process shown in  FIG. 6 , the CPU  11  retains, at S 210 , “initial state” as a processing state, and the “initial state” is set and stored in the RAM  13 . At S 215 , it is determined whether or not a display setting for displaying the tap region and the scroll region is enabled. When the display setting is enabled, the tap region and the scroll region are displayed in mutually different colors such that a user may visually understand the tap region and scroll region distinguished from each other. The user can set in advance the display setting enabled or not. In the screen example shown in  FIG. 3C , the tap-only region  61  and the tap-region-size change region  64  are displayed in the same color that is different from colors for other regions  62 ,  63 ,  65 . The scroll-only region  62  and the scroll-region-size change region  65  are displayed in the same color that is different from colors for other regions  61 ,  63 ,  64 . The common region  63  is displayed in a color that is different from colors for other regions  61 ,  62 ,  64 ,  65 . In other words, the display area  30  is color-coded in three different colors. 
         [0077]    If it is determined at S 215  that the display setting is not enabled, the process proceeds to S 225 . On the other hand, if it is determined at S 215  that the display setting is enabled, the regions  61 - 65  are displayed, at S 220 , in the colors as described above. 
         [0078]    At S 225 , it is determined whether or not touch-start-position coordinates (XN, YN), which is the designated coordinates at the time of detection of the start of the touch, are within the tap-only region  61 . If the touch-start-position coordinates (XN, YN) are within the tap-only region  61 , the list-item image as a pressing target is stored in the RAM  13  at S 230 , and “pressing state” is retained at S 235  as the processing state. Then the process proceeds to S 280 . At S 280 , the touch-start-position coordinates (XN, YN) are stored in the RAM  13  as preceding designated coordinates (X0, Y0). 
         [0079]    If it is determined at S 225  that the touch-start-position coordinates (XN, YN) are not within the tap-only region  61 , it is determined at S 240  whether or not the touch-start-position coordinates (XN, YN) are within the scroll-only region  62 . If it is determined at S 240  the touch-start-position coordinates (XN, YN) are within the scroll-only region  62 , “direction-determination waiting state” is retained at S 245  as the processing state. Then the processing proceeds to S 280 . 
         [0080]    If it is determined at S 240  that the touch-start-position coordinates (XN, YN) are not within the scroll-only region  62 , it is determined at S 250  whether or not the touch-start-position coordinates (XN, YN) are within the common region  63 . If it is determined at S 250  that the touch-start-position coordinates (XN, YN) are within the common region  63 , “pressing or direction-determination waiting state” is retained at S 255  as the processing state. Then the processing proceeds to S 280 . 
         [0081]    If it is determined at S 250  that the touch-start-position coordinates (XN, YN) are not within the common region  63 , it is determined at S 260  whether or not the touch-start-position coordinates (XN, YN) are within the tap-region-size change region  64 . If it is determined at S 260  that the touch-start-position coordinates (XN, YN) are within the tap-region-size change region  64 , “tap-region-change waiting state” is retained at S 265  as the processing state. Then the processing proceeds to S 280 . 
         [0082]    If it is determined at S 260  that the touch-start-position coordinates (XN, YN) are not within the tap-region-size change region  64 , it is determined at S 270  whether or not the touch-start-position coordinates (XN, YN) are within the scroll-region-size change region  65 . If it is determined at S 270  that the touch-start-position coordinates (XN, YN) are not within the scroll-region-size change region  65 , the processing proceeds to S 280 . If it is determined at S 270  that the touch-start-position coordinates (XN, YN) are within the scroll-region-size change region  65 , “scroll-region-change waiting state” is retained at S 275  as the processing state. Then the processing proceeds to S 280 . 
         [0083]    The drag process of S 145  will be explained with reference to  FIG. 7 . When the CPU  11  starts the drag process, the CPU  11  determines at S 310  a movement direction and a movement distance of the touch position of the pointer on the basis of the preceding designated coordinates (X0, Y0) and moved designated coordinates (XN, YN), which is the designated coordinates (XN, YN) stored at S 125  of  FIG. 5 . 
         [0084]    To be more specific, the direction in which the touch position of the pointer actually moved is broken into an x-axis component and a y-axis component. The lengths of the respective two components are compared, and the direction of a longer one of the two components is determined as the movement direction. Accordingly, the movement direction is a lateral direction (the left-right direction) when the x-axis component is longer. The movement direction is a vertical direction (the up-down direction or the scroll direction) when the y-axis component is longer. The movement distance is the length of the one of the x-axis component and the y-axis component in the distance by which the touch position of the pointer actually moved, the one of the x-axis component and the y-axis component being determined as the movement direction. 
         [0085]    At S 315 , it is determined whether the processing state is “initial state” or not. If it is determined at S 315  that the processing state is the initial state, the drag process ends. If it is determined at S 315  that the processing state is not the initial state, it is determined at S 320  whether or not the drag operation is the first one performed after the start of the touch. As described above, when the drag operation has been performed for the first time after the start of the touch, the information indicative that the drag operation is the first one performed after the start of the touch is already stored in the RAM  13 . If it is determined at S 320  that the drag operation is not the first one after the start of the touch, the processing proceeds to S 340 . If it is determined at S 320  that the drag operation is the first one after the start of the touch, it is determined at S 325  whether the movement direction is the vertical direction or the lateral direction. If it is determined at S 325  that the movement direction is the vertical direction, “vertical direction” is retained at S 330  in the RAM  13  as a processing direction. Then the process proceeds to S 340 . If it is determined at S 325  that the movement direction is the lateral direction, “lateral direction” is retained at S 335  in the RAM  13  as the processing direction. Then the process proceeds to S 340 . 
         [0086]    At S 340 , it is determined whether or not the processing state is “pressing state”. If it is determined at S 340  that the processing state is the pressing state, the process proceeds to S 360 . If it is determined at S 340  that the processing state is not the pressing state, it is determined at S 345  whether or not the processing direction is “vertical direction”. If it is determined at S 345  that the processing direction is the vertical direction, the process proceeds to S 350  for the vertical-direction process and then proceeds to S 360 . If it is determined at S 345  that processing direction is the lateral direction, the process proceeds to S 355  for the lateral-direction process and then proceeds to S 360 . At S 360 , the moved designated coordinates (XN, YN) are stored in the RAM  13  as the preceding designated coordinates (X0, Y0). The vertical-direction process of S 350  is shown in  FIG. 8 . The lateral-direction process of S 355  is shown in  FIG. 9 . 
         [0087]    When the CPU  11  starts the vertical-direction process shown in  FIG. 8 , the CPU  11  determines at S 410  whether or not the current movement direction, which is the movement direction determined at S 310  in  FIG. 7 , is the vertical direction. If it is determined at S 410  that the current movement direction is not the vertical direction, the process proceeds to S 460  and “initial state” is retained as the processing state. On the other hand, If it is determined at S 410  that the current movement direction is the vertical direction, it is determined at S 415  whether the processing state is one of “direction-determination waiting state” or “pressing or direction-determination waiting state”. 
         [0088]    If it is determined at S 415  that the processing state is one of “direction-determination waiting state” or “pressing or direction-determination waiting state”, it is determined at S 420  whether or not the moved designated coordinates (XN, YN) are within a scroll-available region, i.e., in the scroll-only region  62  or the common region  63 . If it is determined at S 420  that the moved designated coordinates (XN, YN) are not within the scroll-available region, “initial state” is retained at S 430  as the processing state. Then the process proceeds to S 440 . If it is determined at S 420  that the moved designated coordinates (XN, YN) are within the scroll-available region, “scroll state” is retained at S 425  as the processing state. Subsequently, at S 435 , the image is scrolled according to the movement distance and the movement direction, and the process subsequently proceeds to S 440 . Thus, the menu-list image  31  is scrolled in the movement direction by a distance corresponding to the movement distance. At S 440 , the moved designated coordinates (XN, YN) are stored in the RAM  13  as the preceding designated coordinates (X0, Y0). 
         [0089]    If it is judged at S 415  that the processing state is neither “direction-determination waiting state” nor “the pressing or direction-determination waiting state”, it is determined at S 445  whether or not the processing state is “scroll state”. If it is determined at S 445  that the processing state is not the scroll state, the process proceeds to S 460 . If it is determined at S 445  that the processing state is the scroll state, it is determined at S 450  whether or not the moved designated coordinates (XN, YN) are within the scroll-available region, as determined at S 420 . If it is determined at S 450  that the moved designated coordinates (XN, YN) are not within the scroll-available region, the process proceeds to S 430 . If it is determined at S 450  that the moved designated coordinates (XN, YN) are within the scroll-available region, the image is scrolled at S 455  according to the movement distance and the movement direction, as scrolled at S 435 , and the process subsequently proceeds to S 440 . 
         [0090]    In the meantime, when the CPU  11  starts the lateral-direction processing shown in  FIG. 9 , the CPU  11  determines at S 510  whether or not the current movement direction is the lateral direction. If it is determined at S 510  that the current movement direction is not the lateral direction, the process proceeds to S 590  at which “initial state” is retained as the processing state. If it is determined at S 510  that the current movement direction is the lateral direction, it is determined at S 515  whether the processing state is one of “direction-determination waiting state” or “pressing or direction-determination waiting state”. 
         [0091]    If it is determined at S 510  that the processing state is one of “direction-determination waiting state” or “pressing or direction-determination waiting state”, it is determined at S 520  whether or not the moved designated coordinates (XN, YN) are within a list region. The list region refers to an entire region in which the menu-list image  31  is displayed. If it is determined at S 520  that the moved designated coordinates (XN, YN) are not within the list region, “the initial state” is retained as the processing state at S 550  and the process proceeds to S 540 . If it is determined at S 520  that the moved designated coordinates (XN, YN) are within the list region, it is determined at S 525  whether or not the movement distance falls within 30 dots. 
         [0092]    If it is determined at S 525  that the movement distance falls within 30 dots, “region change state” is retained as the processing state in the RAM  13  at S 530 . Subsequently, at S 535 , the width of each region is changed according to the preceding designated coordinates (X0, Y0), the movement distance, and the movement direction, and the process then proceeds to S 540 . At S 535  the width of each region is changed as described below. When the preceding designated coordinates (X0, Y0) are within the scroll region, which is combination of the scroll-only region  62  and the common region  63 , and when the movement direction is the leftward direction, the entirety of the scroll region and the scroll-region-size change region  65  is enlarged in the leftward direction by an amount that corresponds to the movement distance. At the same time, the entirety of the tap region and the tap-region-size change region  64  is reduced in the leftward direction by an amount that corresponds to the enlargement amount of the scroll region. 
         [0093]    If it is determined at S 525  that the movement distance exceeds 30 dots, it is determined at S 545  that the flick operation has been performed. Thus, the tap region and the scroll region are switched with each other, and the process subsequently proceeds to S 550 . In other words, the positional relationship between the tap region and the scroll region is reversed in the left-right direction. 
         [0094]    If it is determined at S 515  that the processing state is neither “direction-determination waiting state” nor “pressing or direction-determination waiting state”, it is determined at S 555  whether or not the processing state is “region change state”. If it is determined at S 555  that the processing state is the region change state, it is determined at S 560  whether or not the moved designated coordinates (XN, YN) are within the list region. If it is determined at S 560  that the moved designated coordinates (XN, YN) are not within the list region, the process proceeds to S 550 . If it is determined at S 560  that the moved designated coordinates (XN, YN) are within the list region, the process proceeds to S 535  at which the width of each region is changed as described above. 
         [0095]    If it is determined at S 555  that the processing state is not “region change state”, it is determined at S 565  whether or not the processing state is “tap-region-change waiting state”. If it is determined at S 565  that the processing state is the tap-region-change waiting state, it is determined at S 570  whether or not the moved designated coordinates (XN, YN) are within the tap-region-size change region  64 . If it is determined at S 570  that the moved designated coordinates (XN, YN) are not within the tap-region-size change region  64 , the process proceeds to S 550 . If it is determined at S 570  that the moved designated coordinates (XN, YN) are within the tap-region-size change region  64 , the process proceeds to S 585 . At S 585 , the width of only the region on which the pointer is touching is changed according to the preceding designated coordinates (X0, Y0), the movement distance, and the movement direction. In a case where the process has proceeded to S 585  after determination that the moved designated coordinates (XN, YN) are within the tap-region-size change region  64  at S 570 , the pointer is touching on the tap-region-size change region  64 . Therefore, in this case, the tap region and the tap-region-size change region  64  are enlarged or reduced in the movement direction by an amount that corresponds to the movement distance. More specifically, the tap region and the tap-region-size change region  64  are enlarged where the movement direction is the rightward direction while the tap region and the tap-region-size change region  64  are reduced where the movement direction is the leftward direction. After S 585 , the process proceeds to S 540 . 
         [0096]    If it is determined at S 565  that the processing state is not “tap-region-change waiting state”, it is determined at S 575  whether or not the processing state is “scroll-region-change waiting state”. If it is determined at S 575  that the processing state is not the scroll-region-change waiting state, the process proceeds to S 550 . If it is determined at S 575  that the processing state is the scroll-region-change waiting state, it is determined at S 580  whether or not the moved designated coordinates (XN, YN) are within the scroll-region-size change region  65 . If it is determined at S 580  that the moved designated coordinates (XN, YN) are not within the scroll-region-size change region  65 , the process proceeds to S 550 . If it is determined at S 580  that the moved designated coordinates (XN, YN) are within the scroll-region-size change region  65 , the process proceeds to S 585 . In a case where the process proceeds to S 585  after determination that the moved designated coordinates (XN, YN) are within the scroll-region-size change region  65  at S 580 , the pointer is touching on the scroll-region-size change region  65 . Therefore, the scroll region and the scroll-region-size change region  65  are enlarged or reduced in the movement direction by an amount that corresponds to the movement distance. More specifically, the scroll region and the scroll-region-size change region  65  are enlarged where the movement direction is the leftward direction. The scroll region and the scroll-region-size change region  65  are reduced where the movement direction is the rightward direction. After S 585 , the process proceeds to S 540 . At S 540 , the moved designated coordinates (XN, YN) are stored as the preceding designated coordinates (X0, Y0) in the RAM  13 . 
         [0097]    The release process of S 155  in  FIG. 5  will be explained with respect to  FIG. 10 . When the CPU  11  starts the release process, the CPU  11  determines at S 610  whether the processing state is not “initial state”. If it is determined at S 610  that the processing state is the initial state, the process proceeds to S 635 . If it is determined at S 6010  that the processing state is not the initial state, the process proceeds to S 615  at which it is determined whether or not the processing state is “pressing state”. If it is determined at S 615  that the processing state is not the pressing state, the process proceeds to S 630 . If it is determined at  615  that the processing state is the pressing state, the process proceeds to S 620  at which it is determined whether or not the designated coordinates (XN, YN) at the time of release are in one of the list-item images as the pressing target at the time of the start of the touch. In other words, it is determined whether or not the pointer has been touching on the same list-item image from the start of the touch till the release. 
         [0098]    Where the list-item image as the pressing target at the time of the start of the touch is different from the list-item image as the pressing target at the time of the release, the process proceeds to S 630 . If the list-item image as the pressing target at the time of the start of the touch is the same as the list-item image as the pressing target at the time of the release, corresponding process assigned for the list-item image as the pressing target is executed at S 625 . 
         [0099]    At S 630 , “initial state” is retained in the RAM  13  as the processing state. As determined at S 215  in  FIG. 6 , it is determined at S 635  whether or not the display setting is enabled. If it is determined that the display setting is not enabled, the release process ends. If it is determined that the display setting is enabled, displaying of the regions  61 - 65  in different colors is cancelled at S 640 . 
         [0100]    There have been explained various processes executed for the screen example shown in  FIG. 3C  with reference to  FIGS. 4-10 . The processes described with reference to  FIGS. 4-10  may be executed for the screen examples shown in  FIGS. 2A-2C  and  FIGS. 3A-3B  in which no common region is set. For example, the tap region  51  and the scroll region  52  in the screen examples shown in  FIG. 2 , etc., may correspond to the tap-only region  61  and the scroll-only region  62  in  FIG. 3C , respectively. 
         [0101]    In the MFP  1  described above, the display area  30  which includes the list region in which the menu-list image  31  is displayed is visually divided into the tap region and the scroll region. In the tap region, the tap operation by the pointer is acceptable. In the scroll region, the drag operation in the vertical direction by the pointer is acceptable. More specifically, in the display area in which the object images are displayed, there are set: the first operation region in which, where the pointer touches the first operation region, predetermined process for the object image that is being displayed at a position of the touch is executed; and the second operation region in which, where the pointer that is touching the second operation region moves in the arrangement direction with the touch maintained, the object images are scrolled. The first operation region and the second operation region are individually set, but may partially overlap each other. Further, each object image is included in both of the first operation region and the second operation region. Accordingly, where the user wishes to select a certain specific list-item image, the user taps a portion of the specific list-item image, which portion is displayed in the tap region, whereby corresponding process to the list-item image can be executed. On the other hand, where the user wishes to scroll the menu-list image  31 , the user performs the drag operation with the pointer in the scroll region, whereby the menu-list image  31  can be scrolled. Accordingly, the user can easily obtain an intended operation result without suffering from conventionally experienced deterioration in the operability for the user. 
         [0102]    In the MFP  1  described above, each of the tap region and the scroll region can be enlarged and reduced by the drag operation in the lateral direction. In this instance, the width of only one of the tap region and the scroll region can be changed. Further, the width of the other of the tap region and the scroll region can be changed in conjunction with the width change of the one of the tap region and the scroll region. In other words, where the one of the tap region and the scroll region is enlarged, the other of the tap region and the scroll region is reduced. Moreover, the tap region and the scroll region can be switched with each other by the flick operation in the lateral direction. Accordingly, it is possible to improve the operability and the usability for the user. 
       Modified Embodiments 
       [0103]    It is understood that the present invention is not limited to the details of the illustrated embodiment but may be otherwise embodied without departing from the technical scope of the invention. 
         [0104]    For instance, there may be considered various methods for initial setting of the widths of the regions  51 ,  52 . In other words, there may be considered various methods for initial setting of the boundary between the two regions  51 ,  52 , in the initial screen shown in  FIG. 2A . Each width of the regions  51 ,  52  may be set on the basis of the maximum number of characters of character strings in each of the list-item images  41 - 45  included in the menu-list image  31 . The characters in the character strings of the respective list-item images  41 - 45  are left-justified as shown in the drawings. Accordingly, the rightmost end of the character string that has the maximum character number is defined as the boundary between the two regions  51 ,  52 . 
         [0105]    In an example shown in  FIG. 11A , the number of characters in the character string “D . . . ” of the list-item image  44  is maximum (i.e., nine characters). Accordingly the right side of the ninth character is defined as the boundary between the regions  51  and  52 . In an example shown in  FIG. 11B , the number of characters in the character string “B . . . ” of the list-item image  42  is maximum (five characters). Accordingly the right side of the fifth character is defined as the boundary between the regions  51  and  52 . 
         [0106]    In an example shown in  FIG. 11C , the number of characters in the character string “E . . . ” of the list-item image  45  is maximum (i.e., fifteen characters). Accordingly the right side of the fifteenth character may be defined as the boundary between the regions  51  and  52 . However, the width of the scroll region  52  may be small as the maximum character number increases so as to cause failure of the drag operation. To avoid such failure, an upper limit of the maximum character number (e.g., twelve characters) may be set such that the tap region  51  may be configured not to be enlarged beyond the maximum character number. Hereinafter, the upper limit of the maximum character number may be referred as “region-securing character number”. In the example shown in  FIG. 11C , the maximum character number is fifteen, which is in excess of twelve. Accordingly, the right side of the twelfth character is defined as the boundary between the regions  51  and  52 . Thus, the width of the tap region  51  is limited so as to correspond to twelve characters at the maximum. 
         [0107]    With reference to  FIG. 12 , there will be explained automatic-region-determining process executed by the CPU  11  for implementing a function for initial setting of the boundary between the two regions  51 ,  52  in accordance with the number of characters. When the CPU  11  starts the automatic-region-determining process for displaying the initial screen, the CPU  11  initially obtains at S 710  the maximum character number among character numbers of the respective list-item images to be currently displayed in the form of a list. It is determined at S 715  whether or not the obtained maximum character number is in excess of the region-securing character number. If it is determined at S 715  that the obtained maximum character number is in excess of the region-securing character number, a criterion character number for determining the right end of the tap region  51  is set to the region-securing character number at S 720 . If it is determined at S 715  that the obtained maximum character number is not in excess of the region-securing character number, the criterion character number is set to the maximum one of the character numbers of the list-item images  41 - 45  at S 725 . Subsequently, at S 730 , the boundary between the scroll region  52  and the tap region  51  is defined according to the set criterion character number. 
         [0108]    The initial setting of the boundary between the two regions  51 ,  52  is thus performed in accordance with the number of characters, whereby the tap region  51  has a necessary and sufficient width, in the initial screen, enough to accommodate the character string. Further, as the width of the tap region  51  is determined in the above-described manner, the scroll region  52  also has an enough width. Accordingly, it is possible to further improve the operability for the user. 
         [0109]    In the embodiment illustrated above, for visually distinguishing the tap region  51  and the scroll region  52  from other regions, the tap region  51  and the scroll region  52  are displayed in different colors. Other methods may be employed. For instance, as shown in  FIG. 13A , the tap region  51  and the scroll region  52  may be visually distinguished by displaying: a tap-region indication image  71  of letters “TAP” and arrows indicative of a range; and a scroll-region indication image  72  of letters “SCROLL” and arrows indicative of a range. 
         [0110]    In the embodiment illustrated above, the menu-list image  31  in which the plurality of list-item images  41 ,  42 , . . . are arranged in the up-down direction is scrolled in the up-down direction. The invention is applicable to a menu-list image  86  shown in  FIG. 13B  in which list-item images  81 ,  82 ,  83 ,  84  . . . are arranged in the lateral direction and which is configured to be scrolled in the lateral direction. In the screen example of  FIG. 13B , approximately a lower half portion of the entire menu-list image  86  is defined as a tap region  91  while approximately an upper half portion is defined as a scroll region  92 . 
         [0111]    It is noted that the present invention is applicable to not only the UI of the KR, but also any UI configured such that a tap operation or a scroll operation can be performed on a list image in which a plurality of object images are arranged.