Abstract:
A display control unit of a display control device displays an image containing a window-operation button on a display unit. An operation verification unit verifies the contact coordinates indicating a position contacted by a user, and the continuous-contact interval thereof The display control unit retrieves the data for the icon of a smart-window manager from a storage unit, and displays the same at a prescribed position on the screen of the display unit so as to be superimposed on the displayed image. The display control unit also identifies a window-operation button corresponding to a tapped icon by referring to correlation information expressing the correlation between the icon stored in the storage unit and the window-operation button, when it is determined that the user has tapped an icon, on the basis of the contact coordinates and the continuous contact interval. The display control unit also produces an event by generating event information indicating that the identified window-operation button has been operated.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a display control device equipped with a touch panel, a thin client system, a display control method and a recording medium. 
       BACKGROUND ART 
       [0002]    Windows (registered trademark) OSs (Operating Systems) display windows on a screen of a display device for a personal computer. The window operation buttons such as the minimizing button, the maximizing button, and the close button of the windows are often appear in a corner of the windows such as the upper right or the upper left corner. Users relatively frequently use these window operation buttons. 
         [0003]    Techniques related to the window operation buttons include PTLs 1 to 4, for example. 
       CITATION LIST 
     Patent Literature 
       [0004]    PTL 1: Japanese Laid-Open Patent Publication No. 2002-259001 
         [0005]    PTL 2: Japanese Laid-Open Patent Publication No. 2008-166927 
         [0006]    PTL 3: Japanese Laid-Open Patent Publication No. 2008-234687 
         [0007]    PTL 4: Japanese Laid-Open Patent Publication No. 2012-083831 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0008]    If window operation buttons are displayed on the screen of a touch panel display, a user directly touches and manipulates one of the window operation buttons with a finger or points to and manipulates one of the window operation buttons with a cursor. 
         [0009]    However, when the window is maximized, the window operation buttons are displayed in a corner of the touch panel display since the window operation button is typically in a corner of the window. 
         [0010]    Accordingly, the window operation buttons have the problem of poor user operability even though they are frequently used. In addition, in a small -sized touch panel display, the window operation buttons are small, which causes a problem that a user is difficult to operate the buttons. 
         [0011]    The techniques in PTLs 1 to 4 do not improve the operability of window operation buttons displayed on the screen of a touch panel display. 
         [0012]    The present invention has been made in light of the circumstances described above and an object of the present invention is to provide a display control device, a thin client system, a display control method and a recording medium that improves the operability of window operation buttons displayed on the screen of a touch panel display. 
       Solution to Problem 
       [0013]    A display control device according to a first aspect of the present invention, the display control device being equipped with a touch panel display, characterized by includes: 
         [0014]    screen display means for displaying an image including a window operation button for manipulating a window on a screen of the touch panel display; 
         [0015]    operation recognition means for recognizing a contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration in which the user has been in contact with the screen of the touch panel display; 
         [0016]    icon display means for displaying an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; 
         [0017]    correspondence information storage means for storing correspondence information indicating a correspondence between the icon and the window operation button; and 
         [0018]    event issuing means for, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying a window operation button corresponding to the icon with reference to the correspondence information and generating event information indicating that the identified window operation button has been operated. 
         [0000]    A thin client system according to a second aspect of the present invention, the thin client system being in which a server and a display control device equipped with a touch panel display are interconnected through a network, 
         [0019]    characterized by the server includes screen transmission means for transmitting screen information indicating an image including a window operation button for manipulating a window to the display control device; 
         [0020]    the display control device includes: 
         [0021]    image receiving means for receiving the screen information from the server; 
         [0022]    screen display means for displaying an image including the window operation button on a screen of the touch panel display on the basis of the screen information; 
         [0023]    operation recognition means for recognizing a contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration in which the user has been in contact with the screen of the touch panel display; 
         [0024]    icon display means for displaying an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; 
         [0025]    correspondence information storage means for storing correspondence information indicating a correspondence between the icon and the window operation button; 
         [0026]    event issuing means for, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying a window operation button corresponding to the icon with reference to the correspondence information and generating event information indicating that the identified window operation button has been operated; and 
         [0027]    event transmitting means for transmitting the event information generated by the event issuing means to the server; and 
         [0028]    the server includes: 
         [0029]    action information storage means for storing action information indicating a correspondence between an event indicated by the event information and an action; 
         [0030]    event receiving means for receiving the event information from the display control device; and 
         [0031]    execution means for executing an action associated with an event indicated by the received event information with reference to the action information. 
         [0000]    A display control method according to a third aspect of the present invention characterized byincludes: 
         [0032]    a screen display step of displaying an image including a window operation button for manipulating a window on a screen of a touch panel display; 
         [0033]    an operation recognition step of recognizing a contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration during which the user has been in contact with the screen of the touch panel display; 
         [0034]    an icon display step of displaying an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; and 
         [0035]    an event issuing step of, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying a window operation button corresponding to the icon with reference to stored correspondence information that indicates a correspondence between an icon and a window operation button, and generating event information indicating that the identified window operation button has been operated. 
         [0000]    A display control method according to a forth aspect of the present invention, the display control method being in a thin client system in which a server and a display control device equipped with a touch panel display are interconnected through a network, characterized by includes: 
         [0036]    a screen transmission step of transmitting, by the server, screen information indicating an image including a window operation button for manipulating a window to the display control device; 
         [0037]    an image receiving step of receiving, by the display control device, the screen information from the server; 
         [0038]    a screen display step of displaying, by the display control device, an image including the window operation button on a screen of the touch panel display on the basis of the screen information; 
         [0039]    an operation recognition step of recognizing, by the display control device, a contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration in which the user has been in contact with the screen of the touch panel display; 
         [0040]    an icon display step of displaying, by the display control device, an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; 
         [0041]    an event issuing step of, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying, by the display control device, a window operation button corresponding to the icon with reference to stored correspondence information that indicates a correspondence between an icon and a window operation button, and generating event information indicating that the identified window operation button has been operated; 
         [0042]    an event transmission step of transmitting, by the display control device, the event information generated at the event issuing step to the server; 
         [0043]    an event receiving step of receiving, by the server, the event information from the display control device; and 
         [0044]    an execution step of executing, by the server, an action associated with an event indicated by the received event information with reference to stored action information that indicates a correspondence between an event indicated by the event information and an action. 
         [0000]    A computer-readable recording medium according to a fifth aspect of the present invention, the computer-readable recording medium storing with a program, the program causing a computer equipped with a touch panel display to function as: 
         [0045]    screen display means for displaying an image including a window operation button for manipulating a window on a screen of the touch panel display; 
         [0046]    operation recognition means for recognizing contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration in which the user has been in contact with the screen of the touch panel display; 
         [0047]    icon display means for displaying an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; 
         [0048]    correspondence information storage means for storing correspondence information indicating a correspondence between the icon and the window operation button; and 
         [0049]    event issuing means for, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying a window operation button corresponding to the icon with reference to the correspondence information and generating event information indicating that the identified window operation button has been operated. 
       Advantageous Effects of Invention 
       [0050]    The present invention improves the operability of window operation buttons displayed on the screen of a touch panel display. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0051]      FIG. 1  is a diagram illustrating display of icons of a smart window manager according to a first exemplary embodiment of the present invention. 
           [0052]      FIG. 2  is a block diagram illustrating an exemplary configuration of a display control device according to the first exemplary embodiment. 
           [0053]      FIG. 3  is a diagram illustrating an operation input on the display control device according to the first exemplary embodiment. 
           [0054]      FIG. 4  is a flowchart illustrating one example of an operation of the display control device according to the first exemplary embodiment. 
           [0055]      FIG. 5  is a flowchart illustrating one example of an operation of a display control device according to a second exemplary embodiment of the present invention. 
           [0056]      FIG. 6  is a block diagram illustrating an exemplary configuration of a thin client system according to a third exemplary embodiment of the present invention. 
           [0057]      FIG. 7  is a block diagram illustrating an exemplary hardware configuration of a display control device according to an exemplary embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0058]    Exemplary embodiments of the present invention will be described below. In the following description, a display control application according to the present invention will be referred to as a smart window manager. 
       First Exemplary Embodiment 
       [0059]      FIG. 1  is a diagram illustrating display of icons of a smart window manager according to a first exemplary embodiment of the present invention. A display control device  1  according to the first exemplary embodiment is equipped with a touch panel display D and displays a window including window operation buttons B. The window operation buttons B in the example in  FIG. 1  includes a window minimizing button B 1 , maximizing button B 2  and close button B 3 . 
         [0060]    Assume here that the smart window manager is activated when the window including the window operation buttons B is displayed. Then the display control device  1  displays icons I of the smart window manager superimposed on an image displayed on a screen in a predetermined location of the touch panel display D. In a multiwindow display, the display control device  1  displays the icons I of the smart window manager on an active window (which is displayed at the top of the window stack). 
         [0061]    The icons I of the smart window manager are translucently displayed. Displaying translucently means that pixels are computed and displayed so that the image on which the icons I are superimposed can be seen through the icons I. The icons I are enlarged versions of the window operation buttons B and emulate the window operation buttons B. The icons I include an icon I 1  corresponding to the minimizing button B 1 , an icon I 2  corresponding to the maximizing button B 2 , and an icon I 3  corresponding to the close button B 3 . Although the icons I are positioned near the frame like the window operation buttons B, the icons I are easier to press because the icons I are larger in size. 
         [0062]    When any of the icons I is tapped, the display control device  1  inputs the same operation that would be input when the corresponding one of the window operation buttons B is tapped. Accordingly the user can input the same operation by tapping one of the icons I that corresponds to the window operation button B that the user wants to operate. Tapping means that the user touches a display region of interest in a manner that satisfies predetermined conditions and will be detailed later. 
         [0063]    Note that the icons I of the smart window manager are not limited to the window minimizing button B 1 , maximizing button B 2  and close button B 3 . Other icons such as browser resizing button, a back button, and a forward button, which are associated with the window operation buttons B, may be provided. In addition, an active window select icon (for example, an icon for selecting windows one after another, starting with the one at the forefront or the backmost icon) may be provided. 
         [0064]      FIG. 2  is a block diagram illustrating an exemplary configuration of the display control device  1  according to the first exemplary embodiment. The display control device  1  includes a display unit  11 , an input unit  12 , an operation recognition unit  13 , a storage  14  and a display control unit  15 . 
         [0065]    The display unit  11  is constituted by a liquid-crystal panel or the like and displays a screen as directed by the display control unit  15 . The input unit  12  is constituted by a position input device, such as a touch pad, which is placed on a surface of the liquid-crystal panel constituting the display unit  11  and detects a touch. The input unit  12  accepts an input by a touch by a user. The display unit  11  and the input unit  12  are implemented by a touch panel display D. 
         [0066]    The operation recognition unit  13  acquires the position on the touch panel display D where the input unit  12  has detected a touch. The operation recognition unit  13  then compares the coordinates of the acquired position on the touch panel display D with screen coordinate information indicating coordinates on the screen stored in the storage  14  to recognize the coordinates of the contact point. In addition, the operation recognition unit  13  recognizes the continuous touch duration from the start of a touch detected by the input unit  12  to the end of the touch. The operation recognition unit  13  sends the contact point coordinates and the continuous touch duration to the display control unit  15 . 
         [0067]    The display control unit  15  retrieves screen information indicating a window including window operation buttons B from the storage  14  and causes the display unit  11  to display the window. 
         [0068]    Upon activation of the smart window manager, the display control unit  15  retrieves data indicating icons I of the smart window manager from the storage  14  and causes the icons Ito be displayed in a predetermined position on the screen of the display unit  11 . Since the icons I are displayed translucently, an image under the icons I can be seen through the icons I. Accordingly, the icons I displayed do not interfere with operations. 
         [0069]    The user taps the icons I of the smart window manager on the touch panel display D to operate the window operation buttons B. 
         [0070]    Based on contact point coordinates and a continuous touch duration received from the operation recognition unit  13 , the display control unit  15  determines whether or not the user has tapped any of the icons I of the smart window manager. 
         [0071]    In this exemplary embodiment, when the contact point coordinates at the start of a touch is within the display region of an icon I and the continuous touch duration is greater than or equal to a threshold a and less than or equal to a threshold β, it is determined that the icon I has been tapped. The provision of the threshold a can prevent a touch in a short continuous touch duration such as an unintentional touch by a user from being determined to be a tap. The provision of the threshold β allows the user to undo a touch of a wrong icon I by continuing touching for a long time. 
         [0072]    In addition, a threshold may be provided for displacement from the contact point coordinates at the start of a touch to allow the user to undo an operation by moving from the touched position. Furthermore, whenever contact point coordinates at the start of a touch are within the display region of an icon I and the continuous touch duration is greater than or equal to 0, it may be determined that the icon I has been tapped. 
         [0073]    When the display control unit  15  determines that the user has tapped an icon I, the display control unit  15  refers to correspondence information indicating the correspondences between the icons I and the window operation buttons B which is stored in the storage  14 . The display control unit  15  identifies the window operation button B that corresponds to the tapped icon I. The display control unit  15  generates event information indicating that the identified window operation button B has been operated and issues an event. 
         [0074]    Furthermore, the display control unit  15  refers to action information indicating the correspondences between events and actions that is stored in the storage  14  and executes the action associated with the issued event. Note that another function unit of the display control device  1 , instead of the display control unit  15 , may refer to the action information and execute the action associated with the issued event. 
         [0075]      FIG. 3  is a diagram illustrating an operation input on the display control device  1  according to the first exemplary embodiment. Window operation buttons B in the example in  FIG. 3  include a window minimizing button B 1 , maximizing button B 2  and close button B 3 . Icons I that emulate the window operation buttons B include an icon I 1  corresponding to the minimizing button B 1 , an icon I 2  corresponding to the maximizing button B 2  and an icon I 3  corresponding to the close button B 3 . 
         [0076]    When the window is maximized, the close button B 3  is displayed in the upper right corner of the screen as illustrated in  FIG. 3 . When the user wants to operate the close button B 3 , the user activates the smart window manager to display the icons I. The user then taps the icon I 3  to input the same operation as an operation input when the close button B 3  is tapped. Since the icon I 3  is an enlarged version of the close button B 3  and is larger than the close button B 3 , the icon I 3  is easier for the user to tap even though the icon I 3  is located near the frame. 
         [0077]      FIG. 4  is a flowchart illustrating an example of an operation of the display control device  1  according to the first exemplary embodiment. The process illustrated in the flowchart in  FIG. 4  starts when the user activates the smart window manager. The display control unit  15  retrieves data indicating the icons I of the smart window manager from the storage  14 . The display control unit  15  then displays the icons I superimposed on an image displayed on the screen of the display unit  11  in a predetermined location (step S 11 ). 
         [0078]    When the input unit  12  detects a touch (step S 12 : YES), the operation recognition unit  13  acquires the position on the touch panel display D where the input unit  12  has detected the touch and compares the position with screen coordinate information stored in the storage  14  to recognize contact point coordinates and a continuous touch duration (step S 13 ). The operation recognition unit  13  sends the contact point coordinates and the continuous touch duration to the display control unit  15 . When the input unit  12  does not detect a touch (step S 12 : NO), the input unit  12  repeats step S 12 . 
         [0079]    Based on the contact point coordinates and the continuous touch duration received from the operation recognition unit  13 , the display control unit  15  determines whether or not any of the icons I of the smart window manager has been tapped (step S 14 ). When any of the icons I has been tapped (step S 14 : YES), the display control unit  15  compares the tapped icon I with correspondence information stored in the storage  14  to identify the window operation button B that corresponds to the tapped icon I (step S 15 ). 
         [0080]    The display control unit  15  generates event information indicating that the identified window operation button B has been operated, issues an event (step S 16 ), and proceeds to step S 17 . The display control unit  15  refers to action information and executes the action associated with the issued event. 
         [0081]    On the other hand, when none of the icons I have been tapped (step S 14 : NO), step S 13  to step S 17  are repeated, while the input unit  12  is detecting the touch (step S 17 : NO). When the input unit  12  no longer detects the touch (step S 17 : YES), determination is made as to whether or not the smart window manager is turned off (step S 18 ). When the smart window manager is not turned off (step S 18 : NO), step S 12  to step S 18  are repeated. When the smart window manager is turned off (step S 18 : YES), the process ends. 
         [0082]    In the display control device  1  according to the first exemplary embodiment, the icons I that emulate the window operation buttons B displayed on the screen of the touch panel display D are enlarged versions of the window operation buttons B. Accordingly, the user can easily operate the window operation buttons B by operating the icons I which are large in size. 
       Second Exemplary Embodiment 
       [0083]    A display control device  1  according to a second exemplary embodiment has a configuration similar to that of the display control device  1  according to the first exemplary embodiment. In the second exemplary embodiment, icons I of a smart window manager can be freely moved by dragging the icons I. 
         [0084]      FIG. 5  is a flowchart illustrating an example of an operation of the display control device  1  according to the second exemplary embodiment of the present invention. The process illustrated in the flowchart in  FIG. 5  starts when a user activates the smart window manager. A display control unit  15  retrieves data indicating the icons I of the smart window manager from a storage  14 . The display control unit  15  displays the icons I superimposed on an image displayed on a screen of a display unit  11  in a predetermined location (step S 21 ). 
         [0085]    When the input unit  12  detects a touch (step S 22 : YES), the operation recognition unit  13  acquires the position on the touch panel display D where the input unit  12  has detected the touch and compares the position with screen coordinate information stored in the storage  14  to recognize contact point coordinates and a continuous touch duration (step S 23 ). The operation recognition unit  13  sends the contact point coordinates and the continuous touch duration to the display control unit  15 . When the input unit  12  does not detect a touch (step S 22 : NO), the input unit  12  repeats step S 22 . 
         [0086]    The display control unit  15  determines whether or not the contact point coordinates received from the operation recognition unit  13  are included in the display region of the icons I of the smart window manager (step S 24 ). If the contact point coordinates are not included in the display region of the icons I (step S 24 : NO), the display control unit  15  proceeds to step S 30 . 
         [0087]    If the contact point coordinates are included in the display region of the icons I (step S 24 : YES), the display control unit  15  determines, based on the continuous touch duration received from the operation recognition unit  13 , whether or not any of the icons I has been tapped (step S 25 ). When any of the icons I has been tapped (step S 25 : YES), the display control unit  15  compares the tapped icon I with correspondence information stored in the storage  14  to identify the window operation button B that corresponds to the tapped icon I (step S 26 ). The display control unit  15  determines that any of the icons I has been tapped if the contact point coordinates at the start of the touch is within the display region of the icons I and a displacement from the contact point coordinates at the start of the touch is less than or equal to a threshold γ. 
         [0088]    The display control unit  15  generates event information indicating that the identified window operation button B has been operated, issues an event (step S 27 ), and proceeds to step S 30 . The display control unit  15  refers to action information and executes the action associated with the issued event. 
         [0089]    On the other hand, if none of the icons I have been tapped (step S 25 : NO), the display control unit  15  determines, based on the continuous touch duration received from the operation recognition unit  13 , whether or not the icons I have been dragged (step S 28 ). If the icons I have been dragged (step S 28 : YES), the display control unit  15  moves the icons I to the position of the changed contact point coordinates (step S 29 ) and proceeds to step S 30 . When the contact point coordinates at the start of the touch is within the display region of the icons I and a displacement from the contact point coordinates at the start of the touch is greater than the threshold γ, the display control unit  15  determines that the icons I have been dragged. 
         [0090]    If the icons I have not been dragged (step S 28 : NO), the input unit  12  repeats step S 23  to step S 30  while the touch is being detected (step S 30 : NO). When the touch is no longer detected (step S 30 : YES), the input unit  12  determines whether or not the smart window manager is turned off (step S 31 ). If the smart window manager is not turned off (step S 31 : NO), the step S 22  to step S 31  are repeated. When the smart window manager is turned off (step S 31 : YES), the process ends. 
         [0091]    According to the display control device  1  in the second exemplary embodiment, the icons I that emulate the window operation buttons B displayed on the screen of the touch panel display D are enlarged version of the window operation buttons B and can be placed in any position. Accordingly, the user can easily operate the window operation buttons B by operating the icons I which are in any position and large in size. 
         [0092]    According to this exemplary embodiment, when the contact point coordinates at the start of a touch is within the display region of the icons I and a displacement from the contact point coordinates at the start of the touch is less than or equal to the threshold γ, it is determined that any of the icons I has been tapped; when the displacement is greater than the threshold γ, it is determined that the icons I have been dragged. However, the present invention is not so limited. The threshold for determining that the icons I have been tapped and the threshold for determining that the icons I have been dragged may be different from each other. Furthermore, whenever the contact point coordinates at the start of a touch is within the display region of the icons I, it may be determined that the icons I have been tapped. Moreover, whenever the contact point coordinates at the start of a touch is within the display region of the icons I and the contact point coordinates have changed during the continuous touch on the icons I, it may be determined that the icons I have been dragged. 
       Third Exemplary Embodiment 
       [0093]      FIG. 6  is a block diagram illustrating an exemplary configuration of a thin client system  100  according to a third exemplary embodiment of the present invention. The thin client system  100  is made up of a display control device  1  and a server  2 . The display control device  1  includes a display unit  11 , an input unit  12 , an operation recognition unit  13 , a storage  14 , a display control unit  15 , a screen receiving unit  16  and an event transmitting unit  17 . The server  2  includes an execution unit  21 , a storage  22 , a screen transmitting unit  23  and an event receiving unit  24 . 
         [0094]    Separate symbols indicating communications of the screen receiving unit  16  and the event transmitting unit  17  of the display control device  1  with the screen transmitting unit  23  and the event receiving unit  24 , respectively, of the server  2  are depicted. However, in reality, the same communication devices communicate with each other. 
         [0095]    The display unit  11 , the input unit  12 , the operation recognition unit  13  and the storage  14  of the display control device  1  have the same configurations as those of the first exemplary embodiment. The screen receiving unit  16  receives screen information indicating a window including window operation buttons B from the screen transmitting unit  23  of the server  2 . The display control unit  15  of this exemplary embodiment causes a window including the window operation buttons B to be displayed on the display unit  11  on the basis of screen information received by the screen receiving unit  16 . 
         [0096]    The display control unit  15  determines, based on contact point coordinates and a continuous touch duration received from the operation recognition unit  13 , whether or not a user has tapped an icon I of the smart window manager. When the display control unit  15  determines that the user has tapped the icons I, the display control unit  15  refers to correspondence information indicating the correspondences between icons I and the window operation buttons B that is stored in the storage  14  to identify the window operation button B that corresponds to the tapped icon I. The display control unit  15  generates event information indicating that the identified window operation button B has been operated and issues an event. 
         [0097]    The display control unit  15  sends the generated event information to the event transmitting unit  17 . The event transmitting unit  17  transmits the event information received from the display control unit  15  to the event receiving unit  24  of the server  2 . 
         [0098]    The execution unit  21  of the server  2  retrieves screen information indicating a window including the window operation buttons B from the storage  22  and sends the screen information to the image transmitting unit  23  to cause the screen transmitting unit  23  to transmit the screen information to the screen receiving unit  16  of the display control device  1 . 
         [0099]    The event receiving unit  24  receives event information from the event transmitting unit  17  of the display control device  1  and sends the event information to the execution unit  21 . The execution unit  21  refers to action information indicating the correspondences between events and actions that is stored in the storage  22  and executes the action that corresponds to the received event information. The execution unit  21  retrieves screen information indicating an action screen of the executed action from the storage  22  and sends the screen information to the image transmitting unit  23  to cause the image transmitting unit  23  to transmit the screen information to the screen receiving unit  16  of the display control device  1 . 
         [0100]    When the screen receiving unit  16  of the display control device  1  receives the screen information indicating the action screen from the screen transmitting unit  23  of the server  2 , the display control unit  15  causes the action screen to be displayed on the display unit  11  on the basis of the screen information received by the screen receiving unit  16 . 
         [0101]    The display control device  1  of the second exemplary embodiment as well as the display control device  1  of the first exemplary embodiment can constitute a thin client system  100 . 
         [0102]    In the third exemplary embodiment, the display control device  1  identifies the window operation button B that corresponds to a tapped icon I on the basis of contact point coordinates and a continuous touch duration. The display control device  1  then generates event information indicating that the identified window operation button B has been operated and issues an event. However, the present invention is not so limited. 
         [0103]    The display control device  1  transmits the contact point coordinates and the continuous touch duration to the server  2  and the server  2  identifies the window operation button B that corresponds to the tapped icon I on the basis of the contact point coordinates and the continuous touch duration. The server  2  may generate event information indicating that the identified window operation button B has been operated and may issue an event. 
         [0104]    In the thin client system  100  according to the third exemplary embodiment, the load on the display control device  1  is reduced because actions are executed on the server  2 . This enables reduction in the cost and size of the display control device  1 . 
         [0105]    If the server  2  in the thin client system  100  is equipped with a display, a screen for the display of the server  2  is displayed on the touch panel display D of the display control device  1 . If the touch panel display D of the display control device  1  is smaller than the display of the server  2 , the screen is reduced in size and the reduced screen is displayed on the touch panel display D. Accordingly, the window operation buttons B in a corner of a window is reduced in size and can be further difficult to operate. Applying the present invention to the thin client system has the effect of improving the operability of the window operation buttons B displayed on the screen of the touch panel display D. 
         [0106]    Note that while the user directly touch an icon I of the smart window manager with a finger to operate the icon I in the embodiments described above, an embodiment may be configured in which the user points to an icon I with a pointer. While the icons I are translucently displayed in the embodiments described above, the icons I may be icons through which an image under the icons cannot be seen. 
         [0107]      FIG. 7  is a block diagram illustrating an exemplary hardware configuration of a display control device  1  according to an embodiment. 
         [0108]    A control unit  31  is constituted by a CPU (Central Processing Unit) or the like. The control unit  31  executes processes of the operation recognition unit  13  and the display control unit  15  according to a control program  39  stored in an external storage  33 . 
         [0109]    The main memory  32  is constituted by a RAM (Random-Access Memory) or the like. The control program  39  stored in the external storage  33  is loaded into the main memory  32 , which is used by the control unit  31  as a work area. 
         [0110]    The external storage  33  is constituted by a nonvolatile memory such as a flash memory, a hard disk, a DVD-RAM (Digital Versatile Disc Random-Access Memory), or a DVD-RW (Digital Versatile Disc ReWritable). The external storage  33  stores beforehand a program for causing the control unit  31  to perform processes of the display control device  1 . The external storage  33  provides data stored by the program to the control unit  31  according to instructions from the control unit  31  and stores data provided from the control unit  31 . The storage  14  is constituted by the external storage  33 . 
         [0111]    An operation unit  34  is constituted by an interface device that connects a position input device such as a touch pad to an internal bus  30 . When a user performs an operation input, an instruction is provided to the control unit  31  through the operation unit  34 . The operation unit  34  functions as the input unit  12 . 
         [0112]    A display unit  35  is constituted by a CRT (Cathode Ray tube), an LCD (Liquid Crystal Display) or the like and displays application screens and the like. The display unit  35  functions as the display unit  11 . 
         [0113]    A timer  36  provides the current time to the control unit  31  via the internal bus  30  at regular intervals. The control unit  31  recognizes a continuous touch duration on the basis of the current time provided from the timer  36 . 
         [0114]    Note that the display control device  1  in a thin client system  100  further includes a communication unit constituted by network terminal equipment or radio communication equipment connecting to a network, and a serial interface or a LAN (Local Area Network) interface that connects to the equipment. The communication unit connects to the server  2  through the network. The communication unit functions as the screen receiving unit  16  and the event transmitting unit  17 . 
         [0115]    The processes performed by the display unit  11 , the input unit  12 , the operation recognition unit  13 , the storage  14  and the display control unit  15  illustrated in  FIG. 2  are accomplished by the control program  39  using the control unit  31 , the main memory  32 , the external storage  33 , the operation unit  34 , the display unit  35  and the timer  36  as resources to perform processing. 
         [0116]    The hardware configurations and the flowcharts described above are illustrative only and changes and modification can be made as appropriate. 
         [0117]    The core part that is constituted by the control unit  31 , the main memory  32 , the external storage  33 , the internal bus  30  and the like and performs control processing can be implemented by a conventional computer system instead of a specialized system. For example, a computer program for executing the operations described above may be stored on a computer-readable recording medium (such as a flexible disk, a CD-ROM, a DVD-ROM or the like) and distributed. Then the distributed computer program may be installed in a computer to configure the display control device  1  that executes the processes described above. Alternatively, the computer program may be stored in a storage device of a server device on a communication network such as the Internet and may be downloaded to a conventional computer system to configure the display control device  1 . 
         [0118]    If the functions of the display control device  1  are implemented by sharing or cooperation between an OS and an application program, the application program alone may be stored on a recording medium or a storage device. 
         [0119]    Furthermore, the computer program may be superimposed on a carrier wave and distributed through a communication network. For example, the computer program may be posted on a BBS (Bulletin Board System) on a communication network and may be distributed through the network. Then the computer program may be activated and executed under the control of an OS in the same way as other application programs are executed so that the processes described above can be executed. 
         [0120]    Various embodiments and variations of the present invention are possible without departing from the broad spirit and scope of the present invention. The exemplary embodiments described above are illustrative of the present invention and are not intended to limit the scope of the present invention. In other words, the scope of the present invention is defined by the claims and not by the exemplary embodiments. Various variations made within the scope of the claims and within the meaning of the present invention that is equivalent to the claims are considered to fall within the scope of the present invention. 
         [0121]    Some or all of the exemplary embodiments described above can be set forth as in the following supplementary notes but the present invention is not limited thereto. 
       (Supplementary Note 1) 
       [0122]    A display control device equipped with a touch panel display, the display control device characterized by including: 
         [0123]    screen display means for displaying an image including a window operation button for manipulating a window on a screen of the touch panel display; 
         [0124]    operation recognition means for recognizing a contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration in which the user has been in contact with the screen of the touch panel display; 
         [0125]    icon display means for displaying an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; 
         [0126]    correspondence information storage means for storing correspondence information indicating a correspondence between the icon and the window operation button; and 
         [0127]    event issuing means for, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying a window operation button corresponding to the icon with reference to the correspondence information and generating event information indicating that the identified window operation button has been operated. 
       (Supplementary Note 2) 
       [0128]    The display control device according to Supplementary Note 1, characterized by the predetermined condition is that the continuous touch duration is greater than or equal to a predetermined threshold duration. 
       (Supplementary Note 3) 
       [0129]    The display control device according to Supplementary Notes 1 or 2, characterized by, when the contact point coordinate at the start of a touch is within the display region of the icon and the contact point coordinate is changed while the touch is continuously maintained on the basis of the contact point coordinate and the continuous touch duration, the icon display means moves the display position of the icon to the position at the changed contact point coordinate. 
       (Supplementary Note 4) 
       [0130]    The display control device according to any one of Supplementary Notes 1 to 3, characterized in that the icon display means translucently displays the icon. 
       (Supplementary Note 5) 
       [0131]    A thin client system in which a server and a display control device equipped with a touch panel display are interconnected through a network, 
         [0132]    characterized by the server includes screen transmission means for transmitting screen information indicating an image including a window operation button for manipulating a window to the display control device; 
         [0133]    the display control device includes: 
         [0134]    image receiving means for receiving the screen information from the server; 
         [0135]    screen display means for displaying an image including the window operation button on a screen of the touch panel display on the basis of the screen information; 
         [0136]    operation recognition means for recognizing a contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration in which the user has been in contact with the screen of the touch panel display; 
         [0137]    icon display means for displaying an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; 
         [0138]    correspondence information storage means for storing correspondence information indicating a correspondence between the icon and the window operation button; 
         [0139]    event issuing means for, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying a window operation button corresponding to the icon with reference to the correspondence information and generating event information indicating that the identified window operation button has been operated; and 
         [0140]    event transmitting means for transmitting the event information generated by the event issuing means to the server; and 
         [0141]    the server includes: 
         [0142]    action information storage means for storing action information indicating a correspondence between an event indicated by the event information and an action; 
         [0143]    event receiving means for receiving the event information from the display control device; and 
         [0144]    execution means for executing an action associated with an event indicated by the received event information with reference to the action information. 
       (Supplementary Note 6) 
       [0145]    A display control method characterized byincluding: 
         [0146]    a screen display step of displaying an image including a window operation button for manipulating a window on a screen of a touch panel display; 
         [0147]    an operation recognition step of recognizing a contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration during which the user has been in contact with the screen of the touch panel display; 
         [0148]    an icon display step of displaying an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; and 
         [0149]    an event issuing step of, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying a window operation button corresponding to the icon with reference to stored correspondence information that indicates a correspondence between an icon and a window operation button, and generating event information indicating that the identified window operation button has been operated. 
       (Supplementary Note 7) 
       [0150]    A display control method for a thin client system in which a server and a display control device equipped with a touch panel display are interconnected through a network, characterized by the display control method including: 
         [0151]    a screen transmission step of transmitting, by the server, screen information indicating an image including a window operation button for manipulating a window to the display control device; 
         [0152]    an image receiving step of receiving, by the display control device, the screen information from the server; 
         [0153]    a screen display step of displaying, by the display control device, an image including the window operation button on a screen of the touch panel display on the basis of the screen information; 
         [0154]    an operation recognition step of recognizing, by the display control device, a contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration in which the user has been in contact with the screen of the touch panel display; 
         [0155]    an icon display step of displaying, by the display control device, an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; 
         [0156]    an event issuing step of, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying, by the display control device, a window operation button corresponding to the icon with reference to stored correspondence information that indicates a correspondence between an icon and a window operation button, and generating event information indicating that the identified window operation button has been operated; 
         [0157]    an event transmission step of transmitting, by the display control device, the event information generated at the event issuing step to the server; 
         [0158]    an event receiving step of receiving, by the server, the event information from the display control device; and 
         [0159]    an execution step of executing, by the server, an action associated with an event indicated by the received event information with reference to stored action information that indicates a correspondence between an event indicated by the event information and an action. 
       (Supplementary Note 8) 
       [0160]    A computer-readable recording medium stored with a program, the program causing a computer equipped with a touch panel display to function as: 
         [0161]    screen display means for displaying an image including a window operation button for manipulating a window on a screen of the touch panel display; 
         [0162]    operation recognition means for recognizing contact point coordinate indicating a position in which a user has touched the screen of the touch panel display and a continuous touch duration in which the user has been in contact with the screen of the touch panel display; 
         [0163]    icon display means for displaying an icon superimposed on the image on the screen of the touch panel display, the icon being an enlarged version of the window operation button and emulating the window operation button; 
         [0164]    correspondence information storage means for storing correspondence information indicating a correspondence between the icon and the window operation button; and 
         [0165]    event issuing means for, when the contact point coordinate at the start of a touch are within a display region of the icon and the continuous touch duration satisfies a predetermined condition on the basis of the contact point coordinate and the continuous touch duration, identifying a window operation button corresponding to the icon with reference to the correspondence information and generating event information indicating that the identified window operation button has been operated. 
         [0166]    The present invention is based upon Japanese Patent Application No. 2012-192639 filed on 31 Aug., 2012. The entire contents of the specification, claims, and drawings of Japanese Patent Application No. 2012-192639 are incorporated herein by reference. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           1  Display control device 
           2  Server 
           11  Display unit 
           12  Input unit 
           13  Operation recognition unit 
           14  Storage 
           15  Display control unit 
           16  Screen receiving unit 
           17  Event transmitting unit 
           21  Execution unit 
           22  Storage 
           23  Screen transmitting unit 
           24  Event receiving unit 
           30  Internal bus 
           31  Control unit 
           32  Main memory 
           33  External storage 
           34  Operation unit 
           35  Display unit 
           36  Timer 
           39  Control program 
           100  Thin client system 
         B Window operation button 
         B 1  Minimizing button 
         B 2  Maximizing button 
         B 3  Close button 
         D Touch panel display 
         I, I 1 , I 2 , I 3  Icon