Patent Publication Number: US-2016231878-A1

Title: Communication system, communication terminal, storage medium, and display method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The disclosure of Japanese Patent Application No. 2015-21207, filed on Feb. 5, 2015, is incorporated herein by reference. 
     FIELD 
     The exemplary embodiment relates to a technique for enabling users to exchange messages. 
     BACKGROUND AND SUMMARY 
     Known in the art is an instant messenger, which is an application that enables users to perform real-time communication via a network. 
     An exemplary embodiment provides a communication system including a first communication terminal and a second communication terminal. The communication system causes the first communication terminal and the second communication terminal to display at least a message and an image in chronological order. The first communication terminal includes a first accepting unit that accepts an input of a message, a second accepting unit that accepts a selection of an image to be associated with the message, and a sending unit that sends, to the second communication terminal, message information indicative of the message and image information indicative of the image in association with each other. The second communication terminal includes a receiving unit that receives the message information and the image information, and a first display control unit that causes a first display unit to display the message indicated by the received message information and the image indicated by the received image information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an example of a configuration of communication system  1 . 
         FIG. 2  shows an example of a hardware configuration of communication terminal  10 . 
         FIG. 3  shows an example of a hardware configuration of server device  20 . 
         FIG. 4  shows an example of a functional configuration for displaying a message. 
         FIG. 5  shows an example of a group selection screen. 
         FIG. 6  shows an example of transition of messages displayed in avatar display area Ar 12 . 
         FIGS. 7A to 7C  show an example of transition of group selection screens. 
         FIG. 8  shows an example of a message display screen. 
         FIG. 9  shows an example of a functional configuration for creating and exchanging a message. 
         FIG. 10  shows an example of a frame image creation screen. 
         FIG. 11  shows an example of a message display screen. 
         FIG. 12  shows an example of an operation of communication system  1 . 
     
    
    
     DETAILED DESCRIPTION OF NON-LIMITING EXAMPLE EMBODIMENTS 
     1. Exemplary Embodiment 
     1-1. Hardware Configuration 
     1-1-1. Communication System  1   
       FIG. 1  is a block diagram showing an example of a configuration of communication system  1  of an exemplary embodiment. Communication system  1  includes plural communication terminals  10 - 1  to  10 - n  and server device  20 . Communication terminals  10 - 1  to  10 - n  are coupled with server device  20  via network  30 . Communication terminals  10 - 1  to  10 - n  will be hereinafter referred to as “communication terminal  10 ” except where it is necessary to specify otherwise. Network  30  includes, for example, a mobile telephone network, a wireless local area network (LAN), or the Internet. Communication system  1  provides users of communication terminals  10  with a messaging service, or specifically an instant messaging service, which enables communication terminals  10  to exchange messages. 
     1-1-2. Communication Terminal  10   
       FIG. 2  is a block diagram showing an example of a hardware configuration of communication terminal  10 . Communication terminal  10  is a computer device such as a smartphone, a tablet terminal, or a game machine. Communication terminal  10  may be a stationary computer device. Communication terminal  10  exchanges a message with another communication terminal  10  via server device  20  and network  30 . 
     Communication terminal  10  includes control unit  11 , storage unit  12 , touch screen unit  13 , and communication unit  14 , as shown in  FIG. 2 . Control unit  11  includes a processing unit such as a central processing unit (CPU), and a memory. A CPU controls components of communication terminal  10  by executing a program stored in the memory or storage unit  12 . 
     Storage unit  12  is a storage device such as a flash memory or a hard disk. Storage unit  12  stores programs executed by a CPU and various types of data. Storage unit  12  stores message application  121  in particular, which is a program for displaying, creating, exchanging, and managing messages. Functions of message application  121  will be described later. 
     Storage unit  12  also stores message database  122 , which stores data on messages exchanged using message application  121 . The term “database” will hereinafter be referred to as “DB.” Message DB  122  stores received message data and sent message data. Each item of received message data includes, for example, a sender user ID, a receipt time and date, a message body, a group ID, and a background image ID. Each item of sent message data includes, for example, a receiver user ID, a transmission time and date, a message body, a group ID, and a background image ID. 
     Storage unit  12  also stores friend information DB  123 , which stores data on friends of a user of communication terminal  10 . A “friend” as used herein refers to a communication partner of a user of communication terminal  10 . A friend may be, for example, a user of another communication terminal  10 , who has performed a predetermined approval procedure in relation to a user of communication terminal  10 . The predetermined approval procedure, for example, may be performed as follows: a user sends a friend request to another user; and the other user approves the friend request. Data on each friend stored in friend information DB  123  may include, for example, a user ID, a user name, profile information, and avatar data. A user name is identification information for identifying a user; specifically, a communication address such as a mail address or a telephone number. 
     An avatar is an image of a character displayed as a user&#39;s alter ego in a virtual space created on a computer network or in a game. A character shown in an avatar is characterized mainly by its face, hairstyle, hair color, body shape, skin color, clothes, and accessories, which characteristics differentiate one avatar from another. A character shown in an avatar may have an appearance of a human or of any entity that can be used as a user&#39;s alter ego, other than a human, such as an animal or a robot. 
     An avatar may be a two-dimensional image or a three-dimensional image. An avatar may be a still image or an animated image. An avatar may be created by a user using an application, or may be selected by a user from among candidates pre-stored in storage unit  12 . Avatar data of a user of communication terminal  10  is stored in storage unit  12 . 
     Storage unit  12  also stores group information DB  124 , which stores data on groups formed by one or more friends. A “group” as used herein refers to a community in which plural friends share a message simultaneously. A group may be, for example, formed through the following procedure: a user invites a friend user to a group; and the friend user accepts the invitation. A group may be formed by two friends including a user of communication terminal  10 . Data of each group stored in group information DB  124  includes, for example, a group ID, a group name, and user IDs of users forming a group. 
     Storage unit  12  also stores background image DB  125 , which stores data on background images used in exchanging a message. A “background image” as used herein refers to an image constituting a frame image, described later, on which a message and an avatar are superimposed. In a background image, a balloon is displayed, which is an area in which a message is superimposed. A background image may be a still image or an animated image. Data relevant to each background image stored in background image DB  125  includes, for example, a background image ID, background image data, and display control data. “Display control data” as used herein refers to data defining a method by which an avatar is displayed in a background image. Display control data is, specifically, data defining a feature of an avatar shown in a background image, such as a position, a facial expression, an action, clothes, or accessories. 
     Touch screen unit  13  includes a display panel and a touch sensor disposed on the display panel. The display panel is, for example, a liquid crystal display or an organic electroluminescence (EL) display. The touch sensor is, for example, a capacitance-type or resistance-film-type touch sensor. Touch screen unit  13  displays an image under control of control unit  11 , and receives an instruction from a user using his/her finger or a stylus. 
     Communication unit  14  is a communication interface such as a data communication card. Communication unit  14  controls data communication with server device  20 . 
     1-1-3. Server Device  20   
       FIG. 3  is a block diagram showing an example of a hardware configuration of server device  20 . Server device  20  is an instant message server that relays a message between communication terminals  10 . Server device  20  includes control unit  21 , storage unit  22 , and communication unit  23 , as shown in  FIG. 3 . 
     Control unit  21  includes a processing unit such as a CPU, and a memory. A CPU controls components of server device  20  by executing a program stored in the memory or storage unit  22 . 
     Storage unit  22  is a storage device such as a hard disk. Storage unit  22  stores programs executed by a CPU and various types of data. Storage unit  22  also stores group information DB  221 , which stores data on groups formed by users of communication terminals  10 . Group information DB  221  collectively stores group data stored in group information DBs  221  of communication terminals  10 . Each item of group data stored in group information DB  221  includes, for example, a group ID, a group name, and user IDs of users forming a group. 
     Communication unit  23  is a communication interface such as a data communication card. Communication unit  23  controls data communication with communication terminal  10 . 
     1-2. Functional Configurations 
     Functional configurations of communication terminal  10  will be described. Specifically, a functional configuration for displaying a message and a functional configuration for creating and exchanging a message will be described. The functions are provided by executing message application  121  stored in storage unit  12 . 
     1-2-1. Message Display Function 
       FIG. 4  is a block diagram showing an example of a functional configuration for displaying a message. Execution of message application  121  provides screen generating unit  111 , display control unit  112 , obtaining unit  113 , and accepting unit  114 , as shown in  FIG. 4 . 
     Screen generating unit  111  generates a group selection screen in response to initiation of message application  121 . The group selection screen is a screen showing a list of plural groups, each of which includes plural users who share messages. The group selection screen shows message information for each of the plural groups. “Message information” as used herein refers to a message posted in a group, which satisfies a predetermined condition, and information indicative of a user who has posted the message. A message may be expressed by an image. A message that satisfies a predetermined condition is, specifically, a message posted recently or a last posted message. Information indicative of a user who has posted a message is, specifically, an avatar representing the user. Screen generating unit  111  generates the group selection screen with reference to message DB  122 , friend information DB  123 , and group information DB  124 . 
     Display control unit  112  causes touch screen unit  13  to display a group selection screen generated by screen generating unit  111 . 
       FIG. 5  is a diagram showing an example of a group selection screen displayed by display control unit  112 . The group selection screen shown in  FIG. 5  is a home screen of message application  121 , which is displayed in response to initiation of the application. On the group selection screen, three groups appear so that any one of the groups is selectable. Each of the groups is displayed in one of group display areas Ar 1 , which have a rectangular shape. Group display areas Ar 1  are arranged in a vertical direction. Group display areas Ar 1  are also arranged in a descending order of a posting time and date (in other words, a receiving time and date; the same shall apply hereinafter) of a latest message posted in each group. The group selection screen can be vertically scrolled to display preceding or subsequent group display areas Ar 1 . 
     An image showing each of group display areas Ar 1  may be a two-dimensional image or a three-dimensional image. A three-dimensional image may be obtained by capturing an image of avatars arranged in a virtual space using a virtual camera. Each of group display areas Ar 1  includes group information display area Ar 11  and avatar display area Ar 12 . Group information display area Ar 11  and avatar display area Ar 12  each have a substantially rectangular shape. They are stacked in a vertical direction. In group information display area Ar 11 , a group name, the number of active users, and a latest posting time and date may appear. In group information display area Ar 11  for group A shown in  FIG. 5 , a group name “GROUP A,” the number of active users “0,” and a posting time and date “3 HRS 38 MINS AGO” appear. The number of active users is the number of users belonging to a group, who are displaying or creating a message when a group selection screen is displayed. 
     In avatar display area Ar 12 , avatars Av 1  of users belonging to a group are arranged for display in a horizontal direction. Avatars Av 1  displayed in avatar display area Ar 12  are, in particular, avatars of not more than five users belonging to a group, who have recently posted a message. Positions of avatars Av 1  are determined based on a posting time and date of a latest message posted by each user represented by an avatar. Specifically, avatar Av 1  of a user who has posted a latest message is positioned at the left side, avatar Av 1  of a user who has posted a second latest message is positioned at the right side, avatar Av 1  of a user who has posted a third latest message is positioned at a second space from the left, avatar Av 1  of a user who has posted a fourth latest message is positioned at a second space from the right, and avatar Av 1  of a user who has posted a fifth latest message is positioned at the center. In short, avatars of users who have posted latest messages are positioned farthest from the center. 
     Each of avatars Av 1  shows a standing full-faced character. Each of avatars Av 1  is an animated image of a character, whose facial expression or action changes over time. A type of animation may differ for each avatar, which may be determined according to a predetermined condition. For example, a type of animation may be determined based on, for example, a situation of message posting in a group. Specifically, an animated image showing a sleeping character may be displayed in a situation where no message has been posted in a group for a predetermined time period. 
     In avatar display area Ar 12 , also appearing are messages that have been posted by users represented by displayed avatars Av 1 . Each message is displayed in association with avatar Av 1  of a user who has posted the message. Specifically, each message is displayed near avatar Av 1  of a user who has posted the message. More specifically, each message is displayed in, for example, an oval balloon, which corresponds to avatar Av 1  of a user who has posted the message. Each message is enclosed in a balloon that is indicated as coming from corresponding avatar Av 1 , which clarifies an association between the message and avatar Av 1 . In the group selection screen shown in  FIG. 5 , a message “HELLO!” appears above avatars Av 1  as a message posted by a user represented by leftmost avatar Av 1 . A part of a message that cannot be included in a balloon is hidden. 
     Messages are displayed in a descending order of a posting time and date in a case where plural avatars Av 1  are displayed, as in the case of avatar display area Ar 12  for group A shown in  FIG. 5 .  FIG. 6  is a diagram showing an example of transition of messages displayed in avatar display area Ar 12  for group A shown in  FIG. 5 . As for group A shown in  FIG. 5 , messages corresponding respectively to avatars Av 1   a , Av 1   e , Av 1   b , Av 1   d , and Av 1   c  are displayed in such an order, since a descending order of a posting date and time of a latest message posted by a corresponding user is as follows: avatars Av 1   a , Av 1   e , Av 1   b , Av 1   d , and Av 1   c . The messages are sequentially displayed at regular intervals. Avatar Av 1  of a user, whose message is being displayed, may be highlighted to clarify an association between avatar Av 1  and the message. 
     The foregoing is a description of a group selection screen. 
     A group selection screen described in the foregoing enables a user to check situations of message posting for plural groups by referring only to a single screen. Specifically, the group selection screen enables a user to check, for each group, users who have recently posted a message, and contents of the posted messages. 
     Obtaining unit  113  obtains a posting notice that reports that a new message has been posted in a group registered in group information DB  124 . The posting notice is sent by server device  20 , and obtaining unit  113  obtains the posting notice via communication unit  14 . Obtaining unit  113  may periodically contact server device  20  to check for posting of a new message, instead of merely waiting for a posting notice. The posting notice sent from server device  20  includes a user ID of a poster, a group ID, message information, and a background image ID. 
     When obtaining unit  113  obtains a posting notice while a group selection screen is displayed, screen generating unit  111  generates data to update message information displayed for a group, for which a new message has been posted. Specifically, screen generating unit  111  generates a new group selection screen. Message information as used herein refers to a message posted in a group, which satisfies a predetermined condition, and information indicative of a user who has posted the message. A message that satisfies a predetermined condition is, specifically, a message posted recently or a last posted message. Information indicative of a user who has posted a message is, specifically, an avatar representing the user. To generate a new group selection screen, screen generating unit  111  identifies an avatar of a poster based on a user ID included in the posting notice with reference to friend information DB  123 . 
     Screen generating unit  111  may generate data to update message information displayed for a group, for which a new message has been posted, when obtaining unit  113  obtains a posting notice while a message display screen (described later), instead of a group selection screen, is displayed. 
     Display control unit  112  updates a group selection screen currently displayed on touch screen unit  13  with a new group selection screen generated by screen generating unit  111 . Display control unit  112  may carry out the update in real-time, without waiting for a user&#39;s instruction. Display control unit  112  may carry out an update repeatedly. 
     Display control unit  112 , when obtaining unit  113  obtains a posting notice while a message display screen is displayed, may display a new group selection screen generated by screen generating unit  111  at the top of a message display screen currently displayed on touch screen unit  13 . When doing so, display control unit  112  may temporarily display only an image of avatar display area Ar 12  included in the new group selection screen, which corresponds to a group for which a new message has been posted. 
       FIGS. 7A to 7C  show an example of transition of group selection screens, which is performed in response to posting of a new message during display of a group selection screen.  FIGS. 7A to 7C  show transition of avatar display area Ar 12  for group A in particular, which is included in the group selection screen shown in  FIG. 5 . The transition of group selection screens shown in  FIGS. 7A to 7C  is performed when a new message is posted by a user belonging to group A, whose avatar is not displayed in avatar display area Ar 12 . 
       FIG. 7A  shows an image displayed prior to an update of a group selection screen. The image shown in  FIG. 7A  is identical to that of avatar display area Ar 12  for group A shown in  FIG. 5 . 
       FIG. 7B  shows a scene of a screen transition animation displayed when the group selection screen is updated. The screen transition animation shows a process of switching avatars Av 1 , which is performed in response to posting of a new message. In the process, new avatar Av 1  appears in avatar display area Ar 12 , which represents a user who has posted a new message, and avatar Av 1  whose corresponding posting time and date is oldest disappears from avatar display area Ar 12  among avatars Av 1  appearing in avatar display area Ar 12 . In the group selection screen shown in  FIG. 7B , new avatar Av 1   f , which is to be positioned at the left side of the screen, appears, and avatar Av 1   c  disappears. 
     The screen transition animation also shows a process of relocating avatars Av 1  are in response to posting of a new message. As for avatars Av 1  appearing in avatar display area Ar 12 , which are not switched, an order of a posting time and date of a latest message is lowered by one in response to posting of a new message. Accordingly, each of avatars Av 1  is relocated to a position corresponding to its lowered order. In the group selection screen shown in  FIG. 7B , avatar Av 1   a  is relocated to the right end on the screen, avatar Av 1   e  is relocated to a second space from the left, avatar Av 1   b  is relocated to a second space from the right, and avatar Av 1   d  is relocated to the center. 
     In the above processes of switching and relocating avatars Av 1 , characters represented by avatars Av 1  are shown to move by running. The characters simultaneously move to a new position, while avoiding hitting each other. A new character appearing in avatar display area Ar 12  enters the screen from the left side thereof, and a character disappearing from avatar display area Ar 12  exits the screen from the right side thereof. 
     While the screen transition animation is displayed, display of a message posted in the group may be omitted. A posting time and date of a latest message displayed in group information display area Ar 11  is updated to, for example, “JUST NOW” in response to posting of a new message. 
       FIG. 7C  shows an image displayed subsequent to the update of the group selection screen. In avatar display area Ar 12  shown in  FIG. 7C , avatar Av 1   f , which has been newly added by the above switch, and avatars Av 1   a , Av 1   b , Av 1   d , and Av 1   e , which have been relocated as described above, are displayed. Each of avatars Av 1  shows a standing full-faced character. In avatar display area Ar 12 , messages posted by users represented by displayed avatars Av 1  appear. Each of the messages is displayed within a balloon, which corresponds to avatar Av 1  of a user who has posted the message. The messages are displayed in a descending order of a posting time and date. Specifically, messages corresponding respectively to avatars Av 1   f , Av 1   a , Av 1   e , Av 1   b , and Av 1   d  are displayed in order of avatars Av 1   f , Av 1   a , Av 1   e , Av 1   b , and Av 1   d . The messages are sequentially displayed at regular intervals. 
     The foregoing is a description of transition of a group selection screen. 
     It is to be noted that, although  FIGS. 7A to 7C  show a case example where a new message is posted, plural avatars Av 1  may be switched in a case where plural messages are simultaneously posted by different users. 
     Accepting unit  114  accepts a selection of any one of groups displayed on a group selection screen, via touch screen unit  13 . A group is selected by, for example, tapping group display area Ar 1  displayed on touch screen unit  13 . Alternatively, a group may be selected by an input operation using an input device such as a mouse or a keyboard, or by a vocal input operation using a speech recognition technology. 
     When communication unit  14  accepts a selection of a group, screen generating unit  111  generates a message display screen that displays at least part of messages shared in the selected group. When doing so, screen generating unit  111  generates the message display screen with reference to message DB  122 , friend information DB  123 , and background image DB  125 . Display control unit  112  causes touch screen unit  13  to display the message display screen generated by screen generating unit  111 . 
       FIG. 8  is a diagram showing an example of the message display screen. The message display screen shown in  FIG. 8  shows group name display area Ar 2 , message history display area Ar 3 , background selection field display button B 1 , message input field Ar 4 , and send button B 2 . The display components have a substantially rectangular shape. Group name display area Ar 2 , message history display area Ar 3 , and message input field Ar 4  are arranged vertically on the message display screen. Background selection field display button B 1  is positioned to the left of message input field Ar 4 , and send button B 2  is positioned to the right of the same field. 
     In group name display area Ar 2 , a name of a group, messages of which appear on a message display screen, appears horizontally. 
     In message history display area Ar 3 , plural frame images F 1 , each of which shows a message shared in a group, are arranged vertically for display. In message history display area Ar 3 , frame images F 1  are arranged in chronological order; in other words, a timeline of frame images F 1  are displayed. Specifically, frame images F 1  are arranged from the top in an ascending order of a posting time and date of a message shown in each frame image F 1 . Although  FIG. 8  shows only two frame images F 1 , frame images F 1  appearing in message history display area Ar 3  can be vertically scrolled to display preceding or subsequent frame images F 1 . Frame image F 1  that initially appears in message history display area Ar 3  when a message display screen is displayed, may be, for example, a message that remains unread by a user, and whose posting time and date is oldest. 
     Frame image F 1  is an image showing a frame of a cartoon. A frame of a cartoon as used herein refers to an area in which a picture showing a scene of a cartoon is recorded. A frame of a cartoon is, typically, surrounded by a rectangular border line. A series of frames of a cartoon describes a transition of scenes. 
     Frame image F 1  includes message M 2 , avatar Av 2 , and background image S 1 . Avatar Av 2  is superimposed on background image S 1 , and message M 2  is inserted into a balloon shown in background image S 1 . A method by which avatar Av 2  appears in frame image F 1  is determined based on display control data associated with background image S 1 . 
     If avatar Av 2  constituting frame image F 1  is an animated image, selecting the frame image by, for example, tapping the frame image causes an animated sequence to be played. 
     Background selection field display button B 1  is a button for ordering transition to a frame image creation screen (described later). 
     Message input field Ar 4  accepts an input of a message. A selection of message input field Ar 4  by, for example, tapping the field causes a software keyboard (not shown), or a screen keyboard, to appear at the top of message history display area Ar 3 . The software keyboard enables a user to input a message. 
     Send button B 2  is a button for providing an instruction to post a created frame image. 
     The foregoing is a description of a message display screen. 
     A message display screen described in the foregoing enables a user to read messages exchanged in a group as if reading a cartoon strip. 
     1-2-2. Message Creation and Exchange Function 
       FIG. 9  is a block diagram showing an example of a functional configuration for creating and exchanging a message. Execution of message application  121  provides screen generating unit  111 , display control unit  112 , first accepting unit  115 , second accepting unit  116 , third accepting unit  117 , sending unit  118 , and receiving unit  119 , as shown in  FIG. 9 . 
     Screen generating unit  111  generates a frame image creation screen when background selection field display button B 1  is selected by, for example, tapping the button. When doing so, screen generating unit  111  generates the frame image creation screen with reference to background image DB  125 . 
     Display control unit  112  causes touch screen unit  13  to display a frame image creation screen generated by screen generating unit  111 . 
       FIG. 10  is a diagram showing an example of the frame image creation screen displayed by display control unit  112 . The frame image creation screen shown in  FIG. 10  shows group name display area Ar 2 , preview display area Ar 5 , keyboard button B 3 , message input field Ar 4 , send button B 2 , and background candidate display area Ar 6 . The display components have a substantially rectangular shape. Group name display area Ar 2 , preview display area Ar 5 , message input field Ar 4 , and background candidate display area Ar 6  are arranged vertically on the frame image creation screen. Keyboard button B 3  is positioned to the left of message input field Ar 4 , and send button B 2  is positioned to the right of the same field. 
     In group name display area Ar 2 , a name of a group appears horizontally, in which created frame image F 1  is to be shared. 
     In preview display area Ar 5 , a preview of frame image F 1  appears. A preview of frame image F 1  is displayed to enable a user to check, prior to posting of the frame image, how the image frame appearing in message history display area Ar 3  looks. 
     A preview of frame image F 1  is displayed when background image S 1  is selected in background candidate display area Ar 6 . The preview of frame image F 1  is generated by combining background image S 1  with avatar Av 2  of a user. If background image S 1  or avatar Av 2 , which constitutes the frame image, is an animated image, the animation is shown. 
     When message M 2  is input in message input field Ar 4  during display of the preview of frame image F 1 , a preview of frame image F 1 , into which message M 2  has been further mixed, is displayed. The mixture of message M 2  into frame image F 1  may be performed on a word-by-word basis while message M 2  is being input. 
     When background image S 1  is selected in background candidate display area Ar 6  after another background image S 1  is selected, a preview of new frame image F 1  is displayed, which is generated by combining the newly selected background image with avatar Av 2  of a user. In such a case, if message M 2  has already been input in message input field Ar 4 , a preview of frame image F 1 , to which the message has been further mixed, is generated. A position of message M 2  in frame image F 1  changes depending on a position of a balloon shown in the selected background image. 
     Keyboard button B 3  is a button for providing an instruction to display a software keyboard. When keyboard button B 3  is selected by, for example, tapping the button, a software keyboard (not shown) is caused to appear, for example, at the top of background candidate display area Ar 6 . The displayed software keyboard enables a user to input a message in message input field Ar 4 . 
     Message input field Ar 4  accepts an input of a message. 
     Send button B 2  is a button for providing an instruction to post created frame image F 1 . 
     In background candidate display area Ar 6 , candidates for background image S 1  appear so that any of the candidates is selectable. The candidates for background image S 1  are background images registered in background image DB  125 , which are displayed in background candidate display area Ar 6  in a reduced size. 
     The foregoing is a description of a frame image creation screen. 
     First accepting unit  115  accepts an input of a message. Specifically, first accepting unit  115  accepts a message input in message input field Ar 4 , via touch screen unit  13 . First accepting unit  115  outputs message information indicative of the input message to screen generating unit  111  and sending unit  118 . A message may be input character-by-character using a software keyboard, or may be input by selecting one of the candidates for a message displayed on the screen. 
     Second accepting unit  116  accepts a selection of an image to be associated with a message accepted by first accepting unit  115 . Specifically, second accepting unit  116  accepts a selection of one of the background images displayed in background candidate display area Ar 6 , via touch screen unit  13 . The background image is selected together with the message on a screen, posted together with the message, and displayed together with the message. The selected background image may be an animated image. Second accepting unit  116  outputs image information indicative of the selected background image to screen generating unit  111  and sending unit  118 . The image information is, specifically, a background image ID. 
     Screen generating unit  111 , on obtaining a background image ID output from second accepting unit  116 , generates, based on the background image ID, a frame image to be displayed in preview display area Ar 5 . Specifically, screen generating unit  111  obtains background image data identified by the obtained background image ID from background image DB  125 , to generate a frame image composed of a background image represented by the background image data and an avatar of a user. A method by which the avatar appears in the frame image is determined based on display control data associated with the background image. Display control unit  112  causes the frame image generated by screen generating unit  111  to appear in preview display area Ar 5 . The display of the frame image is carried out prior to posting of the frame image. 
     When screen generating unit  111 , subsequent to the display of the frame image, obtains message information output from first accepting unit  115  that has accepted an input of a message, screen generating unit  111  generates a frame image composed of not only the background image and the avatar but also the message indicated by the message information. Display control unit  112  causes the frame image to appear in preview display area Ar 5 . When second accepting unit  116 , subsequent to the display of the frame image, accepts a selection of a background image that is different from the displayed background image, screen generating unit  111  generates a new frame image to be displayed in preview display area Ar 5 , based on a background image ID output from second accepting unit  116 . In the frame image, display of the already input message is maintained. 
     Third accepting unit  117  accepts a transmission instruction to send message information indicative of a message accepted by first accepting unit  115 , and image information indicative of an image accepted by second accepting unit  116 , in association with each other. In other words, third accepting unit  117  accepts a transmission instruction to send a set of message information and image information. Third accepting unit  117 , specifically, accepts the transmission instruction through a selection of send button B 2  displayed on touch screen unit  13 . Send button B 2  may be selected by tapping the button, by an input operation using an input device such as a mouse or a keyboard, or by a vocal input operation using a speech recognition technology. Send button B 2  enables a user to send a set of message information and image information by a single action. Third accepting unit  117 , on accepting a transmission instruction, notifies sending unit  118  of the acceptance of a transmission instruction. 
     Sending unit  118  sends message information output from first accepting unit  115  and image information output from second accepting unit  116 , to another communication terminal  10  in association with each other. Specifically, sending unit  118  sends a set of message information and image information to another communication terminal  10 . Alternatively, sending unit  118  sends an item of data including a part corresponding to message information and a part corresponding to image information to another communication terminal  10 . Alternatively, sending unit  118  sends image information to which message information has been mixed, to another communication terminal  10 . Image information herein refers to, specifically, a background image ID. Sending unit  118 , when third accepting unit  117  accepts a transmission instruction, carries out the transmission by use of communication unit  14 . When doing so, sending unit  118  further sends processing information to another communication terminal  10 , which is used to process a background image identified by a background image ID. Specifically, sending unit  118  sends processing information to another communication terminal  10  in association with message information and image information. Processing information herein refers to, specifically, information indicative of an avatar of a user. More specifically, processing information is, for example, a user ID. 
     Processing information may be image data representing a user&#39;s avatar. Alternatively, processing information may be a part number indicative of one of a set of parts constituting a user&#39;s avatar, which number differs for each part, or may be a part ID, which identifies one of prepared candidates for a part. 
     After sending unit  118  carries out the transmission, display control unit  112  causes a frame image appearing in preview display area Ar 5  to appear in message history display area Ar 3  of a message display screen.  FIG. 11  is a diagram showing an example of the message display screen displayed after sending unit  118  carries out the transmission. The message display screen shown in  FIG. 11  is displayed when send button B 2  is selected on the above frame image creation screen shown in  FIG. 10 . On the message display screen shown in  FIG. 11 , frame image F 1  that has been displayed in preview display area Ar 5  of the frame image creation screen shown in  FIG. 10  is displayed at the bottom of message history display area Ar 3 , or in other words below a latest frame image F 1  displayed in message history display area Ar 3 . 
     Receiving unit  119  receives a set of message information and image information from another communication terminal  10  via communication unit  14 . Image information herein refers to, specifically, a background image ID. Receiving unit  119  also receives processing information from another communication terminal  10 , which is used to process a background image identified by a background image ID. Processing information herein refers to, specifically, information indicative of an avatar of a user of another communication terminal  10 . More specifically, processing information is, for example, a user ID. 
     Screen generating unit  111  generates a frame image composed of a message indicated by message information received by receiving unit  119  and a background image identified by a background image ID received by receiving unit  119 . The generated frame image is displayed in message history display area Ar 3 . When generating the frame image, screen generating unit  111  processes the background image based on processing information received by receiving unit  119 . Specifically, screen generating unit  111  combines the background image with an avatar of a user of another communication terminal  10 . When doing so, screen generating unit  111  processes a facial expression of a character shown in the avatar, based on the background image to which the avatar is mixed. Specifically, screen generating unit  111  processes the facial expression based on display control data associated with the background image. Screen generating unit  111  also arranges a message at the top of the background image. 
     Display control unit  112  causes the frame image generated by screen generating unit  111  to appear in message history display area Ar 3 . An example of the frame image is shown in  FIG. 11 . 
     1-3. Operation 
     An operation of communication system  1  will be described. Specifically, an operation performed in a process where communication terminals  10  share a message will be described.  FIG. 12  is a sequence chart showing an example of an operation of communication system  1 . In the following description of the operation, it is assumed that two communication terminals  10  share a message. Communication terminal  10  that sends a message will be referred to as “communication terminal  10 A” and communication terminal  10  that receives a message will be referred to as “communication terminal  10 B.” It is to be noted that the number of communication terminals  10  that share a message may be three or more. 
     When a user of communication terminal  10 A selects a background image, inputs a message, and selects send button B 2  on a frame image creation screen illustrated in  FIG. 10  (step S 1 ), communication terminal  10 A sends posting information including a background image ID indicative of the selected background image and message information indicative of the input message to server device  20  (step S 2 ). The posting information also includes a user ID of the user, or a poster, and a group ID of a group in which the message is shared. After sending the posting information, communication terminal  10 A displays, in message history display area Ar 3 , a frame image that has been displayed in preview display area Ar 5  when send button B 2  has been selected (step S 3 ). 
     Server device  20 , on receiving the posting information, identifies communication terminal  10 B as a destination of a posting notice based on the group ID included in the posting information. Specifically, server device  20  identifies communication terminal  10 B by identifying a user ID associated in group information DB  221  with the group ID included in the posting information. Server device  20  sends a posting notice to communication terminal  10 B (step S 4 ). The posting notice includes the message information, the background image ID, the user ID of the user of communication terminal  10 A, and the group ID. 
     Communication terminal  10 B, on receiving the posting notice, registers information on a message included in the posting notice in message DB  122  (step S 5 ). Specifically, communication terminal  10 B registers the user ID of the user of communication terminal  10 A, a receiving time and date, the message information, the group ID, and the background image ID in association with each other. 
     Subsequently, in communication terminal  10 B, when message application  121  is started and a group is selected on a group selection screen, communication terminal  10 B displays a message display screen illustrated in  FIG. 11  (step S 6 ). If the group identified by the group ID registered in step S 5  is selected, communication terminal  10 B displays, in message history display area Ar 3 , a message associated with the group ID in message DB  122 . When doing so, communication terminal  10 B combines the background image identified by the background image ID with the avatar of the user of communication terminal  10 A and the message to generate and display a frame image. 
     2. Modifications 
     The above exemplary embodiment may be modified as described below. Two or more of the following modifications may be combined with each other. 
     2-1. Modification 1 
     A group selection screen illustrated in  FIG. 5  may be modified as described below. In a group selection screen, a set of a user(s) registered in friend information DB  123  and a user of communication terminal  10  may be displayed as a group that can be selected. An update of a group selection screen illustrated in  FIGS. 7A to 7B  may be performed only when a newly posted message satisfies a predetermined condition. For example, a group selection screen may be updated when a level of importance or urgency of a posted message equals or exceeds a predetermined threshold, or when the message has been posted by a predetermined user. An order of group display areas Art arranged on a group selection screen may be an ascending order of a registration time and date at which data on a group has been registered in group information DB  124 , or may be an order predetermined by a user. 
     A user whose avatar is displayed in avatar display area Ar 12  may be a user who has posted a message that satisfies a predetermined condition. The message satisfying a predetermined condition may be a message having a level of importance or urgency that equals or exceeds a predetermined threshold, a message that remains unread, or a message whose posting time and date is within a predetermined time after a group selection screen is displayed. Avatars displayed in avatar display area Ar 12  may be arranged from the left or right of the screen in a descending order of a posting time and date of a latest message posted by a user represented by an avatar. In short, avatars may be arranged in chronological order. 
     The number of users whose avatars are displayed in avatar display area Ar 12  may be less than or more than five. In avatar display area Ar 12 , a user ID, instead of an avatar, may be displayed as information indicative of a user. In avatar display area Ar 12 , only one of an avatar and a message may appear. If a space of avatar display area Ar 12  allows, messages of plural users may be displayed simultaneously. Display of a balloon that encloses a message may be omitted. Display of a balloon shown in a frame image may be omitted. 
     2-2. Modification 2 
     An operation illustrated in  FIG. 12  may be modified as described below. Communication terminal  10 A may send posting information to server device  20 , which includes a part or all of avatar data of a user of the terminal, background image data representing a background image selected by the user, and display control data corresponding to the background image. Server device  20  may send a posting notice to communication terminal  10 B, which includes the data included in the posting information. When doing so, server device  20  may initially send a posting notice to communication terminal  10 B, which merely reports that communication terminal  10 A has posted a message, and send, in response to a data request from communication terminal  10 B, the data included in the posting information to the terminal 
     Communication terminal  10 A may send data other than data indicative of a background image to server device  20 , together with message information. For example, communication terminal  10 A may send data indicative of an image, picture, or video of a two-dimensional or three-dimensional object. Alternatively, communication terminal  10 A may send data indicative of a voice or a vibration pattern. 
     Server device  20  may send question data indicative of a question to communication terminals  10 A and  10 B to activate communication between the terminals. Each communication terminal  10  displays the question indicated by the question data in message history display area Ar 3  of a message display screen. Posting of a response to the question by each user activates communication between communication terminals  10 A and  10 B. 
     Whether question data should be sent to communication terminal  10  may be set for each group. A timing at which question data is sent may be determined depending on a situation of message posting of a group. For example, question data may be sent in a situation where the number of messages posted in a group per unit time is equal or smaller than a predetermined threshold. 
     Messages may be exchanged between communication terminals  10 A and  10 B through peer-to-peer (P2P) communication, without server device  20 . 
     2-3. Modification 3 
     A part or all of data stored in storage unit  12  of communication terminal  10  may be stored in another device on a network such as server device  20 . A display device constituting touch screen unit  13  may separate from communication terminal  10 . 
     2-4. Modification 4 
     When a user of communication terminal  10  has posted a frame image that satisfies a predetermined condition, a frame image posted thereafter by another user may be subjected to a predetermined processing before it is displayed. For example, when a user of communication terminal  10  has posted a frame image showing a character who turns off a light, a frame image posted by another user may be subjected to a processing by which the frame image is darkened. When a user has posted a frame image showing a fairy who casts a spell, a frame image posted by another user may be subjected to a processing by which an expression of a message constituting the frame image is changed. When a user has posted a frame image showing a character who squeezes ketchup out of a bottle, a frame image posted by another user may be subjected to a processing by which an image of ketchup droplets is added to a face part of an avatar constituting the frame image. When a user has posted a frame image showing a scene of snowstorm, a frame image posted by another user may be subjected to a processing by which animation showing shivering is added to an avatar constituting the frame image. 
     The processing illustrated in the foregoing may be determined based on any of a background image, an avatar, and a message that constitute a posted frame image. A subject of a processing may be any of a background image, an avatar, and a message that constitute a frame image. A time period for which frame images are subjected to a processing and the number of frame images subjected to a processing may be set for each type of processing. A processing may be applied in not only communication terminal  10  whose user has posted a frame image that satisfies a predetermined condition, but also another communication terminal  10 , which shares the posted frame image. 
     2-5. Modification 5 
     Message application  121  stored in storage unit  12  of communication terminal  10  may be provided to the terminal via a computer-readable storage medium. The storage medium is, for example, a magnetic storage medium such as a magnetic tape or a magnetic disk, an optical storage medium such as an optical disk, or a semiconductor memory. Message application  121  may be provided to communication terminal  10  via a network such as the Internet.