Programming Flash Communication Server

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Chapter 2: Communication Components

UserColor component is a combo box with 10 preselected colors, as shown in

Figure 2-14. When the user selects a color within the UserColor component, her text

appears in that color within the history window of the Chat component. If the Cur-

sor component is used with the Flash movie, the user’s cursor will be displayed to

other users in the chosen color as well.

Nested Flash UI components

The UserColor component uses the Flash MX UI components ComboBox and

ScrollBar. You can alter the look of this component by changing the appropriate skin

symbol in the Component Skins folder within the Flash document’s Library panel.

How the component works

The UserColor component, like the SetBandwidth component, uses a gFlashCom.

Notifier object in client-side ActionScript to notify other color-aware communica-

tion components of changes made to the user’s color preference. When the user

loads a Flash movie that contains a UserColor component, the UserColor compo-

nent connects to the FlashCom application specified by a SimpleConnect compo-

nent or a custom connection that passed its NetConnection object to the UserColor’s

connect( ) method. In order for the UserColor component to work properly, the set-

Username( ) method of the component must be invoked and passed a string value for

the user’s name. If you use the SimpleConnect component, this happens automati-

cally. The UserColor component also stores its selected color value within the

usercolor property of the client’s global storage object within Server-Side Action-

Script for the duration of the application session.

VideoConference

The VideoConference component enables you to create a Flash client capable of dis-

playing multiple instances of the AVPresence component. As each user connects to

the FlashCom application, a new AVPresence instance is added to the Stage, display-

ing her audio/video stream as shown in Figure 2-15.

This component can be particularly bandwidth-intensive for both client-side and

server-side connections. As each user is added to the AV chat, the stream must man-

age multiple additional streams depending on the number of users—the new user

Figure 2-14. The UserColor component

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Summary of Communication Components

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has one outgoing stream, plus one incoming stream for each existing user. Likewise,

the new user’s stream must be sent to existing users (in addition to the streams they

already have). For example, if you have three users connected to an application using

the VideoConference component, the server is managing nine streams; the server and

each user’s bandwidth must be capable of handling three streams for each user: his

own stream (outgoing) and the two from the other participants (incoming). You can

quickly determine how many streams a server must handle by squaring the number

of participants. For example, five participants will require the server to handle 25

streams (five for each participant).

Nested Flash UI components

The VideoConference component does not use any Flash UI components. It does

however automatically include the AVPresence component symbol. The skin assets

of the VideoConference component are located in the Communication Components

➝ Core Assets - Developer Only ➝ VideoConference Assets folder of your docu-

ment’s Library. You can also change the look of the AVPresence component by mod-

ifying the graphics in the AVPresence Assets

➝ fc_av_icons folder.

Client-side component parameters

The VideoConference component has four parameters that can be set in the Proper-

ties panel or Component Parameters panel:

Show Boundary

This Boolean parameter, corresponding to the

showBoundary property, deter-

mines if the border of the VideoConference instance is displayed. The default

value is

false. You can use Flash’s Transform tool to stretch the dimensions of

the instance without distorting the physical appearance of the AVPresence

instances that will be attached for each user.

Figure 2-15. The runtime look of the VideoConference component