Programming Flash Communication Server

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Chapter 2: Communication Components

for low, medium, and high bit rate Internet connections. (The settings used

depend on the value of the Default Settings parameter or the

defaultSetting

property.) Each setting uses an object with the following properties to adjust the

Camera object’s output:

width (in pixels), height (in pixels), fps, bandwidth (in

Kbps), and

key (for keyframe interval). The object also has a rate property that

controls the sampling rate of the Microphone object. You can override these set-

tings in client-side ActionScript by writing a new value to the

setLow, setMed, and

setHigh properties of the VideoRecord component.

The SetBandwidth component does not apply any changes to the VideoRecord com-

ponent. You can, however, use a ComboBox instance to let the user choose which

quality setting should be applied to a VideoRecord instance.

Component process overview

When the connect( ) method of a VideoRecord instance is invoked and passed a ref-

erence to a NetConnection object, the component creates two streams: an outgoing

stream (

out_ns) for the recording stream and an incoming stream (in_ns) for the

replay stream. Unlike the VideoPlayback component, the VideoRecord component

does not utilize FCPlayStreamClass to create a custom NetStream class. Rather, the

component uses the existing methods of the NetStream class. The component also

invokes a cameraOn( ) method upon connection, which grabs the output from the

Camera and Microphone objects. The cameraOn( ) method invokes the adjustSet-

tings( ) method to control the quality of output captured by the Camera and Micro-

phone objects. You can invoke VideoRecord.adjustSettings( ) from your own custom

UI elements, such as a combo box, to change the quality of recorded output on the

fly.

Whiteboard

The Whiteboard component is, as the name implies, a component that shows the UI

of a whiteboard with drawing and text tools, as shown in Figure 2-18. The menu has

the following options (from top to bottom):

Move/Transform tool

Selects and moves objects on the whiteboard. You can delete an item by clicking

it with the Move/Transform tool and pressing the Delete key. You can use this

tool to resize arrow lines, but you cannot resize text or text boxes with this tool.

Text tool

Creates standard text, in a _serif device font.

Text Box tool

Draws a black-outlined box, using the selected color in the color menu as its fill.

The text in this box uses the _sans device font.

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Summary of Communication Components

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End Arrow Line tool

Draws a line with an arrow point at the end of the line (as determined by the

location of the second click).

Start Arrow Line tool

Works the same as the End Arrow Line tool, except that the arrow point is

placed at the first click point and not the second.

Dual Arrow Line tool

Creates a line with arrow points at both ends.

Color menu

Features eight colors that you can use as fill colors for the Text or Text Box tool

or as line colors for the line tools.

Expand/Collapse button

Expands and collapses the UI of the tools palette.

If you’re looking for a full-featured whiteboard component, check out

Fig Leaf Software’s WYSIdraw at http://products.figleaf.com. This

whiteboard features more drawing tools and can layer JPEG images

with other artwork in a collaborative environment. This component is

priced for enterprise use, starting at $995.

Nested Flash UI components

The Whiteboard component does not use any nested Flash UI components. You can

adjust the look-and-feel of the component by adjusting its skin symbols in the Com-

munication Components

➝ Core Assets - Developer Only ➝ Whiteboard Assets

folder of the document’s Library.

Figure 2-18. The UI menu of the Whiteboard component