ActionScript 3.0 Design Patterns.pdf - VideoTutorials-bg.com

Example 6-23. TailWing.as
package
{
public class TailWing extends Component
{
public function TailWing(weight:Number, damage:Number = 0)
{
graphics.lineStyle(20, 0x999999);
graphics.moveTo(0, 0);
graphics.lineTo(30, 0);
super(weight, damage);
}
}
}
Example 6-24. Engine.as
package
{
public class Engine extends Component
{
public function Engine(weight:Number, damage:Number = 0)
{
graphics.lineStyle(20, 0x666666);
graphics.moveTo(0, 0);
graphics.lineTo(0, 30);
graphics.lineStyle(5, 0x000000);
graphics.moveTo(-20, -12);
graphics.lineTo(20, -12);
super(weight, damage);
}
}
}
Even though our airplane is a simple line drawing (to reduce complexity), it’s possible
to create the airplane components using high fidelity graphic images loaded from
external files.
Building the Composite Structure
Figure 6-9 shows the hierarchical composite structure of the airplane. The fuselage
and main wings are composite nodes. The fuselage contains two main wings and two
tail wings. Each main wing contains an engine.
Example 6-25 shows the Main class that builds the composite airplane structure. This
should be specified as the document class of the Flash document. The plane is displayed
in top-down view, as shown in Figure 6-8. The build procedure is very
straightforward. Each component is instantiated and positioned relative to its parent
by assigning values to its x and y parameters. The component is then added to its
parent composite node using the addChild( ) method. The airPlane variable refer-
238 | Chapter 6: Composite Pattern