Macromedia flex 2 Manual

168

Creating Advanced Visual Components in ActionScript

The properties have the following values:

unscaledWidth

Specifies the width of the component, in pixels, in the component’s 

coordinates, regardless of the value of the 

scaleX

 property of the component. This is the 

width of the component as determined by its parent container. 

unscaledHeight

Specifies the height of the component, in pixels, in the component’s 

coordinates, regardless of the value of the 

scaleY

 property of the component. This is the 

height of the component as determined by its parent container.

Scaling occurs in Flash Player, after 

updateDisplayList()

 executes. For example, a 

component with an 

unscaledHeight

 value of 100, and with a 

scaleY

 property of 2.0, 

appears 200 pixels high in Flash Player. 

Overriding the layout mechanism of the VBox container

The 

VBox

 container lays out its children from the top of the container to the bottom of the 

container in the order in which the children are added to the container. The following 
example overrides the 

updateDisplayList()

 method, which causes the VBox container to 

layout its children from the bottom of the container to the top:

package myComponents
{ 
    // asAdvanced/myComponents/BottomUpVBox.as
    import mx.containers.VBox;
    import mx.core.EdgeMetrics;
    import mx.core.UIComponent;

    public class BottomUpVBox extends VBox
    {
    
        public function BottomUpVBox() {
            super();
        }
        
        override protected function updateDisplayList(unscaledWidth:Number,
            unscaledHeight:Number):void {

            super.updateDisplayList(unscaledWidth, unscaledHeight);
    
            // Get information about the container border area. 
            // The usable area of the container for its children is the 
            // container size, minus any border areas.
            var vm:EdgeMetrics = viewMetricsAndPadding;

            // Get the setting for the vertical gap between children.
            var gap:Number = getStyle("verticalGap");
    
            // Determine the y coordinate of the bottom of the usable area