AS3: beginGradientFIll() doesn't make me a gradient!

Question

I\'m trying to render a circle with a radial gradient but I can\'t seem to figure it out.

var bkgdGrad:Shape = new Shape();
bkgdGrad.graphics.beginGradientFi         


        

Answer 1

You need a Matrix object as well as its createGradientBox() method.

I've made a class called RadialGraident that creates a Shape object with a circle that has a radial gradient. All you need to do is parse the radius, colors, alphas and ratios upon creating the object like in the following example:

package 
{
    import flash.display.Sprite;
    import flash.events.Event;

    public class Main extends Sprite 
    {
        public function Main():void 
        {
            if (stage) init();
            else addEventListener(Event.ADDED_TO_STAGE, init);

        }// end function

        private function init(e:Event = null):void 
        {
            removeEventListener(Event.ADDED_TO_STAGE, init);

            var radialGradient:RadialGradient = new RadialGradient(200, [0x0000FF, 0x00FF00], [1, 1], [0, 255]);
            addChild(radialGradient);

        }// end function

    }// end class

}// end package

import flash.display.GradientType;
import flash.display.Shape;
import flash.geom.Matrix;

internal class RadialGradient extends Shape
{   
    public function RadialGradient(radius:Number, colors:Array, alphas:Array, ratios:Array)
    {
        var matrix:Matrix = new Matrix();
        matrix.createGradientBox(radius * 2, radius * 2);
        graphics.beginGradientFill(GradientType.RADIAL, colors, alphas, ratios, matrix);
        graphics.drawCircle(radius, radius, radius);
        graphics.endFill();

    }// end function

}// end class