function findBlingPoints(o:*, n:Number, s:String="right"){
	var myBitmapData:BitmapData = new BitmapData(o.width, o.height, true, 0x000000);
	myBitmapData.draw(o);
	var pixelValue:uint;
	var pointArray:Array = [];
	var currPixel:Boolean = false;
	var lastPixel:Boolean = false;
	
	for(var i=0; i<myBitmapData.width; i++){
		pixelValue = myBitmapData.getPixel32(i, n);
		if(pixelValue==0){currPixel=false}else{currPixel=true};
		switch (s){
			case "right":
			if(!currPixel&&lastPixel){
				pointArray[pointArray.length]=i;
				pointArray[pointArray.length]=n;
			}
			break;
					
			case "left":
			if(!lastPixel&&currPixel){
				pointArray[pointArray.length]=i;
				pointArray[pointArray.length]=n;
			}
			break;
						
			case "both":
			if(lastPixel!=currPixel){
				pointArray[pointArray.length]=i;
				pointArray[pointArray.length]=n;
			}
			break;
		}						
		lastPixel = currPixel;
	}
	return pointArray;
}

Find edges of an object

ActionScript 3