package {

	import flash.display.Shape;
	import flash.display.Sprite;
	import flash.events.KeyboardEvent;
	import flash.events.Event;
	import flash.events.MouseEvent;
	import flash.filters.GlowFilter;
	import flash.ui.Keyboard;

	[SWF(width=550, height=550, backgroundColor=0)]

	/**
	* Copies a single shape's vector drawings into several other shapes rotated
	* around a common point.
	*/
	public class graphic_flex_image_effects_01_Flex_CopyingGraphics extends Sprite {

		private static const INIT_SEGMENTS:uint = 10;
		private static const MAX_SEGMENTS:uint = 20;
		private static const MIN_SEGMENTS:uint = 3;
		private static const THICKNESS:uint = 1;
		private static const COLOR:uint = 0x66CCCC;
		private static const ROTATION_RATE:uint = 1;

		private var _shapeHolder:Sprite;
		private var _shapes:Vector.<Shape>;

		/**
		* Constructor.
		*/
		public function graphic_flex_image_effects_01_Flex_CopyingGraphics() {
			init();
		}

		/**
		* Initializes shapes and sets up stage listeners.
		*/
		public function init():void {
			_shapeHolder = new Sprite();
			_shapeHolder.x = stage.stageWidth/2;
			_shapeHolder.y = stage.stageHeight/2;
			addChild(_shapeHolder);
			_shapes = new Vector.<Shape>();
			for (var i:uint = 0; i < INIT_SEGMENTS; i++) {
				addSegment();
			}
			positionSegments();
			stage.addEventListener(MouseEvent.MOUSE_DOWN, onStageMouseDown);
			stage.addEventListener(MouseEvent.MOUSE_UP, onStageMouseUp);
			stage.addEventListener(KeyboardEvent.KEY_DOWN, onStageKeyDown);
			filters = [new GlowFilter(COLOR)];
		}

		/**
		* Draws a new line in the master shape and copies the master shape's drawing
		* into the other shapes in the vector array.
		*/
		private function draw():void {
			var shape:Shape = _shapes[0];
			shape.graphics.lineTo(shape.mouseX, shape.mouseY);
			var segments:uint = _shapeHolder.numChildren;
			// when updating, skip initial shape since that is what is being copied
			for (var i:uint = 1; i < segments; i++) {
				_shapes[i].graphics.copyFrom(shape.graphics);
			}
		}

		/**
		* Adds a new shape to the number of rotated shapes.
		*/
		private function addSegment():void {
			var shape:Shape = new Shape();
			// for any but initial shape, simply copy the graphics from the initial shape
			if (_shapes.length > 0) {
				shape.graphics.copyFrom(_shapes[0].graphics);
			// initial shape just needs a linestyle
			} else {
				shape.graphics.lineStyle(THICKNESS, COLOR);
			}
			_shapes.push(shape);
			_shapeHolder.addChild(shape);
		}

		/**
		* Removes a segment from the end of the rotated shapes vector.
		*/
		private function removeSegment():void {
			var shape:Shape = _shapes.pop();
			_shapeHolder.removeChild(shape);
		}

		/**
		* Rotates all the segments so that they are placed at equal angles around central point.
		*/
		private function positionSegments():void {
			var segments:uint = _shapeHolder.numChildren;
			var angle:Number = 360/segments;
			for (var i:uint = 1; i < segments; i++) {
				_shapes[i].rotation = angle*i;
			}
		}

		/**
		* Handler for when the stage is clicked. This moves the pen in the master shape to
		* the clicked position and sets up a listener for ENTER_FRAME.
		*
		* @param event The event dispatched by the stage.
		*/
		private function onStageMouseDown(event:MouseEvent):void {
			var shape:Shape = _shapes[0];
			shape.graphics.moveTo(shape.mouseX, shape.mouseY);
			addEventListener(Event.ENTER_FRAME, onThisEnterFrame);
		}

		/**
		* Handler for when the mouse is released on the stage.
		* This removes the listener for ENTER_FRAME.
		*
		* @param event The event dispatched by the stage.
		*/
		private function onStageMouseUp(event:MouseEvent):void {
			removeEventListener(Event.ENTER_FRAME, onThisEnterFrame);
		}

		/**
		* Handler for the ENTER_FRAME event. This rotates all of the shapes and updates the drawing.
		*
		* @param event The event dispatched by this sprite.
		*/
		private function onThisEnterFrame(event:Event):void {
			_shapeHolder.rotation += ROTATION_RATE;
			draw();
		}

		/**
		* Handler for when a key is pressed. If it is the UP or DOWN arrow, the number of segments
		* is increased or decreased.
		*
		* @param event The event dispatched by the stage.
		*/
		private function onStageKeyDown(event:KeyboardEvent):void {
			switch (event.keyCode) {
				// for UP arrow key, add a segment if we are within limit
				case Keyboard.UP:
					if (_shapeHolder.numChildren < MAX_SEGMENTS) {
						addSegment();
						positionSegments();
					}
					break;
				// for DOWN arrow key, remove a segment if we are within limit
				case Keyboard.DOWN:
					if (_shapeHolder.numChildren > MIN_SEGMENTS) {
						removeSegment();
						positionSegments();
					}
					break;
			}
		}

	}

}