AS3 Captcha

gistfile1.as

/*
   VERSION: 1.0 DATE:2009/11/20
   ACTIONSCRIPT VERSION: 3.0
   AUTHOR: DFdou, [email protected]
   Copyright 2009, nwhy.org. All rights reserved.

   DESCRIPTION:
   Captcha is a simple class to generate Caphtcha Sprite.

   PARAMETERS:
   1) type:String="number": Captcha type you want to create, there are four types ["number","character","math","bt"];
   2) length:uint=5: Captcha length,work with type ["number","character"];
   3) noiseFlag:Boolean=true: if true Captcha will draw noise;
   4) size:uint=18: textfiled's fontsize;

   NOTES:
   - when the Captcha was changed,will dispatch an event named "change",then you can addEventListener to capture it.

   EXAMPLE:
   var cp:Captcha = new Captcha(); //default Captcha as number type width noise,length=5,size=18;
   var cp:Captcha = new Captcha("character", 4); //character type Captcha,length=4;
   var cp:Captcha = new Captcha("bt", 0, false, 20); //bt type Captcha width no noise,and fontsize=20;
 */
package org.nwhy.utils
{
	import flash.display.DisplayObjectContainer;
	import flash.display.Sprite;
	import flash.events.MouseEvent;
	import flash.events.Event;
	import flash.text.TextField;
	import flash.text.TextFormat;
	import flash.text.TextFieldAutoSize;
	
	public class Captcha extends Sprite
	{
		private var __type:String;
		private var __length:uint;
		private var __size:uint;
		private var __tft:TextFormat = new TextFormat();
		private var __noiseFlag:Boolean;
		private var __aryType:Array = ["number", "character", "math", "bt"];
		private var __aryCharacters:Array = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"];
		private var __randCode:String = "";
		
		private const CHANGE:String = "change";
		private var sp_cont:Sprite = new Sprite();
		private var sp_noise:Sprite = new Sprite();
		
		public function Captcha(type:String = "number", length:uint = 5, noiseFlag:Boolean = true, size:uint = 18):void
		{
			__type = type;
			__length = length;
			__noiseFlag = noiseFlag;
			__size = size;
			
			__tft.font = "Arial";
			__tft.size = __size;
			__tft.bold = true;
			sp_cont.x = __size / 2;
			addChild(sp_cont);
			if (__aryType.indexOf(__type) == -1)
			{
				__type = __aryType[3];
			}
			reRandCaptcha(null);
			addEventListener(MouseEvent.MOUSE_DOWN, reRandCaptcha);
		}
		
		private function reRandCaptcha(_e:MouseEvent)
		{
			removeAllChild(sp_cont);
			randCaptcha(__type);
			drawNoise();
			drawBorder();
			dispatchEvent(new Event(CHANGE));
		}
		
		private function randCaptcha(type:String):void
		{
			__randCode = "";
			switch (type)
			{
				case __aryType[0]: 
					randCaptchaWithNumber();
					break;
				case __aryType[1]: 
					randCaptchaWithCharacter();
					break;
				case __aryType[2]: 
					randCaptchaWithMath();
					break;
				case __aryType[3]: 
					randCaptchaWithBt();
					break;
				default: 
					randCaptchaWithNumber();
			}
		}
		
		private function randCaptchaWithNumber():void
		{
			for (var i:uint = 0; i < __length; i++)
			{
				var tf:TextField = new TextField();
				tf.text = String(randInt(0, 9));
				__randCode += tf.text;
				tf.selectable = false;
				tf.x = int(__tft.size) * i;
				tf.textColor = randInt(0, 0x888888);
				tf.autoSize = TextFieldAutoSize.LEFT;
				tf.setTextFormat(__tft);
				sp_cont.addChild(tf);
			}
		}
		
		private function randCaptchaWithCharacter():void
		{
			for (var i:uint = 0; i < __length; i++)
			{
				var tf:TextField = new TextField();
				tf.text = __aryCharacters[randInt(0, 51)];
				__randCode += tf.text;
				tf.selectable = false;
				tf.x = int(__tft.size) * i;
				tf.textColor = randInt(0, 0x888888);
				tf.autoSize = TextFieldAutoSize.LEFT;
				tf.setTextFormat(__tft);
				sp_cont.addChild(tf);
			}
			__randCode = __randCode.toLowerCase();
		}
		
		private function randCaptchaWithMath():void
		{
			var rand1:uint = randInt(0, 5);
			var rand2:uint = randInt(0, 10);
			var rand3:uint = randInt(0, 5);
			var rand4:uint = randInt(0, 10);
			var tf:TextField = new TextField();
			tf.text = "(" + rand1 + "+" + rand2 + ")" + "*(" + rand3 + "+" + rand4 + ")";
			tf.selectable = false;
			tf.textColor = randInt(0, 0x888888);
			tf.autoSize = TextFieldAutoSize.LEFT;
			tf.setTextFormat(__tft);
			sp_cont.addChild(tf);
			__randCode = String((rand1 + rand2) * (rand3 + rand4));
		}
		
		private function randCaptchaWithBt():void
		{
			var rand1:Number = Number(randNumber(0, Math.PI).toFixed(2));
			var rand2:Number = Number(randNumber(0, Math.PI).toFixed(2));
			var tf:TextField = new TextField();
			tf.text = "Math.pow(" + rand1 + ",Math.log(" + rand2 + "))";
			tf.selectable = false;
			tf.textColor = randInt(0, 0x888888);
			tf.autoSize = TextFieldAutoSize.LEFT;
			tf.setTextFormat(__tft);
			sp_cont.addChild(tf);
			__randCode = Math.pow(rand1, Math.log(rand2)).toFixed(3);
		}
		
		private function drawNoise():void
		{
			if (__noiseFlag)
			{
				sp_noise.graphics.clear();
				for (var i = 0; i < 25; i++)
				{
					var ptx = randInt(1, width);
					var pty = randInt(1, height);
					var ex = ptx + randInt(-width, width);
					var ey = pty + randInt(-height, height);
					ex = (ex <= 1) ? 1 : ((ex >= (width)) ? (width) : ex);
					ey = (ey <= 1) ? 1 : ((ey >= height - 1) ? height - 1 : ey);
					sp_noise.graphics.lineStyle(1, randInt(0, 0xFFFFFF), 0.25);
					sp_noise.graphics.moveTo(ptx, pty);
					sp_noise.graphics.lineTo(ex, ey);
				}
				sp_noise.width = sp_cont.width + __size;
				sp_noise.height = sp_cont.height;
				addChild(sp_noise);
			}
			return;
		}
		
		private function drawBorder():void
		{
			graphics.clear();
			graphics.lineStyle(1, 0x006699);
			graphics.drawRect(0, 0, sp_cont.width + __size, height);
			graphics.beginFill(0);
		}
		
		private function removeAllChild(container:DisplayObjectContainer)
		{
			while (container.numChildren > 0)
			{
				container.removeChildAt(0);
			}
		}
		
		private function randInt(min:int, max:int):int
		{
			return Math.random() * (max - min) + min;
		}
		
		private function randNumber(min:Number, max:Number):Number
		{
			return Math.random() * (max - min) + min;
		}
		
		public function get captcha():String
		{
			return __randCode;
		}
	}
}