验证码的一个类，如何就是不出来图片呢

<br><?php  <br />class imageCode{<br>	public $img_width;    //验证码宽度<br>	public $img_height;		//高度<br>	public $arr_char = array();  //验证码上显示的字符<br>	public $font_size;         //字体大小<br>	public $img;				//验证码图片<br>	public $code_result;		//要保存在session中的数或者字符串<br>	public $line_count = 7;		//噪音线数量<br>	private $str_chars = "0123456789abcdefghjkmnpqrstuvwxyzABCEDFGHJKLMNPQRSTUVWXYZ";//验证码字符串<br>	<br>	//构造函数<br>	function __construct($img_width,$img_height,$font_size,$line_count){    <br>		$this->img_width = $img_width;<br>		$this->img_height = $img_height;<br>		$this->font_size = $font_size;<br>		$this->line_count = $line_count;<br>	}<br>	<br>	//验证码生成主方法<br>	function createCodeImg(){<br>		$this->createGraphics();  <br>		$this->getChars();<br>		$this->setNoiceLine();<br>		<br>		$x = rand(2,5);<br>		$arr_X_Y = array(array($x,rand(1,3)),array($x+$this->font_size,rand(1,4)),array($x+2*$this->font_size,rand(1,3)),array($x+3*$this->font_size,rand(1,4)));<br>		print_r($arr_X_Y);<br>		for($i = 0;$i			$text_color = imagecolorallocate($this->img, rand(180,250), rand(180,250), rand(180,250));<br>			imagechar($this->img,$this->font_size,$arr_X_Y[$i][0],$arr_X_Y[$i][1],$this->arr_char[$i],$text_color); <br>		}<br>	}<br><br>     //创建画图板	<br>	function createGraphics(){<br>		header("Content-type: image/png"); <br>		$this->img = @imagecreatetruecolor($this->img_width, $this->img_height) or die("建立图像失败"); //创建图片<br>		$background_color = imagecolorallocate($this->img, 250, 250, 250);<br>		imagefill($this->img,0,0,$background_color);<br>		$border_color = imagecolorallocate($this->img,0,0,0); //边框色<br>		imagerectangle($this->img,0,0,$this->img_width,$this->img_height,$border_color);<br>	}<br>	<br>     //画噪音线<br>	function setNoiceLine(){<br>		for($i = 0;$i line_count;$i ++){<br>			$x1 = rand(3,20);//开始位置<br>			$y1 = rand(2,$this->img_height);<br>			$x2 = rand($this->img_width-20,$this->img_width-2);//结束位置<br>			$y2 = rand(2,$this->img_height);<br>			$line_color = imagecolorallocate($this->img, rand(180,250), rand(180,250), rand(180,250));<br>			imageline($this->img,$x1,$y1,$x2,$y2,$line_color); <br>		}<br>	}<br><br>	//产生随机字符串或者加减字符	<br>	function getChars(){<br>		$strCode = "";<br>		if(rand(0,1) == 1){//字符串类型的 验证码<br>			for($i = 0;$i 				$this->arr_char[$i] = $this->str_chars[rand(0,56)];<br>				$strCode .= $this->arr_char[$i];<br>			}<br>			$this->code_result = $strCode;<br>		}<br>		else{			//加减类型验证码<br>			$first_num = rand(1,10);<br>			$second_num = 0;<br>			$result = 0;<br>			$arr_operater = array("+","-");<br>			$operater = $arr_operater[rand(0,1)];<br>			switch ($operater){<br>				case "+":<br>					$second_num = rand(0,10);<br>					$result = $first_num + $second_num;<br>					break;<br>				case "-":<br>					$second_num = rand(0,$first_num);<br>					$result = $first_num - $second_num;<br>					break;<br>			}<br>			$this->arr_char = array($first_num,$operater,$second_num,"=");<div class="clear">
                 
              
              
        
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