php验证码类

<?php
/**
* 验证码生成类
* @example
* $pic = new uImage();
* $code = $pic->getVerifyCode(); 
* header("Content-type:image/png"); 
* $pic->captchaFromFont($font='RAVIE.TTF'); or $pic->captcha();
*/
class uImage {
	/**
	* 验证码字符
	* @access protected
	*/
	protected $code;

	/**
	* 生成图片验证码,直接输出的是图片,字体大小是内置字体，最大是5
	* @access public
	* @param int $width 验证码图片宽度
	* @param int $height 验证码图片的高度
	* @param int $snow 背景雪花的数量
	* @param int $line 干扰线的条数
	*/
	public function captcha($width=100, $height=30, $snow=80, $line=3) {
		$pic = imagecreatetruecolor($width, $height);
		$backageColor = imagecolorallocate($pic, 0xFF, 0xFF, 0xFF);
		imagefill($pic, 0, 0, $backageColor);
		//打雪花
		for($i=0; $i<=$snow;$i++) {
			$color = imagecolorallocate($pic, mt_rand(150, 230), mt_rand(150, 230), mt_rand(150, 230));
			imagechar($pic, 1, mt_rand(0, $width), mt_rand(0, $height), "*", $color);
			imagecolordeallocate ($pic, $color);
		}
		//画干扰线
		for($i=0; $i<=$line; $i++) {
			$x1 = mt_rand(2, $width * 0.2);
			$x2 = mt_rand($width * 0.8, $width - 2);
			$y1 = mt_rand(2, $height - 2);
			$y2 = mt_rand(2, $height - 2);
			$color = imagecolorallocate($pic, mt_rand(130, 250), mt_rand(130, 250), mt_rand(130, 250));
			imageline($pic, $x1, $y1, $x2, $y2, $color);
			imagecolordeallocate ($pic, $color);
		}
		//画字符
		$code = $this->code;
		$eachW = $width / strlen($code); //图片依据字符个数分配等份数
		$fontWidth = imagefontwidth(5); //取得字体宽度
		$fontHeight = imagefontheight(5); //取得字体高度
		for($i=0; $i<strlen($code);$i++) {
			$color = imagecolorallocate($pic, mt_rand(30, 155), mt_rand(30, 155), mt_rand(30, 150));
			$x = mt_rand($eachW * $i, $eachW * ($i+1)-$fontWidth);
			$y = mt_rand(3, $height-$fontHeight);
			imagechar($pic, 5, $x, $y, $code{$i}, $color); //水平画字符
			imagecolordeallocate ($pic, $color);
		}
		//输出
		ob_start();
		ob_clean();
		imagepng($pic);
		imagedestroy($pic);
	}

	/**
	* 根据自定义字体生成验证码
	* @access public
	* @param string $font 字符文件， TrueType 字体文件，.ttf字体
	* @param int $fontWeight 字符大小
	* @param int $width 图片宽
	* @param int $height 图片高
	* @param int $snow 背景雪花个数
	* @param int $line 干扰线条数
	* @param int $padding 图片内边距
	*/
	public function captchaFromFont($font, $fontWeight=16, $width=100, $height=30, $snow=80, $line=3, $padding=3){
		if(!isset($font)){
			return false;
		}
		$pic = imagecreatetruecolor($width, $height);
		$backageColor = imagecolorallocate($pic, 0xFF, 0xFF, 0xFF);
		imagefill($pic, 0, 0, $backageColor);
		imagecolordeallocate ($pic, $backageColor);
		//打雪花
		for($i=0; $i<=$snow;$i++) {
			$color = imagecolorallocate($pic, mt_rand(150, 230), mt_rand(150, 230), mt_rand(150, 230));
			imagechar($pic, 1, mt_rand(0, $width), mt_rand(0, $height), "*", $color);
			imagecolordeallocate ($pic, $color);
		}
		//画干扰线
		for($i=0; $i<=$line; $i++) {
			$x1 = mt_rand(2, $width * 0.2);
			$x2 = mt_rand($width * 0.8, $width - 2);
			$y1 = mt_rand(2, $height - 2);
			$y2 = mt_rand(2, $height - 2);
			$color = imagecolorallocate($pic, mt_rand(130, 250), mt_rand(130, 250), mt_rand(130, 250));
			imageline($pic, $x1, $y1, $x2, $y2, $color);
			imagecolordeallocate ($pic, $color);
		}
		//画字符
		$code = $this->code;
		$eachW = $width / strlen($code); //图片依据字符个数分配等份数
		$codeArray = str_split($code);
		for($i=0; $i<count($codeArray); $i++){
			//取得字符宽高
			$fontbox = imagettfbbox($fontWeight, 0, $font, $codeArray[$i]);
			$fontWidth = $fontbox[2] - $fontbox[0];
			$fontHeight = $fontbox[1] - $fontbox[7];

			$color = imagecolorallocate($pic, mt_rand(30, 155), mt_rand(30, 155), mt_rand(30, 150)); //字符颜色
			$angle = mt_rand(-20, 20); //字符角度
			if($i==0){
				$start = $eachW * $i+$padding;
				$end = $eachW * ($i+1)-$fontWidth;
			}
			elseif($i == count($codeArray)){
				$start = $eachW * $i;
				$end = $eachW * ($i+1)-$fontWidth-$padding;
			}
			else{
				$start = $eachW * $i;
				$end = $eachW * ($i+1)-$fontWidth-$padding;
			}
			$x = $start < $end ? mt_rand($start, $end) : $start;
			$y = ($fontHeight+$padding) > $height ? $padding : mt_rand($fontHeight+$padding, $height-$padding); 
			imagettftext($pic, $fontWeight, $angle, $x, $y, $color, $font, $codeArray[$i]); //用 TrueType 字体向图像写入文本 
			imagecolordeallocate ($pic, $color);
		}

		//输出
		ob_start();
		ob_clean();
		imagepng($pic);
		imagedestroy($pic);
	}

	/**
	* 获取验证码
	* @access public
	* @param int $len 验证码字符的长度
	* @return strint 生成的验证码字符
	*/
	public function getVerifyCode($len=4){
		if(!isset($this->code)){
			$this->code = $this->getCode($len);
		}
		return $this->code;
	}

	/**
	* 生成验证码
	* @access protected
	* @param int $len 验证码字符的长度
	* @return strint 生成的验证码字符
	*/
	protected function getCode($len) {
		$str = "23456789abcdefghijklmnqrstuvwxyz";
		$code = "";
		for($i=0; $i<$len; $i++) {
			$code .= $str{mt_rand(0, strlen($str)-1)};
		}
		$this->code = $code;
		return $code;
	}
}