为啥我的报错呢？
<?php
Class Captcha{
//字体文件
private $_fontfile ='';
//画布宽度和高度
private $_width =120;
private $_height =40;
//字体大小
private $_size =20;
//验证吗长度
private $_length =4;
//画布资源
private $_image =null;
//干扰元素
//雪花*个数
private $_snow =0;
//像素个数
private $_pixel =0;
//线段个数
private $_line =0;
/**
* 初始化数据
* @param array $config
*/
public function _construct($config=array()){
if(is_array($config)&&count($config)>0){
//检测字体是否存在并且可读
if (isset($config['fontfile'])&&is_file('fontfile')&&is_readable('fontfile')) {
$this->_fontfile = $config['fontfile'];
}else{
return false;
}
//检测是否设置画布宽和高
if (isset($config['width'])&&$config['width']>0) {
$this->_width = (int)$config['width'];
}
if (isset($config['height'])&&$config['height']>0) {
$this->_height = (int)$config['height'];
}
if (isset($config['size'])&&$config['size']>0) {
$this->_size = (int)$config['size'];
}
//检测是否设置验证码长度
if (isset($config['length'])&&$config['length']>0) {
$this->_length = (int)$config['length'];
}
$this->_image = imagecreatetruecolor($this->_width, $this->_height);
return $this->_image;
//配置干扰元素
if (isset($config['snow'])&&$config['snow']>0) {
$this->_snow = (int)$config['snow'];
}
if (isset($config['pixel'])&&$config['pixel']>0) {
$this->_pixel = (int)$config['pixel'];
}
if (isset($config['line'])&&$config['line']>0) {
$this->_line = (int)$config['line'];
}
}else{
return false;
}
}
/**
* 得到验证码
* @return [type] [description]
*/
public function getCaptcha(){
$white = imagecolorallocate($this->_image, 255,255,255);
//填充矩形
imagefilledrectangle($this->_image, 0, 0, $this->_width, $this->_height,$white);
//生成验证码
$str = $this->_generateStr($this->_length);
if (false===$str) {
return false;
}
//绘制验证码
for ($i=0; $i < $this->_length; $i++) {
$size = $this->_size;
$angle = mt_rand(-30,30);
$x = ceil($this->_width/$this->_length)*$i+mt_rand(5,10);
$y = ceil($this->_height/1.5);
$color = $this->_getRandColor();
//中文$text = mb_substr($str,$i,1,'utf-8');
$text = $str($i);
$fontfile = $this->_fontfile;
imagettftext($this->_image, $size, $angle, $x, $y, $color, $fontfile, $text);
}
//雪花，像素和线段
if ($this->_snow) {
//使用雪花当作干扰元素
$this->_getSnow();
}else{
if ($this->_pixel) {
$this->_getPixel();
}
if ($this->_line) {
$this->_getLine();
}
}
//输出图像
header("Content-type:image/png");
imagepng($this->_image);
imagedestroy($this->_image);
return strtolower($str);
}
/**
* 产生雪花
* @return [type] [description]
*/
private function _getSnow(){
for ($i=1; $i <=$this->_snow ; $i++) {
imagestring($this->_image, mt_rand(1,5), mt_rand(0,$this->_width), mt_rand(0,$this->_height), '*', $this->_getRandColor());
}
}
/**
* 绘制像素
* @return [type] [description]
*/
private function _getPixel(){
for ($i=1; $i < $this->_pixel; $i++) {
imagesetpixel($this->_image, mt_rand(0,$this->_width), mt_rand(0,$this->_height), $this->_getRandColor());
}
}
/**
* 绘制线段
* @return [type] [description]
*/
private function _getLine(){
for ($i=1; $i < $this->_line; $i++) {
imageline($this->_image, mt_rand(0,$this->_width), mt_rand(0,$this->_height), mt_rand(0,$this->_width), mt_rand(0,$this->_height), $this->_getRandColor());
}
}
/**
* 产生验证码字符
* @param integer $length 验证码长度
* @return string 随机字符
*/
private function _generateStr($length=4){
if ($length<1 || $length>30) {
return false;
}
$chars = array('a','b','c','d','e','f','g','h','k','m','n','p','x','y','z','A','B','C','D','E','F','G','H','K','M','N','P','X','Y','Z',1,2,3,4,5,6,7,8,9);
$str = join('',array_rand(array_flip($chars),$length));
return $str;
}
private function _getRandColor(){
return imagecolorallocate($this->_image,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));
}
}
?>
