Can't use function return value in write context
<?php
class Captcha{
//字体文件
private $_fontfile='';
//字体大小
private $_size =20;
//画布宽度
private $_width = 120;
//画布高度
private $_height = 40;
//验证码长度
private $_length = 4;
//画布资源
private $_image =null;
//干扰元素
//雪花的个数
private $_snow=0;
//像素点个数
private $_pixel=0;
//线段个数
private $_line=0;
/**
* 初始化数据
* @param array $config [description]
*/
public function __construct($config=array()){
if(is_array($config)&&count($config)>0){
/**
* 检测字体文件是否存在并且可读
*/
if(isset($config['fontfile'])&&is_file($config['fontfile'])&&is_readable($config['fontfile'])){
$this->_fontfile=$config['fontfile'];
}
//检测画布高度和宽度
if(isset($config('width'))&&$config['width']>0){
$this->_width=(int)$config['width'];
}
if(isset($config('height'))&&$config['height']>0){
$this->_height=(int)$config['height'];
}
//检测字符大小
if(isset($config('size'))&&$config['size']>0){
$this->_size=(int)$config['size'];
}
//检测验证码长度
if(isset($config('length'))&&$config['length']>0){
$this->_length=(int)$config['length'];
}
//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'];
}
$this->_image=imagecreatetruecolor($this->_width, $this->_height);
return $this->_image;
}else{
return flase;
}
}
/**
* 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
$fontfile=$this->_fontfile;
for($i=0;$i<$this->$_length;$i++){
$size=$this->_size;
$angle=mt_rand(-15,15);
$x=ceil($this->_width/$this->_height)*$i+mt_rand(5,10);
$y=ceil($this->_height/1.5);
$color=$this->_getRandColor();
$text=$str{$i};
imagettftext($this->_image,$size,$angle,$x,$y,$color,$fontfile,$text);
}
//绘制干扰元素
if ($this->_snow) {
$this->_getSnow();
# code...
}else{
if($this->_pixel){
$this->_getPixel();
}
if($this->_line){
$this->_getLine();
}
}
//绘制图像
header('content-type:image/png');
imagepng($this->_image);
imagedestroy($this->_image);
return strtolower($str);
}
/**
* 生成雪花
* @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());
}
}
/**
* 生成像素点
* @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());
}
}
/**
* 生成线条
* @return [type] [description]
*/
private function _getLine(){
for($i=1;$i<=$this->_line;$i++){
imageline($this->ima, mt_rand(0,$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 $length 验证码长度
* @return [type] 随机字符
*/
public function _generateStr($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),$length));
}
private function _getRandColor(){
return imagecolorallocate($this->_image,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));
}
}
报错; Can't use function return value in write context in D:\pycharm\Demo\Capcha.class.php on line 36
这个怎么解决求证
