最近需要在php上面使用到验证码来验证登录，采用session来保存需要验证的内容。

并且可以使用英文数字或者中文作为随机数

加入各种线条，随机颜色作为干扰。

imgcode.php源代码：

<?php
/**
 * @version        Id:  imgcode.php 2012-11-30   k
 * @package        imgcode.php
 * @Purview        default
 * @link           http://blog.shiniv.com/
 */
    $img = new img_code();
    $img->show();

class img_code{
    private $img_type = 'png';//输出图片类型 png,gif,jpg
    private $line     = TRUE;//是否增加干扰线
    private $text     = '2';//验证码类型：0数字，1字母，2汉字
    private $text_size= 20;//字体大小
    private $length   = 4;//字符串长度
    private $width    = 120;//图片宽度，像素
    private $height   = 40;//图片高度，像素
    private $font_file= 'msyh.ttf';//字体文件
    public  $img      = '';

    /*
     * 创建图片
     */
    private function img_create(){
        $this->img = imagecreate($this->width, $this->height);
         imagecolorallocate($this->img, 255,255,255);

    }
    /*
     * 显示图片
     */
    public function show(){

        @session_start();
        $this->img_create();
        if($this->line){
        $this->img_line();
        }
        $this->img_text();
        $this->img_header();

        imagedestroy($im);
        exit();
    }

    /*
     * 生成字符串
     */
    private function img_text(){
        $rand_string = '';
        $im = &$this->img;
        $fontColor[]  = imagecolorallocate($im, 0x15, 0x15, 0x15);
        $fontColor[]  = imagecolorallocate($im, 0x95, 0x1e, 0x04);
        $fontColor[]  = imagecolorallocate($im, 0x93, 0x14, 0xa9);
        $fontColor[]  = imagecolorallocate($im, 0x12, 0x81, 0x0a);
        $fontColor[]  = imagecolorallocate($im, 0x06, 0x3a, 0xd5);
        if($this->text<2){
            //数字，字母
            for($i=0;$i<$this->length;$i++){
                if($this->text){
                    $c=chr(mt_rand(65,90));
                }else{
                    $c=chr(mt_rand(48,57));
                }
                if( $c=='I' ) $c = 'K';
                if( $c=='O' ) $c = 'E';
                $rand_string[]=$c;
            }  

        }else{
            //汉字,此处可以引入汉字文件
            $arr=array('大','小','多','少','人','天','水','土','木','火','云','东','南','西','北','中');
            for($i=0;$i<$this->length;$i++){
                $l = count($arr)-1;            
                //文件编码为gbk需要转换
                //$rand_string[] = iconv('gb2312','utf-8',$arr[mt_rand(0,$l)]);
                $rand_string[] = $arr[mt_rand(0,$l)];
            }

        }
          $_SESSION['imgcode']=$rand_string;
          $_c = count($rand_string);
          for($i=0;$i<$_c;$i++)
        {
            if($this->text == 1){
            $rand_string[$i] = strtoupper($rand_string[$i]);
            }

            $c_fontColor = $fontColor[mt_rand(0,4)];
            $y = $this->height-($this->height-$this->text_size)/2;
            $x = ($this->width-($this->text_size+2)*$this->length)/2;
            $y_pos = $i==0 ? $x : $i*($this->text_size+2)+$x;
            $c = mt_rand(0, 15);
            @imagettftext($im, $this->text_size, $c, $y_pos, $y, $c_fontColor,$this->font_file, $rand_string[$i]);

        }
    }
    /*
     * 生成线条
     */
    private function img_line(){
        $im = &$this->img;
        $img_width = $this->width;
        $img_height= $this->height;
            //背景横线
        $lineColor1 = imagecolorallocate($im, 0xda, 0xd9, 0xd1);
        for($j=3; $j<=$img_height-3; $j=$j+3)
        {
            imageline($im, 2, $j, $img_width - 2, $j, $lineColor1);
        }

        //背景竖线
        $lineColor2 = imagecolorallocate($im, 0xda,0xd9,0xd1);
        for($j=2;$j<$img_width-6;$j=$j+6)
        {
            imageline($im, $j, 0, $j+8, $img_height, $lineColor2);
        }

        //画边框
        if( $use_boder && $filter_type == 0 )
        {
            $bordercolor = imagecolorallocate($im, 0x9d, 0x9e, 0x96);
            imagerectangle($im, 0, 0, $img_width-1, $img_height-1, $bordercolor);
        }
    }
    /*
     * 生成输出
     */
    private function img_header(){
         header("Pragma:no-cache\r\n");
         header("Cache-Control:no-cache\r\n");
         header("Expires:0\r\n");
        if($this->img_type == 'jpg'){
            header('Content-type: image/jpeg');
            imagejpeg($this->img);
        }else if($this->img_type == 'png'){
            header('Content-type: image/png');
            imagepng($this->img);
        }else{
            header('Content-type: image/gif');
            imagegif($this->img);
        }
    }
}

【声明】本文 PHP 生成验证码类 为柠之漠然原创文章，转载请注明出自 枫之落叶
并保留本文有效链接：https://blog.shiniv.com/2013/05/php-captcha-class/ , 转载请保留本声明！

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