<?php
namespace captcha;
/*
*驗證碼類
*verify方法生成驗證碼字符串
*entry方法生成驗證碼
*特別提醒：這里要先用entry生成驗證碼,再用verify生成驗證碼的字符串,也就是必須先調用entry,然后才能夠調用verify生成驗證碼的字符串,原因代碼已經說明問題了,因為驗證碼的字符串是在entry方法調用captchaImage生成的,所以必須先調用它才行
*有的地方對中文的字體要求比較高,所以,有的地方不支持中文驗證碼
*/
class Captcha{
  //配置參數
  private $config = array();
  //驗證碼
  private $verifyCode = '';
  //獲取配置文件的配置信息,給類傳參數就行,例如new Captcha($config);$config是你的配置文件信息
  public function __construct($config=array('width'=>100,'height'=>40,'length'=>4,'size'=>7,'lines'=>0,'dots'=>0,'font'=>'simfang.ttf','rectangle'=>array(255,55,122),'charset'=>true,'chinese'=>'來到新機場主航站樓建設在婚姻關系存續期間所負債務她在收到要求她償還前夫在婚姻關系存續期間所欠債務的法院傳票后要精益求精善始善終')){
    $this->config = $config;
  }
  //創建驗證碼
  private function captchaImage(){
    //畫布
    $img = imagecreatetruecolor($this->config['width'],$this->config['height']);
    //填充畫布顏色
    imagefill($img,0,0,imagecolorallocate($img,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255)));
    //需要邊框則畫邊框
    if($this->config['rectangle'] && is_array($this->config['rectangle']) && count($this->config['rectangle']) == 3){
      $this->tangle($img);
    }
    $this->verifyCode = $this->code($img,$this->config['charset'],$this->config['chinese']);
    //存在則添加干擾線
    if($this->config['lines']){
      $this->codeLines($img);
    }
    //存在則添加干擾點
    if($this->config['dots']){
      $this->codeDots($img);
    }
    return $img;
  }
  private function codeLines($img){
    //繪制干擾線
    for($i=0;$i<$this->config['lines'];$i++){
      imageline($img,mt_rand(0,$this->config['width'] / 10),mt_rand(0,$this->config['height']),mt_rand($this->config['width'] * 7/ 10,$this->config['width'] * 9/ 10),mt_rand(0,$this->config['height']),imagecolorallocate($img,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255)));
    }
  }
  private function codeDots($img){
    //添加噪點
    for($i=0;$i<$this->config['dots'];$i++){
      //噪點顏色
      $color = imagecolorallocate($img,mt_rand(0,180),mt_rand(0,180),mt_rand(0,180));
      imagestring($img,mt_rand(1,3),mt_rand(0,170),mt_rand(0,30),'*',$color);
    
    }
  }
  /*畫布邊框*/
  private function tangle($img){
    imagerectangle($img,0,0,$this->config['width']-1,$this->config['height']-1,imagecolorallocate($img,$this->config['rectangle'][0],$this->config['rectangle'][1],$this->config['rectangle'][2]));
  }
  /*生成驗證碼,默認英文,$ch為true則為中文*/
  private function code($img,$ch=false,$set=''){
    $str = "";
    //計算間隔
    $span = ceil($this->config['width']/($this->config['length']+1));
    if($ch && !empty($set)){
      //隨機產生字符
      $set = $this->config['chinese'];
      for($i=0;$i<$this->config['length'];$i++){
        $end = strlen($set)/3;
        $pos = mt_rand(0,$end-1);
        $str .= substr($set,$pos*3,3);
      }
      //每次繪制一個字符
      for($i=1;$i<=$this->config['length'];$i++){
        imagettftext($img,16,mt_rand(-30,60),$i*$span,$this->config['height']*3/5,imagecolorallocate($img,mt_rand(0,180),mt_rand(0,180),mt_rand(0,180)),$this->config['font'],substr($str,($i-1)*3,3));
      }
    }else{
      //隨機生成字母或者數字
      for($i=0;$i<$this->config['length'];$i++){
        switch(mt_rand(0,2)){
          case 0:
          $str .= chr(mt_rand(65,90));
          break;
        case 1:
          $str .= chr(mt_rand(97,122));
          break;
        case 2:
          $str .= chr(mt_rand(48,57));
        }
      }
      //每次繪制一個字符
      for($i=1;$i<=$this->config['length'];$i++){
        imagestring($img,$this->config['size'],$i*$span,0,$str[$i-1],imagecolorallocate($img,mt_rand(0,180),mt_rand(0,180),mt_rand(0,180)));
      }
    }
    return $str;
  }
  //獲取驗證碼
  public function verify(){
    return $this->verifyCode;
  }
  //生成驗證碼
  public function entry(){
    header("content-type:image/png");
    imagepng($this->captchaImage());
  }
}
$ob = new Captcha;
$ob->entry();