Laravel下生成验证码的类

<?php
 
namespace app\tool\validate;
 
//验证码类
class validatecode {
  private $charset = 'abcdefghkmnprstuvwxyzabcdefghkmnprstuvwxyz23456789';//随机因子
  private $code;//验证码
  private $codelen = 4;//验证码长度
  private $width = 130;//宽度
  private $height = 50;//高度
  private $img;//图形资源句柄
  private $font;//指定的字体
  private $fontsize = 20;//指定字体大小
  private $fontcolor;//指定字体颜色
 
  //构造方法初始化
  public function __construct()
  {
    $this->font = public_path() . '/fonts/elephant.ttf';//注意字体路径要写对，否则显示不了图片
    $this->createcode();
  }
  //生成随机码
  private function createcode()
  {
    $_len = strlen($this->charset) - 1;
    for ($i = 0;$i < $this->codelen;++$i) {
      $this->code .= $this->charset[mt_rand(0, $_len)];
    }
  }
  //生成背景
  private function createbg()
  {
    $this->img = imagecreatetruecolor($this->width, $this->height);
    $color = imagecolorallocate($this->img, mt_rand(157, 255), mt_rand(157, 255), mt_rand(157, 255));
    imagefilledrectangle($this->img, 0, $this->height, $this->width, 0, $color);
  }
  //生成文字
  private function createfont()
  {
    $_x = $this->width / $this->codelen;
    for ($i = 0;$i < $this->codelen;++$i) {
      $this->fontcolor = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
      imagettftext($this->img, $this->fontsize, mt_rand(-30, 30), $_x * $i + mt_rand(1, 5), $this->height / 1.4, $this->fontcolor, $this->font, $this->code[$i]);
    }
  }
  //生成线条、雪花
  private function createline()
  {
    //线条
    for ($i = 0;$i < 6;++$i) {
      $color = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
      imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $color);
    }
    //雪花
    for ($i = 0;$i < 100;++$i) {
      $color = imagecolorallocate($this->img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255));
      imagestring($this->img, mt_rand(1, 5), mt_rand(0, $this->width), mt_rand(0, $this->height), '*', $color);
    }
  }
  //输出
  private function output()
  {
    header('content-type:image/png');
    imagepng($this->img);
    imagedestroy($this->img);
  }
  //对外生成
  public function doimg()
  {
    $this->createbg();
    $this->createline();
    $this->createfont();
    $this->output();
  }
  //获取验证码
  public function getcode()
  {
    return strtolower($this->code);
  }
}