Detailed explanation of how to create a PHP verification code class file and how to call it

//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 = dirname(__FILE__).'/font/elephant.ttf';//注意字体路径要写对，否则显示不了图片 } //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->createCode(); $this->createLine(); $this->createFont(); $this->outPut(); } //获取验证码 public function getCode() { return strtolower($this->code); } }