突然有個想法，就是去寫一個簡單的驗證碼類，其實驗證碼在很多框架有自帶的，網上一搜也一大把，我只是想當作是練習，熟悉一下過程。

session_start();class He_Captcha{        private $str = "23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVW";    private $text;    private $im;    public    $num;    public    $size;    public    $width;    public    $height;    public    $session_var;    public    $ttfs = array(        'Jura.ttf',        'AntykwaBold.ttf',        'Duality.ttf',        'VeraSansBold.ttf'    );        /*       生成驗證碼     *num     顯示的驗證碼字符數     *size    字符的字體大小     *session_var   驗證碼會話名稱     *width   驗證碼圖片的寬     *height  驗證碼圖片的高    */    public function Captcha($num = 4, $size = 15, $session_var = '', $width = 0, $height = 0){        $this->num = (int)max($this->num, $num);        $this->size = (int)max($this->size, $size);        $this->width = $width ? (int)max($this->width, $width) : $this->num * $this->size;        $this->height = $height ? (int)max($this->height, $height) : $this->size + 10;        $this->session_var = strlen(trim($session_var))>2 ? trim($session_var):'captcha';                        $this->_getText($this->num);        $_SESSION[$this->session_var] = $this->text;        $this->im = imagecreatetruecolor($this->width, $this->height);//畫圖像         $this->_drowBackground();//畫背景         $this->_setNoiseLines();//畫干擾線         $this->_setNoisePoints();//畫干擾點         $this->_writeText();//畫驗證碼         $this->_createCaptcha();    }        /*創建驗證碼內容*/    private function _getText($num){        for( $i = 0; $i < $num; $i++ ){            $this->text .= $this->str[mt_rand(0,strlen($this->str)-1)];        }    }        /*畫背景*/    private function _drowBackground(){        $bg_color = imagecolorallocate($this->im, 235, 236, 237);        imagefilledrectangle($this->im, 0, 0, $this->width, $this->height, $bg_color);    }        /*畫干擾點*/    private function _setNoisePoints(){        $points = 2 * $this->width;        for($i = 0;$i < $points;$i++){            $font_color = imagecolorallocate($this->im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));            imagesetpixel($this->im, mt_rand(0, $this->width), mt_rand(0, $this->height), $font_color);        }    }    /*畫干擾線*/    private function _setNoiseLines(){        $lines = $this->width / 12;        for($i = 0; $i < $lines; $i++){            $font_color = imagecolorallocate($this->im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));            imagearc($this->im, mt_rand( -$this->width, $this->width), mt_rand( -$this->height, $this->height), mt_rand(30, $this->width * 2), mt_rand(20, $this->height * 2), mt_rand(0, 360), mt_rand(0, 360), $font_color);            }    }    /*畫驗證碼*/    private function _writeText(){        for($i = 0; $i < $this->num; $i++){            $ttf = 'fonts/'.$this->ttfs[array_rand($this->ttfs,1)];            $text_color = imagecolorallocate($this->im, mt_rand(0, 200), mt_rand(0, 120), mt_rand(0, 120));            @imagefttext($this->im, $this->size, mt_rand(-10,10), $this->size*$i, $this->size+5, $text_color, $ttf, $this->text[$i]);        }    }        /*生成驗證碼*/    private function _createCaptcha(){        header("Cache-Control: max-age=1, s-maxage=1, no-cache, must-revalidate");        header("Content-Type: image/png; charset=utf-8");        imagepng($this->im);        imagedestroy($this->im);    }}

 

下面為調用以及生成效果：

$c = new He_Captcha();$c->Captcha();

.........