PHP Broken code--Write your own verification code

In fact, there is no need to encapsulate the function, just felt visually good, structure clear point

<?php       class captcha{    //Verification Code-string      private  $codes;     //image Length     private  $img _ length = 150;    //picture height     private  $img _height =  30;    //character list to generate random captcha     private  $charlist  =  ' 1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM ';     //Random code number      private  $code _num = 4;    //Font Size--calculated at initialization      private  $font _size ;    //number of interference lines     private  $line _ num = 5;    //number of interference snowflakes     private  $sterisk _num =  50;    //Verification code--Pictures     private  $img;     // Font file path     private  $ttf  =  './instance/font/elephant.ttf ';         public function __construct () {                    //font size is dynamically generated by picture width and height, but not very perfect           $this->font_size =  ($this->img_height*2/5 >  $this->img_ height*4/5 ?  $this->img_height*4/5 :  $this->img_height*2/5);     }        public function run () {         //creating a picture resource          $this->createimage ();         //Add Snowflakes          $this to the picture Addasterisk ();         //add characters to the picture           $this->addfont()         //add a line to the picture         $ This->addline ();         //image output to browser           $this->outputimg ();     }    //returns the CAPTCHA string      public function getcode () {        return   $this->codes;    }        //Create a picture resource      private function createimage () {        // Create a picture resource          $this->img = imagecreatetruecolor ($this- >img_length, $this->img_height)           //Create color           $color _bg = imagecolorallocate ($this->img, mt_rand (210, 255),  mt_Rand (210, 255),  mt_rand (210, 255))         //Set picture background color         imagefill ($this->img, 0, 0,  $color _BG);     }        //add lines to the picture      Private function addline () {        //Adds a specified number of lines          for  ($i  = 0;  $i  <  $this->line_num;   $i + +)  {            //create random colors--parameters (picture resources, R, B,G)              $color _line =  Imagecolorallocate ($this->img, mt_rand (50, 200),  mt_rand (50, 200),  mt_rand (50,  200));                         //add line, Position random--parameters (picture resource, start-X, Start-y, End-X, end-y, color)              //Non-adjustable             //imageline ($this- >img, mt_rand (0,  $this->img_length),  mt_rand (0,  $this->img_height),  mt_rand ( 0,  $this->img_length),  mt_rand (0,  $this->img_height),  $color _line);             //can adjust the thickness of the line               $src _x = mt_rand (0,  $this->img_length);              $src _y = mt_rand (0,  $this->img_ Height);             $dest _x = mt_rand (0,   $this->img_length);             $dest _y  = mt_rand (0, $This->img_height);            for  ($j  = 0;  $j  < 1;  $j +)  {                 imageline ($this->img,  $src _x+ $j,  $src _y+ $j,  $dest _x+ $j, $dest _y+ $j,  $color _line);             }        }    }    // Add snowflakes to the picture     private function addasterisk () {         //add a specified number of snowflakes         for  ($i  = 0;  $i  <  $this->sterisk_num;  $i + +)  {             //Create random colors--parameters (picture resources, R,b,g)               $color _ster = iMagecolorallocate ($this->img, mt_rand (220, 255),  mt_rand (220, 255),  mt_rand (220,  255));             //add snowflakes, Position random--parameters (picture resource, tilt angle, Lower left-X, lower-left corner-y, Color, string)             imagestring ($this- >img,mt_rand (0,360), Mt_rand (0, $this->img_length), Mt_rand (0, $this->img_height), ' * ', $color _ster);         }    }         private function addfont () {        for  ($i  =  0;  $i  <  $this->code_num;  $i + +)  {             //randomly take a character from a character list               $code  = substr (str_shuffle ($this->charlist), -1);             //record to Captcha string              $this- >codes .=  $code;             // Create random colors--parameters (picture resources, r,b,g)              $color _font  = imagecolorallocate ($this->img, mt_rand (10, 180),  mt_rand (10, 180), &NBSP;MT _rand (10, 180));             //Add Snowflakes, Location Random--parameters (picture resource, font size, tilt angle, lower left corner-X, lower left corner-y, font color, font, string)              //  bottom Left-y, the base height of the font is estimated, because the font size uses points, the length-width pixels of different characters vary greatly              imagettftext ($this->img,  $this->font_size, mt_rand ( -30, 30),   ($this->img_length/$this->code_num) * $i +mt_rand (1, $this->font_size*0.2),  $this->img_ Height*0.7+mt_rand (-$this->img_height*0.2,&nbsp, $this->img_height*0.2),  $color _font,  $this->ttf,  $code);         }    }        //output image to browser     private function  outputimg () {         //Notification Browser is the PNG format         header (' Content-type:image/png ');         //output in PNG format          Imagepng ($this->img);         //destroying image resources in memory          imagedestroy ($this->img);    }         public function __set ($key, $value) {             }        public function __get ($value) {            }        } 

PHP Broken code--Write your own verification code