중국어,알파벳,숫자 를 지원 하 는 PHP 인증 코드

session_start(); 
getCode(4,60,20); 
  
function getCode($num,$w,$h) { 
  $code = ""; 
  for ($i = 0; $i < $num; $i++) { 
    $code .= rand(0, 9); 
  } 
  //4        rand(1000,9999)     
  //         session，      
  $_SESSION["helloweba_num"] = $code; 
  //    ，      
  header("Content-type: image/PNG"); 
  $im = imagecreate($w, $h); 
  $black = imagecolorallocate($im, 0, 0, 0); 
  $gray = imagecolorallocate($im, 200, 200, 200); 
  $bgcolor = imagecolorallocate($im, 255, 255, 255); 
  //     
  imagefill($im, 0, 0, $gray); 
  
  //    
  imagerectangle($im, 0, 0, $w-1, $h-1, $black); 
  
  //        ，      
  $style = array ($black,$black,$black,$black,$black, 
    $gray,$gray,$gray,$gray,$gray 
  ); 
  imagesetstyle($im, $style); 
  $y1 = rand(0, $h); 
  $y2 = rand(0, $h); 
  $y3 = rand(0, $h); 
  $y4 = rand(0, $h); 
  imageline($im, 0, $y1, $w, $y3, IMG_COLOR_STYLED); 
  imageline($im, 0, $y2, $w, $y4, IMG_COLOR_STYLED); 
  
  //            ，     ; 
  for ($i = 0; $i < 80; $i++) { 
    imagesetpixel($im, rand(0, $w), rand(0, $h), $black); 
  } 
  //           ,                       
  $strx = rand(3, 8); 
  for ($i = 0; $i < $num; $i++) { 
    $strpos = rand(1, 6); 
    imagestring($im, 5, $strx, $strpos, substr($code, $i, 1), $black); 
    $strx += rand(8, 12); 
  } 
  imagepng($im);//     
  imagedestroy($im);//         
}