Example code of php custom size verification code

/**
 * php verification code customizable size
 * edit bbs.it-home.org
*/
function vCode($num=4,$size=20, $width=0,$height=0){
! $width && $width = $num*$size*4/5+5;
!$height && $height = $size + 10;
// Removed 0 1 O l etc
$str = "23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVW";
 $code = '';
for ($i=0; $i<$num; $i++){
$code.= $str[mt_rand(0, strlen($str)-1)];
}
/ / Draw an image
$im = imagecreatetruecolor($width,$height);
// Define the color to be used
$back_color = imagecolorallocate($im, 235, 236, 237);
$boer_color = imagecolorallocate($im, 118, 151, 199);
$text_color = imagecolorallocate($im, mt_rand(0,200), mt_rand(0,120), mt_rand(0,120));
// Draw background
imagefilledrectangle($ im,0,0,$width,$height,$back_color);
//Draw a border
imagerectangle($im,0,0,$width-1,$height-1,$boer_color);
//Draw interference Line
for($i=0;$i<5;$i++){
$font_color = imagecolorallocate($im, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255));
imagearc($im,mt_rand (-$width,$width),mt_rand(-$height,$height),mt_rand(30,$width*2),mt_rand(20,$height*2),mt_rand(0,360),mt_rand(0,360),$ font_color);
}
// Draw interference points
for($i=0;$i<50;$i++){
$font_color = imagecolorallocate($im, mt_rand(0,255), mt_rand(0,255), mt_rand(0,255 ));
imagesetpixel($im,mt_rand(0,$width),mt_rand(0,$height),$font_color);
}
// Draw verification code
@imagefttext($im, $size , 0, 5 , $size+3, $text_color, 'c://WINDOWS//Fonts//simsun.ttc',$code);
header("Cache-Control: max-age=1, s-maxage=1, no -cache, must-revalidate");
header("Content-type: image/png");
imagepng($im);
imagedestroy($im);
}
?>

Call example:

//Verification code example
//4 characters, size is 20
vCode(4,20);
?>