I have the following script for generating a captcha code and image, for the most part it works fine, but occasionally it generates a spurious character which appears as a square in image, can anybody figure out why, I can't...

<?php
$length = 8;
$characters = ‘0123456789abcdefghijklmnopqrstuvwxyz’;
$string = ""; 
$file = "../Images/Captcha/Captcha.png";   
$font = "../Fonts/ariblk.ttf";
for ($i = 0; $i < $length; $i++) 
{
    $count = mt_rand(1, strlen($characters));
    $string = $string.$characters[$count];
}
$im = imagecreatetruecolor(148, 60);
$white = imagecolorallocate($im, 255, 255, 255);
$grey = imagecolorallocate($im, 128, 128, 128);
$black = imagecolorallocate($im, 0, 0, 0);
imagefilledrectangle($im, 0, 0, 148, 60, $grey);
imagettftext($im, 12, 0, 18, 32, $grey, $font, $string);
imagettftext($im, 12, 0, 16, 30, $black, $font, $string);
$emboss = array(array(2, 0, 0), array(0, -1, 0), array(0, 0, -1));
imageconvolution($im, $emboss, 1, 127);
imagepng($im,$file);
imagedestroy($im);
echo (
$string
);
?>

Have you tried a different font?

No, but that is a pretty basic font, will try though.

Yeah, your current font is pretty standard, but I figured it was worth a try.

h3g1�ovs Hey! you can see it! this is what I get, what is that fffd stuff? btw I did try different fonts, same result, this one is arial.ttf

Can you provide a link to the page with the captcha?

No, it is on localhost, I can send a zip...

That question mark is related to char encoding.

just after your for loop add this

PHP Code:

$string = utf8_encode($string);