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So my home made captcha displays the text in a straight line but I think because of this, the bots can still sign up - they're getting in.

Can someone show me how to revise my code below to add a function or something that would make each letter display a little higher or lower than the other letters? Please don't mind the dirty coding as I'm not a PHP professional. Thank you everyone for your help. 

$image = imagecreatetruecolor(70, 20); 

for ($i=0; $i < rand(20,40); $i++) {

$x = rand(0, 70);
$y = rand(0, 20);

imageline($image, $x, $y, $x+rand(0,10), $y+rand(0,240), imagecolorallocate($image,     rand(0,255),rand(0,190),rand(1,90)));

imageline($image, $x, $y, $x+rand(0,11), $y+rand(0,34), imagecolorallocate($image, 255,rand(50,240),rand(241,240)));

}
$s = rand(1, 240);
$x = rand(50, 240);
$f = rand(1, 4);
$d = rand(1, 1);
$c = rand(1, 4);

imagestring($image, $c, 3, $f, $_GET["T"], imagecolorallocate($image, $s,$x,$s));
imagestring($image, $c, 4, $f, $_GET["T"], imagecolorallocate($image, 255,rand(50,240),rand(241,240)));

imagecolortransparent($image, imagecolorallocate($image, 255, 0, 0));
imageinterlace($image);

header("Content-type: image/gif");
imagegif($image);
imagedestroy($image);
DK1
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  • 4

1 Answers1

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Le code...

$image = imagecreatetruecolor(70, 20); 

for ($i=0; $i < rand(20,40); $i++) {

$x = rand(0, 70);
$y = rand(0, 20);

imageline($image, $x, $y, $x+rand(0,10), $y+rand(0,240), imagecolorallocate($image, rand(0,255),rand(0,190),rand(1,90)));

imageline($image, $x, $y, $x+rand(0,11), $y+rand(0,34), imagecolorallocate($image, 255,rand(50,240),rand(241,240)));

}
$s = rand(1, 240);
$x = rand(50, 240);
$f = rand(1, 4);
$d = rand(1, 1);
$pos_x = rand(5,10);

$strArr = str_split($_GET["T"]);
foreach ($strArr as $str){
    $font_size = rand(1, 5); // range from 1-5
    imagestring($image, $font_size, $pos_x, $f, $str, imagecolorallocate($image, $s,$x,$s));
    imagestring($image, $font_size, $pos_x, $f, $str, imagecolorallocate($image, 255,rand(50,240),rand(241,240)));
    $pos_x = $pos_x + rand(20,30); //adjust your letter spaceing, depend on max char per chaptcha
}

imagecolortransparent($image, imagecolorallocate($image, 255, 0, 0));
imageinterlace($image);

header("Content-type: image/gif");
imagegif($image);
imagedestroy($image);

nothing special, but functional by your requirements :) added rand size and rand letter space :)

Lukas Greso
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  • Jesus that was beautiful - le code - and I thank you dearly...from there I can play with it more, but my oh my I hope this helps block the dude - he's been hitting me for years... Thanks Lukas (Light) – DK1 Apr 27 '13 at 22:26
  • Lukas, would it be hard to like rotate the font too so it's sort of tilted as well? – DK1 Apr 27 '13 at 22:59
  • for rotating you have to create your own font and then implement it... look closely to imagestring function [link](http://php.net/manual/en/function.imagestring.php) then to imageloadfont [link](http://www.php.net/manual/en/function.imageloadfont.php) and play llbit with it – Lukas Greso Apr 28 '13 at 08:45
  • you can mark my answer as finished (green flag) and then you can create new question with problem how to deal with custom fonts by imageloadfont function :) – Lukas Greso Apr 28 '13 at 09:28
  • Lukas I can't see the green flag or any button that will allow me to mark the answer is finished. – DK1 Apr 28 '13 at 15:50