Capctha creation code in PHP not working

Question

I'm trying to make a captcha in php. This is my code:

$amountChars = 5;
$randString = substr(md5(uniqid()), 0, $amountChars);
$img = imagecreatfromjpeg("noise.jpg");
imageantialias($img, true);

$x = 20;
$y = 35;
$deltaX = 40;

for($i = 0; $i < $amountChars; $i++){
    $size = rand(18, 28);
    $r = rand(0,152);
    $g = rand(0,152);
    $b = rand(0,152);
    $color = imagecolorallocate($img, $r, $g, $b);
    $angle = -30 + rand(0, 60);
    imagettftext($img, $size, $angle, $x, $y, $color, "Blokletters-Balpen.ttf", $randString{$i});
    $x += $deltaX;
}

header("Content-Type: image/png");
imagePNG($img);

Problem is, that it does not work. I'm searching a mistake over an hour, but unsuccessfully.

Please explain what is not working. (And how much a dinar is) — nl-x, May 09 '14 at 18:57
Why are you mixing PNG and JPEG ? (imagecreatefromjpeg, and later imagePNG) Are you sure that is allowed? If not, have you tried converting your base image to a PNG and use imagecreatefrompng ? — nl-x, May 09 '14 at 18:59
**Placeholders_in_use** I have... **nl-x** image doesn't display. — PiraTa, May 09 '14 at 19:00
Does `image_capcha.php` even render the output to a file? That is what you should try first. If that works, then check the PHP code again to see how to render it directly into an image `SRC` tag. — Giacomo1968, May 09 '14 at 20:20
If you look at my answer, this seems to be a simple typographical answer. If there is more to this that we are not understanding, please provide details. — Giacomo1968, May 09 '14 at 21:42

score 0 · Accepted Answer · edited May 23 '17 at 11:50

Trying this again since I got flamed for not giving a real answer... Walking through your code step by step I was able to get it running with the following modifications:

$amountChars = 5;
$randString = substr(md5(uniqid()), 0, $amountChars);
// TYPO: MISSING E
$img = imagecreatefromjpeg("noise.jpg");

// IT'S POSSIBLE THIS FUNCTION ISN'T DEFINED:
// SEE REFERENCE LINK BELOW CODE
// imageantialias($img, true);

$x = 20;
$y = 35;
$deltaX = 40;

for($i = 0; $i < $amountChars; $i++) {
    $size = rand(18, 28);
    $r = rand(0,152);
    $g = rand(0,152);
    $b = rand(0,152);
    $color = imagecolorallocate($img, $r, $g, $b);
    $angle = -30 + rand(0, 60);
    // ADDED ./ TO FONT PATH, CHANGED $randString{$i} TO $randString[$i]
    imagettftext($img, $size, $angle, $x, $y, $color, "./Blokletters-Balpen.ttf", $randString[$i]);
    // WHY IS THIS HERE?
    $x += $deltaX;
}
header("Content-Type: image/png");
imagePNG($img);

The imageantialias function doesn't appear to be available on all systems. It wasn't available on mine, so I just commented it out.

Those changes should at least get your code working. If you're looking for a more in depth example, I recommend you review this tutorial.

You should not add a new answer but rather edit your original answer with this. — Giacomo1968, May 09 '14 at 21:29

score -1 · Answer 2 · answered May 09 '14 at 21:32

I took your code, created a noise.jpg images and even downloaded Blokletters-Balpen.ttf from here to see what’s up. A quick look at your code shows a typo:

$img = imagecreatfromjpeg("noise.jpg");

Shouldn’t that be imagecreatefromjpeg? Note the missing e in your original code:

$img = imagecreatefromjpeg("noise.jpg");

It should work now, I assume? Unless there are issues you are having placing it in <img src="image_capcha.php" />?

Capctha creation code in PHP not working

2 Answers2