Custom captcha question

[crazy4cars69]

How to get started with writing custom captcha?
What are the things necessary for it to work with vichan?
I'm looking to write similar to one in /inc/captcha/ but wanting to write my own

[crazy4cars69]

I got to working on captcha, but ran into some errors.
I'm using Bazukachan fork.
For /templates/post_form.html

<img src="{{ config.captcha.provider_get }}">
<br>
<input type="text" name="captcha_text">
<br>
<input type="hidden" name="captcha_cookie" value="{{ captcha_cookie }}">

For /inc/captcha/captcha2.php

session_start();
header('Cache-Control: no-store, no-cache, must-revalidate');
header('Content-type: image/png');
$captcha = rand(1000, 9999);
$im = imagecreatetruecolor(180, 50); 
$bg = imagecolorallocate($im, 20, 20, 30);
$fg = imagecolorallocate($im, 255, 255, 255);
imagefill($im, 0, 0, $bg);
imagestring($im, rand(1, 7), rand(1, 7), rand(1, 7),  $captcha, $fg);
$_SESSION['captcha_cookie'] = $captcha;
$_SESSION['captcha_text'] = $captcha;
imagepng($im);
imagedestroy($im);

The error it gives me You seem to have mistyped the verification.

[frozenpandaman]

@crazy4cars69, did you ever get this working?

[perdedora]

you probably fucked up something in the captcha verification in post.php