'. t('The CSS CAPTCHA uses CSS tricks to obfuscate a random text code for spam bots. The characters of the code are scrambled in the HTML markup but are displayed in the correct order when rendered with a CSS capable browser.') .'' ;
}
}
/**
* Implementation of hook_menu().
*/
function css_captcha_menu() {
$items = array();
$items['admin/user/captcha/css_captcha'] = array(
'title' => 'CSS CAPTCHA',
'file' => 'css_captcha.admin.inc',
'page callback' => 'drupal_get_form',
'page arguments' => array('css_captcha_settings_form'),
'access arguments' => array('administer CAPTCHA settings'),
'type' => MENU_LOCAL_TASK,
);
return $items;
}
/**
* Implementation of hook_captcha()
*/
function css_captcha_captcha($op, $captcha_type='', $response='') {
switch ($op) {
case 'list':
return array("CSS CAPTCHA");
case 'generate':
if ($captcha_type == "CSS CAPTCHA") {
// get settings
$allowed_chars = _text_captcha_utf8_split(variable_get('css_captcha_allowed_characters', CSS_CAPTCHA_DEFAULT_ALLOWED_CHARACTERS));
$code_length = (int) variable_get('css_captcha_code_length', 6);
// build solution and $code_struct
$solution = '';
$code_struct = array();
for ($i = 0; $i < $code_length; $i++) {
$character = $allowed_chars[array_rand($allowed_chars)];
$code_struct[$i] = array('content' => $character, 'size' => 1.25);
$solution .= $character;
}
// generate css scrambling
while (count($code_struct) > 1) {
// pick random neighbouring items from $code_struct
$i = mt_rand(0, count($code_struct) - 2);
$item_left = $code_struct[$i];
$item_right = $code_struct[$i+1];
// merge
$merged_size = $item_left['size'] + $item_right['size'] + .25;
if (mt_rand(0, 1)) {
// normal merge: $item_left first and $item_right second
$merged_content = "{$item_left['content']}
"
."{$item_right['content']}
";
}
else {
// mirror merge: $item_right first and $item_left second
$merged_content = "{$item_right['content']}
"
."{$item_left['content']}
";
}
// build merged item
$item_merged = array(
'content' => "$merged_content
",
'size' => $merged_size,
);
// replace the two items with the merged one
array_splice($code_struct, $i, 2, array($item_merged));
// make array indices contiguous again
$code_struct = array_values($code_struct);
}
// build CAPTCHA
$captcha = array();
$captcha['solution'] = $solution;
$captcha['form']['captcha_response'] = array(
'#type' => 'textfield',
'#title' => t('Enter the code above'),
'#size' => 10,
'#prefix' => $code_struct[0]['content'],
'#maxlength' => 10,
'#required' => TRUE,
'#description' => t('Enter the code without spaces and pay attention to upper/lower case.')
);
return $captcha;
}
break;
}
}