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<?php
session_start();
//You can customize your captcha settings here
$captcha_code = '';
$captcha_image_height = 50;
$captcha_image_width = 130;
$total_characters_on_image = 6;
//The characters that can be used in the CAPTCHA code.
//avoid all confusing characters and numbers (For example: l, 1 and i)
$possible_captcha_letters = '1234567890';
$captcha_font = dirname(__FILE__)."/monofont.ttf";
$random_captcha_dots = 50;
$random_captcha_lines = 25;
$captcha_text_color = "0x142864";
$captcha_noise_color = "0x142864";
$count = 0;
while ($count < $total_characters_on_image) {
$captcha_code .= substr(
$possible_captcha_letters,
mt_rand(0, strlen($possible_captcha_letters)-1),
1);
$count++;
}
$captcha_font_size = $captcha_image_height * 0.65;
$captcha_image = @imagecreate(
$captcha_image_width,
$captcha_image_height
);
/* setting the background, text and noise colours here */
$background_color = imagecolorallocate(
$captcha_image,
255,
255,
255
);
$array_text_color = hextorgb($captcha_text_color);
$captcha_text_color = imagecolorallocate(
$captcha_image,
$array_text_color['red'],
$array_text_color['green'],
$array_text_color['blue']
);
$array_noise_color = hextorgb($captcha_noise_color);
$image_noise_color = imagecolorallocate(
$captcha_image,
$array_noise_color['red'],
$array_noise_color['green'],
$array_noise_color['blue']
);
/* Generate random dots in background of the captcha image */
for( $count=0; $count<$random_captcha_dots; $count++ ) {
imagefilledellipse(
$captcha_image,
mt_rand(0,$captcha_image_width),
mt_rand(0,$captcha_image_height),
2,
3,
$image_noise_color
);
}
/* Generate random lines in background of the captcha image */
for( $count=0; $count<$random_captcha_lines; $count++ ) {
imageline(
$captcha_image,
mt_rand(0,$captcha_image_width),
mt_rand(0,$captcha_image_height),
mt_rand(0,$captcha_image_width),
mt_rand(0,$captcha_image_height),
$image_noise_color
);
}
/* Create a text box and add 6 captcha letters code in it */
$text_box = imagettfbbox(
$captcha_font_size,
0,
$captcha_font,
$captcha_code
);
$x = ($captcha_image_width - $text_box[4])/2;
$y = ($captcha_image_height - $text_box[5])/2;
imagettftext(
$captcha_image,
$captcha_font_size,
0,
$x,
$y,
$captcha_text_color,
$captcha_font,
$captcha_code
);
/* Show captcha image in the html page */
// defining the image type to be shown in browser widow
header('Content-Type: image/jpeg');
imagejpeg($captcha_image); //showing the image
imagedestroy($captcha_image); //destroying the image instance
$_SESSION['captcha'] = $captcha_code;
function hextorgb ($hexstring){
$integar = hexdec($hexstring);
return array("red" => 0xFF & ($integar >> 0x10),
"green" => 0xFF & ($integar >> 0x8),
"blue" => 0xFF & $integar);
}
?>
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