<?php
session_start();
require_once './setting_web.php';

class CaptchaSecurityImages
{

	private $font;

	public function __construct()
	{
		$this->font = __DIR__. '/../assets/font/font_security_code.ttf';
	}

	function generateCode($characters)
	{
		/* list all possible characters, similar looking characters and vowels have been removed */
		$possible = '0123456789';
		//$possible = '23456789bcdfghjkmnpqrstvwxyz';
		$code = '';
		$i = 0;
		while ($i < $characters) {
			$code .= substr($possible, mt_rand(0, strlen($possible) - 1), 1);
			$i++;
		}
		return $code;
	}

	function CaptchaSecurityImages($width = '100', $height = '40', $characters = '6')
	{
		$code = $this->generateCode($characters);
		/* font size will be 75% of the image height */
		$font_size = $height * 0.40;
		$image = @imagecreate($width, $height) or die('Cannot initialize new GD image stream');
		/* set the colours */
		$background_color = imagecolorallocate($image, 255, 255, 255);
		$text_color = imagecolorallocate($image, 46, 46, 46);
		$text_color2 = imagecolorallocate($image, 255, 255, 255);
		$noise_color = imagecolorallocate($image, 255, 255, 255);
		/* generate random dots in background */
		for ($i = 0; $i < ($width * $height) / 3; $i++) {
			imagefilledellipse($image, mt_rand(0, $width), mt_rand(0, $height), 1, 1, $noise_color);
		}
		/* generate random lines in background */
		for ($i = 0; $i < ($width * $height) / 30; $i++) {
			imageline($image, mt_rand(0, $width), mt_rand(0, $height), mt_rand(0, $width), mt_rand(0, $height), $noise_color);
		}
		/* create textbox and add text */
		$textbox = imagettfbbox($font_size, 0, $this->font, $code) or die('Error in imagettfbbox function');
		$x = ($width - $textbox[4]) / 2;
		$y = ($height - $textbox[5]) / 2;
		imagettftext($image, $font_size, 0, 20, 30, $text_color, $this->font, $code) or die('Error in imagettftext function');
		/* output captcha image to browser */
		header('Content-Type: image/jpeg');
		imagejpeg($image);
		imagedestroy($image);
		echo $_SESSION['security_code'] = $code;
	}
}

$width = isset($_GET['width']) ? $_GET['width'] : '90';
$height = isset($_GET['height']) ? $_GET['height'] : '50';
$characters = isset($_GET['characters']) && $_GET['characters'] > 1 ? $_GET['characters'] : '6';

$captcha = new CaptchaSecurityImages();
$captcha->CaptchaSecurityImages();
