<?php
/**
 * Thumbnail Image Creator
 *
 * @name ImageThumbnailer
 * @version 1.0
 * @author Shay Anderson 9.12
 * @copyright Copyright 2012 ShayAnderson.com <http://www.shayanderson.com>
 * @license MIT License <http://www.opensource.org/licenses/mit-license.php>
 * @link http://www.shayanderson.com/php/simple-php-thumbnail-image-class.htm
 */
class ImageThumbnailer
{
	/**
	 * Supported image types
	 *
	 * @staticvar array
	 */
	public static $__image_types = array(
		0x1 => 'gif',
		0x2 => 'jpeg',
		0x3 => 'png',
		0x6 => 'bmp'
	);

	/**
	 * Allowed image types/file extensions (separate multiple values with pipe '|')
	 *
	 * @var string
	 */
	public $allowed_image_types = 'bmp|gif|jpg|jpeg|png';

	/**
	 * JPEG compression level (0-100, 0 is the most compression)
	 *
	 * @var int
	 */
	public $compression_jpeg = 100;

	/**
	 * PNG compresssion level (0-8, 8 is the most compression, 0 is none)
	 *
	 * @var int
	 */
	public $compression_png = 8;

	/**
	 * Max dimesion (this can control both width and height)
	 *
	 * @var int
	 */
	public $max_dimension = 200;

	/**
	 * Max height dimension (this will override max_dimension property)
	 *
	 * @var int
	 */
	public $max_height = 0;

	/**
	 * Max width dimension (this will override max_dimension property)
	 *
	 * @var int
	 */
	public $max_width = 0;

	/**
	 * Use true color flag
	 *
	 * @var bool
	 */
	public $use_true_color = true;

	/**
	 * Init
	 */
	public function __construct()
	{
		if(!function_exists('getimagesize'))
		{ // check for GD library
			trigger_error(__CLASS__ . ' requires the GD library', E_USER_ERROR);
		}
	}

	/**
	 * Draw/create thumbnail image
	 *
	 * @param string $image_path (source image path)
	 * @param string $target_path (optional, will save image instead of output if set)
	 * @return void
	 */
	public function draw($image_path, $target_path = null)
	{
		if(!file_exists($image_path)) // check if image exists
		{
			trigger_error('Image "' . $image_path . '" does not exist', E_USER_ERROR);
		}

		if(!preg_match('/\.(' . $this->allowed_image_types . ')$/i', $image_path)) // check valid image type
		{
			trigger_error('Invalid image type for image "' . $image_path . '"', E_USER_ERROR);
		}

		$img_info = getimagesize($image_path); // set image info
		list($img_w, $img_h, $img_type) = $img_info;
		$img_mine = null;

		if($img_type > 0 && !isset(self::$__image_types[$img_type])) // check valid image type code
		{
			trigger_error('Invalid image type for image "' . $image_path . '" (image type code: ' . $img_type . ')');
		}

		if(isset($img_info['mime']))
		{
			$img_mine = $img_info['mime'];
		}
		else
		{
			trigger_error('Invalid iamge MIME type for image "' . $image_path . '"', E_USER_ERROR);
		}

		// override max dimesion
		$this->max_dimension = $this->max_height > 0 ? $this->max_height : $this->max_dimension;
		$this->max_dimension = $this->max_width > 0 ? $this->max_width : $this->max_dimension;

		// set new dimensions
		$img_new_w = $img_new_h = 0;
		if($this->max_width > 0 && $img_w > $this->max_width) // resize on width
		{
			$img_new_w = $this->max_width;
			$img_new_h = round($img_h * ($img_new_w / $img_w));
		}
		else if($this->max_height > 0 && $img_h > $this->max_height) // resize on height
		{
			$img_new_h = $this->max_height;
			$img_new_w = round($img_w * ($img_new_h / $img_h));
		}
		else if($img_w > $this->max_dimension || $img_h > $this->max_dimension) // resize on max dim
		{
			$img_new_w = $this->max_dimension;
			$img_new_h = $this->max_dimension;
			if($img_w > $img_h)
			{
				$img_new_h = round($img_h * ($img_new_w / $img_w));
			}
			else
			{
				$img_new_w = round($img_w * ($img_new_h / $img_h));
			}
		}

		$fc = $this->use_true_color ? 'imagecreatetruecolor' : 'imagecreate'; // use truecolor for jpeg
		if($img_new_w > 0 && $img_new_h > 0) // check if resize needed
		{
			$img_new = $fc($img_new_w, $img_new_h);
			$f = 'imagecreatefrom' . self::$__image_types[$img_type];
			$img = $f($image_path);
			imagecopyresampled($img_new, $img, 0, 0, 0, 0, $img_new_w, $img_new_h, $img_w, $img_h);
			imagedestroy($img);
		}
		else
		{
			$img_new = $fc($img_w, $img_h);
			$f = 'imagecreatefrom' . self::$__image_types[$img_type];
			$img_new = $f($image_path);
		}

		$f = 'image' . self::$__image_types[$img_type];
		if(strlen($target_path) < 1) // output image
		{
			header('Content-type: ' . $img_mine);
		}
		switch($img_type)
		{
			case 0x2:
				$f($img_new, $target_path, $this->compression_jpeg);
				break;

			case 0x3:
				$f($img_new, $target_path, $this->compression_png);
				break;

			default:
				$f($img_new, $target_path);
				break;
		}

		imagedestroy($img_new);
	}
}


/*


// include class
require_once './ImageThumbnailer.php';

// set object
$img = new ImageThumbnailer;

// set max dimension
$img->max_dimension = 300;

// output image in browser
$img->draw('./test.png');


// save thumbnail image as file
$img->draw('./test.png', './test_thumb.png');


*/