<?php
 
class thumbnail_exception extends Exception {};
 
class thumbnail {
	protected $image_width = 0;				/* Width of the source image */
	protected $image_height = 0;				/* Height of the source image */
	protected $image_handle;				/* Handle of the source image */
	protected $image_path = "";				/* Path of the source image */
	protected $image_type;					/* Image type of the source image */
 
	protected $thumbnail_path = "";				/* Path where the thumbnail should be saved */
	protected $thumbnail_width = 100;			/* Desired thumbnail width */
	protected $thumbnail_height = 100;			/* Desired thumbnail height */
	protected $thumbnail_type = self::IMAGETYPE_BY_SOURCE;	/* Desired image type of the thumbnail */
	protected $thumbnail_final_width = 100;			/* Final width of the thumbnail picture */
	protected $thumbnail_final_height = 100;		/* Final height of the thumbnail picture */
 
	protected $border_size = 0;				/* Border size */
	protected $border_color = "#000";			/* Border color */
 
	protected $background_color = "#ccc";			/* Background color */
 
	protected $resize = true;				/* Should the thumbnail be resized according to width:height ratio? */
 
	protected $quality = self::RESAMPLE;			/* Quality of the thumbnail */
 
	protected $info_position = self::NO_INFO;		/* Position of the information box, or if it should not be drawn "NO_INFO" */
	protected $info_box_color = "#000";			/* Color of the background of the information box */
	protected $info_text_color = "#FFF";			/* Text color of the information box */
	protected $info_text = "";				/* Text of the information box */
	protected $info_transparency = 0;			/* Transparency of the information box */
	protected $info_size = 16;				/* Height of the information box */
 
	const RESIZE = 1;					/* Only resize, do not resample */
	const RESAMPLE = 2;					/* Resample the image, slower but better quality */
 
	const IMAGETYPE_BY_SOURCE = 100;			/* Choose thumbnail image type like source image type */
 
	const NO_INFO = 0;
	const TOP = 1;
	const BOTTOM = 2;
 
	public function get_width() {
		return $this->image_width;
	}
 
	public function get_height() {
		return $this->image_height; 
	}
 
	public function get_type() {
		switch($this->image_type) {
			case IMAGETYPE_GIF:  return "GIF";
			case IMAGETYPE_JPEG: return "JPG";
			case IMAGETYPE_PNG:  return "PNG";
			default: throw new thumbnail_exception("Image type not supported!");
		}
	}
 
	public function get_filesize() {
		$fsize = filesize($this->image_path);
		/* The filesize function returns the file size in bytes. -> convert value to Kibi/Mebibytes */
		if ($fsize >= 1048576) 
			return round($fsize / 1048576, 2) . " MiB";
		else
			return round($fsize / 1024, 2) . " KiB";
	}
 
	public function set_image($path) {
		$this->image_path = $path;
 
		$info = getimagesize($path);
 
		if ($info == false || ($info[0] + $info[1]) == 0)
			throw new thumbnail_exception("Image could not be read, is not an image or image type is not supported!");
 
		$this->image_height = $info[1];
		$this->image_width  = $info[0];
		$this->image_type   = $info[2];
 
		switch($this->image_type) {
			case IMAGETYPE_GIF:  $this->image_handle = imagecreatefromgif($path); break;
			case IMAGETYPE_JPEG: $this->image_handle = imagecreatefromjpeg($path); break;
			case IMAGETYPE_PNG:  $this->image_handle = imagecreatefrompng($path); break;
			default: throw new thumbnail_exception("Image type not supported!");
		}
 
		return $this;
	}
 
	public function set_information_box($position, $text = "", $box_color = "#000", $text_color = "#FFF", $trans = 0) {
		switch ($position) {
			case self::NO_INFO: $this->info_position = self::NO_INFO; return $this;
			case self::TOP:     $this->info_position = self::TOP; break;
			case self::BOTTOM:  $this->info_position = self::BOTTOM; break;
			default: throw new thumbnail_exception("Position must be NO_INFO, TOP, or BOTTOM.", 1);
		}
 
		/* Checks if the desired information text fits into the thumbnail. */
		if ($this->calculate_info_text_pixels($text) > ($this->thumbnail_width - ($this->border_size * 2)))
			throw new thumbnail_exception("Text "$text" doesn't fit into image.", 3);
 
		$this->info_text = $text;
		$this->info_box_color = $box_color;
		$this->info_text_color = $text_color;
 
		if ($trans < 0 || $trans > 127)
			throw new thumbnail_exception("Transparency must be a number between 0 and 127.", 2);
		$this->info_transparency = $trans;
 
		return $this;
	}
 
	public function set_dimensions($width, $height) {
		if ($width <= 0 || $height <= 0)
			throw new thumbnail_exception("The desired thumbnail width and height must be above 0.");
 
		$this->thumbnail_width  = $width;
		$this->thumbnail_height = $height;
 
		return $this;
	}
 
	public function set_image_type($type) {
		if ($type != self::IMAGETYPE_BY_SOURCE && $type != IMAGETYPE_GIF && $type != IMAGETYPE_PNG && $type != IMAGETYPE_JPEG)
			throw new thumbnail_exception("Image type not supported.");
		$this->thumbnail_type = $type;
 
		return $this;
	}
 
	public function set_destination_path($path) {
		$this->thumbnail_path = $path;
 
		return $this;
	}
 
	public function set_border($size, $color) {
		if ($size < 0)
			throw new thumbnail_exception("Border size must be 0 or higher.");
 
		$this->border_size = $size;
		$this->border_color = $color;
 
		return $this;
	}
 
	public function set_resize($resize) {
		$this->resize = $resize;
 
		return $this;
	}
 
	public function set_background_color($color) {
		$this->background_color = $color;
 
		return $this;
	}
 
	public function set_quality($quality) {
		$this->quality = $quality;
 
		return $this;
	}
 
	public function create_thumbnail() {
		/* Remember values, because if the image gets resized, they would change. */
		$tw_backup = $this->thumbnail_width;
		$th_backup = $this->thumbnail_height;
 
		/* Calculate the final dimensions of the resized image. These values are not the final size of the thumbnail picture,
		 * only the dimensions of the resized image! */
		$total_height = $this->thumbnail_height - ($this->border_size * 2);
		$total_width = $this->thumbnail_width - ($this->border_size * 2);
 
		/* If the information box is drawn, and it is drawn not inside the thumbnail picture, adjust height value. */
		if ($this->info_position != self::NO_INFO && $this->info_transparency == 0) 
			$total_height -= $this->info_size;
 
		/* If the source image is wider than high, recalculate final height to fit aspect ratio. Otherwise recalculate
		 * the width. */
		if ($this->image_width > $this->image_height) {
			$this->thumbnail_final_width = $total_width;
			$this->thumbnail_final_height = round($this->image_height / ($this->image_width / $total_width));
		}
		else {
			$this->thumbnail_final_height = $total_height;
			$this->thumbnail_final_width  = round($this->image_width / ($this->image_height / $total_height));
		}
 
		/* If the thumbnail should get resized according to the aspect ratio (so there is no unfilled space or background
		 * in the final thumbnail) the values for the final size of the thumbnail picture get adjusted. */
		if ($this->resize) {
			$this->thumbnail_width = $this->thumbnail_final_width + (2 * $this->border_size);
			$this->thumbnail_height = $this->thumbnail_final_height + (2 * $this->border_size);
 
			/* Again, if the information box is drawn, and it is drawn not inside the thumbnail picture, adjust height 
			 * value. */
			if ($this->info_position != self::NO_INFO && $this->info_transparency == 0) 
				$this->thumbnail_height += $this->info_size;
		}
 
		$this->thumbnail_handle = imagecreatetruecolor($this->thumbnail_width, $this->thumbnail_height);
 
		$this->draw_background();
		$this->draw_thumbnail();
		$this->draw_border();
		$this->draw_info();
 
		if ($this->thumbnail_type == self::IMAGETYPE_BY_SOURCE) $this->thumbnail_type = $this->image_type;
		switch($this->thumbnail_type) {
			case IMAGETYPE_PNG: imagepng($this->thumbnail_handle, $this->thumbnail_path); break;
			case IMAGETYPE_GIF: imagegif($this->thumbnail_handle, $this->thumbnail_path); break;
			case IMAGETYPE_JPEG: imagejpeg($this->thumbnail_handle, $this->thumbnail_path); break;
		}
 
		/* Now restore the desired thumbnail dimensions, this is needed if more than one thumbnail is generated using the same
		 * class instance. */
		$this->thumbnail_width = $tw_backup;
		$this->thumbnail_height = $th_backup;
	}
 
	protected function draw_border() {
		$border_color = $this->allocate_color_from_hex($this->border_color);
		for ($i = 0; $i < $this->border_size; $i++)
			imagerectangle($this->thumbnail_handle, $i, $i, $this->thumbnail_width - (1 + $i), $this->thumbnail_height - (1 + $i), $border_color);
 
	}
 
	protected function draw_thumbnail() {
		if ($this->info_transparency == 0 && $this->info_position != self::NO_INFO) { $tr = $this->info_size; }
		else { $tr = 0; }
 
		$sx = ($this->thumbnail_width - $this->thumbnail_final_width) / 2;
		$sy = ($this->thumbnail_height - $this->thumbnail_final_height - $tr) / 2;
 
		if ($this->info_position == self::TOP)
			$sy += $tr;
		var_dump($sx,$sy,$this->thumbnail_height, $this->thumbnail_final_height);
		switch($this->quality) {
			case self::RESIZE: $this->image_resize($sx, $sy); break;
			case self::RESAMPLE: $this->image_resample($sx, $sy); break;
			default: throw new thumbnail_exception("Quality can only be one of these: QUALITY_RESIZE, QUALITY_RESAMPLE.");
		}
	}
 
	protected function draw_background() {
		imagefill($this->thumbnail_handle, 1, 1, $this->allocate_color_from_hex($this->background_color));
	}
 
	protected function draw_info() {
		/* Don't draw information box if it would take over the half of the image. */
		if (($this->thumbnail_height / 2) <= $this->info_size)
			return;
 
		switch ($this->info_position) {
			case self::NO_INFO: return;
			case self::TOP:    $position_y = $this->border_size; break;
			/* minus border size (the border at the top), the size of the info bar and 1 (because drawing starts at position 0) */
			case self::BOTTOM: $position_y = $this->thumbnail_height - ($this->border_size + $this->info_size) - 1;
		}
 
		$position_x = $this->border_size;
		$text_x = round((($this->thumbnail_width - ($this->border_size * 2)) - ($this->calculate_info_text_pixels($this->info_text))) / 2);
 
		/* Activate alpha blending when transparency is used. */
		if ($this->info_transparency > 0)
			imagealphablending($this->thumbnail_handle, true);
 
		$bkg_color =  $this->allocate_color_from_hex($this->info_box_color, $this->info_transparency);
		$text_color = $this->allocate_color_from_hex($this->info_text_color, $this->info_transparency);
 
		imagefilledrectangle($this->thumbnail_handle, $position_x, $position_y, 
				     $this->thumbnail_width - $position_x - 1, $position_y + $this->info_size, $bkg_color);
		imagestring($this->thumbnail_handle, 3, $text_x + 1, $position_y + 2, $this->info_text, $text_color);
	}
 
	protected function image_resize($sx, $sy) {
		imagecopyresized($this->thumbnail_handle,
				 $this->image_handle,
				 $sx,
				 $sy, 0, 0,
				 $this->thumbnail_final_width,
				 $this->thumbnail_final_height,
				 $this->image_width, $this->image_height);
	}
 
	protected function image_resample($sx, $sy) {
		imagecopyresampled($this->thumbnail_handle,
				   $this->image_handle,
				   $sx,
				   $sy, 0, 0,
				   $this->thumbnail_final_width,
				   $this->thumbnail_final_height,
				   $this->image_width, $this->image_height);
	}
 
	function allocate_color_from_hex($hex, $trans = 0) {	
		if (strlen($hex) == 4) $hex = '#' . $hex[1] . $hex[1] . $hex[2] . $hex[2] . $hex[3] . $hex[3];
 
		$red   = hexdec(substr($hex, 1, 2));
		$green = hexdec(substr($hex, 3, 2));
		$blue  = hexdec(substr($hex, 5, 2));
 
		if ($trans == 0) return imagecolorallocate($this->thumbnail_handle, $red, $green, $blue);
		return imagecolorallocatealpha($this->thumbnail_handle, $red, $green, $blue, $trans);
	}
 
	function calculate_info_text_pixels($text) {
		return strlen($text) * 7;
	}
}
 
?>

<?php
 
/* Ein einfaches Vorschaubild ohne Info-Box erstellen */
require_once("thumbnail/thumbnail.class.php");
 
try {
	/* Eine neue Instanz der Vorschaubild-Klasse erstellen */
	$thumb = new thumbnail();
 
	/* Festlegen von welchem Bild ein Vorschaubild erstellt werden soll */
	$thumb->set_image("ausgangsbild.png")
 
	/* Wo das Vorschaubild gespeichert werden soll */
	      ->set_destination_path("vorschaubild.png")
 
	/* 1 Pixel breiter schwarzer (#000) Rahmen */
	      ->set_border(1, "#000")
 
	/* Das Bild soll schnell aber mit niedrigerer Qualitaet verkleinert werden */
	      ->set_quality(thumbnail::RESIZE)
 
	/* Legt fest in welchem Bildformat (PNG, JPEG, GIF) das Vorschaubild
	 * gespeichert werden soll, bei IMAGETYPE_BY_SOURCE wird das Bildformat
	 * vom Quellbild genommen */
	      ->set_image_type(thumbnail::IMAGETYPE_BY_SOURCE)
	/* Keine Info-Box anzeigen */
	      ->set_information_box(thumbnail::NO_INFO)
	/* Vorschaubild erstellen */
	      ->create_thumbnail();
}
catch (thumbnail_exception $e) {
	/* Fehler ausgeben falls einer aufgetreten ist */
	echo "Fehler: " . $e->getMessage();
}
 
?>