Crops images to a smaller or bigger size.

thumbnail.php

<?php
	/**
	 * This classes allows you to create thumbnails. Input images will be resized, 
	 * while the ratio keeps intact, and will cropped to the size given.
	 * @author Corné Dorrestijn
	 * @license http://www.gnu.org/copyleft/lesser.html GNU Library General Public License
	 * @package Default
	 */
	class Thumbnail
	{
		private $imageData, $newImage, $sourceWidth, $sourceHeight;
		public  $width, $height;
		public $quality = 1;
		/**
		 * Constructor
		 * @param string $url The url to the local file.
		 * @param integer $width The width of the thumbnail, default 100px.
		 * @param integer $height The height of the thumbnail, default 100px.
		 * @return void|String returns a string if there is a error.
		 */
		public function __construct($url, $width = 100, $height = 100)
		{
			if(!isset($url) && $url === undefined && $url === '') return "No image url given.";
			if(!is_readable($url)) return 'Image "' . $url . '" file not readable.';
			$this->width = $width;
			$this->height = $height;
			$this->imageData = imagecreatefromstring(file_get_contents($url));
			list($this->sourceWidth, $this->sourceHeight) = getimagesize($url);
			$this->redraw();
			return;
		}

		/**
		 * Generates a jpeg image.
		 * @param boolean $redraw If set to true it will redraw the image.
		 * @param string $path If set it will save the image to the given path.
		 * @return void|String returns a string if there is a error.
		 */
		public function getJpeg($redraw = true, $path = '')
		{
			if($redraw) $this->redraw();
			$q = round($this->quality * 99);
			if($path !== '')
			{
				if(!imagejpeg($this->newImage, $path, $q))
				{
					return "Image NOT saved";
				}
			}
			else
			{
				header ('Content-Type: image/jpeg');
				imagejpeg($this->newImage, NULL, $q);
			}

			imagedestroy($this->newImage);
			return;
		}

		/**
		 * Generates a png image.
		 * @param boolean $redraw If set to true it will redraw the image.
		 * @param string $path If set it will save the image to the given path.
		 * @return void|String returns a string if there is a error.
		 */
		public function getPng($redraw = true, $path = '')
		{
			if($redraw) $this->redraw();
			$q = 9-round($this->quality * 9);
			if($path !== '')
			{
				if(!imagepng($this->newImage, $path, $q))
				{
					return "Image NOT saved";
				}
			}
			else
			{
				header ('Content-Type: image/png');
				imagepng($this->newImage, NULL, $q);
			}
			
			imagedestroy($this->newImage);
			return;
		}

		/**
		 * Generates a gif image.
		 * @param boolean $redraw If set to true it will redraw the image.
		 * @param string $path If set it will save the image to the given path.
		 * @return void|String returns a string if there is a error.
		 */
		public function getGif($redraw = true, $path = '')
		{
			if($redraw) $this->redraw();
			if($path !== '')
			{
				if(!imagegif($this->newImage, $path))
				{
					return "Image NOT saved";
				}
			}
			else
			{
				header ('Content-Type: image/gif');
				imagegif($this->newImage);
			}
			imagedestroy($this->newImage);
			return;
		}

		/**
		 * Draws the scaled and cropped image in $this->newImage.
		 * @return void.
		 */
		private function redraw()
		{
			$newWidth = $this->width;
			$newHeight = $this->height;
			$offsetX = 0;
			$offsetY = 0;
			$pr = $this->sourceWidth/$this->sourceHeight;
			$tr = $this->width/$this->height;
			if($pr > $tr)
			{
				$newWidth = round($this->height*$pr);
				$offsetX = -round(($newWidth - $this->width) / 2);
			}
			else
			{
				$newHeight = round($this->width/$pr);
				$offsetY = -round(($newHeight - $this->height) / 2);
			}			
			$this->newImage = imagecreatetruecolor($this->width, $this->height);
			imagecopyresampled($this->newImage, $this->imageData, $offsetX, $offsetY, 0, 0, $newWidth, $newHeight, $this->sourceWidth, $this->sourceHeight);
			return;
		}
	}
?>