Create a scaled image from PHP

scaled.php

/**
	 * Creates scaled version of source image, optionally cropping. 
	 * Handles scaling and centering in target size properly.
	 *
	 * $options = array(
	 *		'upload_dir' => thumbnail destination directory (required)
	 *		'thumb_name' => thumbnail filename in destination directory (required)
	 *		'dst_width' => target image width (required)
	 *		'dst_height' => target image height (required)
	 *		'target_format' => format to save to, defaults to source format, one of 'imagejpeg','imagegif','imagepng'
	 *		'x' => crop X start position
	 *		'y' => crop Y start position
	 *		'width' => crop width
	 *		'height' => crop height
	 * );
	 */
	function create_scaled_image($file_name, $options) {
		$file_path = $options['upload_dir'].$file_name;
		$new_file_path = $options['upload_dir'].$options['thumb_name'];
		$img_data = getimagesize($file_path);
		list($img_width, $img_height) = $img_data;
		if (!$img_width || !$img_height) {
			return array('status' => 'error', 'error' => 'Failed to get image dimensions.', 'src' => $file_path, 'dst' => $new_file_path);
		}
		$dst_x = 0;
		$dst_y = 0;
		if (isset($options['dst_width']) && !isset($options['dst_height'])) {
			$options['dst_height'] = $options['dst_width'] / ($img_width / $img_height);
		} elseif (isset($options['dst_height']) && !isset($options['dst_width'])) {
			$options['dst_width'] = $options['dst_height'] * ($img_width / $img_height);
		} elseif (!isset($options['dst_width']) && !isset($options['dst_height'])) {
			error_log('Cannot create scaled image without dst_width and dst_height');
			return array('status' => 'error', 'error' => 'Cannot create scaled image without dst_width and dst_height');
		}
		$dst_width_inner = $options['dst_width'];
		$dst_height_inner = $options['dst_height'];
		if (!isset($options['x']) && !isset($options['y']) && !isset($options['width']) && !isset($options['height'])) {
			$options['width'] = $img_width;
			$options['height'] = $img_height;
			$options['x'] = 0;
			$options['y'] = 0;
			$src_aspect_ratio = $options['width'] / $options['height'];
			$dst_aspect_ratio = $options['dst_width'] / $options['dst_height'];
			if ($src_aspect_ratio < $dst_aspect_ratio) { // need x-padding
                if(!$options['toggle']) {
                    $dst_x = ($options['dst_width'] - $options['dst_height'] * $src_aspect_ratio) / 2;
                    $dst_width_inner = $options['dst_height'] * $src_aspect_ratio;
                }
			} else if ($src_aspect_ratio > $dst_aspect_ratio) { // need y-padding
                if(!$options['toggle']) {
                    $dst_y = ($options['dst_height'] - $options['dst_width'] / $src_aspect_ratio) / 2;
                    $dst_height_inner = $options['dst_width'] / $src_aspect_ratio;
                }
			}
		}
		/*
		echo '<br />';
		echo 'source aspect ratio: '.@$src_aspect_ratio.'<br />';
		echo 'src_width: '.$options['width'].'<br />';
		echo 'src_height: '.$options['height'].'<br />';
		echo 'dst aspect ratio: '.@$dst_aspect_ratio.'<br />';
		echo 'dst_width: '.$options['dst_width'].'<br />';
		echo 'dst_height: '.$options['dst_height'].'<br />';
		echo 'dst_width_inner: '.$dst_width_inner.'<br />';
		echo 'dst_height_inner: '.$dst_height_inner.'<br />';
		echo 'dst_x: '.$dst_x.'<Br />';
		echo 'dst_y: '.$dst_y.'<br />';
		*/

		$new_width = $options['dst_width'];
		$new_height = $options['dst_height'];
		$new_img = imagecreatetruecolor($new_width, $new_height);
		switch ($img_data['mime']) {
			case 'image/jpg':
			case 'image/jpeg':
				$src_img = imagecreatefromjpeg($file_path);
				$write_image = 'imagejpeg';
				break;
			case 'image/gif':
				imagecolortransparent($new_img, @imagecolorallocate($new_img, 0, 0, 0));
				$src_img = @imagecreatefromgif($file_path);
				$write_image = 'imagegif';
				break;
			case 'image/png':
				imagecolortransparent($new_img, @imagecolorallocate($new_img, 0, 0, 0));
				imagealphablending($new_img, false);
				imagesavealpha($new_img, true);
				$src_img = @imagecreatefrompng($file_path);
				$write_image = 'imagepng';
				break;
			default:
				$src_img = $image_method = null;
		}
		if (isset($options['target_format'])) {
			$write_image = $options['target_format'];
		}
		$quality = null;
		switch ($write_image) {
			case 'imagepng': $quality = 9; break;
			case 'imagejpeg': $quality = 95; break;
		}

		$success = $src_img && @imagecopyresampled(
			$new_img,
			$src_img,
			$dst_x,
			$dst_y, 
			$options['x'],
			$options['y'],
			$dst_width_inner,
			$dst_height_inner,
			$options['width'],
			$options['height']
		) && $write_image($new_img, $new_file_path, $quality);
		// Free up memory (imagedestroy does not delete files):
		imagedestroy($src_img);
		imagedestroy($new_img);
		if ($success) {
			if (USE_AMAZON) {
				$s3 = new AmazonS3();
				$s3->ssl_verification = false;
				$resp = $s3->create_object(
					DATA_BUCKET, $new_file_path,
					$opts = array('body' => file_get_contents($new_file_path), 'acl' => AmazonS3::ACL_PUBLIC)
				);
			}
			$new_file_url = SITE_URI.'/uploads/'.$new_file_path;
			return array(
				'status' => 'ok', 
				'dst_file' => $new_file_url, 
				'dst_path' => $new_file_path, 
				'width' => $new_width, 
				'height' => $new_height
			);
		} else {
			return array('status' => 'error', 'error' => 'There was a problem processing the image.');
		}
	}