imagecreatefromstring_autorotate.php

<?php

function imagecreatefromstring_autorotate($data)
{
	$img = imagecreatefromstring($data);
	
	if (substr($data, 0, 3) == "\xFF\xD8\xFF" && ($data{3} == "\xDB" || $data{3} == "\xE0" || $data{3} == "\xE1")) {
		$orientation = -1;
		
		if (function_exists('exif_read_data')) {
			$data_stream = preg_replace('@^data:@', 'data://', rawurlencode($data));
			$exif = exif_read_data($data_stream);
			if (isset($exif['Orientation']))
				$orientation = $exif['Orientation'];
		} else if (preg_match('@\x12\x01\x03\x00\x01\x00\x00\x00(.)\x00\x00\x00@', $data, $matches)) {
			// Little endian EXIF
			$orientation = ord($matches[1]);
		} else if (preg_match('@\x01\x12\x00\x03\x00\x00\x00\x01\x00(.)\x00\x00@', $data, $matches)) {
			// Big endian EXIF
			$orientation = ord($matches[1]);
		}
		
		switch($orientation) {
			case 2:
				$img = imageflip($img, IMG_FLIP_HORIZONTAL);
				break;
			case 3:
				$img = imagerotate($img, 180, 0);
				break;
			case 4:
				$img = imageflip($img, IMG_FLIP_VERTICAL);
				break;
			case 5:
				$img = imageflip($img, IMG_FLIP_VERTICAL);
				// Fallthrough
			case 6:
				$img = imagerotate($img, -90, 0);
				break;
			case 7:
				$img = imageflip($img, IMG_FLIP_VERTICAL);
				// Fallthrough
			case 8:
				$img = imagerotate($img, 90, 0);
				break;
		}
	}
	
	return $img;
}