How to detect shot angle of photo, and auto rotate for website display like desktop apps do on viewing?

Question

If I take a photo with a camera it stores the orientation/angle of the apparatus so when I view the image on the PC with a good app, it shows auto-rotated to 0.

But when I upload to a website it shows the original angle, so the image doesn't look good.

How can I detect this with PHP and rotate the image, and clear this angle flag from it's meta information.

Answer 1

In order to do that, you must read the EXIF information out of the JPEG file. You can either do that with exif PHP extension or with PEL.

Basically, you have to read the Orientation flag in the file. Here is an example using the exif PHP extension and WideImage for image manipulation.

<?php $exif = exif_read_data($filename); $ort = $exif['Orientation'];  $image = WideImage::load($filename);  // GD doesn't support EXIF, so all information is removed. $image->exifOrient($ort)->saveToFile($filename);  class WideImage_Operation_ExifOrient {   /**    * Rotates and mirrors and image properly based on current orientation value    *    * @param WideImage_Image $img    * @param int $orientation    * @return WideImage_Image    */   function execute($img, $orientation)   {     switch ($orientation) {       case 2:         return $img->mirror();         break;        case 3:         return $img->rotate(180);         break;        case 4:         return $img->rotate(180)->mirror();         break;        case 5:         return $img->rotate(90)->mirror();         break;        case 6:         return $img->rotate(90);         break;        case 7:         return $img->rotate(-90)->mirror();         break;        case 8:         return $img->rotate(-90);         break;        default: return $img->copy();     }   } }