php图片上传旋转压缩方法

用到php的exif扩展，需要开启exif

在php.ini文件中去掉exif组件的注释

extension=php_mbstring.dll  //要放在php_exif.dll前面让它先加载
extension=php_exif.dll

[exif]
exif.encode_unicode = ISO-8859-15
exif.decode_unicode_motorola = UCS-2BE
exif.decode_unicode_intel    = UCS-2LE
exif.encode_jis =
exif.decode_jis_motorola = JIS
exif.decode_jis_intel    = JIS

 　　/**
      * Modified Version of cameraUsed, no longer returns date.
      */
     private function cameraUsed($imagePath)
     {
         // The default empty return
         $return = array(
             'make'      => "",
             'model'     => "",
             'exposure'  => "",
             'aperture'  => "",
             'iso'       => "",
             'Orientation' => 1,
         );

         // Check if the variable is set and if the file itself exists before continuing
         if ((isset($imagePath)) && (file_exists($imagePath)))
         {
             // There are 2 arrays which contains the information we are after, so it's easier to state them both
             $exif_ifd0 = @read_exif_data($imagePath ,'IFD0' ,0);
             $exif_exif = @read_exif_data($imagePath ,'EXIF' ,0);

             // Ensure that we actually got some information
             if (($exif_ifd0 !== false) && ($exif_exif !== false))
             {
                 // Make
                 if (@array_key_exists('Make', $exif_ifd0))
                 {
                     $return['make']     = $exif_ifd0['Make'];
                 }

                 // Model
                 if (@array_key_exists('Model', $exif_ifd0))
                 {
                     $return['model']    = $exif_ifd0['Model'];
                 }

                 // Exposure
                 if (@array_key_exists('ExposureTime', $exif_ifd0))
                 {
                     $return['exposure'] = $exif_ifd0['ExposureTime'];
                 }

                 // Aperture
                 if (@array_key_exists('ApertureFNumber', $exif_ifd0['COMPUTED']))
                 {
                     $return['aperture'] = $exif_ifd0['COMPUTED']['ApertureFNumber'];
                 }

                 // ISO
                 if (@array_key_exists('ISOSpeedRatings',$exif_exif))
                 {
                     $return['iso']     = $exif_exif['ISOSpeedRatings'];
                 }
                 if(@array_key_exists('Orientation',$exif_ifd0)){
                     $return['Orientation'] = $exif_ifd0['Orientation'];
                 }
             }
         }

         // Return either an empty array, or the details which we were able to extrapolate.
         return $return;
     }

     /**
      * resize image and don't rotates images have exif info
      * @param $pic  eg：$_FILES['file']['tmp_name']
      * @param $thumb  image save path
      * @param $thumbwidth
      * @param int $quality
      */
     private function createThumbnail($pic,$thumb,$thumbwidth, $quality = 100)
     {

         $im1 = @imagecreatefromjpeg($pic);

         $exif = $this->cameraUsed($pic);
         if(($exif['Orientation'] > 1)) {
             switch($exif['Orientation']) {
                 case 8:
                     $im1 = @imagerotate($im1,90,0);
                     break;
                 case 3:
                     $im1 = @imagerotate($im1,180,0);
                     break;
                 case 6:
                     $im1 = @imagerotate($im1,-90,0);
                     break;
             }
         }

         $info = @getimagesize($pic);

         $width = $info[0];

         $w2 = @imagesx($im1);
         $h2 = @imagesy($im1);
         $w1 = ($thumbwidth <= $width) ? $thumbwidth : $width;

         $h1 = @floor($h2 * ($w1 / $w2));

         $im2 = @imagecreatetruecolor($w1,$h1);

         @imagecopyresampled ($im2,$im1,0,0,0,0,$w1,$h1,$w2,$h2);
         $path = addslashes($thumb);
         @imagejpeg($im2,$path,$quality);
         @imagedestroy($im1);
         @imagedestroy($im2);
     }