exif_read_data

When the new update came out from Apple for iOS6 it provided the ability for iPad, iPod, and iPhones to be able to upload files from the device through Safari. Obviously this will open up an array of implementations where at one point it was just not possible.

The issue comes when a photo is uploaded it will be dependent on the location of the "button" when the photo was taken. Imagine if you will that you have your iPhone turned with the button at the top and you take a photo. The photo when uploaded to your server might be "upside down".

The following code will ensure that all uploaded photos will be oriented correctly upon upload:
<?php
$image = imagecreatefromstring(file_get_contents($_FILES['image_upload']['tmp_name']));
$exif = exif_read_data($_FILES['image_upload']['tmp_name']);
if(!empty($exif['Orientation'])) {
    switch($exif['Orientation']) {
        case 8:
            $image = imagerotate($image,90,0);
            break;
        case 3:
            $image = imagerotate($image,180,0);
            break;
        case 6:
            $image = imagerotate($image,-90,0);
            break;
    }
}
// $image now contains a resource with the image oriented correctly
?>

What you do with the image resource from there is entirely up to you.

I hope that this helps you identify and orient any image that's uploaded from an iPad, iPhone, or iPod. Orientation for the photo is the key to knowing how to rotate it correctly.

The following code:
<?php
$data = exif_read_data('foo.jpg');
var_dump($data['Keywords']);
?>
produces string(15) "???????????????"

Adding
<?php
ini_set('exif.decode_unicode_motorola', 'UCS-2LE');
?>
before the call to exif_red_data produces
string(15) "landscape;;field"

I wanted some quick and easy functions for computing the shutter speed and f-stop.  I couldn't find any anywhere, so I made some.  It took some research :

<?php
function exif_get_float($value) {
  $pos = strpos($value, '/');
  if ($pos === false) return (float) $value;
  $a = (float) substr($value, 0, $pos);
  $b = (float) substr($value, $pos+1);
  return ($b == 0) ? ($a) : ($a / $b);
}

function exif_get_shutter(&$exif) {
  if (!isset($exif['ShutterSpeedValue'])) return false;
  $apex    = exif_get_float($exif['ShutterSpeedValue']);
  $shutter = pow(2, -$apex);
  if ($shutter == 0) return false;
  if ($shutter >= 1) return round($shutter) . 's';
  return '1/' . round(1 / $shutter) . 's';
}

function exif_get_fstop(&$exif) {
  if (!isset($exif['ApertureValue'])) return false;
  $apex  = exif_get_float($exif['ApertureValue']);
  $fstop = pow(2, $apex/2);
  if ($fstop == 0) return false;
  return 'f/' . round($fstop,1);
}
?>

Please note that when resizing images with GD and most image processing scripts or applications you will loose the EXIF information. What I did as a workaround is book this information into MySQL before I re-size images. 

<?php

// This function is used to determine the camera details for a specific image. It returns an array with the parameters.
function cameraUsed($imagePath) {

    // Check if the variable is set and if the file itself exists before continuing
    if ((isset($imagePath)) and (file_exists($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);
      
      //error control
      $notFound = "Unavailable";
      
      // Make 
      if (@array_key_exists('Make', $exif_ifd0)) {
        $camMake = $exif_ifd0['Make'];
      } else { $camMake = $notFound; }
      
      // Model
      if (@array_key_exists('Model', $exif_ifd0)) {
        $camModel = $exif_ifd0['Model'];
      } else { $camModel = $notFound; }
      
      // Exposure
      if (@array_key_exists('ExposureTime', $exif_ifd0)) {
        $camExposure = $exif_ifd0['ExposureTime'];
      } else { $camExposure = $notFound; }

      // Aperture
      if (@array_key_exists('ApertureFNumber', $exif_ifd0['COMPUTED'])) {
        $camAperture = $exif_ifd0['COMPUTED']['ApertureFNumber'];
      } else { $camAperture = $notFound; }
      
      // Date
      if (@array_key_exists('DateTime', $exif_ifd0)) {
        $camDate = $exif_ifd0['DateTime'];
      } else { $camDate = $notFound; }
      
      // ISO
      if (@array_key_exists('ISOSpeedRatings',$exif_exif)) {
        $camIso = $exif_exif['ISOSpeedRatings'];
      } else { $camIso = $notFound; }
      
      $return = array();
      $return['make'] = $camMake;
      $return['model'] = $camModel;
      $return['exposure'] = $camExposure;
      $return['aperture'] = $camAperture;
      $return['date'] = $camDate;
      $return['iso'] = $camIso;
      return $return;
    
    } else {
      return false; 
    } 
}

?>

An example of it's use follows:

<?php

$camera = cameraUsed("/img/myphoto.jpg");
echo "Camera Used: " . $camera['make'] . " " . $camera['model'] . "<br />";
echo "Exposure Time: " . $camera['exposure'] . "<br />";
echo "Aperture: " . $camera['aperture'] . "<br />";
echo "ISO: " . $camera['iso'] . "<br />";
echo "Date Taken: " . $camera['date'] . "<br />";

?>

Will display the following, depending on the data:

Camera Used: SONY DSC-S930
Exposure Time: 1/400
Aperture: f/4.3
ISO: 100
Date Taken: 2010:12:10 18:18:45

If the image has been re-sized and the information is no longer available then you should receive the following when echoing the same:

Camera Used: Unavailable
Exposure Time: Unavailable
Aperture: Unavailable
ISO: Unavailable
Date Taken: Unavailable

Some cameras do not capture all the information, for instance Blackberry phones do not record an aperture, or iso and you will get Unavailable for those fields.  

I hope you find this helpful.

some cameras (most higher models) have position senzor (gyroskope?) and taking-position is wrote in EXIF, here is simple script for automatic rotating images

<?php
$exif = exif_read_data($filename);
$ort = $exif['IFD0']['Orientation'];
    switch($ort)
    {
        case 1: // nothing
        break;

        case 2: // horizontal flip
            $image->flipImage($public,1);
        break;
                                
        case 3: // 180 rotate left
            $image->rotateImage($public,180);
        break;
                    
        case 4: // vertical flip
            $image->flipImage($public,2);
        break;
                
        case 5: // vertical flip + 90 rotate right
            $image->flipImage($public, 2);
                $image->rotateImage($public, -90);
        break;
                
        case 6: // 90 rotate right
            $image->rotateImage($public, -90);
        break;
                
        case 7: // horizontal flip + 90 rotate right
            $image->flipImage($public,1);    
            $image->rotateImage($public, -90);
        break;
                
        case 8:    // 90 rotate left
            $image->rotateImage($public, 90);
        break;
    }

?>

$image->rotateImage() is inspired by example of http://php.net/manual/en/function.imagerotate.php
$image->flipImage() is inspired by http://php.net/manual/en/function.imagecopy.php#42803 (thank you)

The example provided for displaying exif array content is not working in recent version because not all entry values are of array type. 

This is an alternative echo loop:

 <?php
echo "test1.jpg:<br />\n";
$exif = exif_read_data('tests/test1.jpg', 'IFD0');
echo $exif===false ? "No header data found.<br />\n" : "Image contains headers<br />\n";

$exif = exif_read_data('tests/test2.jpg', 0, true);
echo "test2.jpg:<br />\n";
foreach ($exif as $key => $section) {
   
    if (!is_array ($section)) {
        echo "$key: $section<br />\n";
    } else {
        foreach ($section as $name => $val) {
            echo "$key.$name: $val<br />\n";
        }
    }

}
?>

<?php

// auto rotates an image file based on exif data from camera
// if destination file is specified then it saves file there, otherwise it will display it to user
// note that images already at normal orientation are skipped (when exif data Orientation = 1)

if(!function_exists("gd_auto_rotate")){
    function gd_auto_rotate($original_file, $destination_file=NULL){
        
        $original_extension = strtolower(pathinfo($original_file, PATHINFO_EXTENSION));
        if(isset($destination_file) and $destination_file!=''){
            $destination_extension = strtolower(pathinfo($destination_file, PATHINFO_EXTENSION));
        }
        
        // try to auto-rotate image by gd if needed (before editing it)
        // by imagemagik it has an easy option
        if(function_exists("exif_read_data")){
            
            $exif_data = exif_read_data($original_file);
            $exif_orientation = $exif_data['Orientation'];
            
            // value 1 = normal ?! skip it ?!
            
            if($exif_orientation=='3'  or $exif_orientation=='6' or $exif_orientation=='8'){
                
                $new_angle[3] = 180;
                $new_angle[6] = -90;
                $new_angle[8] = 90;
                
                // load the image
                if($original_extension == "jpg" or $original_extension == "jpeg"){
                    $original_image = imagecreatefromjpeg($original_file);
                }
                if($original_extension == "gif"){
                    $original_image = imagecreatefromgif($original_file);
                }
                if($original_extension == "png"){
                    $original_image = imagecreatefrompng($original_file);
                }
                
                $rotated_image = imagerotate($original_image, $new_angle[$exif_orientation], 0);
                
                // if no destination file is set, then show the image
                if(!$destination_file){
                    header('Content-type: image/jpeg');
                    imagejpeg($rotated_image, NULL, 100);
                }
                        
                // save the smaller image FILE if destination file given
                if($destination_extension == "jpg" or $destination_extension=="jpeg"){
                    imagejpeg($rotated_image, $destination_file,100);
                }
                if($destination_extension == "gif"){
                    imagegif($rotated_image, $destination_file);
                }
                if($destination_extension == "png"){
                    imagepng($rotated_image, $destination_file,9);
                }
                
                imagedestroy($original_image);
                imagedestroy($rotated_image);
            
            }
        }
    }
}

?>

I was needing to use exif_read_data() to read out the orientation flag, only to find that the webhost didn't have the exif extension available for use.  Instead, I hacked up a regex that worked fairly well as a replacement

<?php
$orientation = 1;
if (function_exists('exif_read_data')) {
    $exif = exif_read_data($filename);
    if (isset($exif['Orientation']))
        $orientation = $exif['Orientation'];
} else if (preg_match('@\x12\x01\x03\x00\x01\x00\x00\x00(.)\x00\x00\x00@', file_get_contents($filename), $matches)) {
    $orientation = ord($matches[1]);
}
?>

Windows fields are in a "WINXP" section (the format I don't know), but they are also elsewhere including "comments" & "subject" in null terminated "UTF-16LE" format, this code work for me:

...
$PhotoInfo->Comments    = GetPhotoValueWindows16Bit($IDFO, 'Comments');
$PhotoInfo->Subject     = GetPhotoValueWindows16Bit($IDFO, 'Subject');

 function GetPhotoValueWindows16Bit(&$Array, $Index)
 {
        $Value16 = GetPhotoValue($Array, $Index);
        if  ($Value16 === null)
            $R = null;
        else
        {
            $R = iconv('UTF-16LE', 'UTF-8', $Value16);      //Still ends in a null byte
            $R = str_replace("\x00", '', $R);               //Remove trailing null (but handle any).
        }
        return $R;
    }

this error happens when get jpeg file exif information

exif_read_data(): Error reading from file: got=x3FFA(=16378) != itemlen-2=x4325(=17189)

Problem with "S�o�m�e� �T�e�x�t��" on value(s), exif[IFD0][Title] for example, when they were edited trough windows right click properties and then got read with the read_exif_data() function. 
try:

$exif_['IFD0']['Title']=mb_convert_encoding($exif_['IFD0']['Title'],"auto","byte2le");

works on UTF-8 and so.

//
// outputs all available character encodings and prints on screen
// foreach(mb_list_encodings() as $chr)
//  {$test[$chr]=mb_convert_encoding($image[IFD0][Title],'auto',$chr);}
//  exit(print_r($test));
//

Following up on darkain at darkain dot com  script for grabbing the ShutterSpeedValue from exif data...
@http://php.net/manual/en/function.exif-read-data.php

I have found that the option shown for ShutterSppedValue, can also be ExposureTime in the exif data. 

Also the code as written provides a WRONG return, as the return is always 1 so you get 1/1sec.

Here is corrected code, or a version that corrects what is obviously not working after 5 years since it was originally developed::

Here is the updated version for:: $exif[ExposureTime]

    function exif_get_float($value) { 
        $pos = strpos($value, '/'); 
        if ($pos === false) return (float) $value; 
        $a = (float) substr($value, 0, $pos); 
        $b = (float) substr($value, $pos+1); 
    return ($b == 0) ? ($a) : ($a / $b); 
    };

    function exif_get_exposureTime(&$exif) { 
        if (!isset($exif['ExposureTime'])) return false; 
        $apex    = exif_get_float($exif['ExposureTime']);            
        $shutter = 1/$apex; 
        // above 1 sec exposure time::
        if ($shutter <= 1) return round($apex) . ' seconds'; 

    return '1/' . round(1 / $apex) . 'sec';
    };

This is function, resize image and don't rotates images have exif info

PHP must be enabled: 
extension=php_mbstring.dll 
extension=php_exif.dll

<?php
function CreateThumbnail($pic,$thumb,$thumbwidth, $quality = 100)
{

        $im1=ImageCreateFromJPEG($pic);

        //if(function_exists("exif_read_data")){
                $exif = exif_read_data($pic);
                if(!empty($exif['Orientation'])) {
                switch($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 <= $info[0]) ? $thumbwidth : $info[0]  ;

        $h1=floor($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);
}
?>

From - darkain at darkain dot com 's example.

If all the data is from the same image - simply

<?php
        $exif_data = exif_read_data ( $_FILES['photo']

        $emake =$exif_data['Make'];
        $emodel = $exif_data['Model'];
        $eexposuretime = $exif_data['ExposureTime'];
        $efnumber = $exif_data['FNumber'];
        $eiso = $exif_data['ISOSpeedRatings'];
        $edate = $exif_data['DateTime'];
?>

will work, I tried using the PEL library, and while pretty cool, I can't for the life understand how to call some things, this is simpler if your system is pretty basic or if you're in a rush.  If you have time, try playing with PEL.  It's not maintained at the moment though..

http://pel.sourceforge.net/

When reading EXIF information from the 'WINXP' group, you may need to change used encoding from the default "ISO-8859-15" to "UTF-8". This can be done in php.ini or in your code:

<?php
    ini_set('exif.encode_unicode', 'UTF-8');

    $exif = exif_read_data('TEST.JPG', 0, true);
    echo $exif['WINXP']['Title'];
?>

Useful documentation about EXIF:
http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/EXIF.html
See also comments next to XPTitle and XPAuthor.

I posted the original version of the function, but after using it for a while I discovered I didn't do enough error checking. 

I have re-factored it somewhat, and it now returns an empty array should it not be able to read the image's exif. If it is able to, it will return the details it was able to retrieve. And this should be without error. 

I am suppressing errors, because if you pass it images which cannot parse, you will get a warning. 

<?php 

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

    // Check if the variable is set and if the file itself exists before continuing
    if ((isset($imagePath)) AND (file_exists($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 (($exif_ifd0 !== false) AND ($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'];
            }
        }
    }

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

?>

Using the exif methods to read WINXP data returns unexpected results unless both exif and mbstring are compiled statically.  Please reference the following bug reports:

Bug #31980
Bug #23105

 
Specifically, the last comment on #23105:

"[8 Apr 2003 4:26pm UTC] edink@php.net

This cannot be fixed due to the fact that mbstring has been removed from PHP core (it has been 'unbundled') and the rest of core files and other extensions cannot use mbstring functionality when it is compiled as a shared library (dll).
"

If exif is compiled statically (--enable-exif) and mbstring compiled as a DSO module (--enable-mbstring=shared) then exif_read_data may only return a single character rather than the entire string.

Compiling both exif and mbstring statically (--enable-exif --enable-mbstring) resolves the issue.

Get some EXIFs fields (easy way):

<?php
        $exif_make = exif_read_data ( $_FILES['photo']['tmp_name'] ,'IFD0' ,0 );
        $emake = $exif_make['Make'];
        
        $exif_model = exif_read_data ( $_FILES['photo']['tmp_name'] ,'IFD0' ,0 );
        $emodel = $exif_model['Model'];
        
        $exif_exposuretime = exif_read_data ( $_FILES['photo']['tmp_name'] ,'EXIF' ,0 );
        $eexposuretime = $exif_exposuretime['ExposureTime'];
        
        $exif_fnumber = exif_read_data ( $_FILES['photo']['tmp_name'] ,'EXIF' ,0 );
        $efnumber = $exif_fnumber['FNumber'];

        $exif_iso = exif_read_data ( $_FILES['photo']['tmp_name'] ,'EXIF' ,0 );
        $eiso = $exif_iso['ISOSpeedRatings'];
                
        $exif_date = exif_read_data ( $_FILES['photo']['tmp_name'] ,'IFD0' ,0 );
        $edate = $exif_date['DateTime'];
?>

Photos processed in Picasa often contain garbage data in the "MAKERNOTE" section and under EXIF.MakerNote, (UTF8) like:

[MakerNote] => r
0~Þæ"î2O
Ôy     e §…
b!    

)    


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EI "ÐÓ
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 ?

.}B
úIMG:DIGITAL IXUS 100 IS JPEGFirmware Version 1.00s
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–~Ø“¥ÿÿÿ    Àÿ
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 ‹;ßÊ 
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ÿÿŠ1—ÏàôÉæ׬gªiï

This can't be written to Blob in MySql. The following code removes the garbage tags.

$exif = exif_read_data($process_photo, 0, 'EXIF');

if($exif['IFD0']['Software'] == "Picasa"){

foreach ($exif as $key => $section){

 if($key != "MAKERNOTE"){
  foreach ($section as $name => $val){
   if($name != 'MakerNote'){
    $exifA[$key][$name] = $val;
   }
  }
  $exifB[$key] = $exifA[$key];
 }
}
$serialized_exif = serialize ($exifB);
}else{
$serialized_exif = serialize ($exif);
}