Modifying which EXIF fields are displayed (PHP code)

Nevermind. I figured out how modify util.php to limit the fields that get written to the array and how to control the order.

I'll try to document it once I get it tweaked.

After working on this a lot, I've had to do a lot of customizing and even some "hacks" to make it do as I wanted it to do. There is more EXIF info in the EXIF spec than jhead reports normally, so you have to make it run in verbose mode to get the extra data. Then I had to parse the results and make arrays to translate the data (so that instead of "Flash mode: 89" you get "Flash mode: Flash fired, Red-eye reduction mode, Return illumination detected"). I also modified the Capture date/time display to a more friendly format.

I'm happy to contribute, but it's not as simple as a few dozen lines of code. And not being a programmer, this is not easy stuff for me to do. So if enough people really want to know more about this, request it here and I'll try to document it.

I too am looking and have not had any luck.
getExif(

if ($do_exif) {

$field="EXIF";

it is starting to get blury at this time of the day. I don't think another beer will fix it though. :D

Toddler Have you found a solution? We don't want to reinvent the wheel.

Dave

Hello all,

I just completed the logic for the solution to the problem of how to determine what EXIF fields to display. It requires some understanding of PHP associative array structures, and how Gallery 1.4.4 handles EXIF header information (via jhead).

To implement the solution, a new function called excludeExifFields() is implemented in util.php. The source for this function is as follows:

function excludeExifFields(&$myExif)
  {

  // data source: jhead 2.2, exif.c
  $exif_exclude_list = array
    (
    "File name" => "true",
    "File size" => "true",
    "File date" => "true",
    "Camera make" => "false",
    "Camera model" => "false",
    "Date/Time" => "false",
    "Resolution" => "true",
    "Orientation" => "false",
    "Color/bw" => "false",
    "Flash used" => "false",
    "Focal length" => "false",
    "CCD width" => "false",
    "Exposure time" => "false",
    "Aperture" => "false",
    "Focus dist" => "false",
    "ISO equiv" => "false",
    "Exposure bias" => "false",
    "Whitebalance" => "false",
    "Light Source" => "false",
    "Metering Mode" => "false",
    "Exposure" => "false",
    "Exposure prog" => "false",
    "Jpeg process" => "true",
    "Comment" => "false"
    );
  
  if (!empty($myExif))
    {
    $exif_exclude_array = array_keys($exif_exclude_list, "true");        
    foreach ($exif_exclude_array as $exif_exclude_key)
      {
      foreach ($myExif as $key => $value)
        {
        if ($key == $exif_exclude_key)  
          {
          unset($myExif[$key]);      
          }
        }
      }
    }
    
  }

The value, $myExif, passed in (by reference) is the associative array holding EXIF fields and field values created when a call is made into getExif() in util.php.

Note the reference to jhead, which is the library that Gallery calls into to perform EXIF header extraction. The associative array $exif_exclude_list is derived from this jhead data. Unfortunately, these EXIF fields are hardcoded into the jhead exif.c file, which will require manual updating in the event of a update to EXIF field structures (as proposed in the JEITA EXIF 2.2 specification, released April 2002).

To exclude an EXIF field, set the array value from false to true.

The remaining logic first parses $exif_exclude_list into a list (associative array) of those EXIF fields to exclude. The logic then iterates on the $myExif array, removing (call to unset()) those excluded fields.

To correctly make use of excludeExifFields(), call this function after $myExif is created, but just before Gallery routines display or act upon $myExif.

As an example, in the source fragment below, I implemented the call into excludeExifFields() in util.php, function displayPhotoFields(). Note the #### indicating changes in logic:

...

  if ( $withExif && ($gallery->app->use_exif && (eregi("jpe?g\$", $photo->image->type)))) 
    {
    $myExif = $gallery->album->getExif($index, isset($forceRefresh));
    
    if ($myExif)
      {
      // following line commented out because we were losing
      // comments from the Exif array.  This is probably due
      // to differences in versions of jhead.
      array_shift($myExif); // get rid of file name at beginning
      
// ####
      excludeExifFields($myExif);
      $tables[_("EXIF Data")]  = $myExif;
      }
    }

  if (! isset($tables))
    {
    return;
    }

...

best of luck,

rich

Does anyone know how to modify the exif data display for the version 1.5???

how to determine which EXIF data to be displayed on the photo properties pop-up?

I found another small code solution for this in gallery 1.5.7

I know it's been a while since this thread, but I wanted to include my mod here in case others needed the solution

in util.php, there's a part of the code that actually now includes a section of exif headers to exclude!

on line 591, there is a line:
$unwantedFields = array('File name');

you can add any field to this like:
$unwantedFields = array('File name', 'City', 'Keywords');
and these will not show up.

--
I decided it would be easier to put in the fields I wanted rather than the fields I didn't so I made this modification to util.php. Here's the full function for getExif
I've commented where the mods are...

If you notice, I also modified this to ignore if a particular metadata had already been entered, and then it appends additional exif data with a ", " instead of the "<br>".
I did this to fix the fact that it was only including the first keyword from the keywords field
hope this helps someone