exif_thumbnail

(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

exif_thumbnail — Liest das eingebettete Miniaturbild eines Bildes aus

Beschreibung

exif_thumbnail(
    resource|string $file,
    int &$width = null,
    int &$height = null,
    int &$image_type = null
): string|false

exif_thumbnail() liest das eingebettete Miniaturbild eines Bildes aus.

Wenn man das Miniaturbild mit dieser Funktion ausliefern möchte, sollte man den Mimetype mit Hilfe der Funktion header() mitschicken.

Es kann passieren, dass exif_thumbnail() das Bild nicht erzeugen, aber dessen Größe bestimmen kann. In diesem Fall, ist der Rückgabewert false, obwohl width und height gesetzt sind.

Parameter-Liste

file: Der Ort der Bilddatei. Dies kann entweder ein Dateipfad oder eine Stream-Ressource sein.
width: Die Breite des gelieferten Miniaturbildes als Rückgabewert.
height: Die Höhe des gelieferten Miniaturbildes als Rückgabewert.
image_type: Der Bildtyp des gelieferten Miniaturbildes als Rückgabewert. Dieser ist entweder TIFF oder JPEG.

Rückgabewerte

Gibt das eingebettete Miniaturbild zurück oder false, wenn das Bild kein Miniaturbild enthält.

Changelog

Version	Beschreibung
7.2.0	Der Parameter `file` unterstützt jetzt sowohl lokale Dateien als auch Stream-Ressourcen.

Beispiele

Beispiel #1 exif_thumbnail()-Beispiel

<?php
$image = exif_thumbnail('/Pfad/zum/Bild.jpg', $width, $height, $type);
if ($image!==false) {
    header('Content-type: ' .image_type_to_mime_type($type));
    echo $image;
    exit;
} else {
    // kein Miniaturbild vorhanden. Fehler wird hier verarbeitet
    echo 'Kein Miniaturbild verfügbar';
}
?>

Anmerkungen

Hinweis:
Wird file verwendet, um einen Stream an diese Funktion zu übergeben, dann muss der Stream durchsuchbar sein. Es ist zu beachten, dass sich die Position des Dateizeigers nicht ändert, nachdem diese Funktion aufgerufen wurde.

Siehe auch

exif_read_data() - Liest die EXIF-Header einer Bilddatei aus
image_type_to_mime_type() - Get Mime-Type for image-type returned by getimagesize, exif_read_data, exif_thumbnail, exif_imagetype

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User Contributed Notes 5 notes

down

Eric ¶

20 years ago


This will allow you to manipulate the thumbnail image ($imgJpeg) using the various gd commands:

<?php
  if (($imgJpeg = exif_thumbnail($strImagePath)) === false)
    print "No Thumbnail!";
  else
    $imgJpeg = imageCreateFromString($imgJpeg);
?>

down

thrustvector at 'gee'mail dot com ¶

16 years ago


If you've edited the image with image editing software and it no longer contains an exif thumbnail, I've created a script that will add one back into it, using the "PHP Exif Library": http://pel.sourceforge.net/index.php

<?php
require_once('../PEL/PelJpeg.php');
require_once('../PEL/PelIfd.php');
$fullpath = 'images/DSC_0013c.JPG';  # path of source image (does not contain an exif thumbnail)
      
$jpeg = new PelJpeg($fullpath);
 $exif = $jpeg->getExif();
 $tiff = $exif->getTiff();
 $ifd0 = $tiff->getIfd();        # need this so that we can later link it to the new IFD 

 $ifd1 = $ifd0->getNextIfd();
if (!$ifd1) {        # Only create thumbnail if one doesn't exist (i.e. there is no IFD1)
    $ifd1 = new PelIfd(1);
    $ifd0->setNextIfd($ifd1); # point ifd0 to the new ifd1 (or else ifd1 will not be read)

    $original = ImageCreateFromString($jpeg->getBytes()); # create image resource of original
    $orig_w=imagesx($original);
    $orig_h=imagesy($original);
    $wmax = 160;
    $hmax = 120;

    if ($orig_w>$wmax || $orig_h>$hmax) {
        $thumb_w=$wmax;
        $thumb_h=$hmax;
        if ($thumb_w/$orig_w*$orig_h>$thumb_h)
            $thumb_w=round($thumb_h*$orig_w/$orig_h); # maintain aspect ratio
        else
            $thumb_h=round($thumb_w*$orig_h/$orig_w);
    }
    else { # only set the thumb's size if the original is larger than 'wmax'x'hmax'
        $thumb_w=$orig_w;
        $thumb_h=$orig_h;
    }

        # create image resource with thumbnail sizing
    $thumb=imagecreatetruecolor($thumb_w,$thumb_h); 
        ## Resize original and copy to the blank thumb resource
    imagecopyresampled($thumb,$original,
                               0,0,0,0,$thumb_w,$thumb_h,$orig_w,$orig_h);

        # start writing output to buffer
    ob_start();        
        # outputs thumb resource contents to buffer
    ImageJpeg($thumb);    
        # create PelDataWindow from buffer thumb contents (and end output to buffer)
    $window = new PelDataWindow(ob_get_clean()); 

    if ($window) {    

        $ifd1->setThumbnail($window); # set window data as thumbnail in ifd1
        $outpath = $fullpath; # overwrite original jpg file
        file_put_contents($outpath, $jpeg->getBytes()); # write everything to output filename
            # Show thumbnail in file:
        echo '<img src="thumb_exif.php?image='.$outpath.'" border=0 alt="If you see this, it did not work"><br>';

        
    }
}
else {
    echo 'ifd1 already exists! (IFD1 is where the thumbnail is stored)<br>';
}
?>
<?php # This is the code in thumb_exif.php :
        $imgdat = exif_thumbnail($_REQUEST['image'], $width, $height, $type);
        header('Content-type: ' . image_type_to_mime_type($type));
        echo($imgdat);
?>

If you have a lot of such files, you can easily make a script that searches them out and adds thumbnails to their exif.

down

Miguel Vitorino ¶

17 years ago


use this if you want to embed a thumbnail directly on the HTML page without writing it first to a file:

<?php
$image = exif_thumbnail($file, $width, $height, $type);

echo "<img  width='$width' height='$height' src='data:image/gif;base64,".base64_encode($image)."'>";
?>

down

-1

Anonymous ¶

17 years ago


If you want to convert from TIFF to JPG you can use ImageMagick if it is installed in your server.

<?php
$exec = 'convert /path/to/file.tiff /path/to/file.jpg 2>&1';
@exec($exec, $exec_output, $exec_retval);

//possible error
print_r($exec_output)
?>

down

-2

hanspeter dot debets at dendrite dot com ¶

19 years ago


Great that the thumbnail can be in TIFF format (f.i. Kodak cameras have embedded thumbnail in TIFF) BUT I have not been able to show TIFF as an embedded image in HTML (using the <IMG...> tag). There seems to be no function in PHP to change TIFF to, lets say, JPG. (imagecreatefromstring gives a 'unknown datatype' error for the TIFF stream. So below sample works great for JPEG embedded thumbnail, but not for TIFF embedded (but then, maybe I did something wrong?):

test_exif.php:

<HTML>
<HEAD>
    <TITLE>Test EXIF Read  </TITLE>
</HEAD>
<BODY>
<?php
$image='P0000614.JPG';
echo("<B>". $image. "</B>:<BR><BR>\n");

$exif = exif_read_data($image, 'ANY_TAG',true);
if (!$exif===false)
{
    echo("Image contains headers<br><br>");
    echo("<A href=showthumb.php?image=" . $image ."> <IMG border=0 src=showthumb.php?image=" . $image ."></A><BR><BR>");

    foreach ($exif as $key => $section) 
    {
        foreach ($section as $name => $val) 
        {
            echo "$key.$name: $val<br>\n";
        }
    }
}
else
{
    echo("Sorry, image <B>".$image . "</B> does not contain (readable) EXIF data.");
}
?>
</BODY>
</HTML>

showthumb.php:

<?php
$imgdat = exif_thumbnail($_REQUEST['image'],$width, $height, $type);
header('Content-type: ' . image_type_to_mime_type($type));
echo($imgdat);
?>

When clicking on the <A> opens the TIFF image in the program that windows assigned to this type, but the JPEG opens in the browser.

I am using PHP 4.3.6 on windows iis 4 (yeah, I know.....)

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