exif_thumbnail

(PHP 4 >= 4.2.0, PHP 5)

exif_thumbnail -- Retrieve the embedded thumbnail of a TIFF or JPEG image

Описание

string exif_thumbnail ( string filename [, int &width [, int &height [, int &imagetype]]] )

exif_thumbnail() reads the embedded thumbnail of a TIFF or JPEG image.

If you want to deliver thumbnails through this function, you should send the mimetype information using the header() function.

It is possible that exif_thumbnail() cannot create an image but can determine its size. In this case, the return value is FALSE but width and height are set.

Список параметров

filename

The name of the image file being read. This image contains an embedded thumbnail.

width

The return width of the returned thumbnail.

height

The returned height of the returned thumbnail.

imagetype

The returned image type of the returned thumbnail. This is either TIFF or JPEG.

Возвращаемые значения

Returns the embedded thumbnail, or FALSE if the image contains no thumbnail.

Список изменений

ВерсияОписание
4.3.0 The optional parameters width, height, and imagetype all became available.
4.3.0 May return thumbnails in the TIFF format.

Примеры

Пример 1. exif_thumbnail() example

<?php
if (array_key_exists('file', $_REQUEST)) {
   $image = exif_thumbnail($_REQUEST['file'], $width, $height, $type);
} else {
   $image = false;
}
if ($image!==false) {
   header('Content-type: ' .image_type_to_mime_type($type));
   echo $image;
   exit;
} else {
   // no thumbnail available, handle the error here
   echo 'No thumbnail available';
}
?>

Смотрите также

exif_read_data()
image_type_to_mime_type()



exif_thumbnail
hanspeter dot debets at dendrite dot com
14-Jan-2005 06:35
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.....)
Eric
13-Jun-2004 07:05
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);
?>
neothermic at ya[]o dot com ADD ho IN GAP
26-May-2004 10:01
You can use the EXIF thumbnail function to extract the thumnails for use in an image gallery. I've found this to be faster than using other GD functions to convert the image to a smaller one then save it.

Here is the code I use to generate thumbnails. Remember, this is more of a utility script, although its simple to modifiy it for use...

<?PHP
set_time_limit(0); //use this to make sure the script doesn't time out on large number of images.
//error_reporting(E_NONE); //use this to disable errors in a production script

function getmicrotime() {
   $temparray=split(" ",microtime());
   $returntime=$temparray[0]+$temparray[1];
   return $returntime;
}

//lets make it slightly proper HTML. not valid, but can be changed quickly to be
echo "<html>
<head><title>Processing...</title></head>
<body>";

$maindir = "." ; //change this to what ever directory needs scanning
$mydir = opendir($maindir) ;
$starttime=getmicrotime();
$i = 0; //set the count of images processed to 0
while($fn = readdir($mydir)) //scan through the whole directory
   {//open while

       $startimagetime = getmicrotime();
       $ext = strtolower(substr($fn,strlen($fn)-3)); //get the extension of an image
       if ($ext == "jpg") {
           $i++; //increase the number of images processed
           echo $fn ." is being processed....<br>";
           flush(); //needed to display each image progress
          

           $image = exif_thumbnail($fn, $width, $height, $type);

           if ($image!==false) {
                   //if there is a good enough thumbnail to use, we have it here.
                   //extract it and put it in the file, call it [original image name].thumb.jpg
                 $handle = fopen ($fn.".thumb.jpg", 'a');
                 //write the thumbnail image
                 fwrite($handle, $image);
           } else {
                 // no thumbnail available, handle the error here
                 echo "No thumbnail available for file ".$fn."<br>";
           }
       }
}
closedir($mydir);
$endtime=getmicrotime();

echo "<br>All Images have been processed, script is finshed.<br>Total processing time: ";
print $endtime-$starttime;
echo "<br> Images processed: " .$i;
echo "</body>";
echo "</html>"

?>

Its a bit crude, I must admit, but it can easily be adapted to suit user.

NeoThermic

<exif_tagnameread_exif_data>
 Last updated: Tue, 15 Nov 2005