PHP - Manual: exif_thumbnail

2024-11-15

exif_thumbnail

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

exif_thumbnail — 取得嵌入在 TIFF 或 JPEG 图像中的缩略图

说明

exif_thumbnail(
    string $filename,
    int &$width = ?,
    int &$height = ?,
    int &$imagetype = ?
): string

exif_thumbnail() 读取 TIFF 或 JPEG 图像中的嵌入缩略图。如果图像不包含缩略图则返回 false。

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.

参数

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.

返回值

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

更新日志

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

范例

示例 #1 exif_thumbnail() 例子


<?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";
}
?>

参见

exif_read_data() - 从一个图片文件中读取 EXIF 头信息
image_type_to_mime_type() - 取得 getimagesize，exif_read_data，exif_thumbnail，exif_imagetype 所返回的图像类型的 MIME 类型

add a note

User Contributed Notes 5 notes

down

Eric ¶

18 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 ¶

13 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 ¶

14 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

Anonymous ¶

15 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 ¶

17 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.....)

add a note

官方地址：https://www.php.net/manual/en/function.exif-thumbnail.php

有任何技术问题请点击这里网站运营推广招聘

IT PHP 编程语言 Linux 开发编程科技 Elasticsearch HTML/CSS/XML 网络 JAVA NoSQL 数据库面试 C/C++ Golang Git 算法操作系统正则表达式 Redis 互联网 MySql JavaScript 运维软件国际架构设计 Mac OS TCP/IP Excel Vim Windows Socket Oracle VR MongoDB Python 运营 MemCache 商业硬件电子娱乐设计 nginx 摄影游戏 WordPress HTTP 团建数码电器

php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 [PHP] inet_pton/inet_ntop IP地址转换函数 array_multisort() 多字段排序 PHPMailer设置utf8 PHPMailer字符集CharSet ADORecordSet对象 adodb手册 PHP 8.1 [鸟哥]PHP_INT_MIN 和 -9223372036854775808 opcache预加载 Composer的Packagist资源 mysql面试题 [鸟哥]PHP FFI详解 - 一种全新的PHP扩展方式 PHP7添加redis扩展 PHP mkdir()写出来的权限与mode值不符合 adodb连接mysql多个数据库的问题 Packagist / Composer 中国全量镜像 PHP获取指定函数定义在哪个文件中及行号 ADOConnection 公用函数

略微加速

PHP官方手册 - 互联网笔记

exif_thumbnail

说明

参数

返回值

更新日志

范例

参见

User Contributed Notes 5 notes