PHP 8.1.0 RC 2 available for testing

exif_read_data

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

exif_read_data从一个图片文件中读取 EXIF 头信息

说明

exif_read_data(
    resource|string $file,
    ?string $required_sections = null,
    bool $as_arrays = false,
    bool $read_thumbnail = false
): array|false

exif_read_data() 函数从一个图片文件中读取 EXIF 头信息。这样就可以读取数码相机产生的元数据。

EXIF 头信息往往存在于数码相机生成的 JPEG/TIFF 图片中,但不幸的是每个数码相机制造商的标记都不同,因此(编写代码时)不能依赖于某个特定的 Exif 头信息。

HeightWidth 是用和 getimagesize() 一样的方法计算的,因此它们的值不能是任何返回的头信息的部分。此外 html 是一个可以用于普通的 HTML 中的 height/width 的文本字符串。

当一个 Exif 头信息包含有一个 Copyright 时注意它本身可以包含两个值。解决方案和 Exif 2.10 标准不一致,COMPUTED 区段会同时返回 Copyright.PhotographerCopyright.Editor,但是 IFD0 区段则包含有一个字节数组用 NULL 字符分隔开两个项目。或者只有第一项如果数据类型错误的话(Exif 的正常行为)。COMPUTED 也会包含 Copyright,要么是原始的版权字符串,要么是逗号分隔的摄像与编辑的版权信息。

UserComment 标记和 Copyright 有同样的问题。它也可以存储两个值,第一个是使用的编码方式,第二个是其值本身。如果这样则 IFD 区段仅包含编码方式或者一个字节数组。COMPUTED 区段将存储两个值到 UserCommentEncodingUserCommentUserComment 在两种情况下都可用因此应该优先使用它而不是 IFD0 区段中的该值。

exif_read_data() 还会根据 EXIF 规范(» http://exif.org/Exif2-2.PDF,第 20 页)来验证 EXIF 数据。

参数

file

图片文件的位置。这可以是一个文件路径(和往常一样,流封装也是支持的), 或者是一个流式资源(stream resource)。

required_sections

是需要存在于文件中的逗号分隔的区段列表用来产生结果数组。如果未找到所请求的区段则返回值为 false

FILE FileName, FileSize, FileDateTime, SectionsFound
COMPUTED html,Width,Height,IsColor,可能有更多其它的。Height 和 Width 是用和 getimagesize() 一样的方法计算的,因此它们的值不能是任何返回的头信息的部分。此外 html 是一个可以用于普通的 HTML 中的 height/width 的文本字符串。
ANY_TAG 任何包含有标记的信息,例如 IFD0EXIF,...
IFD0 所有 IFD0 的标记数据。在标准的图像文件中这包含了图像大小及其它。
THUMBNAIL 如果有第二个 IFD,文件应该包含有缩略图。所有有关嵌入缩略图的标记信息都存储在本区。
COMMENT JPEG 图像的注释头信息。
EXIF EXIF 区段是 IFD0 的子区,包含有图像的更多详细信息。大多数内容都是数码相机相关的。

as_arrays

指定了是否每个区段都成为一个数组。required_sections COMPUTEDTHUMBNAILCOMMENT 区段总是成为数组,因为它们里面包含的名字和其它区段冲突。

read_thumbnail

当设定为 true 时,读取缩略图本身。否则只读取标记数据。

返回值

返回一个关联数组,键名是头信息名,值为与其相应的值。如果没有可供返回的数据,exif_read_data() 将返回 false

错误/异常

当遇到不支持的标签,或其他潜在的错误情况时,将抛出E_WARNINGE_NOTICE等级的错误,但这个函数依然会尝试去读取所有可理解的信息。

更新日志

版本 说明
8.0.0 required_sections 现在可以为空。
7.2.0 file 参数现在起支持本地文件和流式资源。
7.2.0 新增了以下 EXIF 格式的支持:
  • Samsung
  • DJI
  • Panasonic
  • Sony
  • Pentax
  • Minolta
  • Sigma/Foveon
  • AGFA
  • Kyocera
  • Ricoh
  • Epson

范例

示例 #1 exif_read_data() 例子

<?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'0true);
echo 
"test2.jpg:<br />\n";
foreach (
$exif as $key => $section) {
    foreach (
$section as $name => $val) {
        echo 
"$key.$name$val<br />\n";
    }
}
?>

第一个调用失败了,因为图像没有头信息。

以上例程的输出类似于:

test1.jpg:
No header data found.
test2.jpg:
FILE.FileName: test2.jpg
FILE.FileDateTime: 1017666176
FILE.FileSize: 1240
FILE.FileType: 2
FILE.SectionsFound: ANY_TAG, IFD0, THUMBNAIL, COMMENT
COMPUTED.html: width="1" height="1"
COMPUTED.Height: 1
COMPUTED.Width: 1
COMPUTED.IsColor: 1
COMPUTED.ByteOrderMotorola: 1
COMPUTED.UserComment: Exif test image.
COMPUTED.UserCommentEncoding: ASCII
COMPUTED.Copyright: Photo (c) M.Boerger, Edited by M.Boerger.
COMPUTED.Copyright.Photographer: Photo (c) M.Boerger
COMPUTED.Copyright.Editor: Edited by M.Boerger.
IFD0.Copyright: Photo (c) M.Boerger
IFD0.UserComment: ASCII
THUMBNAIL.JPEGInterchangeFormat: 134
THUMBNAIL.JPEGInterchangeFormatLength: 523
COMMENT.0: Comment #1.
COMMENT.1: Comment #2.
COMMENT.2: Comment #3end
THUMBNAIL.JPEGInterchangeFormat: 134
THUMBNAIL.Thumbnail.Height: 1
THUMBNAIL.Thumbnail.Height: 1

示例 #2 exif_read_data() with streams available as of PHP 7.2.0

<?php
// Open a the file, this should be in binary mode
$fp fopen('/path/to/image.jpg''rb');

if (!
$fp) {
    echo 
'Error: Unable to open image for reading';
    exit;
}

// Attempt to read the exif headers
$headers exif_read_data($fp);

if (!
$headers) {
    echo 
'Error: Unable to read exif headers';
    exit;
}

// Print the 'COMPUTED' headers
echo 'EXIF Headers:' PHP_EOL;

foreach (
$headers['COMPUTED'] as $header => $value) {
    
printf(' %s => %s%s'$header$valuePHP_EOL);
}
?>

以上例程的输出类似于:

EXIF Headers:
 Height => 576
 Width => 1024
 IsColor => 1
 ByteOrderMotorola => 0
 ApertureFNumber => f/5.6
 UserComment =>
 UserCommentEncoding => UNDEFINED
 Copyright => Denis
 Thumbnail.FileType => 2
 Thumbnail.MimeType => image/jpeg

注释

注意:

If mbstring is enabled, exif will attempt to process the unicode and pick a charset as specified by exif.decode_unicode_motorola and exif.decode_unicode_intel. The exif extension will not attempt to figure out the encoding on its own, and it is up to the user to properly specify the encoding for which to use for decoding by setting one of these two ini directives prior to calling exif_read_data().

注意:

If the file is used to pass a stream to this function, then the stream must be seekable. Note that the file pointer position is not changed after this function returns.

参见

add a note add a note

User Contributed Notes 17 notes

up
72
chadsmith729 at gmail dot com
8 years ago
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.
up
3
b at asdflolinternet dot de
5 years ago
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));
//
up
6
darkain at darkain dot com
13 years ago
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);
}
?>
up
7
drpain at webster dot org dot za
9 years ago
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.
up
1
omerg at lucidcode dot com dot tr
2 years ago
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";
        }
    }

}
?>
up
1
TNTcode
3 years ago
<?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);
           
            }
        }
    }
}

?>
up
1
Tim
1 year ago
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"
up
1
mafo at mafo removethis dot sk
14 years ago
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)
up
0
Eion Robb
6 years ago
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]);
}
?>
up
0
Clive dot Moore at ma-design dot com
7 years ago
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';
    };
up
0
michael [at[ thisiswilson [dot[ com
12 years ago
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/
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0
Anonymous
14 years ago
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.
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-1
iam at thatguy dot co dot za
7 years ago
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;
}

?>
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-1
lincolnzsilva at gmail dot com
12 years ago
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'];
?>
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-1
wdierkes at 5dollarwhitebox dot org
14 years ago
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.
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-1
hoangvu4000 at gmail dot com
8 years ago
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);
}
?>
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-6
kurt at mandella dot biz
8 years ago
Photos processed in Picasa often contain garbage data in the "MAKERNOTE" section and under EXIF.MakerNote, (UTF8) like:

[MakerNote] => r0~Þæ"î2OÔy     e §…b!    )    ) EI "ÐÓ
#s &0{ 'Û (å -Ð`ÿÿ@ÿÿÿìE è€Ýÿÿ  ÿÿÿÿÿÿx "ú»Dóÿ H ?.}BúIMG:DIGITAL IXUS 100 IS JPEGFirmware Version 1.00s›xÇØÿÿÿ–l¥ÿÿÿ  ØÌÌxŒ ÿÿÌÌŸãÿÿÿ¼Ž(½ (½T‹U’‹d–~Ø“¥ÿÿÿ    ÀÿœªãjáÀpgaXfaWb[Te«
8ú5:Áð-3åÿÿ5»ÿ ‹;ßÊ Š €à€`         ¸ ddîÿîÿîÿîÿîÿîÿ
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);
}
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