是否可以在图像中保存元数据？

We create thumb images on our server and I'm looking for a way to save metadata (text) in that image. Is that possible?

我们在服务器上创建拇指图像,我正在寻找一种在该图像中保存元数据(文本)的方法。那可能吗?

At this moment we use PHP and we create JPG images.

此时我们使用PHP并创建JPG图像。

5 个解决方案

#1

You question is the same as writing exif data in php.

你的问题与在php中编写exif数据相同。

My answer is:

我的回答是:

PEL(PHP Exif Library). A library for reading and writing Exif headers in JPEG and TIFF images using PHP.

PEL(PHP Exif库)。使用PHP读取和编写JPEG和TIFF图像的Exif标头的库。

The PHP JPEG Metadata Toolkit. Allows reading, writing and display of the following JPEG metadata formats: EXIF 2.2, XMP / RDF, IPTC-NAA IIM 4.1 ect

PHP JPEG元数据工具包。允许读取,写入和显示以下JPEG元数据格式:EXIF 2.2,XMP / RDF,IPTC-NAA IIM 4.1等

ExifTool by perl. The ExifTool is excellent. It’s basically got it all – EXIF, IPTC and XMP support (read/write) and support for manufacturer extensions.

Perl的ExifTool。 ExifTool非常棒。它基本上是全部 - EXIF,IPTC和XMP支持(读/写)和对制造商扩展的支持。

#2

I hope this helps you!

我希望这可以帮助你!

I modified a class that I found here (thanks debers).

我修改了一个我在这里找到的课程(感谢debers)。

And all the references to IPTC tags can be readed from this PDF

所有对IPTC标签的引用都可以从这个PDF中获取

Code (PHP >= 5.4):

代码(PHP> = 5.4):

<?
define("IPTC_OBJECT_NAME", "005");
define("IPTC_EDIT_STATUS", "007");
define("IPTC_PRIORITY", "010");
define("IPTC_CATEGORY", "015");
define("IPTC_SUPPLEMENTAL_CATEGORY", "020");
define("IPTC_FIXTURE_IDENTIFIER", "022");
define("IPTC_KEYWORDS", "025");
define("IPTC_RELEASE_DATE", "030");
define("IPTC_RELEASE_TIME", "035");
define("IPTC_SPECIAL_INSTRUCTIONS", "040");
define("IPTC_REFERENCE_SERVICE", "045");
define("IPTC_REFERENCE_DATE", "047");
define("IPTC_REFERENCE_NUMBER", "050");
define("IPTC_CREATED_DATE", "055");
define("IPTC_CREATED_TIME", "060");
define("IPTC_ORIGINATING_PROGRAM", "065");
define("IPTC_PROGRAM_VERSION", "070");
define("IPTC_OBJECT_CYCLE", "075");
define("IPTC_BYLINE", "080");
define("IPTC_BYLINE_TITLE", "085");
define("IPTC_CITY", "090");
define("IPTC_PROVINCE_STATE", "095");
define("IPTC_COUNTRY_CODE", "100");
define("IPTC_COUNTRY", "101");
define("IPTC_ORIGINAL_TRANSMISSION_REFERENCE", "103");
define("IPTC_HEADLINE", "105");
define("IPTC_CREDIT", "110");
define("IPTC_SOURCE", "115");
define("IPTC_COPYRIGHT_STRING", "116");
define("IPTC_CAPTION", "120");
define("IPTC_LOCAL_CAPTION", "121");

class IPTC
{
    var $meta = [];
    var $file = null;

    function __construct($filename)
    {
        $info = null;

        $size = getimagesize($filename, $info);

        if(isset($info["APP13"])) $this->meta = iptcparse($info["APP13"]);

        $this->file = $filename;
    }

    function getValue($tag)
    {
        return isset($this->meta["2#$tag"]) ? $this->meta["2#$tag"][0] : "";
    }

    function setValue($tag, $data)
    {
        $this->meta["2#$tag"] = [$data];

        $this->write();
    }

    private function write()
    {
        $mode = 0;

        $content = iptcembed($this->binary(), $this->file, $mode);   

        $filename = $this->file;

        if(file_exists($this->file)) unlink($this->file);

        $fp = fopen($this->file, "w");
        fwrite($fp, $content);
        fclose($fp);
    }         

    private function binary()
    {
        $data = "";

        foreach(array_keys($this->meta) as $key)
        {
            $tag = str_replace("2#", "", $key);
            $data .= $this->iptc_maketag(2, $tag, $this->meta[$key][0]);
        }       

        return $data;
    }

    function iptc_maketag($rec, $data, $value)
    {
        $length = strlen($value);
        $retval = chr(0x1C) . chr($rec) . chr($data);

        if($length < 0x8000)
        {
            $retval .= chr($length >> 8) .  chr($length & 0xFF);
        }
        else
        {
            $retval .= chr(0x80) . 
                       chr(0x04) . 
                       chr(($length >> 24) & 0xFF) . 
                       chr(($length >> 16) & 0xFF) . 
                       chr(($length >> 8) & 0xFF) . 
                       chr($length & 0xFF);
        }

        return $retval . $value;            
    }   

    function dump()
    {
        echo "<pre>";
        print_r($this->meta);
        echo "</pre>";
    }

    #requires GD library installed
    function removeAllTags()
    {
        $this->meta = [];
        $img = imagecreatefromstring(implode(file($this->file)));
        if(file_exists($this->file)) unlink($this->file);
        imagejpeg($img, $this->file, 100);
    }
}

$file = "photo.jpg";
$objIPTC = new IPTC($file);

//set title
$objIPTC->setValue(IPTC_HEADLINE, "A title for this picture");

//set description
$objIPTC->setValue(IPTC_CAPTION, "Some words describing what can be seen in this picture.");

echo $objIPTC->getValue(IPTC_HEADLINE);
?>

#3

EXIF or reuse an old "data-hiding" concept, Stenography

EXIF或重用旧的“数据隐藏”概念,Stenography

#4

Yes, it's possible.

是的,这是可能的。

You can use the almighty Exiftool perl utility, which handles nearly every known set of tags, both standard(EXIF, IPTC, Adobe's XMP, etc) and proprietary ones.

您可以使用全能的Exiftool perl实用程序,它可以处理几乎所有已知的标记集,包括标准(EXIF,IPTC,Adobe的XMP等)和专有标记。

#5

Embedding XMP Metadata in Application Files (PDF)

在应用程序文件中嵌入XMP元数据(PDF)

#1