任何人都可以帮助我如何在Objective C中将元数据添加到pdf

问题描述

任何人都可以帮助我如何在Objective C中将元数据添加到pdf中。我遇到了一个名为CGPDFContextAddDocumentMetadata的类方法，但找不到任何有关如何实现它的文档。有人可以帮帮我吗。

Can anybody help me in how to add the metadata to a pdf in Objective C.I came across a class method called CGPDFContextAddDocumentMetadata,but could not find any documentation of how to achieve it. Can someone please help me.

提前致谢

推荐答案

可添加的元数据此方法是XMP元数据。它是基于XML的，看起来像这样（这里有完整的文档：）：

The metadata that can be added with this method is XMP metadata. It is XML based and looks like this (it is fully documented here: http://www.adobe.com/products/xmp/):

<?xpacket begin="" id="W5M0MpCehiHzreSzNTczkc9d"?>
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="Adobe XMP Core 4.2.1-c041">
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" >
<rdf:Description rdf:about="" xmlns:dc="http://purl.org/dc/elements/1.1/">
  <dc:format>application/pdf</dc:format>
  <dc:title>
    <rdf:Alt>
      <rdf:li />
    </rdf:Alt>
  </dc:title>
  <dc:description>
    <rdf:Alt>
      <rdf:li />
    </rdf:Alt>
  </dc:description>
  <dc:creator>
    <rdf:Seq>
      <rdf:li />
    </rdf:Seq>
  </dc:creator>
</rdf:Description>
<rdf:Description rdf:about="" xmlns:pdf="http://ns.adobe.com/pdf/1.3/">
  <pdf:Keywords />
  <pdf:Producer />
</rdf:Description>
<rdf:Description rdf:about="" xmlns:xmp="http://ns.adobe.com/xap/1.0/">
  <xmp:CreatorTool />
  <xmp:CreateDate>2011-02-10T11:41:05+02:00</xmp:CreateDate>
  <xmp:ModifyDate>2011-02-10T11:41:06+02:00</xmp:ModifyDate>
</rdf:Description></rdf:RDF>
</x:xmpmeta>
<?xpacket end="w"?>

方法如下：

void CGPDFContextAddDocumentMetadata(CGContextRef context,CFDataRef metadata);

'context'是您的pdf上下文，元数据是您的XMP元数据。您可以在NSString对象（下面的xmpString变量）中构造元数据，然后将NSString转换为CFDataRef：

'context' is your pdf context, metadata is your XMP metadata. You can construct the metadata in a NSString object (xmpString variable below) and then convert the NSString to CFDataRef:

CFDataRef xmpDataRef = (CFDataRef)[xmpString dataUsingEncoding:NSUTF8StringEncoding];

这篇关于任何人都可以帮助我如何在Objective C中将元数据添加到pdf的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！