iosxcodepdfmetadata

iOS: Sample Code or Examples for CGPDFContextAddDocumentMetadata

I need to embed some custom meta data to a PDF file using the Apple's Objective C SDK. Is there any working sample code available that does that?

What I need is very basic. Open an existing pdf and add some meta data and then save it.

Example of information stored will be like.... a customer's name, contact number, items ordered.

I saw that this "CGPDFContextAddDocumentMetadata" supports metadata but I don't know how the meta data look like and how is it used passed to this function.

Any help will be greatly appreciated...:)

Solution

  • Metadata is metadata (of course, it is recommended by Adobe that you use XMP XML). So long as you create a valid CFDataRef and pass it into arg two, you're pretty much good to go with anything. For example, here's how to pass the string "Hello World" into a PDF's metadata:

    void MakeAPDF()
{

    CGRect mediaRect = CGRectMake(0, 0, 400, 600);
    // use your own rect instead

    CFMutableDataRef result = CFDataCreateMutable(kCFAllocatorDefault, 0);
    CGDataConsumerRef PDFDataConsumer = CGDataConsumerCreateWithCFData(result);

    // mark the PDF as coming from your program
    CFMutableDictionaryRef auxInfo = CFDictionaryCreateMutable(kCFAllocatorDefault, 1, NULL, NULL);
    CFDictionaryAddValue(auxInfo, kCGPDFContextCreator, CFSTR("Your Programs Name"));
    CFDictionaryRef auxillaryInformation = CFDictionaryCreateCopy(kCFAllocatorDefault, auxInfo);
    CFRelease(auxInfo);

    // create a context to draw into
    CGContextRef graphicContext = CGPDFContextCreate(PDFDataConsumer, &mediaRect, auxillaryInformation);
    CFRelease(auxillaryInformation);
    CGDataConsumerRelease(PDFDataConsumer);

    // actually make the call to embed your String
    NSString* str= @"Hello World";
    NSData* data=[str dataUsingEncoding:NSUTF8StringEncoding];
    CFDataRef cfdata = CFDataCreate(NULL, [data bytes], [data length]);

    CGPDFContextAddDocumentMetadata(graphicContext, cfdata);

    CGContextBeginPage(graphicContext, &mediaRect);
    // do your drawing, like this grey rectangle
    CGContextSetGrayFillColor(graphicContext, 0.5, 0.5);
    CGContextAddRect(graphicContext, mediaRect);
    CGContextFillPath(graphicContext);
    // end your drawing

    CGContextEndPage(graphicContext);
    CGContextFlush(graphicContext);
    CGPDFContextClose(graphicContext);    
}

    An XMP file might look like this:

    <?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"?>