Version dev

# File attachments

The PDF file format offers the possibility of embedding files in the document so that they can then be downloaded as stand-alone documents. Electronic invoices, for example, can be sent as a “human-readable” PDF with an attached computer-readable description (as XML).

Any number of files can be attached, but only one ZUGFeRD invoice.

## Attach files

    <AttachFile description="A nice view"
                type="application/pdf"
                filename="ocean.pdf" />

This command is used to attach a file to the PDF. The type is the mime type of the attached file.

## Attach ZUGFeRD / Factur-X invoices PRO

To attach an electronic invoice, the value at type must be exactly the string `ZUGFeRD invoice`:

    <AttachFile description="Electronic invoice"
                type="ZUGFeRD invoice"
                filename="invoice.xml" />

The output filename is set to `factur-x.xml` for ZUGFeRD version 2 and `ZUGFeRD-invoice.xml` for version 1.

The PDF output must be set to PDF/A-3:

    <PDFOptions format="PDF/A-3" />

This happens automatically if the command `<AttachFile>` is executed at the beginning of the document (before the first page output).

| For a PDF document to be compliant with PDF/A-3, the colors must match the color profiles. In the PDF/A-3 default setting, an OutputIntent is defined for a CMYK color profile. Accordingly, the colors in the document must be defined in this color space. Or another color profile must be embedded.

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