🚀 go-pugleaf

You can use PDFMark instructions in the PostScript.  Though I'm not
entirely sure that we mean the same thing by a "comment".  You can't
generate comment (%) lines. 

Aandi Inston

Fair enough. I want to put hidden text into the PS that distiller will transfer to the PDF.

This hidden text should only be visible when viewing the PDF binary data.

And I'm using GDI to create the PS, so I'll need to know how GDI can create the relevant PDFMark instructions.

So you don't want the text to be part of the PDF page, or to appear
when you copy/paste.... just somewhere in the PDF.  Where in the PDF,
and what tool would you use to extract the comments?  There are
already a number of places in a PDF to store textual metadata.

To get the pdfmark instructions into the PostScript you would use the
PASSTHRU escape or similar.

Aandi Inston

That's right, I don't want the text to be part of the PDF. Ideally I'd like to use acrobat reader to look at the comments. And one of the standard places seems like a good idea. Perhaps a note annotation, although note annotations seem to be limited to about 4k of text. By PASSTHRU, I assume you mean:
ExtEscape( , POSTSCRIPT_PASSTHROUGH,...)

In GDI, how can I add data to a PS that distiller will convert to one of these text metadata fields, preferably unlimited in size?

That escape sounds correct.  The PostScript you add will be a pdfmark
instruction. See the pdfmark reference.

Aandi Inston

The pdfmark reference <http://partners.adobe.com/asn/developer/acrosdk/docs/PDF_Creation_APIs/pdfmarkReference.pdf> says in section 2.1.1 that the max length of a text annotation is 65,535 characters. I need more than this.

How can I get more room for my comment text?

I would think that is a limit in Acrobat too, so there would be no way
to make a longer single annotation of the text type. 

Aandi Inston

Is there another kind of normally hidden text that can be embedded in a PDF that doesn't have the 64K limitation?

Anything that comes from a string will have a 64K limitation, but you
can store multiple strings. Streams don't have a length limit. But you
said you wanted to be able to use Reader... that implies using one of
the standard types understood by Reader.

Aandi Inston