can I use Ghostscript to overlay a text (fax) header onto a PDF and/or TIFF?

问题

I'm writing an application that faxes a document (many supported types) provided by the end user. A requirement is that the end user can also provide text to be used as part of a custom fax header.

I've been using Ghostscript to render PDFs as TIFFs and it's been working great so far, but I have yet to find a straightforward way of overlaying the custom header at the top of a PDF. I've tried out a few recommendations:

How can I make a program overlay text on a postscript file?
How can I add a footer to the bottom of each page of a postscript or pdf file in linux?
Add comments to PDF files automagically with regular expressions
Stamp PDF file with control for position of stamp file

... with no luck.

I've used ImageMagick to do this successfully with documents rendered to TIFF via other tools, and I'm aware that ImageMagick can render PDF-to-TIFF on its own. However, I want to stick with Ghostscript because in my experience it has performed better and rendered clearer TIFFs.

Is this possible using Ghostscript and perhaps a PS helper script?

Edit:

Ghostscript (v9.04) is not throwing any errors. For example:

gswin64c -dSAFER -dBATCH -dNOPAUSE -dPDFFitPage -sDEVICE=tiffg3 ^
    -sOutputFile=goofy.tif ^
    -c "/Courier findfont 12 scalefont setfont 50 765 moveto (header text) show" ^
    -f goofy.pdf

... produces a TIFF of the original PDF, but without the text I tried to add. If I append showpage to the postscript one-liner it (predictably, I suppose) prints a new, blank-except-for-header page, which doesn't help me much.

回答1:

I would use another commandline tool combined with Ghostscript for this task. This tool is pdftk.exe. Then use a 3 step approach:

The task of Ghostscript would be to create an (otherwise empty) page with the header text:

gswin64c.exe ^
  -o header.pdf ^
  -sDEVICE=pdfwrite ^
  -c "/Courier findfont 12 scalefont setfont" ^
  -c "50 765 moveto (header text) show showpage"

The task of pdftk would be to overlay (stamp or background) the PDF file with the text header over the original PDF:

 pdftk.exe goofy.pdf background header.pdf output goofy-with-header.pdf

 pdftk.exe goofy.pdf stamp header.pdf output goofy-with-header.pdf

The last step is to employ Ghostscript again in order to create your final TIFF output:

gswin64c.exe ^
   -dPDFFitPage ^
   -o goofy-with-header.tif ^
   -sDEVICE=tiffg3 ^
    goofy-with-header.pdf

回答2:

The way I see doping it is appending what you need on the PDF to the PDF file itself - before any conversion - the PDF filew format is designed so that one can append extra information at the end of the file (even information that goes on previous pages).

Unfortunatelly, I never worked on it - so I can'tell you eactly what you need to do - maybe there is aome PDF editing library in a programing language that would make this task easier - else you will have to create the PDF bits yourself. (Tradiditional libraries that render PDF's from some input format won't do, as you have to work inside the structure of your existing document) - but maybe taking a looka t the PDF specification can enlighten you on this approacj, and you check if it is worth: http://www.adobe.com/devnet/pdf/pdf_reference_archive.html

Another approach there would be to work on the "other end" of your files: layout text on the post-rendered TIFF files using an image manipulation library. This is only possible, of course, if there is a fixed space on the pages reserved for you to add the information.

Sorry for not being able to offer a complete solution

回答3:

I just tried your exact same approach with your exact same result. Then I removed -dSAFER from my command-line arguments and it works like a charm.

来源：https://stackoverflow.com/questions/8885483/can-i-use-ghostscript-to-overlay-a-text-fax-header-onto-a-pdf-and-or-tiff

标签

ghostscript

postscript