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Re: Need help with ghostscript command syntax to compress pdf without flattening .

From ken <ken@spamcop.net>
Newsgroups comp.lang.postscript
Subject Re: Need help with ghostscript command syntax to compress pdf without flattening .
Date 2022-11-22 14:38 +0000
Message-ID <MPG.3de6ef321ad72cef9898d4@usenet.plus.net> (permalink)
References <3c149175-4095-43cd-9564-39e76d1311cdn@googlegroups.com>

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In article <3c149175-4095-43cd-9564-39e76d1311cdn@googlegroups.com>, 
cthalkar@nolo.com says...
> 
> I have PDF with form fields, I need to compress pdf but without flattening i.e.  retain ability of fillable form fields after pdf compression.
> 
> Following command is use to compress PDF file it compresses PDF file by 35% but pdf is flatterend i.e. in generated compress PDF does not have editable form fields  
> 
> gs -dSAFER -dBATCH -dNOPAUSE -dQUIET -sDEVICE=pdfwrite -dCompatibilityLevel=1.4 -dPDFSETTINGS=/default -sOutputFile=SAMPLE_compressed_via_gs.pdf SAMPLE.pdf

Ghostscript (more proerly Ghostscript's pdfwrite device) doesn't 
compress PDF files.

If you are prepared to sacrifice quality, then it can reduce the file 
size, but the default settings do not do so (and you are using 
/PDFSETTINGS=/default, which is quite pointless since those are the 
defaults!)

It is possible that the output PDF file may be smaller than the input 
file, but there is absolutely no guarantee that this is so, and it may 
equally well be larger. It all depends on how the input file is 
organised. For more details on the process see:

https://ghostscript.readthedocs.io/en/latest/VectorDevices.html

As to forms....

There are two types of Forms in PDF; AcroForms and XML forms (XFA), you 
don't say which your PDF file is using, and you have not supplied an 
example to look at.

Ghostscript and the pdfwrite device do not support XFA, at all. If your 
file contains XFA forms then the output file may look correct (probably 
won't) but it will no longer contain any XFA and will therefore no 
longer be a form.

The PDF interpreter and pdfwrite device do not preserve the AcroForm and 
do not preserve Widget annotations as annotations. The *content* of the 
form is transferred, as marking objects on the page, so it will look the 
same. But there is no AcroForm in the output file, and so you can no 
longer edit the form fields.

You can't do what you want using Ghostscript currently. That may change 
in the future, but I would not hold my breath waiting for it.


			Ken

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Need help with ghostscript command syntax to compress pdf without flattening . Chandrashekhar Thalkar <cthalkar@nolo.com> - 2022-11-21 06:46 -0800
  Re: Need help with ghostscript command syntax to compress pdf without flattening . ken <ken@spamcop.net> - 2022-11-22 14:38 +0000

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