Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.postscript > #189
| From | ken <ken@spamcop.net> |
|---|---|
| Newsgroups | comp.lang.postscript |
| Subject | Re: Why ps2pdf can even fix pdf files? |
| Date | 2011-05-04 18:01 +0100 |
| Message-ID | <MPG.282b96b0f8afe1ae98983c@usenet.plus.net> (permalink) |
| References | <9f23a9cc-118f-492c-bf90-0c1304071de0@r33g2000prh.googlegroups.com> |
In article <9f23a9cc-118f-492c-bf90-0c1304071de0
@r33g2000prh.googlegroups.com>, pengyu.ut@gmail.com says...
> However, if I run ps2pdf on it which generate a new pdf. This new pdf
> will not have the problem. I'm wondering how come ps2pdf can even fix
> pdf files even though it is designed for converting from ps to pdf
> files.
ps2pdf uses the Ghostscript pdfwrite device to *create* a new PDF file.
Although ps2pdf implies that it can only accept PostScript in fact
pdfwrite can be used with any PDL which the interpreter supports. The
GhostPDL suite includes interpreters for PostScript, PDF, PCL, XPS and
(limited support) SVG.
The interpreter reads the ionput, interprets it into a series of
graphics operations, and pdfwrite rewrites those graphics operations in
PDF syntac.
So the reason it can fix your file is that the Ghostscript PDF
interpreter can read many types of broken PDF files, and pdfwrite always
creates a brand new file from scratch, so it isn't fixing it, its making
a new one.
> This brings to another question: whether ps2pdf can (or can be
> modified to) fix pdf files with other problems?
If Ghostscript can read your PDF file, pdfwrite should be able to write
it.
> The following pdf has ^Z for '(' and ')'. (If you make an pdf index in
> acrobat, and search some text using the index, you will see ^Z). Is
> there a way to fix this pdf file by replacing ^Z with '(' or ')' with
> ps2pdf?
Basically, no. While this can be done it means altering the Encoding of
the font as well as changing the character code in the PDF content
stream, which would be non-trivial to do. Also, how is the application
supposed to know that ^Z is a left bracket ? In another file it might be
something quite different....
Ken
Back to comp.lang.postscript | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Why ps2pdf can even fix pdf files? Peng Yu <pengyu.ut@gmail.com> - 2011-05-04 09:35 -0700 Re: Why ps2pdf can even fix pdf files? ken <ken@spamcop.net> - 2011-05-04 18:01 +0100 Re: Why ps2pdf can even fix pdf files? bonomi@host122.r-bonomi.com (Robert Bonomi) - 2011-05-06 13:51 -0500
csiph-web