resizing PDF files with Ghostscript

[Greg Marks]

I am trying to use Ghostscript to resize PDF files to letter page size,
but on certain files the output is not the correct size. As an example:

$wget https://gmarks.org/abrams_anh_pardo.pdf

$pdfinfo abrams_anh_pardo.pdf
...
Page size: 539 x 737 pts
...

$gs -o resized_file.pdf -sDEVICE=pdfwrite -dFIXEDMEDIA -dPDFFitPage -dDEVICEWIDTHPOINTS=612 -dDEVICEHEIGHTPOINTS=792 -dBATCH -dSAFER abrams_anh_pardo.pdf

$pdfinfo resized_file.pdf
...
Page size: 579.224 x 792 pts
...

Despite the flags -dDEVICEWIDTHPOINTS=612 and -dDEVICEHEIGHTPOINTS=792,
the page size of the output file is 579.224 x 792 pts instead of 612 x
792 pts. (Interestingly, Ghostscript did change the page size, just
not to the correct dimensions.) As some printers will refuse to print
files that aren't 612 x 792, I'd like to be able to convert such files
correctly. How does one do that with Ghostscript?

Incidentally, the command

$pdfjam --outfile resized_file.pdf --paper letter abrams_anh_pardo.pdf

does produce the correct output; however, on certain PDF files, pdfjam
yields output files with blank pages, so I'd like to be able to use
Ghostscript as an alternative.

Best regards,
Greg Marks

[Curt]

On 2023-09-17, Greg Marks <gtm...@gmail.com> wrote:
>
> I am trying to use Ghostscript to resize PDF files to letter page size,
> but on certain files the output is not the correct size. As an example:
>
> $wget https://gmarks.org/abrams_anh_pardo.pdf
>

> $pdfinfo abrams_anh_pardo.pdf=20

> ...
> Page size: 539 x 737 pts
> ...
>
> $gs -o resized_file.pdf -sDEVICE=pdfwrite -dFIXEDMEDIA -dPDFFitPage -d
> DEVICEWIDTHPOINTS=612 -dDEVICEHEIGHTPOINTS=792 -dBATCH -dSAFER abrams_a
> nh_pardo.pdf
>

> $pdfinfo resized_file.pdf=20

> ...
> Page size: 579.224 x 792 pts
> ...
>

It appears the output of pdfwrite has a MediaBox of 612x792 but a CropBox of
595.61x792, which must be the result of scaling A4 down to Letter and
centering that scaled down area on the page.

curty@einstein:~$ pdfinfo -box resized_file.pdf
<snip>

Page size: 579.224 x 792 pts

Page rot: 0
MediaBox: 0.00 0.00 612.00 792.00
CropBox: 16.39 0.00 595.61 792.00
BleedBox: 16.39 0.00 595.61 792.00
TrimBox: 16.39 0.00 595.61 792.00
ArtBox: 16.39 0.00 595.61 792.00
File size: 26538 bytes
Optimized: no
PDF version: 1.7

I'm unaware of another way of "fixing" this but the following kludge (unless
you can tell your printing process to use MediaBox and ignore CropBox).

sed -e "/CropBox/,/]/s#.# #g" resized_file.pdf

curty@einstein:~$ pdfinfo -box resized_file.pdf
<snip>
Page size: 612 x 792 pts (letter)
Page rot: 0
MediaBox: 0.00 0.00 612.00 792.00
CropBox: 0.00 0.00 612.00 792.00
BleedBox: 0.00 0.00 612.00 792.00
TrimBox: 0.00 0.00 612.00 792.00
ArtBox: 0.00 0.00 612.00 792.00
File size: 26538 bytes
Optimized: no
PDF version: 1.7