How to shift PDF page using perl (CAM::PDF, PDF::API2)?

Question

I have a PDF document which I need to shift the pages to the right several inches. Ie like putting a margin on the left hand side of the page.

Can either CAM::PDF or PDF::API2 do it? Or is there anyone have experience with it?

Thanks.

Answer 1

I'm the author of CAM::PDF . The following little program shifts the page contents right by 100 points.

use CAM::PDF;
my $pdf = CAM::PDF->new('my.pdf');
my $page = $pdf->getPage(1);
$page->{MediaBox}->{value}->[0]->{value} -= 100;
$page->{MediaBox}->{value}->[2]->{value} -= 100;
$pdf->cleanoutput('out.pdf');

I used "use Data::Dumper; print Dumper($page);" to remind myself of the $page data structure.

Answer 2

Here's how I would do it in PDF::API2:

use PDF::API2;

my $in  = PDF::API2->open('/path/to/file.pdf');
my $out = PDF::API2->new();

# Choose your margin (72 = one inch)
my $x_offset = 72;
my $y_offset = 0;

foreach my $page_num (1 .. $in->pages()) {
    # Take the source page and import it as an XObject
    my $xobject = $out->importPageIntoForm($in, $page_num);

    # Add the XObject to the new PDF
    my $page = $out->page();
    my $gfx = $page->gfx();
    $gfx->formimage($xobject, $x_offset, $y_offset);
}
$out->saveas('/path/to/new.pdf');

Another way that should work is to adjust the coordinates for the mediabox (and possibly other boxes):

use PDF::API2;

my $pdf = PDF::API2->open('/path/to/file.pdf');

# Choose your margin (72 = one inch)
my $x_offset = 72;
my $y_offset = 0;

foreach my $page_num (1 .. $pdf->pages()) {
    my $page = $pdf->openpage($page_num);

    # Get the coordinates for the page corners
    my ($llx, $lly, $urx, $ury) = $page->get_mediabox();

    # Add the margin by shifting the mediabox in the opposite direction
    $llx -= $x_offset;
    $lly -= $y_offset;
    $urx -= $x_offset;
    $ury -= $y_offset;

    # Store the new coordinates for the page corners
    $page->mediabox($llx, $lly, $urx, $ury);
}

$pdf->saveas('/path/to/new.pdf');

If you run into issues with content getting cut off, you may need to get and set one or more of cropbox , bleedbox , trimbox , and artbox as well, but this should work in most cases.

Answer 3

You can do that also with Ghostscript . I'll give you some example commands for Windows (when using Unix, just replace gswin32c.exe by gs ):

gswin32c.exe ^
   -o input-shifted-pages-1-inch-to-left.pdf ^
   -sDEVICE=pdfwrite ^
   -c "<</PageOffset [-72 0]>> setpagedevice" ^
   -f /path/to/input.pdf

1. -o : specifies the output file. Implicitly also uses -dNOPAUSE -dBATCH -dSAFER .
2. -sDEVICE=... : asks Ghostscript to output PDF.
3. -c <<... : a PostScript code snippet passed on the commandline to make happen the page shift
4. -f ... : specifies the input PDF ( -f is required after using -c ).

The units used by /PageShift are PostScript points. 72 pt == 1 inch. The value [-72 0] shifts 72pt==1in to the left and 0in to top/bottom. Now you know how to shift 2 inches to the right:

gswin32c ^
   -o input-shifted-pages-2-inches-to-right.pdf ^
   -sDEVICE=pdfwrite ^
   -c "<</PageOffset [144 0]>> setpagedevice" ^
   -f /path/to/input.pdf

Wanna shift 0.5 in to the bottom and 1 inch to the right?

gswin32c.exe ^
   -o input-shifted-pages-1-inch-to-right-half-inch-down.pdf ^
   -sDEVICE=pdfwrite ^
   -c "<</PageOffset [72 -36]>> setpagedevice" ^
   -f /path/to/input.pdf