Finding the dimensions of a PostScript image

Andrew — Tue, 08 Sep 2009 16:35:22 +0000

If I have images in .ps or .eps format, how can I tell how big they are? i.e. how big would they print out at ‘natural’ size without any scaling?

If they have a correct bounding box defined — more likely with EPS than PS files — this bit of Perl will show you the width and height in cm:

#!/usr/bin/env perl
 
use strict;
use warnings;
 
# Usage: measure.pl 
# Or send it some data on stdin.
# Assuming the BBox is correct, it'll tell you the 
# dimensions in cm.
 
while( defined ( my $line = <;>; ) )
{
    if( $line =~ /^%%BoundingBox:\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)/ )
    {
        my( $llx, $lly, $urx, $ury ) = ( $1, $2, $3, $4 );
        my $x_pts = $urx - $llx;
        my $y_pts = $ury - $lly;
        my $x_in = $x_pts / 72;
        my $y_in = $y_pts / 72;
        my $x_cm = $x_in * 2.54;
        my $y_cm = $y_in * 2.54;
        printf "%.1f %.1f\n", $x_cm, $y_cm;
        last;
    }
}

Dead handy when preparing images for a paper.

PS if you are hazy about the difference between PS and EPS — like me — have a look at this article.

biotext.org.uk » graphics

Finding the dimensions of a PostScript image