#! /usr/bin/perl

#
# scpi-screen-grab
#
# Copyright (c) 2015 Martin Oldfield <bench-tools@mjoldfield.com>
#

use strict;
use warnings;

package MSO;

use base qw(IO::Socket::INET);

sub new
  {
    my ($c, @args) = @_;
    return $c->SUPER::new(PeerPort => 5025, @args);
  }

sub get_ieee_binary_block
  {
    my $io = shift;
    
    # We get an IEEE block in response. See e.g.
    # http://na.support.keysight.com/pna/help/latest/Programming/Learning_about_GPIB/Getting_Data_from_the_Analyzer.htm#block
    my $header;
    read($io, $header, 2);
  
    # length of length
    my ($m) = ($header =~ /^#(\d)$/)
	or die "Unable to parse header A: $header, ";

    # length of data
    read($io, $header, $m);
    my ($n) = ($header =~ /^(\d+)$/)
	or die "Unable to parse header B: $header, ";

    # data
    my $data;
    read($io, $data, $n);

    # end-of-line
    $io->getline;

    return $data;
  }
  
package main;

use Pod::Usage;
use Getopt::Long;

my %Opt;
GetOptions(\%Opt, "help!", "info!");
  
pod2usage(-verbose => 2)
    if $Opt{help} || $Opt{info};

my $addr = shift || 'mso.local';
my $file = shift || 'mso.png';

my $mso = MSO->new(PeerAddr => $addr)
  or die "Unable to open MSO connection, ";

$mso->print("*IDN?\n");
print "Connected to:\n", $mso->getline;

$mso->print("DISP:DATA?\n");
my $data = $mso->get_ieee_binary_block;
    
open(my $fh, '>', $file);
print {$fh} $data;

__END__
  
=head1 NAME
 
scpi-screen-grab - Grab the screen from an SCPI device
 
=head1 USAGE

    $ scpi-screen-grab mso.local mso.png

    $ scpi-screen-grab mso.local

    $ scpi-screen-grab

    
=head1 DESCRIPTION

Grab the screen from a network attached device
using the DISP:DATA? SCPI command

It has been tested with the Agilent MSO-X 3034A scope
but might work more generally

=head1 OPTIONS

You can specify two positional arguments: address and filename.

Named arguments also exist:

=over

=item --help, --info

Display this page.

=back

=head1 DEPENDENCIES

None for the core code, C<Pod::Usage> and C<Getopt::Long> for
the the friendly fluff.

=head1 ACKNOWLEDGEMENTS

The 3000 X-Series programming guide explained what needed to be
done. You can get that from 
L<http://www.keysight.com/upload/cmc_upload/All/3000_series_prog_guide.pdf>

Key features:

=over

=item Reading Definite-Length Block Query Response Data

Shows how the binary image data are returned.

=item :DISPlay:DATA

Shows how to request the image.

=item *IDN (Identification Number)

Shows how to identify the instrument.

=item Telnet Sockets

Describes the network interface.

=back
 
=head1 BUGS AND LIMITATIONS

This program is a quick hack: do not rely on it for critical
appliations.

Please report problems to the author.

Patches are welcome.

=head1 WEBSITE

Available from GitHub L<https://github.com/mjoldfield/bench-tools>
 
=head1 AUTHOR

M J Oldfield, bench-tools@mjoldfied.com

=head1 LICENCE AND COPYRIGHT
 
Copyright (c) 2015, M J Oldfield
 
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.