gd::graph returns unicode

lutus65 has asked for the wisdom of the Perl Monks concerning the following question:

New to GD:Graph. I have tried several examples from site to test module. All result in some unicode string. What is my problem? Thanks

#!/usr/bin/perl -w
use 5.010;
use strict;
use warnings;
use GD::Graph::bars;

print"Hello world!\n";

my @data =([1,2,3,4],[5,3,8,9]);
my $graph = GD::Graph::bars->new(400,300);
$graph->set(
    x_label     => 'X num',
    y_label     => 'Y num',
    title       => 'Test',
) or warn $graph->error;

my $myimage = $graph->plot(\@data) or die $graph->error;

print "Content-type: image/png\n\n";
print $myimage->png;
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Re: gd::graph returns unicode by kennethk (Abbot) on Jul 09, 2013 at 16:51 UTC
Since you are printing binary image data, you should be setting binmode: `binmode STDOUT; print $myimage->png;` [download] Also, if you are writing a web service, I'd suggest using CGI rather than rolling your own headers. See Ovid's CGI Course - Resurrected and Updated! for a tutorial. #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply] [d/l]
Re^2: gd::graph returns unicode by lutus65 (Initiate) on Jul 09, 2013 at 17:05 UTC
Thanks. works.	[reply]
Re: gd::graph returns unicode by Khen1950fx (Canon) on Jul 09, 2013 at 19:43 UTC
According to the author, the use of `@data` is legacy code. I rewrote it to reflect the newer usage. Note that the usual way to print is... `open(IMG, '>test.png'); binmode IMG; print IMG $gd->png;` [download] The full script: `#!/usr/bin/perl -l use strict; use warnings; use GD::Graph::bars; use GD::Graph::Data; print "Hello world!\n"; my $data = GD::Graph::Data->new([ [1,2,3,4], [5,3,8,9], ]) or die $!; my $graph = GD::Graph::bars->new(); $graph->set( x_label => 'X num', y_label => 'Y num', title => 'Test', ) or die $graph->error; my $gd = $graph->plot($data) or die $!; open(IMG, '>test.png'); binmode IMG; print IMG $gd->png;` [download]	[reply] [d/l] [select]