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

I can get both "func" and "points" to create a plot file under Linux, but in Windows the "points" output file is empty while the "func" output file looks right. Uncomment the "func" line and comment the points line. I included the "gnuplot" path for Windows. Here is my test code: 
#!/usr/bin/perl

use warnings;
use Chart::Gnuplot;

my $chart = Chart::Gnuplot->new(
     gnuplot => 'e:\apps\gnuplot\bin\wgnuplot.exe',
     output => 'testfile.gif',
     terminal => "gif transparent",
);

my @xy = (
    [1.1, -3],
    [1.2, -2],
    [3.5, 0]
);

my $dataSet = Chart::Gnuplot::DataSet->new(
    points => \@xy
#    func => "20*sin(x)"
);

$chart->plot2d($dataSet);

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Also, is there a way to find out if gnuplot is complaining about something through Chart::Gnuplot ?

Replies are listed 'Best First'.
Re: Chart::Gnuplot dataset under Windows XP empty GIF
by toolic (Bishop) on Feb 15, 2009 at 02:26 UTC
    is there a way to find out if gnuplot is complaining about something through Chart::Gnuplot ?
    You could make a copy of the source code of Chart::Gnuplot and edit the code to check the return value of the call to system in sub _execute: 
    if (system("$gnuplot $self->{_script}")) {
   die "Error: $gnuplot $self->{_script}: $?"
}

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      Thanks, that brings me a step closer. I am now getting: 
      Error: e:\apps\gnuplot\bin\wgnuplot.exe E:\tmp\xhxbHAg9oN\plot: 256 at
+ C:/strawberry/perl/site/lib/Chart/Gnuplot.pm line 841.

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      I'm not sure what the 256 is yet, but there are many temporary directories and files created and destroyed along the way. I can break the program at various points to see what is happening.

      Note: I used "set TMP=e:\tmp" to override placing the temporary files deep in my docs and settings folder.

      Note: Strawberry perl stores copies of its CPAN modules in three places, using Windows "Find" revealed C:\strawberry\perl\site\lib\Chart\Gnuplot.pm to be the working version.
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        There seems a bug in the block "Data in points" in the subroutine _thaw. Please try to replace the lines 
        my $dirTmp = tempdir(CLEANUP => 1, DIR => '/tmp');
my $fileTmp = "$dirTmp/data";

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        and by the following line 
        my $fileTmp = $self->{_data};

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Re: Chart::Gnuplot dataset under Windows XP empty GIF
by anthonyt (Novice) on Feb 16, 2009 at 15:38 UTC
    The problem turns out to be that the string in the plot file used double quotes around the data file name, like:
        plot "E:\tmp\xxxx\data" title ""

    When I tried that directly in gnuplot, the complaint was: 
        warning: Skipping unreadable file "E:tmpxxxxdata"
    No data in plot

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    For Windows, it appears that single quotes are needed to allow the single slash character \ to go through. I changed the line around 1381 from:
        $string = "\"$fileTmp\"";
    to
        $string = "'$fileTmp'";

    The previous issue of the temp files existing was me not realizing that they all get destroyed on exit, I had to insert a "sleep 30" command in the module after the plot was executed so I could see what the plot and data files looked like before they were removed. Gnuplot errors were not printed to the DOS window.
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