#!/usr/bin/perl
use warnings;
use strict;
use Tk;
use Tk::ROText;
use IPC::Open3;

$|++;

my $mw = MainWindow->new;
my $canvas = $mw->Canvas(
                  -bg => 'white',
		  -height =>400,
		  -width =>500,
		  )->pack();


my $button = $mw -> Button(-text => "Quit", 
		-command => \&quit)->pack(-side=>'left');
	                  		  

my $text = $mw->ROText(-bg=>'white')
     ->pack( -fill => 'both', -expand => 1 );

$text->tagConfigure( 'red', -foreground => 'red' );

my $pid = open3( \*IN, \*OUT, \*ERR, "c:/gnuplot/bin/gnuplot.exe" ) || die;
$mw->fileevent( \*OUT, readable => \&read_out );
$mw->fileevent( \*ERR, readable => \&read_err );

print IN "set term tkcanvas perltk interactive\n";
print IN "set output \'plot.pl\'\n";
#print IN "a=1\n";
#print IN "plot a\n";
#print IN "plot sin(x)/x\n";
#print IN "splot sin(x*y/20)\n";
print IN "plot sin(x) title 'Sine Function', tan(x) title 'Tangent'\n";
my $gnuplot = do "plot.pl";

$gnuplot->($canvas);

MainLoop;

sub read_out {
}

sub read_err {
    print "read_err()\n";
    my $num = sysread(ERR, my $buffer, 1024 );
    $text->insert( 'end', $buffer, 'red' );
}

sub quit{close $pid; exit}

##</code><code>##

open PROC, "| c:/gnuplot/bin/gnuplot.exe" || die "Could not start gnuplot: $!";
#above :the first character in the filename is a pipe symbol (|)
print PROC "set xlabel 'Time'; set ylabel 'Amplitude';";
print PROC "set o 'graph.png';";
print PROC "set t png;";
print PROC "plot '-' u 1:2 t 'data' w l\n";
for( $x = 0.0; $x <= 10.0; $x += 0.1 ) {
$y = exp(-$x/5)*sin( $x );
print PROC "$x $y\n";
}
print PROC "e\n";
close PROC;