#!/usr/local/bin/perl
#
# Simple Plot Demo program
#
# This plots a data file consisting of columns of X-Y coordinates
# You can vary the color of the line and the style of the markers
# 
# Larry Gales, 04-14-1999
#
require 'cgi-lib.pl';
&ReadParse(*in);

$gnuplot = "/usr/local/bin/gnuplot";

$color = $in{'color'};
SWITCH: {
   if ($color =~ "red")   {$color = 1; last SWITCH;}
   if ($color =~ "blue")  {$color = 3; last SWITCH;}
   if ($color =~ "green") {$color = 2; last SWITCH;}
   $color = 1;
}

$marker = $in{'marker'};
SWITCH: {
   if ($marker =~ "square")   {$mark1 = 0; $mark2 = 4; last SWITCH;}
   if ($marker =~ "circle")   {$mark1 = 0; $mark2 = 6; last SWITCH;}   
   if ($marker =~ "triangle") {$mark1 = 0; $mark2 = 8; last SWITCH;}   
   $mark1 = 3; $mark2 = 6;
}  
$fname = $in{'datafile'};

if (! open(FILE,"<" . $fname )) {
   &file_Error( 500, " File Access Error, Cannot open file: $fname!");
} else {
  &run_gnuplot();
  &convert_ps_to_jpg();
}

# Create PS Gnuplot file ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
sub run_gnuplot
{
  open (GNUPLOT, "|$gnuplot");
  print GNUPLOT <<GnuPlotCommands;

  set xrange [-20:130]                 # X-axis ranges from -20 to 130
  set title "Line Plot w/ Markers"     # Specify a title
  set terminal postscript portrait color 'Courier' 22
  set key 120,-5                       # Locate the legend at (120,-5)
  set grid                             # Overlay a grid
  set xlabel "Here Is My X-axis"
  set ylabel "Here Is My Y-axis"
  set xtics 20,40,100                  # Set tic marks every 40 units
  set output "my.ps"
    # Now plot data in -xy.dat- with line color 4 and markers
  plot "$fname" with line $color, "$fname" with points $mark1 $mark2
  quit
GnuPlotCommands
  close(GNUPLOT);
} # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv


# Convert the PS to JPEG ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
sub convert_ps_to_jpg
{
  $| = 1;
  print "Content-type: image/jpeg", "\n\n";
  $cmmd="gs -sDEVICE=jpeg -sOutputFile=- -q my.ps ";
  $cmmd = $cmmd . " 2>/dev/null";        
  system($cmmd);
} # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv


# Object if a file is not there ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
sub file_Error
{
  local ($errorN, $errorMsg) = @_;
  print "Content-type: text/html", "\n\n";
  print "ERROR: $errorN $errorMsg \n";
} # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv