#!/usr/bin/perl
#
# $Id: graph.png,v 1.21 2003/03/26 21:52:37 matthew Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA 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.
#
# LON-CAPA 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 LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/cgi-bin/graph.gif
#
# http://www.lon-capa.org/
#
# The LearningOnline Network with CAPA
# Behrouz Minaei
# YEAR=2001
# 9/13/01, 9/25/01, 10/6/01, 10/9/01, 12/25/01
# YEAR=2002
# 2/1/, 5/13, 5/15
# YEAR=2003
# 1/7/, 1/13
# A CGI script that dynamically outputs a graphical chart for lonstatistics.
# 
#### 

use strict;
use GD::Graph::bars;
use GD::Graph::colour;
use GD::Graph::Data;

sub unescape {
    my $str=shift;
    $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
    return $str;
}

$|=1;   # Autoflush after each print/write
my ($Titr,$xlab,$ylab,$Max,$PNo,$data1,$data2)=split(/&/,$ENV{'QUERY_STRING'});
$Titr = &unescape($Titr);
$xlab = &unescape($xlab);
$ylab = &unescape($ylab);

my @data11=split(/\,/,$data1);
my @data12=split(/\,/,$data2);
my $skip_x = 1;
my $bar_space=10;

my @xlabels;

if ($Titr =~ /^Percentage$/){
    for (my $nIdx=0; $nIdx<$PNo; $nIdx++ ) {
        $xlabels[$nIdx]=$nIdx;
    }
    @data11=();
    @data11=split(/\,/,$data2);
    @data12=();
    $Titr = '';
} else {
     for (my $nIdx=0; $nIdx<$PNo; $nIdx++ ) {
         $xlabels[$nIdx]=$nIdx+1;
     }
} 

my @data =(\@xlabels,\@data11,\@data12);

my $width;
my $height = 200;

if ($xlab=~/^Concepts$/){
    $width=270;
} elsif ($xlab=~/^Problem\snumber$/){
    $width=450;
} else {
    $width=($PNo==100) ? 800 : (120+$PNo*10); 
    $skip_x=5;
    $bar_space=1;
}

my $x_tick_offset = 0;
if ($skip_x > 1) {
    $x_tick_offset = $skip_x - 1;
}

my $MyGraph = GD::Graph::bars->new($width,$height);

$MyGraph->set( 
    x_label         => $xlab,
    y_label         => $ylab,
    x_label_position => 0.5,
    long_ticks      => 1,
    tick_length     => 0,
    x_ticks         => 0,
    title           => $Titr,
    y_max_value     => $Max,
#    y_tick_number   => $ytic,
    y_label_skip    => 5,
    x_label_skip    => $skip_x,   
    x_tick_offset   => $x_tick_offset,

    dclrs           => [ qw( lgreen dgreen lyellow lpurple cyan lorange)],
    
    bar_spacing     => $bar_space,
    cumulate        => 2,
    zero_axis        => 1,

#    legend_placement    => 'RT',

    fgclr               => 'black',
    boxclr              => 'white',
    accentclr           => 'dblue',
    valuesclr           => '#ffff77',
    l_margin            => 10,
    b_margin            => 10,
    r_margin            => 10,
    t_margin            => 10,

    transparent     => 0,
) or warn $MyGraph->error; 


# Tell the server we are sending a png graphic
print <<END;
Content-type: image/png

END

my $BinaryData=$MyGraph->plot(\@data)->png;
undef $MyGraph;
binmode(STDOUT);
#open IMG,"|pngtopnm|ppmtogif 2>/dev/null"; # convert into a gif image
#print IMG $BinaryData; # output image
#$|=1; # be sure to flush before closing
#close IMG;
print $BinaryData;