--- loncom/cgi/graph.png	2003/01/13 17:41:45	1.20
+++ loncom/cgi/graph.png	2003/10/08 15:44:49	1.22
@@ -1,6 +1,6 @@
 #!/usr/bin/perl
 #
-# $Id: graph.png,v 1.20 2003/01/13 17:41:45 minaeibi Exp $
+# $Id: graph.png,v 1.22 2003/10/08 15:44:49 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -25,24 +25,51 @@
 # 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.
 # 
 #### 
 
+=pod
+
+=head1 NAME
+
+graph.png
+
+=head1 SYNOPSIS
+
+produces plots based on input
+
+=head1 DESCRIPTION
+
+graph.png is a cgi-bin script which produces plots based on input data.
+
+The query string is expected to be as follows (without whitespace):
+
+escape(Plot title) & escape(X label)& escape(Y label) & Maximum Y value &
+Number of bars & $data1 & $data2
+
+$data1 and $data2 are expected to be comma seperated lists of numbers.
+escape( value ) means the values must be run through lonnet::escape.
+
+=cut
+
 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);
@@ -67,25 +94,30 @@ if ($Titr =~ /^Percentage$/){
 
 my @data =(\@xlabels,\@data11,\@data12);
 
-my $Range1;
-my $Range2 = 200;
+my $width;
+my $height = 200;
 
 if ($xlab=~/^Concepts$/){
-    $Range1=270;
-} elsif ($xlab=~/^Problem_number$/){
-    $Range1=450;
+    $width=270;
+} elsif ($xlab=~/^Problem\snumber$/){
+    $width=450;
 } else {
-    $Range1=($PNo==100) ? 800 : (120+$PNo*10); 
+    $width=($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 $MyGraph = GD::Graph::bars->new($Range1,$Range2);
+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,
@@ -94,6 +126,7 @@ $MyGraph->set(
 #    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)],