--- loncom/xml/lonplot.pm	2001/12/21 15:27:29	1.13
+++ loncom/xml/lonplot.pm	2001/12/21 16:59:01	1.14
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Dynamic plot
 #
-# $Id: lonplot.pm,v 1.13 2001/12/21 15:27:29 matthew Exp $
+# $Id: lonplot.pm,v 1.14 2001/12/21 16:59:01 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -26,7 +26,7 @@
 # http://www.lon-capa.org/
 #
 # 12/15/01 Matthew
-# 12/18 12/19 12/20 Matthew
+# 12/17 12/18 12/19 12/20 12/21 Matthew
 package Apache::lonplot;
 
 use strict;
@@ -56,9 +56,9 @@ sub BEGIN {
 ##
 ##  @labels: $labels[$i] = \%label
 ##           %label: text, xpos, ypos, justify
-## 
+##
 ##  @curves: $curves[$i] = \%curve
-##        %curve: name, linestyle, ( function | data )
+##           %curve: name, linestyle, ( function | data )
 ##
 ##  $curves[$i]->{'data'} = [ [x1,x2,x3,x4],
 ##                            [y1,y2,y3,y4] ]
@@ -158,13 +158,23 @@ sub end_plot {
 	##
 	## Make sure we have all the input we need:
 	if (! defined(%plot  )) { &set_defaults(\%plot,\%plot_defaults); }
-	if (! defined(%key   )) {} # No key for this plot 
+	if (! defined(%key   )) {} # No key for this plot
 	if (! defined(%axis  )) { &set_defaults(\%axis,\%axis_defaults); }
-	if (! defined($title )) {} # No title for this plot 
-	if (! defined($xlabel)) {} # No xlabel for this plot 
-	if (! defined($ylabel)) {} # No ylabel for this plot 
+	if (! defined($title )) {} # No title for this plot
+	if (! defined($xlabel)) {} # No xlabel for this plot
+	if (! defined($ylabel)) {} # No ylabel for this plot
 	if ($#labels < 0) { } # No labels for this plot
-	if ($#curves < 0) { } # This is an error
+	if ($#curves < 0) { 
+	    &Apache::lonxml::warning("No curves specified for plot!!!!");
+	    return '';
+	}
+	my $curve;
+	foreach $curve (@curves) {
+	    if (!defined($curve->{'function'})&&!defined($curve->{'data'})){
+		&Apache::lonxml::warning("One of the curves specified did not contain any <data> or <function> declarations\n");
+		return '';
+	    }
+	}
 	##
 	## Determine filename
 	my $tmpdir = '/home/httpd/perl/tmp/';
@@ -172,10 +182,8 @@ sub end_plot {
 	    '_'.time.'_'.$$.'_plot.data';
 	## Write the plot description to the file
 	my $fh=Apache::File->new(">$tmpdir$filename");
-	$result .= '<pre>';
-	$result .= $filename.$/;
 	print $fh &write_gnuplot_file();
-	$result .= '</pre>'.$/;
+	close($fh);
 	## return image tag for the plot
 	$result .= <<"ENDIMAGE";
 <img src = "/cgi-bin/plot.gif?$filename"