--- loncom/xml/lonplot.pm	2013/01/21 02:25:38	1.171
+++ loncom/xml/lonplot.pm	2016/01/22 22:30:07	1.176
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Dynamic plot
 #
-# $Id: lonplot.pm,v 1.171 2013/01/21 02:25:38 raeburn Exp $
+# $Id: lonplot.pm,v 1.176 2016/01/22 22:30:07 damieng Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -78,7 +78,7 @@ BEGIN {
 ##  align
 ##
 ##  @labels: $labels[$i] = \%label
-##           %label: text, xpos, ypos, justify
+##           %label: text, xpos, ypos, justify, rotate, zlayer
 ##
 ##  @curves: $curves[$i] = \%curve
 ##           %curve: name, linestyle, ( function | data )
@@ -105,7 +105,7 @@ my %linetypes =			# For png use these li
     );
 my %ps_linetypes = 		# For ps the line types are different!
    (
-    solid          => 0,
+    solid          => 1,
     dashed         => 7
    );
 
@@ -258,7 +258,7 @@ my %gnuplot_defaults =
 	 test        => sub {$_[0]=~/^(left|right|middle|center)$/},
 	 description => 'Alignment for image in HTML',
 	 edit_type   => 'choice',
-	 choices     => ['left','right','middle']
+	 choices     => ['left','right','middle','center']
 	 },
      texwidth     => {
          default     => '93',
@@ -421,7 +421,14 @@ my %label_defaults =
          description => 'Rotation of label (degrees)',
          edit_type   => 'entry',
          size        => '10',
-     }
+     },
+     zlayer => {
+         default => '',
+         test => sub {$_[0]=~/^(front|back)$/},
+         description => 'Z position of label',
+         edit_type   => 'choice',
+         choices     => ['front','back'], 
+     },
      );
 
 my @tic_edit_order = ('location','mirror','start','increment','end',
@@ -732,13 +739,19 @@ sub end_gnuplot {
 	$filename = &escape($filename);
 	## return image tag for the plot
 	if ($target eq 'web') {
-	    $result .= <<"ENDIMAGE";
-<img src    = "/cgi-bin/plot.$weboutputformat?file=$filename.data" 
-     width  = "$Apache::lonplot::plot{'width'}"
-     height = "$Apache::lonplot::plot{'height'}"
-     align  = "$Apache::lonplot::plot{'align'}"
-     alt    = "$Apache::lonplot::plot{'alttag'}" />
-ENDIMAGE
+            my $srcatt = "src=\"/cgi-bin/plot.$weboutputformat?file=$filename.data\"";
+            my $widthatt = "width=\"$Apache::lonplot::plot{'width'}\"";
+            my $heightatt = "height=\"$Apache::lonplot::plot{'height'}\"";
+            my $alignatt = "align=\"$Apache::lonplot::plot{'align'}\"";
+            my $altatt = "alt=\"$Apache::lonplot::plot{'alttag'}\"";
+            if ($Apache::lonplot::plot{'align'} eq 'center') {
+                $result .= '<div style="text-align:center">'.
+                    "<img $srcatt $widthatt $heightatt $altatt>".
+                    "</div>\n";
+
+            } else {
+              $result .= "<img $srcatt $widthatt $heightatt $alignatt $altatt>";
+            }
         } elsif ($target eq 'tex') {
 	    &Apache::lonxml::debug(" gnuplot wid = $Apache::lonplot::plot{'width'}");
 	    &Apache::lonxml::debug(" gnuplot ht  = $Apache::lonplot::plot{'height'}");
@@ -746,7 +759,13 @@ ENDIMAGE
 	    &Apache::lonxml::register_ssi("/cgi-bin/plot.gif?file=$filename.data&output=eps");
 	    $result  = "%DYNAMICIMAGE:$Apache::lonplot::plot{'width'}:$Apache::lonplot::plot{'height'}:$Apache::lonplot::plot{'texwidth'}\n";
 	    $result .= '\graphicspath{{'.$tmpdir.'}}'."\n";
+            if ($Apache::lonplot::plot{'align'} eq 'center') {
+                $result .= '\begin{center}';
+            }
 	    $result .= '\includegraphics[width='.$Apache::lonplot::plot{'texwidth'}.' mm]{'.&unescape($filename).'.eps}';
+            if ($Apache::lonplot::plot{'align'} eq 'center') {
+                $result .= '\end{center}';
+            }
 	}
     } elsif ($target eq 'edit') {
 	$result.=&Apache::edit::tag_end($target,$token);
@@ -1714,7 +1733,7 @@ sub generate_tics {
     my $result   = '';
 
 
-    if (defined %$spec) {
+    if ((ref($spec) eq 'HASH') && (keys(%{$spec}) > 0)) {
 
 	
 
@@ -1967,7 +1986,10 @@ sub write_gnuplot_file {
         $gnuplot_input .= ' '.$label->{'justify'};
 
         if ($target eq 'tex') {
-	    $gnuplot_input .=' font "'.$font_properties->{'printname'}.','.$fontsize.'pt"' ;
+	    $gnuplot_input .=' font "'.$font_properties->{'printname'}.','.$fontsize.'pt"';
+        }
+        if (($label->{'zlayer'} eq 'front') || ($label->{'zlayer'} eq 'back')) {
+            $gnuplot_input .= ' '.$label->{'zlayer'};
         }
         $gnuplot_input .= $/;
     }
@@ -1984,7 +2006,7 @@ sub write_gnuplot_file {
     #
     my $linestyle_index = 50;
     my $line_width   = '';
-    my $plots;
+    my $plots = '';
 
     # If arrows are needed there will be an arrow style for each as well:
     #
@@ -1993,8 +2015,11 @@ sub write_gnuplot_file {
 
     for (my $i = 0;$i<=$#curves;$i++) {
 	$curve = $curves[$i];
-	my $plot_command;
-	my $plot_type = ', ' if ($i > 0);
+	my $plot_command = '';
+	my $plot_type = '';
+	if ($i > 0) {
+	    $plot_type = ', ';
+	}
 	if ($target eq 'tex') {
 	    $curve->{'linewidth'} *= 2;
 	}