--- loncom/xml/lonplot.pm	2012/07/17 10:49:53	1.162
+++ loncom/xml/lonplot.pm	2012/07/24 10:50:54	1.163
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Dynamic plot
 #
-# $Id: lonplot.pm,v 1.162 2012/07/17 10:49:53 foxr Exp $
+# $Id: lonplot.pm,v 1.163 2012/07/24 10:50:54 foxr Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -537,6 +537,7 @@ my %axis_defaults =
      	},
      );
 
+
 my @curve_edit_order = ('color','name','linestyle','linewidth','linetype',
 			'pointtype','pointsize','limit', 'arrowhead', 'arrowstyle', 
 			'arrowlength', 'arrowangle', 'arrowbackangle'
@@ -649,6 +650,8 @@ my %curve_defaults =
 undef %Apache::lonplot::plot;
 my (%key,%axis,$title,$xlabel,$ylabel,@labels,@curves,%xtics,%ytics);
 
+my $current_tics;		# Reference to the current tick hash
+
 sub start_gnuplot {
     undef(%Apache::lonplot::plot);   undef(%key);    undef(%axis);
     undef($title);  undef($xlabel); undef($ylabel);
@@ -748,6 +751,8 @@ sub start_xtics {
     if ($target eq 'web' || $target eq 'tex') {
 	&get_attributes(\%xtics,\%tic_defaults,$parstack,$safeeval,
 		    $tagstack->[-1]);
+	$current_tics = \%xtics;
+	&Apache::lonxml::register('Apache::lonplot', 'tic');
     } elsif ($target eq 'edit') {
 	$result .= &Apache::edit::tag_start($target,$token,'xtics');
 	$result .= &edit_attributes($target,$token,\%tic_defaults,
@@ -766,6 +771,7 @@ sub end_xtics {
     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
     my $result = '';
     if ($target eq 'web' || $target eq 'tex') {
+	&Apache::lonxml::deregister('Apache::lonplot', 'tic');
     } elsif ($target eq 'edit') {
 	$result.=&Apache::edit::tag_end($target,$token);
     }
@@ -779,6 +785,8 @@ sub start_ytics {
     if ($target eq 'web' || $target eq 'tex') {
 	&get_attributes(\%ytics,\%tic_defaults,$parstack,$safeeval,
 		    $tagstack->[-1]);
+	$current_tics = \%ytics;
+	&Apache::lonxml::register('Apache::lonplot', 'tic');
     } elsif ($target eq 'edit') {
 	$result .= &Apache::edit::tag_start($target,$token,'ytics');
 	$result .= &edit_attributes($target,$token,\%tic_defaults,
@@ -797,12 +805,55 @@ sub end_ytics {
     my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
     my $result = '';
     if ($target eq 'web' || $target eq 'tex') {
+	&Apache::lonxml::deregister('Apache::lonplot', 'tic');
     } elsif ($target eq 'edit') {
 	$result.=&Apache::edit::tag_end($target,$token);
     }
     return $result;
 }
 
+
+##----------------------------------------------------------------
+#
+#  Tic handling:
+#   The <tic> tag allows users to specify exact Tic positions and labels
+#   for each axis.  In this version we only support level 0 tics (major tic).
+#   Each tic has associated with it a position and a label
+#   $current_tics is a reference to the current tick description hash.
+#   We add elements to an array  in that has: ticspecs whose elements
+#   are 'pos' - the tick position and 'label' - the tic label.
+#
+
+
+sub start_tic {
+    my ($target, $token, $tagstack, $parstack, $parser, $safeeval, $style)  = @_;
+
+    my $result = '';
+    if ($target eq 'web' || $target eq 'tex') {
+	my $tic_location = &Apache::lonxml::get_param('location', $parstack, $safeeval);
+	my $tic_label    = &Apache::lonxml::get_all_text('/tic', $parser);
+
+	# Tic location must e a real:
+
+	if (!&$real_test($tic_location)) {
+	    &Apache::lonxml::warning("Tic location: $tic_location must be a real number");
+	} else {
+
+	    if (!defined  $current_tics->{'ticspecs'}) {
+		$current_tics->{'ticspecs'} = [];
+	    }
+	    my $ticspecs = $current_tics->{'ticspecs'};
+	    push (@$ticspecs, {'pos' => $tic_location, 'label' => $tic_label});
+	}
+    }
+
+    return $result;
+}
+
+sub end_tic {
+    return '';
+}
+
 ##-----------------------------------------------------------------font
 my %font_properties =
     (
@@ -1457,6 +1508,8 @@ sub start_function {
 						     $style);
 	$function = &Apache::run::evaluate($function,$safeeval,$$parstack[-1]);
         $function=~s/\^/\*\*/gs;
+	$function=~ s/^\s+//;	# Trim leading
+	$function=~ s/\s+$//;   # And trailing whitespace.
 	$curves[-1]->{'function'} = $function; 
     } elsif ($target eq 'edit') {
 	$result .= &Apache::edit::tag_start($target,$token,'Gnuplot compatible curve function');
@@ -1652,30 +1705,44 @@ sub generate_tics {
 
     if (defined %$spec) {
 
+	
 
+	# Major tics: - If there are 'ticspecs' these override any other
+	#               specifications:
 
-	# Major tics:
-
+	
+	
 	$result .= "set $type $spec->{'location'}  ";
 	$result .= ($spec->{'mirror'} eq 'on') ? 'mirror ' : 'nomirror ';
-	$result .= "$spec->{'start'}, ";
-	$result .= "$spec->{'increment'}, ";
-	$result .= "$spec->{'end'} ";
+	if (defined $spec->{'ticspecs'}) {
+	    $result .= '( ';
+	    my @ticspecs;
+	    my $ticinfo = $spec->{'ticspecs'};
+	    foreach my $tic (@$ticinfo) {
+		push(@ticspecs,  '"' . $tic->{'label'} . '" ' . $tic->{'pos'} );
+	    }
+	    $result .= join(', ', (@ticspecs));
+	    $result .= ' )';
+	} else {
+	    $result .= "$spec->{'start'}, ";
+	    $result .= "$spec->{'increment'}, ";
+	    $result .= "$spec->{'end'} ";
+	}
 	if ($target eq 'tex' ) {
 	    $result .= 'font "Helvetica,22"';
 	}
 	$result .= "\n";
-
+	
 	# minor frequency:
-
+	
 	if ($spec->{'minorfreq'} != 0) {
 	    $result .= "set m$type $spec->{'minorfreq'}\n";
 	}
     } else {
 	$result .= "set $type font " . '"Helvetica,22"' ."\n";
     }
-
-
+    
+    
     return $result;
 }
 
@@ -2014,7 +2081,7 @@ sub write_gnuplot_file {
 	$linestyle_index++;	# Each curve get a unique linestyle.
     }
     # Write the output to a file.
-    &Apache::lonnet::logthis($gnuplot_input);
+    # &Apache::lonnet::logthis($gnuplot_input); # uncomment to log the gnuplot input.
     open (my $fh, "> $tmpdir$filename.data");
     binmode($fh, ':utf8');
     print $fh $gnuplot_input;