--- loncom/xml/lonplot.pm	2004/05/26 19:44:20	1.96
+++ loncom/xml/lonplot.pm	2004/08/30 15:23:23	1.101
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Dynamic plot
 #
-# $Id: lonplot.pm,v 1.96 2004/05/26 19:44:20 matthew Exp $
+# $Id: lonplot.pm,v 1.101 2004/08/30 15:23:23 matthew Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -36,8 +36,17 @@ use Apache::response;
 use Apache::lonxml;
 use Apache::edit;
 
+use vars qw/$weboutputformat $versionstring/;
+
 BEGIN {
-  &Apache::lonxml::register('Apache::lonplot',('gnuplot'));
+    &Apache::lonxml::register('Apache::lonplot',('gnuplot'));
+    #
+    # Determine the version of GNUPLOT
+    $weboutputformat = 'gif';
+    $versionstring = `gnuplot --version 2>/dev/null`;
+    if ($versionstring =~ /^gnuplot 4/) {
+        $weboutputformat = 'png';
+    }
 }
 
 ## 
@@ -110,7 +119,11 @@ my $words_test     = sub {$_[0]=~s/\s+/
 ###################################################################
 my @gnuplot_edit_order = 
     qw/alttag bgcolor fgcolor height width font transparent grid samples 
-    border align texwidth texfont plottype/;
+    border align texwidth texfont plottype lmargin rmargin tmargin bmargin 
+    major_ticscale minor_ticscale/;
+
+my $margin_choices = ['default',
+                      qw{0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20}];
 
 my %gnuplot_defaults = 
     (
@@ -209,6 +222,48 @@ my %gnuplot_defaults =
 	 edit_type   => 'choice',
          choices     => ['Cartesian','Polar']
          },
+     lmargin   => {
+	 default     => 'default',
+	 test        => sub {$_[0]=~/^(default|\d+)$/},
+	 description => 'Left margin width (pts):',
+	 edit_type   => 'choice',
+         choices     => $margin_choices,
+         },
+     rmargin   => {
+	 default     => 'default',
+	 test        => sub {$_[0]=~/^(default|\d+)$/},
+	 description => 'Right margin width (pts):',
+	 edit_type   => 'choice',
+         choices     => $margin_choices,
+         },
+     tmargin   => {
+	 default     => 'default',
+	 test        => sub {$_[0]=~/^(default|\d+)$/},
+	 description => 'Top margin width (pts):',
+	 edit_type   => 'choice',
+         choices     => $margin_choices,
+         },
+     bmargin   => {
+	 default     => 'default',
+	 test        => sub {$_[0]=~/^(default|\d+)$/},
+	 description => 'Bottm margin width (pts):',
+	 edit_type   => 'choice',
+         choices     => $margin_choices,
+         },
+     major_ticscale  => {
+         default     => '1',
+         test        => $real_test,
+         description => 'Size of major tic marks (plot coordinates)',
+         edit_type   => 'entry',
+         size        => '5'
+         },
+     minor_ticscale  => {
+         default     => '0.5',
+         test        => $real_test,
+         description => 'Size of minor tic mark (plot coordinates)',
+         edit_type   => 'entry',
+         size        => '5'
+         },
      );
 
 my %key_defaults = 
@@ -302,7 +357,7 @@ my %tic_defaults =
      minorfreq => {
 	 default => '0',
 	 test => $int_test,
-	 description => 'Number of minor tics between major tic marks',
+	 description => 'Number of minor tics per major tic mark',
 	 edit_type   => 'entry',
 	 size        => '10'
 	 },         
@@ -460,7 +515,7 @@ sub end_gnuplot {
 	## return image tag for the plot
 	if ($target eq 'web') {
 	    $result .= <<"ENDIMAGE";
-<img src    = "/cgi-bin/plot.gif?file=$filename.data&output=gif" 
+<img src    = "/cgi-bin/plot.gif?file=$filename.data&output=$weboutputformat" 
      width  = "$plot{'width'}"
      height = "$plot{'height'}"
      align  = "$plot{'align'}"
@@ -945,6 +1000,24 @@ sub write_gnuplot_file {
     my $gnuplot_input = '';
     my $curve;
     my $pt = $plot{'texfont'};
+    #
+    # Check to be sure we do not have any empty curves
+    my @curvescopy;
+    foreach my $curve (@curves) {
+        if (exists($curve->{'function'})) {
+            if ($curve->{'function'} !~ /^\s*$/) {
+                push(@curvescopy,$curve);
+            }
+        } elsif (exists($curve->{'data'})) {
+            foreach my $data (@{$curve->{'data'}}) {
+                if (scalar(@$data) > 0) {
+                    push(@curvescopy,$curve);
+                    last;
+                }
+            }
+        }
+    }
+    @curves = @curvescopy;
     # Collect all the colors
     my @Colors;
     push @Colors, $plot{'bgcolor'};
@@ -975,6 +1048,22 @@ sub write_gnuplot_file {
     } else {
         # Assume Cartesian
     }
+    # margin
+    if (lc($plot{'lmargin'}) ne 'default') {
+        $gnuplot_input .= 'set lmargin '.$plot{'lmargin'}.$/;
+    }
+    if (lc($plot{'rmargin'}) ne 'default') {
+        $gnuplot_input .= 'set rmargin '.$plot{'rmargin'}.$/;
+    }
+    if (lc($plot{'tmargin'}) ne 'default') {
+        $gnuplot_input .= 'set tmargin '.$plot{'tmargin'}.$/;
+    }
+    if (lc($plot{'bmargin'}) ne 'default') {
+        $gnuplot_input .= 'set bmargin '.$plot{'bmargin'}.$/;
+    }
+    # tic scales
+    $gnuplot_input .= 'set ticscale '.
+        $plot{'major_ticscale'}.' '.$plot{'minor_ticscale'}.$/;
     # grid
     $gnuplot_input .= 'set grid'.$/ if ($plot{'grid'} eq 'on');
     # border