# The LearningOnline Network with CAPA
# Dynamic plot
#
# $Id: lonplot.pm,v 1.131 2007/10/09 22:11:51 albertel Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#

package Apache::lonplot;

use strict;
use warnings FATAL=>'all';
no warnings 'uninitialized';
use Apache::File;
use Apache::response;
use Apache::lonxml;
use Apache::edit;
use Apache::lonnet;
use LONCAPA;
 

use vars qw/$weboutputformat $version/;



BEGIN {
    &Apache::lonxml::register('Apache::lonplot',('gnuplot'));
    #
    # Determine the version of GNUPLOT
    $weboutputformat = 'gif';
    my $versionstring = `gnuplot --version 2>/dev/null`;
    ($version) = ($versionstring =~ /^gnuplot ([\d.]+)/);
    if ($version >= 4) {
        $weboutputformat = 'png';
    }
    
}


## 
## Description of data structures:
##
##  %plot       %key    %axis
## --------------------------
##  height      title   color
##  width       box     xmin
##  bgcolor     pos     xmax
##  fgcolor             ymin
##  transparent         ymax
##  grid
##  border
##  font
##  align
##
##  @labels: $labels[$i] = \%label
##           %label: text, xpos, ypos, justify
##
##  @curves: $curves[$i] = \%curve
##           %curve: name, linestyle, ( function | data )
##
##  $curves[$i]->{'data'} = [ [x1,x2,x3,x4],
##                            [y1,y2,y3,y4] ]
##

###################################################################
##                                                               ##
##        Tests used in checking the validitity of input         ##
##                                                               ##
###################################################################

my $max_str_len = 50;    # if a label, title, xlabel, or ylabel text
                         # is longer than this, it will be truncated.

my %linestyles = 
    (
     lines          => 2,     # Maybe this will be used in the future
     linespoints    => 2,     # to check on whether or not they have 
     dots	    => 2,     # supplied enough <data></data> fields
     points         => 2,     # to use the given line style.  But for
     steps	    => 2,     # now there are more important things 
     fsteps	    => 2,     # for me to deal with.
     histeps        => 2,
     errorbars	    => 3,
     xerrorbars	    => [3,4],
     yerrorbars	    => [3,4],
     xyerrorbars    => [4,6],
     boxes          => 3,
     filledcurves   => 2,
     vector	    => 4
    );		    

my $int_test       = sub {$_[0]=~s/\s+//g;$_[0]=~/^\d+$/};
my $real_test      = 
    sub {$_[0]=~s/\s+//g;$_[0]=~/^[+-]?\d*\.?\d*([eE][+-]\d+)?$/};
my $pos_real_test  =
    sub {$_[0]=~s/\s+//g;$_[0]=~/^[+]?\d*\.?\d*([eE][+-]\d+)?$/};
my $color_test     = sub {$_[0]=~s/\s+//g;$_[0]=~/^x[\da-fA-F]{6}$/};
my $onoff_test     = sub {$_[0]=~/^(on|off)$/};
my $key_pos_test   = sub {$_[0]=~/^(top|bottom|right|left|outside|below| )+$/};
my $sml_test       = sub {$_[0]=~/^(\d+|small|medium|large)$/};
my $linestyle_test = sub {exists($linestyles{$_[0]})};
my $words_test     = sub {$_[0]=~s/\s+/ /g;$_[0]=~/^([\w~!\@\#\$\%^&\*\(\)-=_\+\[\]\{\}:\;\'<>,\.\/\?\\]+ ?)+$/};

###################################################################
##                                                               ##
##                      Attribute metadata                       ##
##                                                               ##
###################################################################
my @gnuplot_edit_order = 
    qw/alttag bgcolor fgcolor height width texwidth fontface font texfont
    transparent grid samples 
    border align plotcolor plottype gridtype lmargin rmargin
    tmargin bmargin major_ticscale minor_ticscale boxwidth gridlayer fillstyle
    pattern solid/;

my $margin_choices = ['default',0..20];

my %gnuplot_defaults = 
    (
     alttag       => {
	 default     => 'dynamically generated plot',
	 test        => $words_test,
	 description => 'Brief description of the plot',
      	 edit_type   => 'entry',
	 size        => '40'
	 },
     height       => {
	 default     => 300,
	 test        => $int_test,
	 description => 'Height of image (pixels)',
      	 edit_type   => 'entry',
	 size        => '10'
	 },
     width        => {
	 default     => 400,
	 test        => $int_test,
	 description => 'Width of image (pixels)',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     bgcolor      => {
	 default     => 'xffffff',
	 test        => $color_test, 
	 description => 'Background color of image (xffffff)',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     fgcolor      => {
	 default     => 'x000000',
	 test        => $color_test,
	 description => 'Foreground color of image (x000000)',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     transparent  => {
	 default     => 'off',
	 test        => $onoff_test, 
	 description => 'Transparent image',
	 edit_type   => 'onoff'
	 },
     grid         => {
	 default     => 'on',
	 test        => $onoff_test, 
	 description => 'Display grid',
	 edit_type   => 'onoff'
	 },
     gridlayer    => {
	 default     => 'off',
	 test        => $onoff_test, 
	 description => 'Display grid front layer over filled boxes or filled curves',
	 edit_type   => 'onoff'
	 },
     box_border   => {
	 default     => 'noborder',
	 test        => sub {$_[0]=~/^(noborder|border)$/},
	 description => 'Draw border for boxes',
	 edit_type   => 'choice',
	 choices     => ['border','noborder']
	 },
     border       => {
	 default     => 'on',
	 test        => $onoff_test, 
	 description => 'Draw border around plot',
	 edit_type   => 'onoff'
	 },
     font         => {
	 default     => '9',
	 test        => $sml_test,
	 description => 'Font size to use in web output (pts)',
	 edit_type   => 'choice',
	 choices     => [['5','5 (small)'],'6','7','8',['9','9 (medium)'],'10',['11','11 (large)'],'12','15']
	 },
     fontface     => {
        default     => 'sans-serif',
        test        => sub {$_[0]=~/^(sans-serif|serif|classic)$/},
        description => 'Type of font to use',
        edit_type   => 'choice',
        choices     => ['sans-serif','serif', 'classic']
        },
     samples      => {
	 default     => '100',
	 test        => $int_test,
	 description => 'Number of samples for non-data plots',
	 edit_type   => 'choice',
	 choices     => ['100','200','500','1000','2000','5000']
	 },
     align        => {
	 default     => 'middle',
	 test        => sub {$_[0]=~/^(left|right|middle|center)$/},
	 description => 'Alignment for image in HTML',
	 edit_type   => 'choice',
	 choices     => ['left','right','middle']
	 },
     texwidth     => {
         default     => '93',
         test        => $int_test,
         description => 'Width of plot when printed (mm)',
         edit_type   => 'entry',
         size        => '5'
         },
     texfont      => {
         default     => '22',
         test        => $int_test,
         description => 'Font size to use in TeX output (pts):',
         edit_type   => 'choice',
         choices     => [qw/8 10 12 14 16 18 20 22 24 26 28 30 32 34 36/],
         },
     plotcolor    => {
         default     => 'monochrome',
         test        => sub {$_[0]=~/^(monochrome|color|colour)$/},
         description => 'Color setting for printing:',
         edit_type   => 'choice',
         choices     => [qw/monochrome color colour/],
         },
     pattern      => {
	 default     => '',
	 test        => $int_test,
	 description => 'Pattern value for boxes:',
	 edit_type   => 'choice',
         choices     => [0,1,2,3,4,5,6]
         },
     solid        => {
         default     => 0,
         test        => $real_test,
         description => 'The density of fill style for boxes',
         edit_type   => 'entry',
         size        => '5'
         },
     fillstyle    => {
	 default     => 'empty',
	 test        => sub {$_[0]=~/^(empty|solid|pattern)$/},
	 description => 'Filled style for boxes:',
	 edit_type   => 'choice',
         choices     => ['empty','solid','pattern']
         },
     plottype     => {
	 default     => 'Cartesian',
	 test        => sub {$_[0]=~/^(Polar|Cartesian)$/},
	 description => 'Plot type:',
	 edit_type   => 'choice',
         choices     => ['Cartesian','Polar']
         },
     gridtype     => {
	 default     => 'Cartesian',
	 test        => sub {$_[0]=~/^(Polar|Cartesian|Linear-Log|Log-Linear|Log-Log)$/},
	 description => 'Grid type:',
	 edit_type   => 'choice',
         choices     => ['Cartesian','Polar','Linear-Log','Log-Linear','Log-Log']
         },
     lmargin      => {
	 default     => 'default',
	 test        => sub {$_[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 => 'Bottom margin width (pts):',
	 edit_type   => 'choice',
         choices     => $margin_choices,
         },
     boxwidth     => {
	 default     => '',
	 test        => $real_test, 
	 description => 'Width of boxes, default is auto',
	 edit_type   => 'entry',
         size        => '5'
         },
     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 = 
    (
     title => { 
	 default => '',
	 test => $words_test,
	 description => 'Title of key',
	 edit_type   => 'entry',
	 size        => '40'
	 },
     box   => { 
	 default => 'off',
	 test => $onoff_test,
	 description => 'Draw a box around the key?',
	 edit_type   => 'onoff'
	 },
     pos   => { 
	 default => 'top right', 
	 test => $key_pos_test, 
	 description => 'Position of the key on the plot',
	 edit_type   => 'choice',
	 choices     => ['top left','top right','bottom left','bottom right',
			 'outside','below']
	 }
     );

my %label_defaults = 
    (
     xpos    => {
	 default => 0,
	 test => $real_test,
	 description => 'X position of label (graph coordinates)',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     ypos    => {
	 default => 0, 
	 test => $real_test,
	 description => 'Y position of label (graph coordinates)',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     justify => {
	 default => 'left',    
	 test => sub {$_[0]=~/^(left|right|center)$/},
	 description => 'justification of the label text on the plot',
	 edit_type   => 'choice',
	 choices     => ['left','right','center']
     }
     );

my @tic_edit_order = ('location','mirror','start','increment','end',
                      'minorfreq');
my %tic_defaults =
    (
     location => {
	 default => 'border', 
	 test => sub {$_[0]=~/^(border|axis)$/},
	 description => 'Location of major tic marks',
	 edit_type   => 'choice',
	 choices     => ['border','axis']
	 },
     mirror => {
	 default => 'on', 
	 test => $onoff_test,
	 description => 'Mirror tics on opposite axis?',
	 edit_type   => 'onoff'
	 },
     start => {
	 default => '-10.0',
	 test => $real_test,
	 description => 'Start major tics at',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     increment => {
	 default => '1.0',
	 test => $real_test,
	 description => 'Place a major tic every',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     end => {
	 default => ' 10.0',
	 test => $real_test,
	 description => 'Stop major tics at ',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     minorfreq => {
	 default => '0',
	 test => $int_test,
	 description => 'Number of minor tics per major tic mark',
	 edit_type   => 'entry',
	 size        => '10'
	 },         
     );

my @axis_edit_order = ('color','xmin','xmax','ymin','ymax');
my %axis_defaults = 
    (
     color   => {
	 default => 'x000000', 
	 test => $color_test,
	 description => 'Color of grid lines (x000000)',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     xmin      => {
	 default => '-10.0',
	 test => $real_test,
	 description => 'Minimum x-value shown in plot',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     xmax      => {
	 default => ' 10.0',
	 test => $real_test,
	 description => 'Maximum x-value shown in plot',	 
	 edit_type   => 'entry',
	 size        => '10'
	 },
     ymin      => {
	 default => '-10.0',
	 test => $real_test,
	 description => 'Minimum y-value shown in plot',	 
	 edit_type   => 'entry',
	 size        => '10'
	 },
     ymax      => {
	 default => ' 10.0',
	 test => $real_test,
	 description => 'Maximum y-value shown in plot',	 
	 edit_type   => 'entry',
	 size        => '10'
	 }
     );

my @curve_edit_order = ('color','name','linestyle','linewidth','pointtype','pointsize','limit');

my %curve_defaults = 
    (
     color     => {
	 default => 'x000000',
	 test => $color_test,
	 description => 'Color of curve (x000000)',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     name      => {
	 default => '',
	 test => $words_test,
	 description => 'Name of curve to appear in key',
	 edit_type   => 'entry',
	 size        => '20'
	 },
     linestyle => {
	 default => 'lines',
	 test => $linestyle_test,
	 description => 'Line style',
	 edit_type   => 'choice',
	 choices     => [keys(%linestyles)]
	 },
     linewidth => {
         default     => 1,
         test        => $int_test,
         description => 'Line width (may not apply to all line styles)',
         edit_type   => 'choice',
         choices     => [1,2,3,4,5,6,7,8,9,10]
         },
     pointsize => {
         default     => 1,
         test        => $pos_real_test,
         description => 'Point size (may not apply to all line styles)',
         edit_type   => 'entry',
         size        => '5'
         },
     pointtype => {
         default     => 1,
         test        => $int_test,
         description => 'Point type (may not apply to all line styles)',
         edit_type   => 'choice',
         choices     => [0,1,2,3,4,5,6]
         },
     limit     => {
         default     => 'closed',
	 test        => sub {$_[0]=~/^(closed|x1|x2|y1|y2)$/},
         description => 'Point to fill -- for filledcurves',
         edit_type   => 'choice',
         choices     => ['closed','x1','x2','y1','y2']
         },
     );

###################################################################
##                                                               ##
##                    parsing and edit rendering                 ##
##                                                               ##
###################################################################

undef %Apache::lonplot::plot;
my (%key,%axis,$title,$xlabel,$ylabel,@labels,@curves,%xtics,%ytics);

sub start_gnuplot {
    undef(%Apache::lonplot::plot);   undef(%key);    undef(%axis);
    undef($title);  undef($xlabel); undef($ylabel);
    undef(@labels); undef(@curves);
    undef(%xtics);  undef(%ytics);
    #
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    &Apache::lonxml::register('Apache::lonplot',
	     ('title','xlabel','ylabel','key','axis','label','curve',
	      'xtics','ytics'));
    push (@Apache::lonxml::namespace,'lonplot');
    if ($target eq 'web' || $target eq 'tex') {
	&get_attributes(\%Apache::lonplot::plot,\%gnuplot_defaults,$parstack,$safeeval,
			$tagstack->[-1]);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'GnuPlot');
	$result .= &edit_attributes($target,$token,\%gnuplot_defaults,
				    \@gnuplot_edit_order)
	    .&Apache::edit::end_row()
	    .&Apache::edit::start_spanning_row();
    } elsif ($target eq 'modified') {
	my $constructtag=&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%gnuplot_defaults));
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    }
    return $result;
}

sub end_gnuplot {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    pop @Apache::lonxml::namespace;
    &Apache::lonxml::deregister('Apache::lonplot',
	('title','xlabel','ylabel','key','axis','label','curve'));
    my $result = '';
    my $randnumber;
    # need to call rand everytime start_script would evaluate, as the
    # safe space rand number generator and the global rand generator 
    # are not separate
    if ($target eq 'web' || $target eq 'tex' || $target eq 'grade' ||
	$target eq 'answer') {
      $randnumber=int(rand(1000));
    }
    if ($target eq 'web' || $target eq 'tex') {
	&check_inputs(); # Make sure we have all the data we need
	##
	## Determine filename
	my $tmpdir = '/home/httpd/perl/tmp/';
	my $filename = $env{'user.name'}.'_'.$env{'user.domain'}.
	    '_'.time.'_'.$$.$randnumber.'_plot';
	## Write the plot description to the file
	&write_gnuplot_file($tmpdir,$filename,$target);
	$filename = &escape($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    = "$Apache::lonplot::plot{'alttag'}" />
ENDIMAGE
        } elsif ($target eq 'tex') {
	    &Apache::lonxml::debug(" gnuplot wid = $Apache::lonplot::plot{'width'}");
	    &Apache::lonxml::debug(" gnuplot ht  = $Apache::lonplot::plot{'height'}");
	    #might be inside the safe space, register the URL for later
	    &Apache::lonxml::register_ssi("/cgi-bin/plot.gif?file=$filename.data&output=eps");
	    $result  = "%DYNAMICIMAGE:$Apache::lonplot::plot{'width'}:$Apache::lonplot::plot{'height'}:$Apache::lonplot::plot{'texwidth'}\n";
	    $result .= '\graphicspath{{/home/httpd/perl/tmp/}}'."\n";
	    $result .= '\includegraphics[width='.$Apache::lonplot::plot{'texwidth'}.' mm]{'.&unescape($filename).'.eps}';
	}
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}


##--------------------------------------------------------------- xtics
sub start_xtics {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	&get_attributes(\%xtics,\%tic_defaults,$parstack,$safeeval,
		    $tagstack->[-1]);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'xtics');
	$result .= &edit_attributes($target,$token,\%tic_defaults,
				    \@tic_edit_order);
    } elsif ($target eq 'modified') {
	my $constructtag=&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%tic_defaults));
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    }
    return $result;
}

sub end_xtics {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}

##--------------------------------------------------------------- ytics
sub start_ytics {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	&get_attributes(\%ytics,\%tic_defaults,$parstack,$safeeval,
		    $tagstack->[-1]);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'ytics');
	$result .= &edit_attributes($target,$token,\%tic_defaults,
				    \@tic_edit_order);
    } elsif ($target eq 'modified') {
	my $constructtag=&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%tic_defaults));
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    }
    return $result;
}

sub end_ytics {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}

##-----------------------------------------------------------------font
my %font_properties =
    (
     'classic'    => {
	 face       => 'classic',
	 file       => 'DejaVuSansMono-Bold',
	 printname  => 'Helvetica',
	 tex_no_file => 1,
     },
     'sans-serif' => {
	 face       => 'sans-serif',
	 file       => 'DejaVuSans',
	 printname  => 'DejaVuSans',
     },
     'serif'      => {
	 face       => 'serif',
	 file       => 'DejaVuSerif',
	 printname  => 'DejaVuSerif',
     },
     );

sub get_font {
    my ($target) = @_;
    my ($size, $selected_font);

    if ( $Apache::lonplot::plot{'font'} =~ /^(small|medium|large)/) {
	$selected_font = $font_properties{'classic'};
	if ( $Apache::lonplot::plot{'font'} eq 'small') {
	    $size = '5';
	} elsif ( $Apache::lonplot::plot{'font'} eq 'medium') {
	    $size = '9';
	} elsif ( $Apache::lonplot::plot{'font'} eq 'large') {
	    $size = '11';
	} else {
	    $size = '9';
	}
    } else {
	$size = $Apache::lonplot::plot{'font'};
	$selected_font = $font_properties{$Apache::lonplot::plot{'fontface'}};
    }
    if ($target eq 'tex' && defined($Apache::lonplot::plot{'texfont'})) {
	$size = $Apache::lonplot::plot{'texfont'};
    }
    return ($size, $selected_font);
}

##----------------------------------------------------------------- key
sub start_key {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	&get_attributes(\%key,\%key_defaults,$parstack,$safeeval,
		    $tagstack->[-1]);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Plot Key');
	$result .= &edit_attributes($target,$token,\%key_defaults);
    } elsif ($target eq 'modified') {
	my $constructtag=&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%key_defaults));
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    }
    return $result;
}

sub end_key {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}

sub parse_label {
    my ($target,$text) = @_;
    my $parser=HTML::LCParser->new(\$text);
    my $result;
    while (my $token=$parser->get_token) {
	if ($token->[0] eq 'S') {
	    if ($token->[1] eq 'sub') {
		$result .= '_{';
	    } elsif ($token->[1] eq 'sup') {
		$result .= '^{';
	    } else {
		$result .= $token->[4];
	    }
	} elsif ($token->[0] eq 'E') {
	    if ($token->[1] eq 'sub'
		|| $token->[1] eq 'sup') {
		$result .= '}';
	    } else {
		$result .= $token->[2];
	    }
	} elsif ($token->[0] eq 'T') {
	    $result .= &replace_entities($target,$token->[1]);
	}
    }
    return $result;
}


my %lookup = 
    ('(pi|#960)' => {'tex' => '{/Symbol p}', 'web' => "\x{3C0}"},);

sub replace_entities {
    my ($target,$text) = @_;
    $text =~ s{([_^~\{\}]|\\\\)}{\\\\$1}g;
    while (my ($re, $replace) = each(%lookup)) {
	$text =~ s/&$re;/$replace->{$target}/g;
    }
    $text =~ s{(&)}{\\\\$1}g;
    return $text;
}

##------------------------------------------------------------------- title
sub start_title {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	$title = &Apache::lonxml::get_all_text("/title",$parser,$style);
	$title=&Apache::run::evaluate($title,$safeeval,$$parstack[-1]);
	$title =~ s/\n/ /g;
	if (length($title) > $max_str_len) {
	    $title = substr($title,0,$max_str_len);
	}
	$title = &parse_label($target,$title);
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_start($target,$token,'Plot Title');
	my $text=&Apache::lonxml::get_all_text("/title",$parser,$style);
	$result.=&Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	$result.=&Apache::edit::rebuild_tag($token);
	$result.=&Apache::edit::modifiedfield("/title",$parser);
    }
    return $result;
}

sub end_title {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}
##------------------------------------------------------------------- xlabel
sub start_xlabel {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	$xlabel = &Apache::lonxml::get_all_text("/xlabel",$parser,$style);
	$xlabel=&Apache::run::evaluate($xlabel,$safeeval,$$parstack[-1]);
	$xlabel =~ s/\n/ /g;
	if (length($xlabel) > $max_str_len) {
	    $xlabel = substr($xlabel,0,$max_str_len);
	}
	$xlabel = &parse_label($target,$xlabel);
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_start($target,$token,'Plot Xlabel');
	my $text=&Apache::lonxml::get_all_text("/xlabel",$parser,$style);
	$result.=&Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	$result.=&Apache::edit::rebuild_tag($token);	
	$result.=&Apache::edit::modifiedfield("/xlabel",$parser);
    }
    return $result;
}

sub end_xlabel {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}

##------------------------------------------------------------------- ylabel
sub start_ylabel {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	$ylabel = &Apache::lonxml::get_all_text("/ylabel",$parser,$style);
	$ylabel = &Apache::run::evaluate($ylabel,$safeeval,$$parstack[-1]);
	$ylabel =~ s/\n/ /g;
	if (length($ylabel) > $max_str_len) {
	    $ylabel = substr($ylabel,0,$max_str_len);
	}
	$ylabel = &parse_label($target,$ylabel);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Plot Ylabel');
	my $text = &Apache::lonxml::get_all_text("/ylabel",$parser,$style);
	$result .= &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	$result.=&Apache::edit::rebuild_tag($token);
	$result.=&Apache::edit::modifiedfield("/ylabel",$parser);
    }
    return $result;
}

sub end_ylabel {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}

##------------------------------------------------------------------- label
sub start_label {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	my %label;
	&get_attributes(\%label,\%label_defaults,$parstack,$safeeval,
		    $tagstack->[-1]);
	my $text = &Apache::lonxml::get_all_text("/label",$parser,$style);
	$text = &Apache::run::evaluate($text,$safeeval,$$parstack[-1]);
	$text =~ s/\n/ /g;
	$text = substr($text,0,$max_str_len) if (length($text) > $max_str_len);
	$label{'text'} = &parse_label($target,$text);
	push(@labels,\%label);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Plot Label');
	$result .= &edit_attributes($target,$token,\%label_defaults);
	my $text = &Apache::lonxml::get_all_text("/label",$parser,$style);
	$result .= &Apache::edit::end_row().
	    &Apache::edit::start_spanning_row().
	    &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%label_defaults));
	$result.=&Apache::edit::rebuild_tag($token);
	$result.=&Apache::edit::modifiedfield("/label",$parser);
    }
    return $result;
}

sub end_label {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}

##------------------------------------------------------------------- curve
sub start_curve {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    &Apache::lonxml::register('Apache::lonplot',('function','data'));
    push (@Apache::lonxml::namespace,'curve');
    if ($target eq 'web' || $target eq 'tex') {
	my %curve;
	&get_attributes(\%curve,\%curve_defaults,$parstack,$safeeval,
		    $tagstack->[-1]);
	push (@curves,\%curve);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Curve');
	$result .= &edit_attributes($target,$token,\%curve_defaults,
                                    \@curve_edit_order)
	    .&Apache::edit::end_row()
	    .&Apache::edit::start_spanning_row();

    } elsif ($target eq 'modified') {
	my $constructtag=&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%curve_defaults));
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    }
    return $result;
}

sub end_curve {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    pop @Apache::lonxml::namespace;
    &Apache::lonxml::deregister('Apache::lonplot',('function','data'));
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    }
    return $result;
}

##------------------------------------------------------------ curve function
sub start_function {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	if (exists($curves[-1]->{'data'})) {
	    &Apache::lonxml::warning
                ('Use of the <b>curve function</b> tag precludes use of '.
                 ' the <b>curve data</b> tag.  '.
                 'The curve data tag will be omitted in favor of the '.
                 'curve function declaration.');
	    delete $curves[-1]->{'data'} ;
	}
        my $function = &Apache::lonxml::get_all_text("/function",$parser,
						     $style);
	$function = &Apache::run::evaluate($function,$safeeval,$$parstack[-1]);
	$curves[-1]->{'function'} = $function; 
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Gnuplot compatible curve function');
	my $text = &Apache::lonxml::get_all_text("/function",$parser,$style);
	$result .= &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	$result.=&Apache::edit::rebuild_tag($token);
	$result.=&Apache::edit::modifiedfield("/function",$parser);
    }
    return $result;
}

sub end_function {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::end_table();
    }
    return $result;
}

##------------------------------------------------------------ curve  data
sub start_data {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	if (exists($curves[-1]->{'function'})) {
	    &Apache::lonxml::warning
                ('Use of the <b>curve function</b> tag precludes use of '.
                 ' the <b>curve data</b> tag.  '.
                 'The curve function tag will be omitted in favor of the '.
                 'curve data declaration.');
	    delete($curves[-1]->{'function'});
	}
	my $datatext = &Apache::lonxml::get_all_text("/data",$parser,$style);
	$datatext=&Apache::run::evaluate($datatext,$safeeval,$$parstack[-1]);
	# Deal with cases where we're given an array...
	if ($datatext =~ /^\@/) {
	    $datatext = &Apache::run::run('return "'.$datatext.'"',
					  $safeeval,1);
	}
	$datatext =~ s/\s+/ /g;
	# Need to do some error checking on the @data array - 
	# make sure it's all numbers and make sure each array 
	# is of the same length.
	my @data;
	if ($datatext =~ /,/) { # comma deliminated
	    @data = split /,/,$datatext;
	} else { # Assume it's space separated.
	    @data = split / /,$datatext;
	}
	for (my $i=0;$i<=$#data;$i++) {
	    # Check that it's non-empty
	    if (! defined($data[$i])) {
		&Apache::lonxml::warning(
		    'undefined curve data value.  Replacing with '.
		    ' pi/e = 1.15572734979092');
		$data[$i] = 1.15572734979092;
	    }
	    # Check that it's a number
	    if (! &$real_test($data[$i]) & ! &$int_test($data[$i])) {
		&Apache::lonxml::warning(
		    'Bad curve data value of '.$data[$i].'  Replacing with '.
		    ' pi/e = 1.15572734979092');
		$data[$i] = 1.15572734979092;
	    }
	}
	# complain if the number of data points is not the same as
	# in previous sets of data.
	if (($curves[-1]->{'data'}) && ($#data != $#{@{$curves[-1]->{'data'}->[0]}})){
	    &Apache::lonxml::warning
		('Number of data points is not consistent with previous '.
		 'number of data points');
	}
	push  @{$curves[-1]->{'data'}},\@data;
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Comma or space deliminated curve data');
	my $text = &Apache::lonxml::get_all_text("/data",$parser,$style);
	$result .= &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	$result.=&Apache::edit::rebuild_tag($token);
	$result.=&Apache::edit::modifiedfield("/data",$parser);
    }
    return $result;
}

sub end_data {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::end_table();
    }
    return $result;
}

##------------------------------------------------------------------- axis
sub start_axis {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result='';
    if ($target eq 'web' || $target eq 'tex') {
	&get_attributes(\%axis,\%axis_defaults,$parstack,$safeeval,
			$tagstack->[-1]);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Plot Axes');
	$result .= &edit_attributes($target,$token,\%axis_defaults,
				    \@axis_edit_order);
    } elsif ($target eq 'modified') {
	my $constructtag=&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%axis_defaults));
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	}
    }
    return $result;
}

sub end_axis {
    my ($target,$token,$tagstack,$parstack,$parser,$safeeval,$style)=@_;
    my $result = '';
    if ($target eq 'web' || $target eq 'tex') {
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_end($target,$token);
    } elsif ($target eq 'modified') {
    }
    return $result;
}

###################################################################
##                                                               ##
##        Utility Functions                                      ##
##                                                               ##
###################################################################

##----------------------------------------------------------- set_defaults
sub set_defaults {
    my ($var,$defaults) = @_;
    my $key;
    foreach $key (keys(%$defaults)) {
	$var->{$key} = $defaults->{$key}->{'default'};
    }
}

##------------------------------------------------------------------- misc
sub get_attributes{
    my ($values,$defaults,$parstack,$safeeval,$tag) = @_;
    foreach my $attr (keys(%{$defaults})) {
	if ($attr eq 'texwidth' || $attr eq 'texfont') {
	    $values->{$attr} = 
		&Apache::lonxml::get_param($attr,$parstack,$safeeval,undef,1);
	} else {
	    $values->{$attr} = 
		&Apache::lonxml::get_param($attr,$parstack,$safeeval);
	}
	if ($values->{$attr} eq '' | !defined($values->{$attr})) {
	    $values->{$attr} = $defaults->{$attr}->{'default'};
	    next;
	}
	my $test = $defaults->{$attr}->{'test'};
	if (! &$test($values->{$attr})) {
	    &Apache::lonxml::warning
		($tag.':'.$attr.': Bad value.'.'Replacing your value with : '
		 .$defaults->{$attr}->{'default'} );
	    $values->{$attr} = $defaults->{$attr}->{'default'};
	}
    }
    return ;
}

##------------------------------------------------------- write_gnuplot_file
sub write_gnuplot_file {
    my ($tmpdir,$filename,$target)= @_;
    my ($fontsize, $font_properties) =  &get_font($target);
    my $gnuplot_input = '';
    my $curve;
    #
    # 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, $Apache::lonplot::plot{'bgcolor'};
    push @Colors, $Apache::lonplot::plot{'fgcolor'}; 
    push @Colors, (defined($axis{'color'})?$axis{'color'}:$Apache::lonplot::plot{'fgcolor'});
    foreach $curve (@curves) {
	push @Colors, ($curve->{'color'} ne '' ? 
		       $curve->{'color'}       : 
		       $Apache::lonplot::plot{'fgcolor'}        );
    }
    # set term
    if ($target eq 'web') {
	$gnuplot_input .= 'set terminal png enhanced nocrop ';
	$gnuplot_input .= 'transparent ' if ($Apache::lonplot::plot{'transparent'} eq 'on');
	$gnuplot_input .= 'font "'.$Apache::lonnet::perlvar{'lonFontsDir'}.
	    '/'.$font_properties->{'file'}.'.ttf" ';
	$gnuplot_input .= $fontsize;
	$gnuplot_input .= ' size '.$Apache::lonplot::plot{'width'}.','.$Apache::lonplot::plot{'height'}.' ';
	$gnuplot_input .= "@Colors\n";
	# set output
	$gnuplot_input .= "set output\n";
    } elsif ($target eq 'tex') {
	$gnuplot_input .= "set term postscript eps enhanced $Apache::lonplot::plot{'plotcolor'} solid ";
	if (!$font_properties->{'tex_no_file'}) {
	    $gnuplot_input .=
		'fontfile "'.$Apache::lonnet::perlvar{'lonFontsDir'}.
		'/'.$font_properties->{'file'}.'.pfb" ';
	}
	$gnuplot_input .= ' "'.$font_properties->{'printname'}.'" ';
	$gnuplot_input .= $fontsize;
	$gnuplot_input .= "\nset output \"/home/httpd/perl/tmp/".
	    &unescape($filename).".eps\"\n";
    }
    # cartesian or polar plot?
    if (lc($Apache::lonplot::plot{'plottype'}) eq 'polar') {
        $gnuplot_input .= 'set polar'.$/;
    } else {
        # Assume Cartesian
    }
    # cartesian or polar grid?
    if (lc($Apache::lonplot::plot{'gridtype'}) eq 'polar') {
        $gnuplot_input .= 'set grid polar'.$/;
    } elsif (lc($Apache::lonplot::plot{'gridtype'}) eq 'linear-log') {
        $gnuplot_input .= 'set logscale x'.$/;
    } elsif (lc($Apache::lonplot::plot{'gridtype'}) eq 'log-linear') {
        $gnuplot_input .= 'set logscale y'.$/;
    } elsif (lc($Apache::lonplot::plot{'gridtype'}) eq 'log-log') {
        $gnuplot_input .= 'set logscale x'.$/;
        $gnuplot_input .= 'set logscale y'.$/;
    } else {
        # Assume Cartesian
    }
    # solid or pattern for boxes?
    if (lc($Apache::lonplot::plot{'fillstyle'}) eq 'solid') {
        $gnuplot_input .= 'set style fill solid '.
	    $Apache::lonplot::plot{'solid'}.$Apache::lonplot::plot{'box_border'}.$/;
    } elsif (lc($Apache::lonplot::plot{'fillstyle'}) eq 'pattern') {
        $gnuplot_input .= 'set style fill pattern '.$Apache::lonplot::plot{'pattern'}.$Apache::lonplot::plot{'box_border'}.$/;
    } elsif (lc($Apache::lonplot::plot{'fillstyle'}) eq 'empty') {
    }
    # margin
    if (lc($Apache::lonplot::plot{'lmargin'}) ne 'default') {
        $gnuplot_input .= 'set lmargin '.$Apache::lonplot::plot{'lmargin'}.$/;
    }
    if (lc($Apache::lonplot::plot{'rmargin'}) ne 'default') {
        $gnuplot_input .= 'set rmargin '.$Apache::lonplot::plot{'rmargin'}.$/;
    }
    if (lc($Apache::lonplot::plot{'tmargin'}) ne 'default') {
        $gnuplot_input .= 'set tmargin '.$Apache::lonplot::plot{'tmargin'}.$/;
    }
    if (lc($Apache::lonplot::plot{'bmargin'}) ne 'default') {
        $gnuplot_input .= 'set bmargin '.$Apache::lonplot::plot{'bmargin'}.$/;
    }

    # tic scales
    if ($version > 4) {
	$gnuplot_input .= 'set tics scale '.
	    $Apache::lonplot::plot{'major_ticscale'}.', '.$Apache::lonplot::plot{'minor_ticscale'}.$/;
    } else {
    	$gnuplot_input .= 'set ticscale '.
	    $Apache::lonplot::plot{'major_ticscale'}.' '.$Apache::lonplot::plot{'minor_ticscale'}.$/;
    }
    #boxwidth
    if (lc($Apache::lonplot::plot{'boxwidth'}) ne '') {
	$gnuplot_input .= 'set boxwidth '.$Apache::lonplot::plot{'boxwidth'}.$/;
    }
    # gridlayer
    $gnuplot_input .= 'set grid noxtics noytics front '.$/ 
	if ($Apache::lonplot::plot{'gridlayer'} eq 'on');

    # grid
    $gnuplot_input .= 'set grid'.$/ if ($Apache::lonplot::plot{'grid'} eq 'on');
    # border
    $gnuplot_input .= ($Apache::lonplot::plot{'border'} eq 'on'?
		       'set border'.$/           :
		       'set noborder'.$/         );
    # sampling rate for non-data curves
    $gnuplot_input .= "set samples $Apache::lonplot::plot{'samples'}\n";
    # title, xlabel, ylabel
    # titles
    my $extra_space_x = ($xtics{'location'} eq 'axis') ? ' 0, -0.5 ' : '';
    my $extra_space_y = ($ytics{'location'} eq 'axis') ? ' -0.5, 0 ' : '';

    if ($target eq 'tex') {
	$gnuplot_input .= "set title  \"$title\"          font \"".$font_properties->{'printname'}.",".$fontsize."pt\"\n" if (defined($title)) ;
	$gnuplot_input .= "set xlabel \"$xlabel\" $extra_space_x font \"".$font_properties->{'printname'}.",".$fontsize."pt\"\n" if (defined($xlabel));
	$gnuplot_input .= "set ylabel \"$ylabel\" $extra_space_y font \"".$font_properties->{'printname'}.",".$fontsize."pt\"\n" if (defined($ylabel));
    } else {
        $gnuplot_input .= "set title  \"$title\"          \n" if (defined($title)) ;
        $gnuplot_input .= "set xlabel \"$xlabel\" $extra_space_x \n" if (defined($xlabel));
        $gnuplot_input .= "set ylabel \"$ylabel\" $extra_space_y \n" if (defined($ylabel));
    }
    # tics
    if (%xtics) {    
	$gnuplot_input .= "set xtics $xtics{'location'} ";
	$gnuplot_input .= ( $xtics{'mirror'} eq 'on'?"mirror ":"nomirror ");
	$gnuplot_input .= "$xtics{'start'}, ";
	$gnuplot_input .= "$xtics{'increment'}, ";
	$gnuplot_input .= "$xtics{'end'}\n";
        if ($xtics{'minorfreq'} != 0) {
            $gnuplot_input .= "set mxtics ".$xtics{'minorfreq'}."\n";
        } 
    }
    if (%ytics) {    
	$gnuplot_input .= "set ytics $ytics{'location'} ";
	$gnuplot_input .= ( $ytics{'mirror'} eq 'on'?"mirror ":"nomirror ");
	$gnuplot_input .= "$ytics{'start'}, ";
	$gnuplot_input .= "$ytics{'increment'}, ";
        $gnuplot_input .= "$ytics{'end'}\n";
        if ($ytics{'minorfreq'} != 0) {
            $gnuplot_input .= "set mytics ".$ytics{'minorfreq'}."\n";
        } 
    }
    # axis
    if (%axis) {
	$gnuplot_input .= "set xrange \[$axis{'xmin'}:$axis{'xmax'}\]\n";
	$gnuplot_input .= "set yrange \[$axis{'ymin'}:$axis{'ymax'}\]\n";
    }
    # Key
    if (%key) {
	$gnuplot_input .= 'set key '.$key{'pos'}.' ';
	if ($key{'title'} ne '') {
	    $gnuplot_input .= 'title "'.$key{'title'}.'" ';
	} 
	$gnuplot_input .= ($key{'box'} eq 'on' ? 'box ' : 'nobox ').$/;
    } else {
	$gnuplot_input .= 'set nokey'.$/;
    }
    # labels
    my $label;
    foreach $label (@labels) {
	$gnuplot_input .= 'set label "'.$label->{'text'}.'" at '.
	    $label->{'xpos'}.','.$label->{'ypos'}.' '.$label->{'justify'};
        if ($target eq 'tex') {
	    $gnuplot_input .=' font "'.$font_properties->{'printname'}.','.$fontsize.'pt"' ;
        }
        $gnuplot_input .= $/;
    }
    if ($target eq 'tex') {
        $gnuplot_input .="set size 1,".$Apache::lonplot::plot{'height'}/$Apache::lonplot::plot{'width'}*1.38;
        $gnuplot_input .="\n";
    }
    # curves
    $gnuplot_input .= 'plot ';
    for (my $i = 0;$i<=$#curves;$i++) {
	$curve = $curves[$i];
	$gnuplot_input.= ', ' if ($i > 0);
	if ($target eq 'tex') {
	    $curve->{'linewidth'} *= 2;
	}
	if (exists($curve->{'function'})) {
	    $gnuplot_input.= 
		$curve->{'function'}.' title "'.
		$curve->{'name'}.'" with '.
                $curve->{'linestyle'};

            if (($curve->{'linestyle'} eq 'points')      ||
                ($curve->{'linestyle'} eq 'linespoints') ||
                ($curve->{'linestyle'} eq 'errorbars')   ||
                ($curve->{'linestyle'} eq 'xerrorbars')  ||
                ($curve->{'linestyle'} eq 'yerrorbars')  ||
                ($curve->{'linestyle'} eq 'xyerrorbars')) {
                $gnuplot_input.=' pointtype '.$curve->{'pointtype'};
                $gnuplot_input.=' pointsize '.$curve->{'pointsize'};
            } elsif ($curve->{'linestyle'} eq 'filledcurves') { 
                $gnuplot_input.= ' '.$curve->{'limit'};
            }
            $gnuplot_input.= ' linewidth '.$curve->{'linewidth'};

	} elsif (exists($curve->{'data'})) {
	    # Store data values in $datatext
	    my $datatext = '';
	    #   get new filename
	    my $datafilename = "$tmpdir/$filename.data.$i";
	    my $fh=Apache::File->new(">$datafilename");
	    # Compile data
	    my @Data = @{$curve->{'data'}};
	    my @Data0 = @{$Data[0]};
	    for (my $i =0; $i<=$#Data0; $i++) {
		my $dataset;
		foreach $dataset (@Data) {
		    $datatext .= $dataset->[$i] . ' ';
		}
		$datatext .= $/;
	    }
	    #   write file
	    print $fh $datatext;
	    close($fh);
	    #   generate gnuplot text
	    $gnuplot_input.= '"'.$datafilename.'" title "'.
		$curve->{'name'}.'" with '.
		$curve->{'linestyle'};
            if (($curve->{'linestyle'} eq 'points')      ||
                ($curve->{'linestyle'} eq 'linespoints') ||
                ($curve->{'linestyle'} eq 'errorbars')   ||
                ($curve->{'linestyle'} eq 'xerrorbars')  ||
                ($curve->{'linestyle'} eq 'yerrorbars')  ||
                ($curve->{'linestyle'} eq 'xyerrorbars')) {
                $gnuplot_input.=' pointtype '.$curve->{'pointtype'};
                $gnuplot_input.=' pointsize '.$curve->{'pointsize'};
            } elsif ($curve->{'linestyle'} eq 'filledcurves') { 
                $gnuplot_input.= ' '.$curve->{'limit'};
            }
            $gnuplot_input.= ' linewidth '.$curve->{'linewidth'};
	}
    }
    # Write the output to a file.
    open (my $fh,">$tmpdir$filename.data");
    binmode($fh, ":utf8");
    print $fh $gnuplot_input;
    close($fh);
    # That's all folks.
    return ;
}

#---------------------------------------------- check_inputs
sub check_inputs {
    ## Note: no inputs, no outputs - this acts only on global variables.
    ## Make sure we have all the input we need:
    if (! %Apache::lonplot::plot) { &set_defaults(\%Apache::lonplot::plot,\%gnuplot_defaults); }
    if (! %key ) {} # No key for this plot, thats okay
#    if (! %axis) { &set_defaults(\%axis,\%axis_defaults); }
    if (! defined($title )) {} # No title for this plot, thats okay
    if (! defined($xlabel)) {} # No xlabel for this plot, thats okay
    if (! defined($ylabel)) {} # No ylabel for this plot, thats okay
    if ($#labels < 0) { }      # No labels for this plot, thats okay
    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 curve data or curve function declarations\n");
	    return '';
	}
    }
}

#------------------------------------------------ make_edit
sub edit_attributes {
    my ($target,$token,$defaults,$keys) = @_;
    my ($result,@keys);
    if ($keys && ref($keys) eq 'ARRAY') {
        @keys = @$keys;
    } else {
	@keys = sort(keys(%$defaults));
    }
    foreach my $attr (@keys) {
	# append a ' ' to the description if it doesn't have one already.
	my $description = $defaults->{$attr}->{'description'};
	$description .= ' ' if ($description !~ / $/);
	if ($defaults->{$attr}->{'edit_type'} eq 'entry') {
	    $result .= &Apache::edit::text_arg
		($description,$attr,$token,
		 $defaults->{$attr}->{'size'});
	} elsif ($defaults->{$attr}->{'edit_type'} eq 'choice') {
	    $result .= &Apache::edit::select_or_text_arg
		($description,$attr,$defaults->{$attr}->{'choices'},$token);
	} elsif ($defaults->{$attr}->{'edit_type'} eq 'onoff') {
	    $result .= &Apache::edit::select_or_text_arg
		($description,$attr,['on','off'],$token);
	}
	$result .= '<br />';
    }
    return $result;
}


###################################################################
##                                                               ##
##           Insertion functions for editing plots               ##
##                                                               ##
###################################################################

sub insert_gnuplot {
    my $result = '';
    #  plot attributes
    $result .= "\n<gnuplot ";
    foreach my $attr (keys(%gnuplot_defaults)) {
	$result .= "\n     $attr=\"$gnuplot_defaults{$attr}->{'default'}\"";
    }
    $result .= ">";
    # Add the components (most are commented out for simplicity)
    # $result .= &insert_key();
    # $result .= &insert_axis();
    # $result .= &insert_title();    
    # $result .= &insert_xlabel();    
    # $result .= &insert_ylabel();    
    $result .= &insert_curve();
    # close up the <gnuplot>
    $result .= "\n</gnuplot>";
    return $result;
}

sub insert_tics {
    my $result;
    $result .= &insert_xtics() . &insert_ytics;
    return $result;
}

sub insert_xtics {
    my $result;
    $result .= "\n    <xtics ";
    foreach my $attr (keys(%tic_defaults)) {
	$result .= "\n        $attr=\"$tic_defaults{$attr}->{'default'}\" ";
    }
    $result .= "/>";
    return $result;
}

sub insert_ytics {
    my $result;
    $result .= "\n    <ytics ";
    foreach my $attr (keys(%tic_defaults)) {
	$result .= "\n        $attr=\"$tic_defaults{$attr}->{'default'}\" ";
    }
    $result .= "/>";
    return $result;
}

sub insert_key {
    my $result;
    $result .= "\n    <key ";
    foreach my $attr (keys(%key_defaults)) {
	$result .= "\n         $attr=\"$key_defaults{$attr}->{'default'}\"";
    }
    $result .= " />";
    return $result;
}

sub insert_axis{
    my $result;
    $result .= "\n    <axis ";
   foreach my $attr (keys(%axis_defaults)) {
	$result .= "\n         $attr=\"$axis_defaults{$attr}->{'default'}\"";
    }
    $result .= " />";
    return $result;
}

sub insert_title  { return "\n    <title></title>"; }
sub insert_xlabel { return "\n    <xlabel></xlabel>"; }
sub insert_ylabel { return "\n    <ylabel></ylabel>"; }

sub insert_label {
    my $result;
    $result .= "\n    <label ";
    foreach my $attr (keys(%label_defaults)) {
	$result .= "\n         $attr=\"".
            $label_defaults{$attr}->{'default'}."\"";
    }
    $result .= "></label>";
    return $result;
}

sub insert_curve {
    my $result;
    $result .= "\n    <curve ";
    foreach my $attr (keys(%curve_defaults)) {
	$result .= "\n         $attr=\"".
	    $curve_defaults{$attr}->{'default'}."\"";
    }
    $result .= " >";
    $result .= &insert_data().&insert_data()."\n    </curve>";
}

sub insert_function {
    my $result;
    $result .= "\n        <function></function>";
    return $result;
}

sub insert_data {
    my $result;
    $result .= "\n        <data></data>";
    return $result;
}

##----------------------------------------------------------------------
1;
__END__


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