File:  [LON-CAPA] / loncom / xml / lonplot.pm
Revision 1.85: download - view: text, annotated - select for diffs
Tue Jun 10 18:46:02 2003 UTC (20 years, 10 months ago) by matthew
Branches: MAIN
CVS tags: version_1_0_2, version_1_0_1, version_1_0_0, version_0_99_5, version_0_99_4, version_0_99_3, version_0_99_2, HEAD
Putting <tag> in html output supresses the display the thing in "<",">"'s.
Who knew?

# The LearningOnline Network with CAPA
# Dynamic plot
#
# $Id: lonplot.pm,v 1.85 2003/06/10 18:46:02 matthew 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/
#
# 12/15/01 Matthew
# 12/17 12/18 12/19 12/20 12/21 12/27 12/28 12/30 12/31 Matthew
# 01/01/02 Matthew
# 01/02 01/03 01/04 01/07 01/08 01/09 Matthew
# 01/21 02/05 02/06 2/28Matthew

package Apache::lonplot;

use strict;
use Apache::File;
use Apache::response;
use Apache::lonxml;
use Apache::edit;

BEGIN {
  &Apache::lonxml::register('Apache::lonplot',('gnuplot'));
}

## 
## 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,
     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]=~/^(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 font transparent grid samples 
    border align texwidth/;

my $gnuplot_help_text = <<"ENDPLOTHELP";
<p>
The <b>gnuplot</b> tag allows an author to design a plot which can
be created on the fly.  This is intended for use in homework problems
where each student needs to see a distinct plot.  It can be used in
conjunction with a <b>script</b> tag to generate random plots.
</p><p>
A <b>gnuplot</b> tag can contain the following sub-tags:
</p>
<dl>
<dt> Plot Label
    <dd> Allows you to place text at a given (x,y) coordinate on the plot.
<dt> Plot Title
    <dd> The title of the plot
<dt> Plot Xlabel
    <dd> The label on the horizontal axis of the plot
<dt> Plot Ylabel
    <dd> The label on the vertical axis of the plot
<dt> Plot Axes
    <dd> allows specification of the x and y ranges displayed in the plot
<dt> Plot Key
    <dd> Lists the functions displayed in the plot.
<dt> Plot Curve
    <dd> Sets the data used in the plot.
<dt> Plot Tics
    <dd> Allows specification of the x and y coordinate 'tics' on the axes.
This is mostly used to adjust the grid lines when a grid is displayed.
</dl>
If you are having trouble with your plot, please read the help
available on Plot Curve.
ENDPLOTHELP

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'
	 },
     border       => {
	 default     => 'on',
	 test        => $onoff_test, 
	 description => 'Draw border around plot',
	 edit_type   => 'onoff'
	 },
     font         => {
	 default     => 'medium',
	 test        => $sml_test,
	 description => 'Size of font to use',
	 edit_type   => 'choice',
	 choices     => ['small','medium','large']
	 },
     samples         => {
	 default     => '100',
	 test        => $int_test,
	 description => 'Number of samples for non-data plots',
	 edit_type   => 'choice',
	 choices     => ['100','200','500','1000','2000','5000']
	 },
     align        => {
	 default     => 'center',
	 test        => sub {$_[0]=~/^(left|right|center)$/},
	 description => 'alignment for image in html',
	 edit_type   => 'choice',
	 choices     => ['left','right','center']
	 },
     texwidth     => {
         default     => '93',
         test        => $int_test,
         description => 'Width of plot when printed (mm)',
         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');
my %tic_defaults =
    (
     location => {
	 default => 'border', 
	 test => sub {$_[0]=~/^(border|axis)$/},
	 description => 'Location of tick marks',
	 edit_type   => 'choice',
	 choices     => ['border','axis']
	 },
     mirror => {
	 default => 'on', 
	 test => $onoff_test,
	 description => 'mirror ticks on opposite axis?',
	 edit_type   => 'onoff'
	 },
     start => {
	 default => '-10.0',
	 test => $real_test,
	 description => 'Start ticks at',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     increment => {
	 default => '1.0',
	 test => $real_test,
	 description => 'Place a tick every',
	 edit_type   => 'entry',
	 size        => '10'
	 },
     end => {
	 default => ' 10.0',
	 test => $real_test,
	 description => 'Stop ticks at ',
	 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_help_text = <<"ENDCURVEHELP";
The <b>curve</b> tag is where you set the data to be plotted by gnuplot.
There are two ways of entering the information:
<dl>
    <dt> Curve Data
    <dd> Using a <b>data</b> tag you can specify the numbers used to produce 
the plot.  
<p>
By default, two <b>data</b> tags will be available in a plot.  The
first will specify X coordinates of the data and the second will
give the Y coordinates of the data.  When working with a linestyle that 
requires more than two data sets, inserting another <b>data</b> tag is
required.  Unfortunately, you must make sure the <b>data</b> tags appear
in the order gnuplot expects the data.
</p><p>
Specifying the data should usually be done with a perl variable or array, 
such as \@Xdata and \@Ydata.  You may also specify numerical data seperated 
by commas.  Again, the order of the <b>data</b> tags is important.  The
first tag will be the X data and the second will be the Y data.
</p>
    <dt> Curve Function
    <dd> The <b>function</b> tag allows you to specify the curve to be 
plotted as a formula that gnuplot can understand.  <b>Be careful using this
tag.</b>  It is surprisingly easy to give gnuplot a function it cannot deal
with properly.  Be explicit: 2*sin(2*3.141592*x/4) will work but
2sin(2*3.141592x/4) will not.  If you do not receive any errors in the
gnuplot data but still do not have an image produced, it is likely there
is an error in your <b>function</b> tag.
</dl>
ENDCURVEHELP

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

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)]
	 },
# gnuplots term=gif driver does not handle linewidth :(
#     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]
         }
     );

###################################################################
##                                                               ##
##                    parsing and edit rendering                 ##
##                                                               ##
###################################################################
my (%plot,%key,%axis,$title,$xlabel,$ylabel,@labels,@curves,%xtics,%ytics);

sub start_gnuplot {
    %plot    = ();      %key     = ();      %axis   = (); 
    $title   = undef;   $xlabel  = undef;   $ylabel = undef;
    $#labels = -1;      $#curves = -1;
    %xtics    = ();      %ytics    = ();
    #
    my ($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' || $target eq 'tex') {
	&get_attributes(\%plot,\%gnuplot_defaults,$parstack,$safeeval,
			$tagstack->[-1]);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'GnuPlot');
	$result .= &make_javascript();
	$result .= &help_win($gnuplot_help_text);
	$result .= &edit_attributes($target,$token,\%gnuplot_defaults,
				    \@gnuplot_edit_order);
    } elsif ($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 $randnumber;
    # need to call rand everytime start_script would evaluate, as the
    # safe space rand number generator and the global rand generator 
    # are not seperate
    if ($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);
	$filename = &Apache::lonnet::escape($filename);
	## return image tag for the plot
	if ($target eq 'web') {
	    $result .= <<"ENDIMAGE";
<img src    = "/cgi-bin/plot.gif?file=$filename.data&output=gif" 
     width  = "$plot{'width'}"
     height = "$plot{'height'}"
     align  = "$plot{'align'}"
     alt    = "$plot{'alttag'}" />
ENDIMAGE
        } elsif ($target eq 'tex') {
	    &Apache::lonnet::ssi("/cgi-bin/plot.gif?file=$filename.data&output=eps");

	    $result = '\graphicspath{{/home/httpd/perl/tmp/}}\includegraphics[width='.$plot{'texwidth'}.' mm]{'.&Apache::lonnet::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;
}


##----------------------------------------------------------------- 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;
}

##------------------------------------------------------------------- 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);
	$title=&Apache::run::evaluate($title,$safeeval,$$parstack[-1]);
	$title =~ s/\n/ /g;
	if (length($title) > $max_str_len) {
	    $title = substr($title,0,$max_str_len);
	}
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_start($target,$token,'Plot Title');
	my $text=&Apache::lonxml::get_all_text("/title",$parser);
	$result.=&Apache::edit::end_row().
	    &Apache::edit::start_spanning_row().
	    &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	my $text=$$parser[-1]->get_text("/title");
	$result.=&Apache::edit::rebuild_tag($token);
	$result.=&Apache::edit::modifiedfield($token);
    }
    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);
	$xlabel=&Apache::run::evaluate($xlabel,$safeeval,$$parstack[-1]);
	$xlabel =~ s/\n/ /g;
	if (length($xlabel) > $max_str_len) {
	    $xlabel = substr($xlabel,0,$max_str_len);
	}
    } elsif ($target eq 'edit') {
	$result.=&Apache::edit::tag_start($target,$token,'Plot Xlabel');
	my $text=&Apache::lonxml::get_all_text("/xlabel",$parser);
	$result.=&Apache::edit::end_row().
	    &Apache::edit::start_spanning_row().
	    &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	my $text=$$parser[-1]->get_text("/xlabel");
	$result.=&Apache::edit::rebuild_tag($token);	
	$result.=&Apache::edit::modifiedfield($token);
    }
    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);
	$ylabel = &Apache::run::evaluate($ylabel,$safeeval,$$parstack[-1]);
	$ylabel =~ s/\n/ /g;
	if (length($ylabel) > $max_str_len) {
	    $ylabel = substr($ylabel,0,$max_str_len);
	}
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Plot Ylabel');
	my $text = &Apache::lonxml::get_all_text("/ylabel",$parser);
	$result .= &Apache::edit::end_row().
	    &Apache::edit::start_spanning_row().
	    &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	my $text=$$parser[-1]->get_text("/ylabel");
	$result.=&Apache::edit::rebuild_tag($token);
	$result.=&Apache::edit::modifiedfield($token);
    }
    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);
	$text = &Apache::run::evaluate($text,$safeeval,$$parstack[-1]);
	$text =~ s/\n/ /g;
	$text = substr($text,0,$max_str_len) if (length($text) > $max_str_len);
	$label{'text'} = $text;
	push(@labels,\%label);
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Plot Label');
	$result .= &edit_attributes($target,$token,\%label_defaults);
	my $text = &Apache::lonxml::get_all_text("/label",$parser);
	$result .= &Apache::edit::end_row().
	    &Apache::edit::start_spanning_row().
	    &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%label_defaults));
	$result.=&Apache::edit::rebuild_tag($token);
	my $text=$$parser[-1]->get_text("/label");
	$result.=&Apache::edit::modifiedfield($token);
    }
    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');
	$result .= &help_win($curve_help_text);
	$result .= &edit_attributes($target,$token,\%curve_defaults,
                                    \@curve_edit_order);
    } elsif ($target eq 'modified') {
	my $constructtag=&Apache::edit::get_new_args
	    ($token,$parstack,$safeeval,keys(%curve_defaults));
	if ($constructtag) {
	    $result = &Apache::edit::rebuild_tag($token);
	    $result.= &Apache::edit::handle_insert();
	}
    }
    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);
	$function = &Apache::run::evaluate($function,$safeeval,$$parstack[-1]);
	$curves[-1]->{'function'} = $function; 
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Gnuplot compatible curve function');
	my $text = &Apache::lonxml::get_all_text("/function",$parser);
	$result .= &Apache::edit::end_row().
	    &Apache::edit::start_spanning_row().
	    &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	$result.=&Apache::edit::rebuild_tag($token);
	my $text=$$parser[-1]->get_text("/function");
	$result.=&Apache::edit::modifiedfield($token);
    }
    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);
	$datatext=&Apache::run::evaluate($datatext,$safeeval,$$parstack[-1]);
	# Deal with cases where we're given an array...
	if ($datatext =~ /^\@/) {
	    $datatext = &Apache::run::run('return "'.$datatext.'"',
					  $safeeval,1);
	}
	$datatext =~ s/\s+/ /g;
	# Need to do some error checking on the @data array - 
	# make sure it's all numbers and make sure each array 
	# is of the same length.
	my @data;
	if ($datatext =~ /,/) { # comma deliminated
	    @data = split /,/,$datatext;
	} else { # Assume it's space seperated.
	    @data = split / /,$datatext;
	}
	for (my $i=0;$i<=$#data;$i++) {
	    # Check that it's non-empty
	    if (! defined($data[$i])) {
		&Apache::lonxml::warning(
		    'undefined curve data value.  Replacing with '.
		    ' pi/e = 1.15572734979092');
		$data[$i] = 1.15572734979092;
	    }
	    # Check that it's a number
	    if (! &$real_test($data[$i]) & ! &$int_test($data[$i])) {
		&Apache::lonxml::warning(
		    'Bad curve data value of '.$data[$i].'  Replacing with '.
		    ' pi/e = 1.15572734979092');
		$data[$i] = 1.15572734979092;
	    }
	}
	# complain if the number of data points is not the same as
	# in previous sets of data.
	if (($curves[-1]->{'data'}) && ($#data != $#{@{$curves[-1]->{'data'}->[0]}})){
	    &Apache::lonxml::warning
		('Number of data points is not consistent with previous '.
		 'number of data points');
	}
	push  @{$curves[-1]->{'data'}},\@data;
    } elsif ($target eq 'edit') {
	$result .= &Apache::edit::tag_start($target,$token,'Comma or space deliminated curve data');
	my $text = &Apache::lonxml::get_all_text("/data",$parser);
	$result .= &Apache::edit::end_row().
	    &Apache::edit::start_spanning_row().
	    &Apache::edit::editline('',$text,'',60);
    } elsif ($target eq 'modified') {
	$result.=&Apache::edit::rebuild_tag($token);
	my $text=$$parser[-1]->get_text("/data");
	$result.=&Apache::edit::modifiedfield($token);
    }
    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})) {
	$values->{$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 $gnuplot_input = '';
    my $curve;
    # Collect all the colors
    my @Colors;
    push @Colors, $plot{'bgcolor'};
    push @Colors, $plot{'fgcolor'}; 
    push @Colors, (defined($axis{'color'})?$axis{'color'}:$plot{'fgcolor'});
    foreach $curve (@curves) {
	push @Colors, ($curve->{'color'} ne '' ? 
		       $curve->{'color'}       : 
		       $plot{'fgcolor'}        );
    }
    # set term
    if ($target eq 'web') {
	$gnuplot_input .= 'set term gif ';
	$gnuplot_input .= 'transparent ' if ($plot{'transparent'} eq 'on');
	$gnuplot_input .= $plot{'font'} . ' ';
	$gnuplot_input .= 'size '.$plot{'width'}.','.$plot{'height'}.' ';
	$gnuplot_input .= "@Colors\n";
	# set output
	$gnuplot_input .= "set output\n";
    } elsif ($target eq 'tex') {
	$gnuplot_input .= "set term postscript eps monochrome solid\n";
	$gnuplot_input .= "set output \"/home/httpd/perl/tmp/".
	    &Apache::lonnet::unescape($filename).".eps\"\n";
    }
    # grid
    $gnuplot_input .= 'set grid'.$/ if ($plot{'grid'} eq 'on');
    # border
    $gnuplot_input .= ($plot{'border'} eq 'on'?
		       'set border'.$/           :
		       'set noborder'.$/         );
    # sampling rate for non-data curves
    $gnuplot_input .= "set samples $plot{'samples'}\n";
    # title, xlabel, ylabel
    # titles
    $gnuplot_input .= "set title  \"$title\"\n"  if (defined($title)) ;
    $gnuplot_input .= "set xlabel \"$xlabel\"\n" if (defined($xlabel));
    $gnuplot_input .= "set ylabel \"$ylabel\"\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 (%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";
    }
    # 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') {
        $gnuplot_input .="set size 1,".$plot{'height'}/$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 (exists($curve->{'function'})) {
	    $gnuplot_input.= 
		$curve->{'function'}.' title "'.
		$curve->{'name'}.'" with '.
                $curve->{'linestyle'};
            $gnuplot_input.= ' linewidth 4 ' if ($target eq 'tex');
            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 (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'};
            $gnuplot_input.= ' linewidth 4 ' if ($target eq 'tex');
            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'};
            }
	}
    }
    # Write the output to a file.
    my $fh=Apache::File->new(">$tmpdir$filename.data");
    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 (! %plot) { &set_defaults(\%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') {
	    $result .= &Apache::edit::select_arg
		($description,$attr,$defaults->{$attr}->{'choices'},$token);
	} elsif ($defaults->{$attr}->{'edit_type'} eq 'onoff') {
	    $result .= &Apache::edit::select_arg
		($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;
}

##----------------------------------------------------------------------
# Javascript functions to display help for tags

sub make_javascript {
    my $helpwindowwidth  = 400;
    my $helpwindowheight = 400;
    my $result = '';
    $result.=<<"ENDFUNCTION";
<script language="JavaScript">
function openWin(text)
{
  newWin = open("", "new_W", "width=$helpwindowwidth,height=$helpwindowheight,resizable=1,scrollbars=1");
  newWin.document.open("text/html", "replace");
  newWin.document.writeln(text);
  newWin.document.writeln('<center><a href=\"javascript:window.close()\">close this window</a></center>');
  newWin.document.close();
}
</script>
ENDFUNCTION
    return $result;
}

sub help_win {
    my ($helptext)=@_;
    $helptext =~ s/\n/ /g;
    $helptext =~ s/\'/\\\'/g;
    my $result = '';
    $result.=<<"ENDWIN";
<table width="100%"><tr><td align="right">
<a href="javascript:openWin('$helptext')">help</a>
</td></tr></table><hr />
ENDWIN
    return $result;
}
##----------------------------------------------------------------------
1;
__END__



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