=head1 NAME

  PDL::Graphics::TriD::Contours - 3D Surface contours for TriD

=head1 SYNOPSIS

=for usage

    # A simple contour plot in black and white

    use PDL::Graphics::TriD;
    use PDL::Graphics::TriD::Contours;
    $size = 25;
    $x = (xvals zeroes $size,$size) / $size;
    $y = (yvals zeroes $size,$size) / $size;
    $z = (sin($x*6.3) * sin($y*6.3)) ** 3;
    $data=new PDL::Graphics::TriD::Contours($z,
               [$z->xvals/$size,$z->yvals/$size,0]);
    PDL::Graphics::TriD::graph_object($data)

=cut 

package PDL::Graphics::TriD::Contours;
use strict;
use PDL;
use PDL::Graphics::TriD;
use PDL::Graphics::TriD::Rout;
use PDL::Graphics::TriD::Labels;
#use Data::Dumper;

use base qw/PDL::Graphics::TriD::GObject/;
use fields qw/ContourSegCnt Labels LabelStrings/;

=head1 FUNCTIONS

=head2 new()

=for ref

Define a new contour plot for TriD.  

=for example

  $data=new PDL::Graphics::TriD::Contours($d,[$x,$y,$z],[$r,$g,$b],$options);

where $d is a 2D pdl of data to be contoured. [$x,$y,$z] define a 3D
map of $d into the visualization space [$r,$g,$b] is an optional [3,1]
piddle specifing the contour color and $options is a hash reference to
a list of options documented below.  Contours can also be colored by
value using the set_color_table function.

=for opt

  ContourInt  => 0.7  # explicitly set a contour interval
  ContourMin  => 0.0  # explicitly set a contour minimum
  ContourMax  => 10.0 # explicitly set a contour maximum
  ContourVals => $pdl # explicitly set all contour values
  Label => [1,5,$myfont] # see addlabels below 
  Font =>  $font      # explicitly set the font for contour labels

  If ContourVals is specified ContourInt, ContourMin, and ContourMax
  are ignored.  If no options are specified, the algorthym tries to
  choose values based on the data supplied.  Font can also be specified or
  overwritten by the addlabels() function below.

=cut

sub new{
  my($type,$data,$points,$colors,$options) = @_;

  if(! defined $points){
	 $points = [$data->xvals,$data->yvals,$data->zvals];
  }

  if(ref($colors) eq "HASH"){
    $options=$colors ;
    undef $colors;
  }

  $colors = PDL::Graphics::TriD::realcoords("COLOR",pdl[1,1,1]) unless defined $colors;

  my $this = $type->SUPER::new($points,$colors,$options);

  my $grid = $this->{Points};

  $this->{ContourSegCnt} = [];

  my @lines;
  my($xmin,$dx,$ymin,$dy);

  my @dims = $data->dims();

  my $d0 = $dims[0]-1;
  my $d1 = $dims[1]-1;

  
  my ($min,$max) = $data->minmax();


  my $fac=1;

  unless(defined $this->{Options}{ContourMin}){
    while($fac*($max-$min)<10){
      $fac*=10;
    }
    if(int($fac*$min) == $fac*$min){
      $this->{Options}{ContourMin} = $min;
    }else{      
      $this->{Options}{ContourMin} = int($fac*$min+1)/$fac;
      print "ContourMin =  ",$this->{Options}{ContourMin},"\n"
		  if($PDL::Graphics::TriD::verbose);
    }
  }
  unless(defined $this->{Options}{ContourMax} && 
			$this->{Options}{ContourMax} > $this->{Options}{ContourMin} ){
    if(defined $this->{Options}{ContourInt}){
      $this->{Options}{ContourMax} = $this->{Options}{ContourMin};
      while($this->{Options}{ContourMax}+$this->{Options}{ContourInt} < $max){
	$this->{Options}{ContourMax}= $this->{Options}{ContourMax}+$this->{Options}{ContourInt};
      }
    }else{
      if(int($fac*$max) == $fac*$max){
	$this->{Options}{ContourMax} = $max;
      }else{
	$this->{Options}{ContourMax} = (int($fac*$max)-1)/$fac;
      print "ContourMax =  ",$this->{Options}{ContourMax},"\n"
		  if($PDL::Graphics::TriD::verbose);
      }
    }
  }
  unless(defined $this->{Options}{ContourInt} &&  $this->{Options}{ContourInt}>0){
    $this->{Options}{ContourInt} = int($fac*($this->{Options}{ContourMax}-$this->{Options}{ContourMin}))/(10*$fac);
    print "ContourInt =  ",$this->{Options}{ContourInt},"\n"
		if($PDL::Graphics::TriD::verbose);
  }
#
# The user could also name cvals
#
  my $cvals;
  if( !defined($this->{Options}{ContourVals}) || $this->{Options}{ContourVals}->isempty){
    $cvals=zeroes(int(($this->{Options}{ContourMax}-$this->{Options}{ContourMin})/$this->{Options}{ContourInt}+1));
    $cvals = $cvals->xlinvals($this->{Options}{ContourMin},$this->{Options}{ContourMax});  
  }else{
    $cvals = $this->{Options}{ContourVals};
    $this->{Options}{ContourMax}=$cvals->max;
    $this->{Options}{ContourMin}=$cvals->min;
  }
  $this->{Options}{ContourVals} = $cvals;

  print "Cvals = $cvals\n" if($PDL::Graphics::TriD::verbose);  
  
  $this->contour_segments($cvals,$data,$grid);

  $this->addlabels($this->{Options}{Labels}) if(defined $this->{Options}{Labels});

  return $this;
}      



sub get_valid_options{
  return{ ContourInt => undef, 
			 ContourMin => undef, 
			 ContourMax=>  undef, 
			 ContourVals=> pdl->null,
			 UseDefcols=>1,
	                 Labels=> undef,
			 Font=>$PDL::Graphics::TriD::GL::fontbase}
}




=head2 addlabels()

=for ref

Add labels to a contour plot 

=for usage

  $contour->addlabels($labelint,$segint,$font);

$labelint is the integer interval between labeled contours.  If you
have 8 countour levels and specify $labelint=3 addlabels will attempt
to label the 1st, 4th, and 7th contours.  $labelint defaults to 1.

$segint specifies the density of labels on a single contour
level.  Each contour level consists of a number of connected 
line segments, $segint defines how many of these segments get labels.
$segint defaults to 5, that is every fifth line segment will be labeled.
  

=cut

sub addlabels{
  my ($self,$labelint, $segint ,$font) = @_;

  $labelint = 1 unless(defined $labelint);
  $font =  $self->{Options}{Font} unless(defined $font);
  $segint = 5 unless(defined $segint);

  my $cnt=0;

  my $strlist;
  my $lp=pdl->null;

  my $pcnt = 0;
  my $cnt;
  my $offset = pdl[0.5,0.5,0.5];

  for(my $i=0; $i<= $#{$self->{ContourSegCnt}}; $i++){
    next unless defined $self->{ContourSegCnt}[$i];
    $cnt = $self->{ContourSegCnt}[$i];
    my $val = $self->{Options}{ContourVals}->slice("($i)");
   
    my $leg =  $self->{Points}->slice(":,$pcnt:$cnt");
    $pcnt=$cnt+1;

    next if($i % $labelint);

    for(my $j=0; $j< $leg->getdim(1); $j+=2){
      next if(($j/2) % $segint);

		my $j1=$j+1;

      my $lp2 = $leg->slice(":,($j)") + 
                $offset*($leg->slice(":,($j1)") -       
					  $leg->slice(":,($j)"));

		
		$lp = $lp->append($lp2);
# need a label string for each point    
		push(@$strlist,$val);

	 }
	 
  }
  if($lp->nelem>0){
	 $self->{Points} = $self->{Points}->xchg(0,1)
		->append($lp->reshape(3,$lp->nelem/3)->xchg(0,1))->xchg(0,1);
	 $self->{Labels} = [$cnt+1,$cnt+$lp->nelem/3];
	 $self->{LabelStrings} = $strlist;
	 $self->{Options}{Font}=$font;
  }

}

=head2 set_colortable($table)

=for ref

Sets contour level colors based on the color table.

=for usage 

$table is passed in as either a piddle of [3,n] colors, where n is the
number of contour levels, or as a reference to a function which
expects the number of contour levels as an argument and returns a
[3,n] piddle.  It should be straight forward to use the
L<PDL::Graphics::LUT> tables in a function which subsets the 256
colors supplied by the look up table into the number of colors needed
by Contours.

=cut

sub set_colortable{
  my($self,$table) = @_;
  my $colors;
  if(ref($table) eq "CODE"){
	 my $min = $self->{Options}{ContourMin};
	 my $max = $self->{Options}{ContourMax};  
	 my $int = $self->{Options}{ContourInt};
	 my $ncolors=($max-$min)/$int+1;  
	 $colors= &$table($ncolors);
  }else{
	 $colors = $table;
  }

  if($colors->getdim(0)!=3){
    $colors->reshape(3,$colors->nelem/3);
  }
  print "Color info ",$self->{Colors}->info," ",$colors->info,"\n" if($PDL::Graphics::TriD::verbose);
 
  $self->{Colors} = $colors;
}

=head2 coldhot_colortable()

=for ref 

A simple colortable function for use with the set_colortable function.

=for usage 

coldhot_colortable defines a blue red spectrum of colors where the
smallest contour value is blue, the highest is red and the others are
shades in between.

=cut 

sub coldhot_colortable{
  my($ncolors) = @_;
  my $colorpdl;
  # 0 red, 1 green, 2 blue
  for(my $i=0;$i<$ncolors;$i++){
    my $color = zeroes(float,3);
    (my $t = $color->slice("0")) .= 0.75*($i)/$ncolors;
    ($t = $color->slice("2")) .= 0.75*($ncolors-$i)/$ncolors;
    if($i==0){
      $colorpdl = $color;
    }else{
      $colorpdl = $colorpdl->append($color);
    }
  }
  return($colorpdl);  
}
  
1;