#
# Created by BAD2_demo.pm.PL
#  ** DO NOT EDIT THIS FILE **
#
package PDL::Demos::BAD2_demo;
use PDL;
use PDL::IO::Misc;
use PDL::Graphics::PGPLOT;

use File::Spec;

PDL::Demos::Routines->import();
sub comment($);
sub act($);
sub output;

sub run {


$ENV{PGPLOT_XW_WIDTH}=0.6;
$ENV{PGPLOT_DEV}=$^O =~ /MSWin32/ ? '/GW' : "/XSERVE";

# try and find m51.fits
$d = File::Spec->catdir( "PDL", "Demos" );
$m51path = undef;
foreach my $path ( @INC ) {
    my $check = File::Spec->catdir( $path, $d );
    if ( -d $check ) { $m51path = $check; last; }
}
barf "Unable to find directory ${m51path} within the perl libraries.\n"
    unless defined $m51path;

comment q|
    This demo is just a bit of eye-candy to show bad values in action,
    and requires PGPLOT support in PDL. It makes use of the image of
    M51 kindly provided by the Hubble Heritage group at the
    Space Telescope Science Institute.

    It also serves to demonstrate that you often don't need to change
    your code to handle bad values, as the routines may 'do it' for you.

|;

act q|

    # read in the image ($m51path has been set up by this demo to
    # contain the location of the file)
    $m51 = rfits "$m51path/m51.fits";

    # display it
    $just = { JUSTIFY => 1 };
    imag $m51, $just;

    # These are used to create the next image
    ( $nx, $ny ) = $m51->dims;
    $centre = [ $nx/2, $ny/2 ];
|;

act q|

    # now, let's mask out the central 40 pixels and display it
    $masked = $m51->setbadif( $m51->rvals({CENTRE=>$centre}) < 40 );

    # since imag auto-scales the output, the bad values are not displayed
    imag $masked, $just;

    # compare the statistics of the images
    # (as $PDL::verbose = 1, stats prints out the answers itself)
    print "Original:\n"; $m51->stats;
    print "Masked:\n";   $masked->stats;

|;

act q|

    # let's filter it a little bit
    use PDL::Image2D;
    $nb = 15;
    $filtered = med2d $masked, ones($nb,$nb), { Boundary => 'Truncate' };

    # this is a model of the diffuse component of M51
    imag $filtered, $just;

|;

act q|

    # unsharp masking, to bring out the small-scale detail
    $unsharp = $masked - $filtered;

    imag $unsharp, $just;

|;

act q|

    # add on some contours showing the large scale structure of the galaxy
    imag $unsharp, $just;
    hold;
    cont $filtered;
    rel;

|;


}

1;

