LUT(3)							User Contributed Perl Documentation						    LUT(3)

NAME

       PDL::Graphics::LUT - provides access to a number of look-up tables

SYNOPSIS

	use PDL::Graphics::PGPLOT;
	use PDL::Graphics::LUT;

	# what tables are available
	my @tables = lut_names();

	# get the reversed colour table 'smooth',
	# with the gamma intensity ramp
	my ( $l, $r, $g, $b ) = lut_data( 'smooth', 1, 'gamma' );

	# use the table idl5 in ctab
	ctab( lut_data('idl5') );

DESCRIPTION

       PDL::Graphics::LUT contains a number of colour look-up tables (in rgb format) and intensity ramps, and provides routines to access this
       data.  The format of the data is suitable for use by "ctab" in PDL::Graphics::PGPLOT.

       Unlike the initial release of the package, the data tables are now stored within the PDL distribution as FITS files (see $tabledir and
       $rampdir), rather than in the module itself.  Changes to these directories will be picked up on the next call to one of the package func-
       tions.

FUNCTIONS

       lut_names()

       Return, as a list, the names of the available colour tables.

	@tables = lut_names();

       lut_ramps()

       Return, as a list, the names of the available intensity ramps.

	@ramps = lut_ramps();

       lut_data()

       Load in the requested colour table and intensity ramp.

	( $l, $r, $g, $b ) = lut_data( $table, [ $reverse, [ $ramp ] ] );

       Returns the levels and r, g, b components of the colour table $table. If $reverse is 1 (defaults to 0 if not supplied), then the r, g, and
       b components are reversed before being returned.  If not supplied, $ramp defaults to "ramp" (this is a linear intensity ramp).

       The returned values are piddles containing values in the range 0 to 1 inclusive, and are floats.

VARIABLES

       $tabledir

       The directory in which the colour tables (in rgb format) are stored.

       $rampdir

       The directory in which the intensity ramps are stored.

       $suffix

       The suffix for the data files in $tabledir and $rampdir.

FURTHER INFORMATION

       The colour tables were taken from the STARLINK GAIA package, and are provided under the GNU copyleft.  See http://star-www.rl.ac.uk/ and
       http://star-www.dur.ac.uk/~pdraper/ for more details.

AUTHOR

       Doug Burke (djburke@cpan.org), with thanks to Peter Draper/STARLINK for providing the colour-table data, and Christian Soeller and Karl
       Glazebrook for their help.

       All rights reserved. There is no warranty. You are allowed to redistribute this software / documentation under certain conditions. For
       details, see the file COPYING in the PDL distribution. If this file is separated from the PDL distribution, the copyright notice should be
       included in the file.

perl v5.8.0							    2002-04-24								    LUT(3)