LUT(T)         User Contributed Perl Documentation         LUT(T)



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 (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 functions.

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_names();


       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 sup-
       plied), 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 pack-
       age, 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 (burke@ifa.hawaii.edu), 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 cer-
       tain 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 v5.6.1                 2000-04-23                     LUT(T)