1LUT(3)                User Contributed Perl Documentation               LUT(3)
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NAME

6       PDL::Graphics::LUT - provides access to a number of look-up tables
7

SYNOPSIS

9        use PDL::Graphics::PGPLOT;
10        use PDL::Graphics::LUT;
11
12        # what tables are available
13        my @tables = lut_names();
14
15        # get the reversed colour table 'smooth',
16        # with the gamma intensity ramp
17        my ( $l, $r, $g, $b ) = lut_data( 'smooth', 1, 'gamma' );
18
19        # use the table idl5 in ctab
20        ctab( lut_data('idl5') );
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DESCRIPTION

23       PDL::Graphics::LUT contains a number of colour look-up tables (in rgb
24       format) and intensity ramps, and provides routines to access this data.
25       The format of the data is suitable for use by ctab.
26
27       Unlike the initial release of the package, the data tables are now
28       stored within the PDL distribution as FITS files (see $tabledir and
29       $rampdir), rather than in the module itself.  Changes to these
30       directories will be picked up on the next call to one of the package
31       functions.
32

FUNCTIONS

34   lut_names()
35       Return, as a list, the names of the available colour tables.
36
37        @tables = lut_names();
38
39   lut_ramps()
40       Return, as a list, the names of the available intensity ramps.
41
42        @ramps = lut_ramps();
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44   lut_data()
45       Load in the requested colour table and intensity ramp.
46
47        my ( $l, $r, $g, $b ) = lut_data( $table, [ $reverse, [ $ramp ] ] );
48
49       Returns the levels and r, g, b components of the colour table $table.
50       If $reverse is 1 (defaults to 0 if not supplied), then the r, g, and b
51       components are reversed before being returned.  If not supplied, $ramp
52       defaults to "ramp" (this is a linear intensity ramp).
53
54       The returned values are piddles containing values in the range 0 to 1
55       inclusive, and are floats.
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VARIABLES

58   $tabledir
59       The directory in which the colour tables (in rgb format) are stored.
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61   $rampdir
62       The directory in which the intensity ramps are stored.
63
64   $suffix
65       The suffix for the data files in $tabledir and $rampdir.
66

FURTHER INFORMATION

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

73       Doug Burke (djburke@cpan.org), with thanks to Peter Draper/STARLINK for
74       providing the colour-table data, and Christian Soeller and Karl
75       Glazebrook for their help.
76
77       All rights reserved. There is no warranty. You are allowed to
78       redistribute this software / documentation under certain conditions.
79       For details, see the file COPYING in the PDL distribution. If this file
80       is separated from the PDL distribution, the copyright notice should be
81       included in the file.
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85perl v5.32.0                      2020-09-17                            LUT(3)
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