Graphics::Toolkit::Color::Name - access values of color constants

       Herbert Breunung, <lichtkind@cpan.org>

perl v5.36.0                                       2023-11-03                Graphics::Toolkit::Color::Name(3pm)

       Copyright 2022-23 Herbert Breunung.

       This program is free software; you can redistribute it and/or modify it under same terms as Perl itself.

       RGB and HSL values of named colors from the X11, HTML(CSS), SVG standard and Pantone report. Allows also
       nearby search, reverse search and storage (not permanent) of additional names. One color may have
       multiple names.  Own colors can be (none permanently) stored for later reference by name.  For this a
       name has to be chosen, that is not already taken. The corresponding color may be defined by an RGB or HSL
       triplet.

       No symbol is imported by default. The sub symbols: "rgb_from_name", "hsl_from_name", "name_from_rgb",
       "name_from_hsl" may be imported individually or by:

           use Graphics::Toolkit::Color::Name qw/:all/;

       Graphics::Toolkit::Color::Name - access values of color constants

rgb_from_name
       Red, Green and Blue value of the named color.  These values are integer in 0 .. 255.

           my @rgb = Graphics::Toolkit::Color::Name::rgb_from_name('darkblue');
           @rgb = Graphics::Toolkit::Color::Name::rgb_from_name('dark_blue'); # same result
           @rgb = Graphics::Toolkit::Color::Name::rgb_from_name('DarkBlue');  # still same

   hsl_from_name
       Hue, saturation and lightness of the named color.  These are integer between 0 .. 359 (hue) or 100 (sat.
       & light.).  A hue of 360 and 0 (degree in a cylindrical coordinate system) is considered to be the same,
       this modul deals only with the ladder.

           my @hsl = Graphics::Toolkit::Color::Name::hsl_from_name('darkblue');

   name_from_rgb
       Returns name of color with given rgb value triplet.  Returns empty string if color is not stored. When
       several names define given color, the shortest name will be selected in scalar context.  In array context
       all names are given.

           say Graphics::Toolkit::Color::Name::name_from_rgb( 15, 10, 121 );  # 'darkblue'
           say Graphics::Toolkit::Color::Name::name_from_rgb([15, 10, 121]);  # works too

   name_from_hsl
       Returns name of color with given hsl value triplet.  Returns empty string if color is not stored. When
       several names define given color, the shortest name will be selected in scalar context.  In array context
       all names are given.

           say scalar Graphics::Toolkit::Color::Name::name_from_hsl( 0, 100, 50 );  # 'red'
           scalar Graphics::Toolkit::Color::Name::name_from_hsl([0, 100, 50]);  # works too
           say for Graphics::Toolkit::Color::Name::name_from_hsl( 0, 100, 50 ); # 'red', 'red1'

   names_in_hsl_range
       Color names in selected neighbourhood of hsl color space, that look similar.  It requires two arguments.
       The first one is an array containing three values (hue, saturation and lightness), that define the center
       of the neighbourhood (searched area).

       The second argument can either be a number or again an array with three values (h,s and l). If its just a
       number, it will be the radius r of a ball, that defines the neighbourhood. From all colors inside that
       ball, that are equal distanced or nearer to the center than r, one name will returned.

       If the second argument is an array, it has to contain the tolerance (allowed distance) in h, s and l
       direction. Please note the h dimension is circular: the distance from 355 to 0 is 5. The s and l
       dimensions are linear, so that a center value of 90 and a tolerance of 15 will result in a search of in
       the range 75 .. 100.

       The results contains only one name per color (the shortest).

           # all bright red'ish clors
           my @names = Graphics::Toolkit::Color::Name::names_in_hsl_range([0, 90, 50], 5);
           # approximates to :
           my @names = Graphics::Toolkit::Color::Name::names_in_hsl_range([0, 90, 50],[ 3, 3, 3]);

   all
       A sorted list of all stored color names.

   taken
       A perlish pseudo boolean tells if the color name (first and only, required argument) is already in use.

   add_rgb
       Adding a color to the store under an not taken (not already used) name.  Arguments are name, red, green
       and blue value (integer < 256, see rgb).

           Graphics::Toolkit::Color::Name::add_rgb('nightblue',  15, 10, 121 );
           Graphics::Toolkit::Color::Name::add_rgb('nightblue', [15, 10, 121]);

   add_hsl
       Adding a color to the store under an not taken (not already used) name.  Arguments are name, hue,
       saturation and lightness value (see hsl).

           Graphics::Toolkit::Color::Name::add_rgb('lucky',  0, 100, 50 );
           Graphics::Toolkit::Color::Name::add_rgb('lucky', [0, 100, 50]);

       Color::Library

       Graphics::ColorNamesLite::All

           use Graphics::Toolkit::Color::Name qw/:all/;
           my @names = Graphics::Toolkit::Color::Name::all();
           my @rgb  = rgb_from_name('darkblue');
           my @hsl  = hsl_from_name('darkblue');

           Graphics::Toolkit::Color::Value::add_rgb('lucky', [0, 100, 50]);