Chart::Color::Value(3)                     User Contributed Perl Documentation


NAME
       Chart::Color::Value - check, convert and measure color values

SYNOPSIS
           my @names = Chart::Color::Value::all_names();
           my @rgb  = Chart::Color::Value::rgb_from_name('darkblue');
           my @hsl  = Chart::Color::Value::hsl_from_name('darkblue');
           my @hsl2 = Chart::Color::Value::hsl_from_rgb( 5 ,10, 100);
           my $d = Chart::Color::Value::distance_hsl( \@hsl, \@hsl2);

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

DESCRIPTION
       RGB and HSL values of named colors from the X11 and HTML standard and
       Pantone report. Allows also reverse search, storage and conversion of
       color values.

       This module is supposed to be used by Chart::Color and not directly by
       the user (for the most part). It converts a stored color name into its
       values (rgb, hsl or both) and back. One color can have multiple names.
       Also nearby (similar) colors can be searched. 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. Independently of that can any
       color be converted from rgb to hsl and back.

ROUTINES
   check_rgb
       Return error message if RGB value triplet is not valid (in range).

   check_hsl
       Return error message if HSL value triplet is not valid (in range).

   trim_rgb
       Change RGB triplet to the nearest valid values.

   trim_hsl
       Change HSL triplet to the nearest valid values.

   hsl_from_rgb
       Converting an rgb value triplet into the corresponding hsl

       Red, Green and Blue are integer in 0 .. 255.  Hue is an integer between
       0 .. 359 (hue) and saturation and lightness are 0 .. 100 (percentage).
       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.

   rgb_from_hsl
       Converting an hsl value triplet into the corresponding rgb (see
       rgb_from_name and hsl_from_name). Please not that back and forth
       conversion can lead to drifting results due to rounding.

           my @rgb = Chart::Color::Value::rgb_from_hsl(0, 90, 50);
           my @rgb = Chart::Color::Value::rgb_from_hsl([0, 90, 50]); # works too
           # for real (none integer results), any none zero value works as second arg
           my @rgb = Chart::Color::Value::rgb_from_hsl([0, 90, 50], 'real');

   distance_rgb
       Distance in (linear) rgb color space between two coordinates.

           my $d = Chart::Color::Value::distance_rgb([1,1,1], [2,2,2]);  # approx 1.7

   distance_hsl
       Distance in (cylindrical) hsl color space between two coordinates.

           my $d = Chart::Color::Value::distance_rgb([1,1,1], [356, 3, 2]); # approx 6

COPYRIGHT & LICENSE
       Copyright 2022 Herbert Breunung.

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

AUTHOR
       Herbert Breunung, <lichtkind@cpan.org>

perl v5.36.0                      2022-09-05            Chart::Color::Value(3)