NAME Color::RGB::Util - Utilities related to RGB colors VERSION This document describes version 0.594 of Color::RGB::Util (from Perl distribution Color-RGB-Util), released on 2019-02-13. SYNOPSIS use Color::RGB::Util qw( mix_2_rgb_colors mix_rgb_colors rand_rgb_color assign_rgb_color rgb2grayscale rgb2sepia reverse_rgb_color rgb_luminance tint_rgb_color rgb_distance rgb_diff rgb_is_light rgb_is_dark ); say mix_2_rgb_colors('#ff0000', '#ffffff'); # pink (red + white) say mix_2_rgb_colors('ff0000', 'ffffff', 0.75); # pink with a whiter shade say mix_rgb_colors('ff0000', 1, 'ffffff', 1); # pink (red + white 1 : 1) say mix_rgb_colors('ff0000', 1, 'ffffff', 3); # pink with a whiter shade (red + white 1 : 3) say mix_rgb_colors('ff0000', 1, 'ffffff', 1, '0000ff', 0.5); # bluish pink say rand_rgb_color(); say rand_rgb_color('000000', '333333'); # limit range say assign_rgb_color("foo"); # 0b5d33 say rgb2grayscale('0033CC'); # => 555555 say rgb2sepia('0033CC'); # => 4d4535 say reverse_rgb_color('0033CC'); # => ffcc33 say rgb_luminance('d090aa'); # => ffcc33 say tint_rgb_color('#ff8800', '#0033cc'); # => b36e3c say rgb_distance('000000', '000000') # => 0 say rgb_distance('01f000', '04f400') # => 5 say rgb_distance('ffff00', 'ffffff') # => 255 say rgb_is_dark('404040'); # => 1 say rgb_is_dark('a0a0a0'); # => 0 say rgb_is_light('404040'); # => 0 say rgb_is_light('a0a0a0'); # => 1 say rgb_diff('000000', '000000'); # => 0 say rgb_diff('01f000', '04f400'); # => 5 say rgb_diff('ffff00', 'ffffff'); # => 255 say rgb_diff('000000', '000000', 'approx1'); # => 0 say rgb_diff('01f000', '04f400', 'approx1'); # => 9.06 say rgb_diff('ffff00', 'ffffff', 'approx1'); # => 360.98 DESCRIPTION FUNCTIONS None are exported by default, but they are exportable. mix_2_rgb_colors Usage: my $mixed_rgb = mix_2_rgb_colors($rgb1, $rgb2, $pct); Mix 2 RGB colors. $pct is a number between 0 and 1, by default 0.5 (halfway), the closer to 1 the closer the resulting color to $rgb2. mix_rgb_colors Usage: my $mixed_rgb = mix_rgb_colors($color1, $weight1, $color2, $weight2, ...); Mix several RGB colors. rand_rgb_color Usage: my $rgb = rand_rgb_color([ $low_limit [ , $high_limit ] ]); Generate a random RGB color. You can specify the limit. Otherwise, they default to the full range (000000 to ffffff). assign_rgb_color Usage: my $rgb = assign_rgb_color($str); Map a string to an RGB color. This is done by producing SHA-1 digest (160bit, 20 bytes) of the string, then taking the first, 10th, and last byte to become the RGB color. rgb2grayscale Usage: my $rgb_gs = rgb2grayscale($rgb); Convert $rgb to grayscale RGB value. rgb2sepia Usage: my $rgb_sepia = rgb2sepia($rgb); Convert $rgb to sepia tone RGB value. reverse_rgb_color Usage: my $reversed = reverse_rgb_color($rgb); Reverse $rgb. rgb_luminance Usage: my $luminance = rgb_luminance($rgb); Calculate standard/objective luminance from RGB value using this formula: (0.2126*R) + (0.7152*G) + (0.0722*B) where R, G, and B range from 0 to 1. Return a number from 0 to 1. tint_rgb_color Usage: my $new_rgb = tint_rgb_color($rgb, $tint_rgb, $pct) Tint $rgb with $tint_rgb. $pct is by default 0.5. It is similar to mixing, but the less luminance the color is the less it is tinted with the tint color. This has the effect of black color still being black instead of becoming tinted. rgb_distance Usage: my $dist = rgb_distance($rgb1, $rgb2) Calculate the euclidean RGB distance, using this formula: ( (R1-R2)**2 + (G1-G2)**2 + (B1-B2)**2 )**0.5 For example, the distance between "000000" and "ffffff" is ~441.67, while the distance between "ffff00" and "ffffff" is 255. rgb_diff Usage: my $dist = rgb_diff($rgb1, $rgb2[ , $algo ]) Calculate difference between two RGB colors, using one of several algorithms. The default ("euclidean") simply calculates the distance as: ( (R1-R2)**2 + (G1-G2)**2 + (B1-B2)**2 )**0.5 which is the same as what "rgb_distance"() would produce. Another algorithm ("approx1") uses the following formula: ( 2*(R1-R2)**2 + 4*(G1-G2)**2 + 3*(B1-B2)**2 + Rm*((R1-R2)**2 - (B1-B2)**2)/256 )**0.5 where, Rm or "R mean" is (R1+R2)/2. For more details about color difference, refer to . rgb_is_dark Usage: my $is_dark = rgb_is_dark($rgb) Return true if $rgb is a "dark" color, which is determined by checking if the RGB distance to "000000" is smaller than to "ffffff". rgb_is_light Usage: my $is_light = rgb_is_light($rgb) Return true if $rgb is a "light" color, which is determined by checking if the RGB distance to "000000" is larger than to "ffffff". HOMEPAGE Please visit the project's homepage at . SOURCE Source repository is at . BUGS Please report any bugs or feature requests on the bugtracker website When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature. SEE ALSO Color::ANSI::Util AUTHOR perlancar COPYRIGHT AND LICENSE This software is copyright (c) 2019, 2018, 2015, 2014, 2013 by perlancar@cpan.org. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.