Algorithm for finding the color between two others - in the colorspace of painted colors

Question

When mixing blue and yellow paint, the result is some sort of green.

I have two rgb colors:

blue = (0, 0, 255)

and yellow = (255, 255, 0)

Wha

Answer 1

Use Convert::Color to produce this sort of output:

mauve        is 0xE0B0FF  sRGB=[224,176,255]  HSV=[276, 31,100] 
vermilion    is 0xE34234  sRGB=[227, 66, 52]  HSV=[  5, 77, 89] 
mix          is 0xE2799A  sRGB=[226,121,154]  HSV=[341, 46, 89] 

red          is 0xFF0000  sRGB=[255,  0,  0]  HSV=[  0,100,100] 
blue         is 0x0000FF  sRGB=[  0,  0,255]  HSV=[240,100,100] 
red+blue     is 0x800080  sRGB=[128,  0,128]  HSV=[300,100, 50] 

black        is 0xFFFFFF  sRGB=[255,255,255]  HSV=[  0,  0,100] 
white        is 0x000000  sRGB=[  0,  0,  0]  HSV=[  0,  0,  0] 
grey         is 0x808080  sRGB=[128,128,128]  HSV=[  0,  0, 50] 

dark red     is 0xFF8080  sRGB=[255,128,128]  HSV=[  0, 50,100] 
light red    is 0x800000  sRGB=[128,  0,  0]  HSV=[  0,100, 50] 

pink         is 0x800080  sRGB=[128,  0,128]  HSV=[300,100, 50] 
deep purple  is 0xBF80FF  sRGB=[191,128,255]  HSV=[270, 50,100] 

When running this sort of code:

#!/usr/bin/env perl
use strict;
use warnings;

use Convert::Color;

main();
exit;

sub rgb($$$) {
    my($r, $g, $b) = @_;
    return new Convert::Color:: "rgb8:$r,$g,$b";
}

sub show($$) {
    my ($name, $color) = @_;
    printf "%-12s is 0x%6s", $name,  uc $color->hex;
    printf "  sRGB=[%3d,%3d,%3d] ",     $color->rgb8;

    my ($h,$s,$v) = $color->as_hsv->hsv;
    for ($s, $v) { $_ *= 100 }
    printf " HSV=[%3.0f,%3.0f,%3.0f] ",  $h, $s, $v;
    print "\n";
}

sub main {
    my $vermilion = rgb 227,  66,  52;
    my $mauve     = rgb 224, 176, 255;
    show mauve      => $mauve;
    show vermilion  => $vermilion;

    my $mix = alpha_blend $mauve $vermilion;
    show mix => $mix;
    print "\n";

    my $red   = rgb 255,   0,   0;
    my $blue  = rgb   0,   0, 255;
    show red  => $red;
    show blue => $blue;

    $mix = alpha_blend $red $blue;
    show "red+blue" => $mix;
    print "\n";

    my $black = rgb 255, 255, 255;
    my $white = rgb 0,     0,   0;
    show black => $black;
    show white => $white;

    my $grey  = alpha_blend $black $white;
    show grey  => $grey;
    print "\n";

    my $dark_red  = alpha_blend $red $black;
    my $light_red = alpha_blend $red $white;

    show "dark red"  => $dark_red;
    show "light red" => $light_red;
    print "\n";

    my $magenta = rgb 255, 0, 255;
    my $violet  = rgb 127, 0, 255;

    my $pink        = alpha_blend $magenta $white;
    my $deep_purple = alpha_blend $violet  $black;

    show pink          => $pink;
    show "deep purple" => $deep_purple;;
}