Re: Re: Hex color degrader

[BrowserUk]

Agreed. That makes perfect sense. However, why not take it one step further and make the function darken or lighten as required.

#! perl -sw
use strict;
local $\=$/;

sub Dlighken {
  return sprintf '%02x'x3,
      map{ ($_ *= 1+$_[1]) > 0xff ? 0xff : $_  }
      map hex, unpack 'A2'x3, $_[0];
}

my @colors = qw/800000 808000 008000 008080 000080 808080 c0c0c0/;

print '<table>';
print '<tr><td>&nbsp;</td>', map{ 
    '<th>'.$_.'</th>' 
} @colors, '</tr>'; 

for my $scale ( -5 .. +5 ) {
    print '<tr><td>'.($scale/10).'</td>';
    print '<td bgcolor="#', $_, '">', $_, '</td>' 
        for map{ Dlighken($_, $scale/10) } @colors;
    print '</tr>';
}
print '</table>';
__END__

renders as

	800000	808000	008000	008080	000080	808080	c0c0c0
-0.5	400000	404000	004000	004040	000040	404040	606060
-0.4	4c0000	4c4c00	004c00	004c4c	00004c	4c4c4c	737373
-0.3	590000	595900	005900	005959	000059	595959	868686
-0.2	660000	666600	006600	006666	000066	666666	999999
-0.1	730000	737300	007300	007373	000073	737373	acacac
0	800000	808000	008000	008080	000080	808080	c0c0c0
0.1	8c0000	8c8c00	008c00	008c8c	00008c	8c8c8c	d3d3d3
0.2	990000	999900	009900	009999	000099	999999	e6e6e6
0.3	a60000	a6a600	00a600	00a6a6	0000a6	a6a6a6	f9f9f9
0.4	b30000	b3b300	00b300	00b3b3	0000b3	b3b3b3	ffffff
0.5	c00000	c0c000	00c000	00c0c0	0000c0	c0c0c0	ffffff

---

Cor! Like yer ring! ... HALO dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!

[Aristotle]

Not a bad point, but I'd stick to having a brightness value passed, not a scaling factor. It's a bit easier to have a rough idea of the outcome that way IMO.

sub add_to_hexrgb {
    my @rgb = map hex, unpack "A2"x3, $_[0];
    my $max = (sort {$a <=> $b} @rgb)[-1];
    my $smax = $max + $_[1];

    return
        $smax < 0 ? "000000" :
        $smax > 255 ? "FFFFFF" :
        do {
            my $fact = ($max + $sumd) / $max;
            sprintf "%02X"x3, map { int($_ * $fact) } @rgb
        };
}

Makeshifts last the longest.