From c37471e7de29ef22e46af32074478bd86a48a0b1 Mon Sep 17 00:00:00 2001
From: Mischa POSLAWSKY <perl@shiar.org>
Date: Sun, 1 Nov 2015 00:11:47 +0100
Subject: [PATCH] termcol: generic h/s/v table generator function

Identical results for 256 colours but reusable for other bit sizes.
---
 termcol.plp | 87 ++++++++++++++++++++++++++++++-----------------------
 1 file changed, 50 insertions(+), 37 deletions(-)

diff --git a/termcol.plp b/termcol.plp
index b5f08b2..d945079 100644
--- a/termcol.plp
+++ b/termcol.plp
@@ -252,55 +252,68 @@ print "</table>\n\n";
 <div class="section">
 <h2>256-colour space</h2>
 <:
-my @colmap;  # saturation => value => hue => [name, r,g,b]
-my %greymap;  # name => value
-$greymap{232 + $_} = $_*10 + 8 for 0 .. 23;
+sub coltable_hsv {
+	my ($dim, $rgbval, $greyramp) = @_;
 
-for my $r (0 .. 5) {
-	for my $g (0 .. 5) {
-		for my $b (0 .. 5) {
-			my $index = $r*6*6 + $g*6 + $b + 16;
-			my @rgb = map { $_ && $_*40 + 55 } $r, $g, $b;
+	my $hmax = ($dim + $dim - 1) * 2 + ($dim - 2) * 2 + 3;
+	my $vmax = $dim - 1;
+	my $smax = $dim - 1;
 
-			my $h = Shiar_Sheet::Colour->new(@rgb)->hue * 33;
-			my $v = int(max(@rgb) / 255 * 5);
-			my $s = abs(min(@rgb) - max(@rgb)) / 255 * 7;
+	my %greymap;  # name => value
+	my @colmap;  # saturation => value => hue => [name, r,g,b]
+	my $offset = 16;
 
-			if (!$s) {
-				$greymap{$index} = $rgb[0];
-				next;
-			}
+	for my $r (0 .. $dim - 1) {
+		for my $g (0 .. $dim - 1) {
+			for my $b (0 .. $dim - 1) {
+				my $index = $r*$dim*$dim + $g*$dim + $b + $offset;
+				my @rgb = map { &$rgbval } $r, $g, $b;
+
+				my $h = Shiar_Sheet::Colour->new(@rgb)->hue * $hmax;
+				my $v = int(max(@rgb) / 255 * $vmax);
+				my $s = abs(min(@rgb) - max(@rgb)) / 255 * $smax;
 
-			$v = 5 - $v;
-			$s = 7 - $s - $v;
-			$s-- if $s;
+				if (!$s) {
+					$greymap{$index} = $rgb[0];
+					next;
+				}
 
-			$colmap[$s][$v][$h] = [$index, @rgb];
+				$v = $vmax - $v;
+				$s = $smax - $s - $v;
+
+				$colmap[$s][$v][$h] = [$index, @rgb];
+			}
 		}
 	}
-}
 
-{
-	print '<table class=mapped>';
-	printf '<colgroup span=%d>', 3 * @{$_} for @colmap;
-	for my $h (grep { $colmap[0][0][$_] } 0 .. $#{ $colmap[0][0] }) {
-		print '<tr>';
-		print colcell(@$_) for map { $_->[$h] } map { @{$_} } @colmap;
+	my $out = '<table class=mapped>';
+	$out .= sprintf '<colgroup span=%d>', 3 * @{$_} for @colmap;
+	my $huerow = $colmap[0][0]; # first {$_} map { @{$_} } @colmap;
+	for my $h (grep { $huerow->[$_] } 0 .. $#{$huerow}) {
+		$out .= '<tr>';
+		$out .= colcell(@$_) for map { $_->[$h] } map { @{$_} } @colmap;
 	}
-	print "</table>\n";
-}
-print "\n";
+	$out .= "</table>\n\n";
 
-	print '<table>';
-my $col = 0;
-my $colbreak = keys(%greymap) / 2;  # split into 2 rows
-for my $num (sort { $greymap{$a} <=> $greymap{$b} } keys %greymap) {
-	print '<tr>' unless $col++ % $colbreak;
-	print colcell($num, ($greymap{$num}) x 3);
+	$offset += $dim ** 3;
+	$greymap{$offset++} = $_ for @{$greyramp};
+
+	$out .= '<table>';
+	my $col = 0;
+	my $colbreak = keys(%greymap) / 2;  # split into 2 rows
+	for my $num (sort { $greymap{$a} <=> $greymap{$b} } keys %greymap) {
+		$out .= '<tr>' unless $col++ % $colbreak;
+		$out .= colcell($num, ($greymap{$num}) x 3);
+	}
+	$out .= "</table>\n\n";
+
+	return $out;
 }
-	print "</table>\n";
-print "\n";
 
+print coltable_hsv(6,
+	sub { $_ && $_*40 + 55 },
+	[ map { $_ * 10 + 8 } 0 .. 23 ],
+);
 :></div>
 <: } :>
 <hr>
-- 
2.30.0