From: Mischa POSLAWSKY <perl@shiar.org>
Date: Sun, 7 Feb 2016 23:18:05 +0000 (+0100)
Subject: termcol: avoid hexadecimal conversion for newyuv colours
X-Git-Tag: v1.9~34
X-Git-Url: http://git.shiar.nl/sheet.git/commitdiff_plain/1b74f2fe18e42ec7acd07793fc45da6c0849fcc9

termcol: avoid hexadecimal conversion for newyuv colours

Simplify default initialiser; previous version available as newyuv8().
---

diff --git a/Shiar_Sheet/Colour.pm b/Shiar_Sheet/Colour.pm
index cf22f3e..e431cfe 100644
--- a/Shiar_Sheet/Colour.pm
+++ b/Shiar_Sheet/Colour.pm
@@ -4,7 +4,7 @@ use strict;
 use warnings;
 use List::Util qw( min max );
 
-our $VERSION = '1.04';
+our $VERSION = '1.05';
 
 # ITU-R recommendation 601 luma co-efficients
 our $kr = .299;
@@ -20,12 +20,9 @@ sub new {
 }
 
 sub newyuv {
-	# convert from YPbPr values 0..255 (or hex string)
+	# convert from YPbPr values -1..1
 	my $class = shift;
-	my ($y, $cb, $cr) = @_ >= 3 ? @_ : (map {hex} $_[0] =~ /(..)/g);
-
-	$_ -= 128 for $cb, $cr;
-	$_ /= 255 for $y, $cb, $cr;
+	my ($y, $cb, $cr) = @_;
 
 	my @rgb = map { max(0, min(255, $_ * 255)) } (
 		$y                             + $cr,
@@ -35,6 +32,17 @@ sub newyuv {
 	bless \@rgb, $class;
 }
 
+sub newyuv8 {
+	# convert from YPbPr values 0..255 (or hex string)
+	my $class = shift;
+	my ($y, $cb, $cr) = @_ >= 3 ? @_ : (map {hex} $_[0] =~ /(..)/g);
+
+	$_ -= 128 for $cb, $cr;
+	$_ /= 255 for $y, $cb, $cr;
+
+	$class->newyuv($y, $cb, $cr);
+}
+
 sub luminance {
 	# perceived brightness
 	my ($r, $g, $b) = @{ $_[0] };
diff --git a/termcol.inc.pl b/termcol.inc.pl
index eef6a8b..d4741ed 100644
--- a/termcol.inc.pl
+++ b/termcol.inc.pl
@@ -1,6 +1,6 @@
 use strict;
 use 5.010;
-use Shiar_Sheet::Colour '1.02';
+use Shiar_Sheet::Colour '1.05';
 
 +{
 	html => {
@@ -149,8 +149,8 @@ use Shiar_Sheet::Colour '1.02';
 			}
 
 			# convert to rgb
-			$y *= 255 / 32;
-			$_ = $_ * 127.5 + 128 for $u, $v;
+			$y /= 32;
+			$_ /= 2 for $u, $v;
 			Shiar_Sheet::Colour->newyuv($y, $u, $v)->rgb48;
 		} qw(
 			0    32  10+5 20-5 12+2 16-2 8+0  24-0
@@ -163,8 +163,7 @@ use Shiar_Sheet::Colour '1.02';
 		name => 'MSX',
 		list => [ map {
 			my ($y, @c) = split /;/;
-			$y *= 255;
-			$_ = ($_ - .47) / .53 * 127.5 + 128 for @c;
+			$_ = ($_ - .47) / .53 / 2 for @c;
 			Shiar_Sheet::Colour->newyuv($y, @c)->rgb48;
 		} qw(
 			0.00;0.47;0.47 0.00;0.47;0.47 0.53;0.20;0.07 0.67;0.27;0.17