From d2cf92fd61b43f998ad2ff931d3c8cd9583494f8 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 2 Mar 2019 17:18:39 +0000
Subject: [PATCH] vec2atan

---
 generate-board | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/generate-board b/generate-board
index d99c431..3e4e9bc 100755
--- a/generate-board
+++ b/generate-board
@@ -175,13 +175,14 @@ sub prvec ($) {
 }
 
 sub mkvec ($$) { Math::GSL::Vector->new(\@_) }
+sub vec2atan ($) { my ($dir) = @_; atan2 $dir->get(1), $dir->get(0); }
 
 sub transform_coordinates () {
   # Adjusts coordinates in graph to be [0,0] .. top right (scaled)
   # until it's all in PostScript points
   my @or = map { $region{$_}{Centre} } @{ $c{OrientRegions} };
   my $dir = $or[1] - $or[0];
-  my $theta = atan2 $dir->get(1), $dir->get(0);
+  my $theta = vec2atan($dir);
   my $rotateby = (90. - $c{OrientBearing}) * ((TAU)/360.) - $theta;
   my $s = sin($rotateby);
   my $c = cos($rotateby);
-- 
2.30.2