From babd4884ddc7a3f0d6a47f52e5e3c27ddfda10be Mon Sep 17 00:00:00 2001
From: Lex Neva <github.com@lexneva.name>
Date: Wed, 18 Mar 2020 22:54:25 -0400
Subject: [PATCH] avoid math domain error
---
lib/extensions/convert_to_satin.py | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/lib/extensions/convert_to_satin.py b/lib/extensions/convert_to_satin.py
index c666b6251..cf292281a 100644
--- a/lib/extensions/convert_to_satin.py
+++ b/lib/extensions/convert_to_satin.py
@@ -164,6 +164,13 @@ class ConvertToSatin(InkstitchExtension):
# The dot product of two vectors is |v1| * |v2| * cos(angle).
# These are unit vectors, so their magnitudes are 1.
cos_angle_between = prev_direction * direction
+
+ # Clamp to the valid range for a cosine. The above _should_
+ # already be in this range, but floating point inaccuracy can
+ # push it outside the range causing math.acos to throw
+ # ValueError ("math domain error").
+ cos_angle_between = max(-1.0, min(1.0, cos_angle_between))
+
angle = abs(math.degrees(math.acos(cos_angle_between)))
# Use the square of the angle, measured in degrees.