From 9212c742b75a0dfcf6f2d42efa7cedeb695ff139 Mon Sep 17 00:00:00 2001
From: Patrick Walton <pcwalton@mimiga.net>
Date: Tue, 31 Mar 2020 13:28:55 -0700
Subject: [PATCH] Avoid taking the square root of a negative number in
 `arc_from_cos()`.

---
 content/src/segment.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/content/src/segment.rs b/content/src/segment.rs
index 093ad518..c2115cbf 100644
--- a/content/src/segment.rs
+++ b/content/src/segment.rs
@@ -84,6 +84,10 @@ impl Segment {
         // approximates a small arc", 2004.
         //
         // https://www.tinaja.com/glib/bezcirc2.pdf
+        if cos_sweep_angle >= 1.0 - EPSILON {
+            return Segment::line(LineSegment2F::new(vec2f(1.0, 0.0), vec2f(1.0, 0.0)));
+        }
+
         let term = F32x4::new(cos_sweep_angle, -cos_sweep_angle,
                               cos_sweep_angle, -cos_sweep_angle);
         let signs = F32x4::new(1.0, -1.0, 1.0, 1.0);