From 316dc8bfe96f9443e11aab7b2b70951a35758282 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Anders=20Granskogen=20Bj=C3=B8rnstad?= <anders@imerso.com>
Date: Fri, 10 Nov 2017 13:39:43 +0100
Subject: [PATCH 1/2] test_parsing.py: Add test_roundoff example

This test currently fails due to math.acos(1.0000000000001) raising a
ValueError.
---
 test/test_parsing.py | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/test/test_parsing.py b/test/test_parsing.py
index c052ad8..3cdcfc2 100644
--- a/test/test_parsing.py
+++ b/test/test_parsing.py
@@ -137,3 +137,31 @@ class TestParser(unittest.TestCase):
 
     def test_errors(self):
         self.assertRaises(ValueError, parse_path, 'M 100 100 L 200 200 Z 100 200')
+
+    def test_roundoff(self):
+        """Paths with arc segments may have floating point round-off issues"""
+        path1 = parse_path("""
+        M160.172,102.95
+        L159.922,102.95
+        A0.025,0.025 0 0,1 159.897,102.925
+        L159.897,102.675
+        A0.025,0.025 0 0,1 159.922,102.65
+        L160.172,102.65
+        A0.025,0.025 0 0,1 160.197,102.675
+        L160.197,102.925
+        A0.025,0.025 0 0,1 160.172,102.95""")
+
+        path2 = Path(Line(start=(160.172 + 102.95j), end=(159.922 + 102.95j)),
+                     Arc(start=(159.922 + 102.95j), radius=(0.025 + 0.025j), rotation=0.0,
+                         large_arc=False, sweep=True, end=(159.897 + 102.925j)),
+                     Line(start=(159.897 + 102.925j), end=(159.897 + 102.675j)),
+                     Arc(start=(159.897 + 102.675j), radius=(0.025 + 0.025j), rotation=0.0,
+                         large_arc=False, sweep=True, end=(159.922 + 102.65j)),
+                     Line(start=(159.922 + 102.65j), end=(160.172 + 102.65j)),
+                     Arc(start=(160.172 + 102.65j), radius=(0.025 + 0.025j), rotation=0.0,
+                         large_arc=False, sweep=True, end=(160.197 + 102.675j)),
+                     Line(start=(160.197 + 102.675j), end=(160.197 + 102.925j)),
+                     Arc(start=(160.197 + 102.925j), radius=(0.025 + 0.025j), rotation=0.0,
+                         large_arc=False, sweep=True, end=(160.172 + 102.95j)))
+
+        self.assertEqual(path1, path2)

From ec63d0c312056545cce7450bfb9e91a7033dac58 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Anders=20Granskogen=20Bj=C3=B8rnstad?= <anders@imerso.com>
Date: Fri, 10 Nov 2017 13:44:24 +0100
Subject: [PATCH 2/2] Arc: Handle round-off issue with acos()

math.acos raises outside of valid range [-1, 1]. Handle round-off errors
gracefully by using `round()` here too.
---
 svgpathtools/path.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/svgpathtools/path.py b/svgpathtools/path.py
index 41989de..51378fd 100644
--- a/svgpathtools/path.py
+++ b/svgpathtools/path.py
@@ -1300,10 +1300,13 @@ class Arc(object):
         # delta is the angular distance of the arc (w.r.t the circle)
         # theta is the angle between the positive x'-axis and the start point
         # on the circle
+        u1_real_rounded = u1.real
+        if u1.real > 1 or u1.real < -1:
+            u1_real_rounded = round(u1.real)
         if u1.imag > 0:
-            self.theta = degrees(acos(u1.real))
+            self.theta = degrees(acos(u1_real_rounded))
         elif u1.imag < 0:
-            self.theta = -degrees(acos(u1.real))
+            self.theta = -degrees(acos(u1_real_rounded))
         else:
             if u1.real > 0:  # start is on pos u_x axis
                 self.theta = 0