Merge pull request #43 from meerk40t/1.1.2

Corrections for near collinear quads

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = svgelements
-version = 1.1.1
+version = 1.1.2
 description = Svg Elements Parsing
 long_description_content_type=text/markdown
 long_description = file: README.md

svgelements/svgelements.py

@@ -3308,17 +3308,7 @@ def length(self, error=None, min_depth=None):
         """Calculate the length of the path up to a certain position"""
         a = self.start - 2 * self.control + self.end
         b = 2 * (self.control - self.start)
-        a_dot_b = a.real * b.real + a.imag * b.imag
-
-        if abs(a) < 1e-12:
-            s = abs(b)
-        elif abs(a_dot_b + abs(a) * abs(b)) < 1e-12:
-            k = abs(b) / abs(a)
-            if k >= 2:
-                s = abs(b) - abs(a)
-            else:
-                s = abs(a) * (k ** 2 / 2 - k + 1)
-        else:
+        try:
             # For an explanation of this case, see
             # http://www.malczak.info/blog/quadratic-bezier-curve-length/
             A = 4 * (a.real ** 2 + a.imag ** 2)
@@ -3333,6 +3323,16 @@ def length(self, error=None, min_depth=None):
 
             s = (A32 * Sabc + A2 * B * (Sabc - C2) + (4 * C * A - B ** 2) *
                  log((2 * A2 + BA + Sabc) / (BA + C2))) / (4 * A32)
+        except (ZeroDivisionError, ValueError):
+            # a_dot_b = a.real * b.real + a.imag * b.imag
+            if abs(a) < 1e-10:
+                s = abs(b)
+            else:
+                k = abs(b) / abs(a)
+                if k >= 2:
+                    s = abs(b) - abs(a)
+                else:
+                    s = abs(a) * (k ** 2 / 2 - k + 1)
         return s
 
     def is_smooth_from(self, previous):

test/test_angle.py

@@ -6,6 +6,7 @@
 
 
 class TestElementAngle(unittest.TestCase):
+    """These tests ensure the basic functions of the Angle element."""
 
     def test_angle_init(self):
         self.assertEqual(Angle.degrees(90).as_turns, 0.25)
@@ -40,4 +41,4 @@ def test_orth(self):
         self.assertFalse(Angle.degrees(91).is_orthogonal())
         self.assertFalse(Angle.degrees(181).is_orthogonal())
         self.assertFalse(Angle.degrees(271).is_orthogonal())
-        self.assertFalse(Angle.degrees(361).is_orthogonal())
+        self.assertFalse(Angle.degrees(361).is_orthogonal())

test/test_color.py

@@ -6,6 +6,7 @@
 
 
 class TestElementColor(unittest.TestCase):
+    """These tests test the basic functions of the Color element."""
 
     def test_color_red(self):
         r0 = Color('red')

test/test_element.py

@@ -6,6 +6,7 @@
 
 
 class TestElementElement(unittest.TestCase):
+    """These tests ensure the performance of the SVGElement basecase."""
 
     def test_element_id(self):
         values = {'id': 'my_id', 'random': True}

test/test_length.py

@@ -6,6 +6,7 @@
 
 
 class TestElementLength(unittest.TestCase):
+    """Tests the functionality of the Length Element."""
 
     def test_length_parsing(self):
         self.assertAlmostEqual(Length('10cm'), (Length('100mm')))

test/test_matrix.py

@@ -6,6 +6,7 @@
 
 
 class TestPathMatrix(unittest.TestCase):
+    """Tests the functionality of the Matrix element."""
 
     def test_rotate_css_angles(self):
         matrix = Matrix("rotate(90, 100,100)")

test/test_path.py

@@ -6,6 +6,7 @@
 
 
 class TestPath(unittest.TestCase):
+    """Tests of the SVG Path element."""
 
     def test_subpaths(self):
         path = Path("M0,0 50,50 100,100z M0,100 50,50, 100,0")

test/test_path_dunder.py

@@ -6,6 +6,7 @@
 
 
 class TestPath(unittest.TestCase):
+    """Tests of dunder methods of the SVG Path element."""
 
     def test_path_iadd_str(self):
         p1 = Path("M0,0")

test/test_paths.py

@@ -34,6 +34,7 @@
 # these points religiously. They might be subtly wrong, unless otherwise
 # noted.
 
+
 class LineTest(unittest.TestCase):
 
     def test_lines(self):
@@ -291,6 +292,9 @@ def test_equality(self):
                         CubicBezier(600 + 501j, 600 + 350j, 900 + 650j, 900 + 500j))
         self.assertTrue(segment != Line(0, 400))
 
+    def test_colinear(self):
+        p = Path("M0,0C5,0 15,0 15,0")
+        self.assertAlmostEqual(p.length(), 15)
 
 class QuadraticBezierTest(unittest.TestCase):
 
@@ -340,6 +344,24 @@ def test_equality(self):
         self.assertFalse(segment == Arc(0j, 100 + 50j, 0, 0, 0, 100 + 50j))
         self.assertTrue(Arc(0j, 100 + 50j, 0, 0, 0, 100 + 50j) != segment)
 
+    def test_issue_61(self):
+        p = Path('M 206.5,525 Q 162.5,583 162.5,583')
+        self.assertAlmostEqual(p.length(), 72.80109889280519)
+        p = Path('M 425.781 446.289 Q 410.40000000000003 373.047 410.4 373.047')
+        self.assertAlmostEqual(p.length(), 74.83959997888816)
+        p = Path('M 639.648 568.115 Q 606.6890000000001 507.568 606.689 507.568')
+        self.assertAlmostEqual(p.length(), 68.93645544992873)
+        p = Path('M 288.818 616.699 Q 301.025 547.3629999999999 301.025 547.363')
+        self.assertAlmostEqual(p.length(), 70.40235610403947)
+        p = Path('M 339.927 706.25 Q 243.92700000000002 806.25 243.927 806.25')
+        self.assertAlmostEqual(p.length(), 138.6217876093077)
+        p = Path('M 539.795 702.637 Q 548.0959999999999 803.4669999999999 548.096 803.467')
+        self.assertAlmostEqual(p.length(), 101.17111989594662)
+        p = Path('M 537.815 555.042 Q 570.1680000000001 499.1600000000001 570.168 499.16')
+        self.assertAlmostEqual(p.length(), 64.57177814649368)
+        p = Path('M 615.297 470.503 Q 538.797 694.5029999999999 538.797 694.503')
+        self.assertAlmostEqual(p.length(), 236.70287281737836)
+
 
 class ArcTest(unittest.TestCase):