Merge pull request #1057 from cmyr/erase-corners-extra-segment

Fix extra segment in eraseOpenCorners
googlefonts · Jan 21, 2025 · b0fc3bc · b0fc3bc
2 parents ed39aa3 + 7edf757
commit b0fc3bc
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diff --git a/Lib/glyphsLib/filters/eraseOpenCorners.py b/Lib/glyphsLib/filters/eraseOpenCorners.py
@@ -35,7 +35,9 @@ def _operate(self, *points):
     _qCurveTo = _curveTo = _lineTo = _qCurveToOne = _curveToOne = _operate
 
     def closePath(self):
-        self.segments.append((self._getCurrentPoint(), self.segments[0][0]))
+        # only add a line segment here if the current first and last point aren't equal
+        if self._getCurrentPoint() != self.segments[0][0]:
+            self.segments.append((self._getCurrentPoint(), self.segments[0][0]))
         self.is_closed = True
         self.endPath()
 

diff --git a/tests/eraseOpenCorners_test.py b/tests/eraseOpenCorners_test.py
@@ -158,6 +158,18 @@
                         ("closePath", ()),
                     ],
                 },
+                {
+                    "name": "curveAsLastSegment",
+                    "width": 600,
+                    "outline": [
+                        ("moveTo", ((100, 100),)),
+                        ("lineTo", ((10, 110),)),
+                        ("lineTo", ((15, 120),)),
+                        ("lineTo", ((60, 30),)),
+                        ("curveTo", ((80, 30), (100, 80), (100, 100))),
+                        ("closePath", ()),
+                    ],
+                },
                 # a pathological case, where a curve has two segments.
                 # the naive logic treats this as an open corner, treating the
                 # same curve segment as the 'prev' and 'next'.
@@ -334,6 +346,15 @@ def test_large_crossing(font):
     assert len(newcontour) == 3
 
 
+# there was an issue where we would generate an extra lineto if we erased
+# corners on an outline where the last segment was a curve
+def test_curve_as_last_segment(font):
+    philter = EraseOpenCornersFilter(include={"curveAsLastSegment"})
+    assert philter(font)
+    newcontour = font["curveAsLastSegment"][0]
+    assert structure(newcontour) == ["curve", "line", "line", None, None]
+
+
 def test_only_two_segments(font):
     philter = EraseOpenCornersFilter(include={"justTwoSegments"})
     assert not philter(font)