Remove assert from SkStroke.cpp

If we can't trust the contains tests on the bounding boxes we're already in a bad place.
With this change we'll somewhat arbitrarily get one of the two contours but, hopefully,
given the degeneracy of the geometry it won't matter which one dominates.

BUG=skia:6491
Change-Id: Id6f92f9331dc04a2555267781b07e5218345ef1b
Reviewed-on: https://skia-review.googlesource.com/103460
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>

2 files changed, 23 insertions, 2 deletions

diff --git a/src/core/SkStroke.cpp b/src/core/SkStroke.cpp
index ab8df833c1..4568dc1610 100644
--- a/src/core/SkStroke.cpp
+++ b/src/core/SkStroke.cpp
@@ -299,8 +299,9 @@ void SkPathStroker::finishContour(bool close, bool currIsLine) {
             fOuter.close();
 
             if (fCanIgnoreCenter) {
-                if (!fOuter.getBounds().contains(fInner.getBounds())) {
-                    SkASSERT(fInner.getBounds().contains(fOuter.getBounds()));
+                // If we can ignore the center just make sure the larger of the two paths
+                // is preserved and don't add the smaller one.
+                if (fInner.getBounds().contains(fOuter.getBounds())) {
                     fInner.swap(fOuter);
                 }
             } else {
diff --git a/tests/StrokeTest.cpp b/tests/StrokeTest.cpp
index 43b293fc12..2feaea0ec3 100644
--- a/tests/StrokeTest.cpp
+++ b/tests/StrokeTest.cpp
@@ -160,8 +160,28 @@ static void test_strokerec_equality(skiatest::Reporter* reporter) {
     }
 }
 
+// From skbug.com/6491. The large stroke width can cause numerical instabilities.
+static void test_big_stroke(skiatest::Reporter* reporter) {
+    SkPaint paint;
+    paint.setStyle(SkPaint::kStrokeAndFill_Style);
+    paint.setStrokeWidth(1.49679073e+10f);
+
+    SkPath path;
+    path.setFillType(SkPath::kWinding_FillType);
+    path.moveTo(SkBits2Float(0x46380000), SkBits2Float(0xc6380000));  // 11776, -11776
+    path.lineTo(SkBits2Float(0x46a00000), SkBits2Float(0xc6a00000));  // 20480, -20480
+    path.lineTo(SkBits2Float(0x468c0000), SkBits2Float(0xc68c0000));  // 17920, -17920
+    path.lineTo(SkBits2Float(0x46100000), SkBits2Float(0xc6100000));  // 9216, -9216
+    path.lineTo(SkBits2Float(0x46380000), SkBits2Float(0xc6380000));  // 11776, -11776
+    path.close();
+
+    SkPath strokeAndFillPath;
+    paint.getFillPath(path, &strokeAndFillPath);
+}
+
 DEF_TEST(Stroke, reporter) {
     test_strokecubic(reporter);
     test_strokerect(reporter);
     test_strokerec_equality(reporter);
+    test_big_stroke(reporter);
 }