Loosen check for zero vectors in GrPathUtils::convert_noninflect_cubic_to_quads

In the repro case the conic in question has a replicated control point at the end. These points end up being slightly different by the time they get to convert_noninflect_cubic_to_quads so the initial checks for a zero vector don't fire. The following checks, in the constrainWithinTangents path, do fire however leading to a premature termination of conversion to quads.

BUG=skia:4611

Review URL: https://codereview.chromium.org/1504983003

1 files changed, 7 insertions, 7 deletions

diff --git a/src/gpu/GrPathUtils.cpp b/src/gpu/GrPathUtils.cpp
index 21d115569b..f97a61e1f6 100644
--- a/src/gpu/GrPathUtils.cpp
+++ b/src/gpu/GrPathUtils.cpp
@@ -133,10 +133,10 @@ uint32_t GrPathUtils::generateCubicPoints(const SkPoint& p0,
     if (pointsLeft < 2 ||
         (p1.distanceToLineSegmentBetweenSqd(p0, p3) < tolSqd &&
          p2.distanceToLineSegmentBetweenSqd(p0, p3) < tolSqd)) {
-            (*points)[0] = p3;
-            *points += 1;
-            return 1;
-        }
+        (*points)[0] = p3;
+        *points += 1;
+        return 1;
+    }
     SkPoint q[] = {
         { SkScalarAve(p0.fX, p1.fX), SkScalarAve(p0.fY, p1.fY) },
         { SkScalarAve(p1.fX, p2.fX), SkScalarAve(p1.fY, p2.fY) },
@@ -408,8 +408,8 @@ void convert_noninflect_cubic_to_quads(const SkPoint p[4],
     SkVector ab = p[1] - p[0];
     SkVector dc = p[2] - p[3];
 
-    if (ab.isZero()) {
-        if (dc.isZero()) {
+    if (ab.lengthSqd() < SK_ScalarNearlyZero) {
+        if (dc.lengthSqd() < SK_ScalarNearlyZero) {
             SkPoint* degQuad = quads->push_back_n(3);
             degQuad[0] = p[0];
             degQuad[1] = p[0];
@@ -418,7 +418,7 @@ void convert_noninflect_cubic_to_quads(const SkPoint p[4],
         }
         ab = p[2] - p[0];
     }
-    if (dc.isZero()) {
+    if (dc.lengthSqd() < SK_ScalarNearlyZero) {
         dc = p[1] - p[3];
     }