Use the unswapped end point y for early out case in winding_line

The x-coordinates are not swapped, so using the swapped y will result
in a comparison with the wrong (end) point.

BUG=skia:4265
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1533873002

Review URL: https://codereview.chromium.org/1533873002

diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index d32fb4c..d7e047e 100644 (file)
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -2844,7 +2844,7 @@ static int winding_line(const SkPoint pts[], SkScalar x, SkScalar y, int* onCurv
     if (y < y0 || y > y1) {
         return 0;
     }
-    if (y == y1) {
+    if (y == pts[1].fY) {
         if (y0 == y1 && between(x0, x, x1) && x != x1) {  // check if on horizontal line
             *onCurveCount += 1;
         }
@@ -2853,9 +2853,10 @@ static int winding_line(const SkPoint pts[], SkScalar x, SkScalar y, int* onCurv
     SkScalar cross = SkScalarMul(x1 - x0, y - pts[0].fY) - SkScalarMul(dy, x - x0);
 
     if (!cross) {
-        if (x != x1 || y != pts[1].fY) { // don't test end points since they're also start points
-            *onCurveCount += 1;   // zero cross means the point is on the line
-        }
+        // zero cross means the point is on the line, and since the case where
+        // y of the query point is at the end point is handled above, we can be
+        // sure that we're on the line (excluding the end point) here
+        *onCurveCount += 1;
         dir = 0;
     } else if (SkScalarSignAsInt(cross) == dir) {
         dir = 0;

diff --git a/tests/PathTest.cpp b/tests/PathTest.cpp
index 464943b..aa2ffdb 100644 (file)
--- a/tests/PathTest.cpp
+++ b/tests/PathTest.cpp
@@ -3542,6 +3542,16 @@ static void test_contains(skiatest::Reporter* reporter) {
     REPORTER_ASSERT(reporter, !p.contains(7, 7));
     p.reset();
     p.moveTo(4, 4);
+    p.lineTo(8, 4);
+    p.lineTo(8, 8);
+    p.lineTo(4, 8);
+    // test on vertices
+    REPORTER_ASSERT(reporter, p.contains(4, 4));
+    REPORTER_ASSERT(reporter, p.contains(8, 4));
+    REPORTER_ASSERT(reporter, p.contains(8, 8));
+    REPORTER_ASSERT(reporter, p.contains(4, 8));
+    p.reset();
+    p.moveTo(4, 4);
     p.lineTo(6, 8);
     p.lineTo(2, 8);
     // test on edge