Revert "keep SVG arcs axis aligned"

This reverts commit c3823848483eba33c3fa36187de7713e87651c1c.

Reason for revert: need to add legacy flag to chrome first

Original change's description:
> keep SVG arcs axis aligned
> 
> Computing the arc width introduces rounding errors that cause the
> arc to exceed 1/4 circle and cause integer anchored arcs to start
> outside their marks. A round rect may lose convexity as a result.
> 
> Check if arcTo() inputs are integers and arc is 90 degrees;
> if so, output conics which are axis-aligned on integers as well.
> 
> This is triggered when using SVG to represent a round rect.
> 
> Possible future enhancements are recorded in bug.skia.org/7383
> 
> R=​reed@google.com,djsollen@google.com
> Change-Id: I6609456fcefabcda6c9560a044533ecb5cda2d31
> Reviewed-on: https://skia-review.googlesource.com/79423
> Reviewed-by: Derek Sollenberger <djsollen@google.com>
> Commit-Queue: Derek Sollenberger <djsollen@google.com>

TBR=djsollen@google.com,caryclark@google.com,reed@google.com,caryclark@skia.org

Change-Id: Ia503ea62def15322df2b11da30d377a9543d6999
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/81281
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Cary Clark <caryclark@google.com>

2 files changed, 1 insertions, 47 deletions

diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index ed3f466a4a..c433424635 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -1417,8 +1417,7 @@ void SkPath::arcTo(SkScalar rx, SkScalar ry, SkScalar angle, SkPath::ArcSize arc
     pointTransform.setRotate(angle);
     pointTransform.preScale(rx, ry);
 
-    // the arc may be slightly bigger than 1/4 circle, so allow up to 1/3rd
-    int segments = SkScalarCeilToInt(SkScalarAbs(thetaArc / (2 * SK_ScalarPI / 3)));
+    int segments = SkScalarCeilToInt(SkScalarAbs(thetaArc / (SK_ScalarPI / 2)));
     SkScalar thetaWidth = thetaArc / segments;
     SkScalar t = SkScalarTan(0.5f * thetaWidth);
     if (!SkScalarIsFinite(t)) {
@@ -1426,12 +1425,6 @@ void SkPath::arcTo(SkScalar rx, SkScalar ry, SkScalar angle, SkPath::ArcSize arc
     }
     SkScalar startTheta = theta1;
     SkScalar w = SkScalarSqrt(SK_ScalarHalf + SkScalarCos(thetaWidth) * SK_ScalarHalf);
-    auto scalar_is_integer = [](SkScalar scalar) -> bool {
-        return scalar == SkScalarFloorToScalar(scalar);
-    };
-    bool expectIntegers = SkScalarNearlyZero(SK_ScalarPI/2 - SkScalarAbs(thetaWidth)) &&
-        scalar_is_integer(rx) && scalar_is_integer(ry) &&
-        scalar_is_integer(x) && scalar_is_integer(y);
     for (int i = 0; i < segments; ++i) {
         SkScalar endTheta = startTheta + thetaWidth;
         SkScalar cosEndTheta, sinEndTheta = SkScalarSinCos(endTheta, &cosEndTheta);
@@ -1442,17 +1435,6 @@ void SkPath::arcTo(SkScalar rx, SkScalar ry, SkScalar angle, SkPath::ArcSize arc
         unitPts[0].offset(t * sinEndTheta, -t * cosEndTheta);
         SkPoint mapped[2];
         pointTransform.mapPoints(mapped, unitPts, (int) SK_ARRAY_COUNT(unitPts));
-        /*
-        Computing the arc width introduces rounding errors that cause arcs to start
-        outside their marks. A round rect may lose convexity as a result. If the input
-        values are on integers, place the conic on integers as well.
-         */
-        if (expectIntegers) {
-            SkScalar* mappedScalars = &mapped[0].fX;
-            for (unsigned index = 0; index < sizeof(mapped) / sizeof(SkScalar); ++index) {
-                mappedScalars[index] = SkScalarRoundToScalar(mappedScalars[index]);
-            }
-        }
         this->conicTo(mapped[0], mapped[1], w);
         startTheta = endTheta;
     }
diff --git a/tests/PathTest.cpp b/tests/PathTest.cpp
index b36179000f..b275342e2d 100644
--- a/tests/PathTest.cpp
+++ b/tests/PathTest.cpp
@@ -4915,31 +4915,3 @@ DEF_TEST(NonFinitePathIteration, reporter) {
 
     REPORTER_ASSERT(reporter, verbs == 0);
 }
-
-DEF_TEST(AndroidArc, reporter) {
-    const char* tests[] = {
-        "M50,0A50,50,0,0 1 100,50 L100,85 A15,15,0,0 1 85,100 L50,100 A50,50,0,0 1 50,0z",
-        "M50,0L92,0 A8,8,0,0 1 100,8 L100,92 A8,8,0,0 1 92,100 L8,100"
-            " A8,8,0,0 1 0,92 L 0,8 A8,8,0,0 1 8,0z",
-        "M50 0A50 50,0,1,1,50 100A50 50,0,1,1,50 0"
-    };
-    for (auto test : tests) {
-        SkPath aPath;
-        SkAssertResult(SkParsePath::FromSVGString(test, &aPath));
-        SkASSERT(aPath.isConvex());
-        for (SkScalar scale = 1; scale < 1000; scale *= 1.1f) {
-            SkPath scalePath = aPath;
-            SkMatrix matrix;
-            matrix.setScale(scale, scale);
-            scalePath.transform(matrix);
-            SkASSERT(scalePath.isConvex());
-        }
-        for (SkScalar scale = 1; scale < .001; scale /= 1.1f) {
-            SkPath scalePath = aPath;
-            SkMatrix matrix;
-            matrix.setScale(scale, scale);
-            scalePath.transform(matrix);
-            SkASSERT(scalePath.isConvex());
-        }
-    }
-}