commit db085ab30f58928623447676c46d6bd7a8cc2255
author hstern <hstern@google.com> Tue Aug 16 15:10:34 2016 -0700
committer Commit bot <commit-bot@chromium.org> Tue Aug 16 15:10:34 2016 -0700
tree 93b06bc3e242774138e39f96317e17dc36c39890
parent 087905a730241939da320092543c19dc06d5a7b4

Fix bug in cubic derivative coefficient with missing parens

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2242603002

Review-Url: https://codereview.chromium.org/2242603002

src/utils/SkCurveMeasure.cpp

diff --git a/src/utils/SkCurveMeasure.cpp b/src/utils/SkCurveMeasure.cpp
index 60fbf34..a82008e 100644
--- a/src/utils/SkCurveMeasure.cpp
+++ b/src/utils/SkCurveMeasure.cpp
@@ -106,11 +106,11 @@
             float Cy = pts[2].y();
 
             // precompute coefficients for derivative
-            xCoeff[0] = Sk8f(2.0f*(Ax - 2*Bx + Cx));
-            xCoeff[1] = Sk8f(2.0f*(Bx - Ax));
+            xCoeff[0] = Sk8f(2*(Ax - 2*Bx + Cx));
+            xCoeff[1] = Sk8f(2*(Bx - Ax));
 
-            yCoeff[0] = Sk8f(2.0f*(Ay - 2*By + Cy));
-            yCoeff[1] = Sk8f(2.0f*(By - Ay));
+            yCoeff[0] = Sk8f(2*(Ay - 2*By + Cy));
+            yCoeff[1] = Sk8f(2*(By - Ay));
         }
             break;
         case kCubic_SegType:
@@ -125,13 +125,13 @@
             float Dy = pts[3].y();
 
             // precompute coefficients for derivative
-            xCoeff[0] = Sk8f(3.0f*(-Ax + 3.0f*(Bx - Cx) + Dx));
-            xCoeff[1] = Sk8f(3.0f*(2.0f*(Ax - 2.0f*Bx + Cx)));
-            xCoeff[2] = Sk8f(3.0f*(-Ax + Bx));
+            xCoeff[0] = Sk8f(3*(-Ax + 3*(Bx - Cx) + Dx));
+            xCoeff[1] = Sk8f(6*(Ax - 2*Bx + Cx));
+            xCoeff[2] = Sk8f(3*(-Ax + Bx));
 
-            yCoeff[0] = Sk8f(3.0f*(-Ay + 3.0f*(By - Cy) + Dy));
-            yCoeff[1] = Sk8f(3.0f * -Ay + By + 2.0f*(Ay - 2.0f*By + Cy));
-            yCoeff[2] = Sk8f(3.0f*(-Ay + By));
+            yCoeff[0] = Sk8f(3*(-Ay + 3*(By - Cy) + Dy));
+            yCoeff[1] = Sk8f(6*(Ay - 2*By + Cy));
+            yCoeff[2] = Sk8f(3*(-Ay + By));
         }
             break;
         case kConic_SegType: