impl SkConvertQuadToCubic w/ Sk2s

src/core/SkGeometry.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGeometry.h"
 #include "SkMatrix.h"
 #include "Sk2x.h"
@@ skipping 293 matching lines @@
     SkScalar t = SkFindQuadMaxCurvature(src);
     if (t == 0) {
         memcpy(dst, src, 3 * sizeof(SkPoint));
         return 1;
     } else {
         SkChopQuadAt(src, dst, t);
         return 2;
     }
 }
 
-#define SK_ScalarTwoThirds  (0.666666666f)
+void SkConvertQuadToCubic(const SkPoint src[3], SkPoint dst[4]) {
+    Sk2s scale(SkDoubleToScalar(2.0 / 3.0));
+    Sk2s s0 = from_point(src[0]);
+    Sk2s s1 = from_point(src[1]);
+    Sk2s s2 = from_point(src[2]);
 
-void SkConvertQuadToCubic(const SkPoint src[3], SkPoint dst[4]) {
-    const SkScalar scale = SK_ScalarTwoThirds;
     dst[0] = src[0];
-    dst[1].set(src[0].fX + SkScalarMul(src[1].fX - src[0].fX, scale),
-               src[0].fY + SkScalarMul(src[1].fY - src[0].fY, scale));
-    dst[2].set(src[2].fX + SkScalarMul(src[1].fX - src[2].fX, scale),
-               src[2].fY + SkScalarMul(src[1].fY - src[2].fY, scale));
+    dst[1] = to_point(s0 + (s1 - s0) * scale);
+    dst[2] = to_point(s2 + (s1 - s2) * scale);
     dst[3] = src[2];
 }
 
 //////////////////////////////////////////////////////////////////////////////
 ///// CUBICS // CUBICS // CUBICS // CUBICS // CUBICS // CUBICS // CUBICS /////
 //////////////////////////////////////////////////////////////////////////////
 
 static void get_cubic_coeff(const SkScalar pt[], SkScalar coeff[4]) {
     coeff[0] = pt[6] + 3*(pt[2] - pt[4]) - pt[0];
     coeff[1] = 3*(pt[4] - pt[2] - pt[2] + pt[0]);
@@ skipping 921 matching lines @@
     Sk2s ww(fW);
 
     Sk2s p20 = p2 - p0;
     Sk2s p10 = p1 - p0;
 
     Sk2s C = ww * p10;
     Sk2s A = ww * p20 - p20;
     Sk2s B = p20 - C - C;
 
     return to_vector(quad_poly_eval(A, B, C, Sk2s(t)));
-#if 0
-    static void conic_deriv_coeff(const SkScalar src[],
-                                  SkScalar w,
-                                  SkScalar coeff[3]) {
-        const SkScalar P20 = src[4] - src[0];
-        const SkScalar P10 = src[2] - src[0];
-        const SkScalar wP10 = w * P10;
-        coeff[0] = w * P20 - P20;
-        coeff[1] = P20 - 2 * wP10;
-        coeff[2] = wP10;
-    }
-
-    static SkScalar conic_eval_tan(const SkScalar coord[], SkScalar w, SkScalar t) {
-        SkScalar coeff[3];
-        conic_deriv_coeff(coord, w, coeff);
-        return t * (t * coeff[0] + coeff[1]) + coeff[2];
-    }
-#endif
 }
 
 static SkScalar subdivide_w_value(SkScalar w) {
     return SkScalarSqrt(SK_ScalarHalf + w * SK_ScalarHalf);
 }
 
 static Sk2s twice(const Sk2s& value) {
     return value + value;
 }
 
@@ skipping 260 matching lines @@
         matrix.preScale(SK_Scalar1, -SK_Scalar1);
     }
     if (userMatrix) {
         matrix.postConcat(*userMatrix);
     }
     for (int i = 0; i < conicCount; ++i) {
         matrix.mapPoints(dst[i].fPts, 3);
     }
     return conicCount;
 }