align top and bounds computations

src/pathops/SkPathOpsCurve.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "SkPathOpsBounds.h"
+#include "SkPathOpsRect.h"
+#include "SkPathOpsCurve.h"
+
+SkDPoint SkDCurve::conicTop(const SkPoint curve[3], SkScalar curveWeight, 
+        double startT, double endT, double* topT) {
+    SkDPoint topPt = fConic[0];
+    *topT = startT;
+    if (topPt.fY > fConic[2].fY || (topPt.fY == fConic[2].fY && topPt.fX > fConic[2].fX)) {
+        *topT = endT;
+        topPt = fConic[2];
+    }
+    if (!fConic.monotonicInY()) {
+        double extremeT;
+        if (SkDConic::FindExtrema(&fConic.fPts.fPts[0].fY, fConic.fWeight, &extremeT)) {
+            SkDConic dCurve;
+            dCurve.set(curve, curveWeight);
+            extremeT = startT + (endT - startT) * extremeT;
+            SkDPoint test = dCurve.ptAtT(extremeT);
+            if (topPt.fY > test.fY || (topPt.fY == test.fY && topPt.fX > test.fX)) {
+                *topT = extremeT;
+                topPt = test;
+            }
+        }
+    }
+    return topPt;
+}
+
+SkDPoint SkDCurve::cubicTop(const SkPoint curve[4], SkScalar ,
+        double startT, double endT, double* topT) {
+    SkDPoint topPt = fCubic[0];
+    *topT = startT;
+    if (topPt.fY > fCubic[3].fY || (topPt.fY == fCubic[3].fY && topPt.fX > fCubic[3].fX)) {
+        *topT = endT;
+        topPt = fCubic[3];
+    }
+    double extremeTs[2];
+    if (!fCubic.monotonicInY()) {
+        int roots = SkDCubic::FindExtrema(&fCubic.fPts[0].fY, extremeTs);
+        SkDCubic dCurve;
+        dCurve.set(curve);
+        for (int index = 0; index < roots; ++index) {
+            double t = startT + (endT - startT) * extremeTs[index];
+            SkDPoint mid = dCurve.ptAtT(t);
+            if (topPt.fY > mid.fY || (topPt.fY == mid.fY && topPt.fX > mid.fX)) {
+                *topT = t;
+                topPt = mid;
+            }
+        }
+    }
+    return topPt;
+}
+
+SkDPoint SkDCurve::lineTop(const SkPoint[2], SkScalar , double startT, double endT, double* topT) {
+    SkDPoint topPt = fLine[0];
+    *topT = startT;
+    if (topPt.fY > fLine[1].fY || (topPt.fY == fLine[1].fY && topPt.fX > fLine[1].fX)) {
+        *topT = endT;
+        topPt = fLine[1];
+    }
+    return topPt;
+}
+
+SkDPoint SkDCurve::quadTop(const SkPoint curve[3], SkScalar ,
+        double startT, double endT, double* topT) {
+    SkDPoint topPt = fQuad[0];
+    *topT = startT;
+    if (topPt.fY > fQuad[2].fY || (topPt.fY == fQuad[2].fY && topPt.fX > fQuad[2].fX)) {
+        *topT = endT;
+        topPt = fQuad[2];
+    }
+    if (!fQuad.monotonicInY()) {
+        double extremeT;
+        if (SkDQuad::FindExtrema(&fQuad.fPts[0].fY, &extremeT)) {
+            SkDQuad dCurve;
+            dCurve.set(curve);
+            extremeT = startT + (endT - startT) * extremeT;
+            SkDPoint test = dCurve.ptAtT(extremeT);
+            if (topPt.fY > test.fY || (topPt.fY == test.fY && topPt.fX > test.fX)) {
+                *topT = extremeT;
+                topPt = test;
+            }
+        }
+    }
+    return topPt;
+}
+
+SkDPoint (SkDCurve::* const Top[])(const SkPoint curve[], SkScalar curveWeight,
+        double tStart, double tEnd, double* topT) = {
+    NULL,
+    &SkDCurve::lineTop,
+    &SkDCurve::quadTop,
+    &SkDCurve::conicTop,
+    &SkDCurve::cubicTop
+};
+
+void SkDCurve::setConicBounds(const SkPoint curve[3], SkScalar curveWeight,
+        double tStart, double tEnd, SkPathOpsBounds* bounds) {
+    SkDConic dCurve;
+    dCurve.set(curve, curveWeight);
+    SkDRect dRect;
+    dRect.setBounds(dCurve, fConic, tStart, tEnd);
+    bounds->set(SkDoubleToScalar(dRect.fLeft), SkDoubleToScalar(dRect.fTop),
+            SkDoubleToScalar(dRect.fRight), SkDoubleToScalar(dRect.fBottom));
+}
+
+void SkDCurve::setCubicBounds(const SkPoint curve[4], SkScalar , 
+        double tStart, double tEnd, SkPathOpsBounds* bounds) {
+    SkDCubic dCurve;
+    dCurve.set(curve);
+    SkDRect dRect;
+    dRect.setBounds(dCurve, fCubic, tStart, tEnd);
+    bounds->set(SkDoubleToScalar(dRect.fLeft), SkDoubleToScalar(dRect.fTop),
+            SkDoubleToScalar(dRect.fRight), SkDoubleToScalar(dRect.fBottom));
+}
+
+void SkDCurve::setLineBounds(const SkPoint[2], SkScalar , 
+        double , double , SkPathOpsBounds* bounds) {
+    bounds->setPointBounds(fLine[0]);
+    bounds->add(fLine[1]);
+}
+
+void SkDCurve::setQuadBounds(const SkPoint curve[3], SkScalar ,
+        double tStart, double tEnd, SkPathOpsBounds* bounds) {
+    SkDQuad dCurve;
+    dCurve.set(curve);
+    SkDRect dRect;
+    dRect.setBounds(dCurve, fQuad, tStart, tEnd);
+    bounds->set(SkDoubleToScalar(dRect.fLeft), SkDoubleToScalar(dRect.fTop),
+            SkDoubleToScalar(dRect.fRight), SkDoubleToScalar(dRect.fBottom));
+}
+
+void (SkDCurve::* const SetBounds[])(const SkPoint curve[], SkScalar curveWeight,
+        double tStart, double tEnd, SkPathOpsBounds* bounds) = {
+    NULL,
+    &SkDCurve::setLineBounds,
+    &SkDCurve::setQuadBounds,
+    &SkDCurve::setConicBounds,
+    &SkDCurve::setCubicBounds
+};