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diff --git a/gfx/skia/skia/src/core/SkEdge.cpp b/gfx/skia/skia/src/core/SkEdge.cpp
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+++ b/gfx/skia/skia/src/core/SkEdge.cpp
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+/*
+ * 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 "src/core/SkEdge.h"
+
+#include "include/private/base/SkTo.h"
+#include "src/base/SkMathPriv.h"
+#include "src/core/SkFDot6.h"
+
+#include <utility>
+
+/*
+ In setLine, setQuadratic, setCubic, the first thing we do is to convert
+ the points into FDot6. This is modulated by the shift parameter, which
+ will either be 0, or something like 2 for antialiasing.
+
+ In the float case, we want to turn the float into .6 by saying pt * 64,
+ or pt * 256 for antialiasing. This is implemented as 1 << (shift + 6).
+
+ In the fixed case, we want to turn the fixed into .6 by saying pt >> 10,
+ or pt >> 8 for antialiasing. This is implemented as pt >> (10 - shift).
+*/
+
+static inline SkFixed SkFDot6ToFixedDiv2(SkFDot6 value) {
+ // we want to return SkFDot6ToFixed(value >> 1), but we don't want to throw
+ // away data in value, so just perform a modify up-shift
+ return SkLeftShift(value, 16 - 6 - 1);
+}
+
+/////////////////////////////////////////////////////////////////////////
+
+#ifdef SK_DEBUG
+void SkEdge::dump() const {
+ int realLastY = SkScalarToFixed(fLastY);
+ if (fCurveCount > 0) {
+ realLastY = static_cast<const SkQuadraticEdge*>(this)->fQLastY;
+ } else if (fCurveCount < 0) {
+ realLastY = static_cast<const SkCubicEdge*>(this)->fCLastY;
+ }
+ SkDebugf("edge (%c): firstY:%d lastY:%d (%g) x:%g dx:%g w:%d\n",
+ fCurveCount > 0 ? 'Q' : (fCurveCount < 0 ? 'C' : 'L'),
+ fFirstY,
+ fLastY,
+ SkFixedToFloat(realLastY),
+ SkFixedToFloat(fX),
+ SkFixedToFloat(fDX),
+ fWinding);
+}
+#endif
+
+int SkEdge::setLine(const SkPoint& p0, const SkPoint& p1, const SkIRect* clip, int shift) {
+ SkFDot6 x0, y0, x1, y1;
+
+ {
+#ifdef SK_RASTERIZE_EVEN_ROUNDING
+ x0 = SkScalarRoundToFDot6(p0.fX, shift);
+ y0 = SkScalarRoundToFDot6(p0.fY, shift);
+ x1 = SkScalarRoundToFDot6(p1.fX, shift);
+ y1 = SkScalarRoundToFDot6(p1.fY, shift);
+#else
+ float scale = float(1 << (shift + 6));
+ x0 = int(p0.fX * scale);
+ y0 = int(p0.fY * scale);
+ x1 = int(p1.fX * scale);
+ y1 = int(p1.fY * scale);
+#endif
+ }
+
+ int winding = 1;
+
+ if (y0 > y1) {
+ using std::swap;
+ swap(x0, x1);
+ swap(y0, y1);
+ winding = -1;
+ }
+
+ int top = SkFDot6Round(y0);
+ int bot = SkFDot6Round(y1);
+
+ // are we a zero-height line?
+ if (top == bot) {
+ return 0;
+ }
+ // are we completely above or below the clip?
+ if (clip && (top >= clip->fBottom || bot <= clip->fTop)) {
+ return 0;
+ }
+
+ SkFixed slope = SkFDot6Div(x1 - x0, y1 - y0);
+ const SkFDot6 dy = SkEdge_Compute_DY(top, y0);
+
+ fX = SkFDot6ToFixed(x0 + SkFixedMul(slope, dy)); // + SK_Fixed1/2
+ fDX = slope;
+ fFirstY = top;
+ fLastY = bot - 1;
+ fEdgeType = kLine_Type;
+ fCurveCount = 0;
+ fWinding = SkToS8(winding);
+ fCurveShift = 0;
+
+ if (clip) {
+ this->chopLineWithClip(*clip);
+ }
+ return 1;
+}
+
+// called from a curve subclass
+int SkEdge::updateLine(SkFixed x0, SkFixed y0, SkFixed x1, SkFixed y1)
+{
+ SkASSERT(fWinding == 1 || fWinding == -1);
+ SkASSERT(fCurveCount != 0);
+// SkASSERT(fCurveShift != 0);
+
+ y0 >>= 10;
+ y1 >>= 10;
+
+ SkASSERT(y0 <= y1);
+
+ int top = SkFDot6Round(y0);
+ int bot = SkFDot6Round(y1);
+
+// SkASSERT(top >= fFirstY);
+
+ // are we a zero-height line?
+ if (top == bot)
+ return 0;
+
+ x0 >>= 10;
+ x1 >>= 10;
+
+ SkFixed slope = SkFDot6Div(x1 - x0, y1 - y0);
+ const SkFDot6 dy = SkEdge_Compute_DY(top, y0);
+
+ fX = SkFDot6ToFixed(x0 + SkFixedMul(slope, dy)); // + SK_Fixed1/2
+ fDX = slope;
+ fFirstY = top;
+ fLastY = bot - 1;
+
+ return 1;
+}
+
+void SkEdge::chopLineWithClip(const SkIRect& clip)
+{
+ int top = fFirstY;
+
+ SkASSERT(top < clip.fBottom);
+
+ // clip the line to the top
+ if (top < clip.fTop)
+ {
+ SkASSERT(fLastY >= clip.fTop);
+ fX += fDX * (clip.fTop - top);
+ fFirstY = clip.fTop;
+ }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+/* We store 1<<shift in a (signed) byte, so its maximum value is 1<<6 == 64.
+ Note that this limits the number of lines we use to approximate a curve.
+ If we need to increase this, we need to store fCurveCount in something
+ larger than int8_t.
+*/
+#define MAX_COEFF_SHIFT 6
+
+static inline SkFDot6 cheap_distance(SkFDot6 dx, SkFDot6 dy)
+{
+ dx = SkAbs32(dx);
+ dy = SkAbs32(dy);
+ // return max + min/2
+ if (dx > dy)
+ dx += dy >> 1;
+ else
+ dx = dy + (dx >> 1);
+ return dx;
+}
+
+static inline int diff_to_shift(SkFDot6 dx, SkFDot6 dy, int shiftAA = 2)
+{
+ // cheap calc of distance from center of p0-p2 to the center of the curve
+ SkFDot6 dist = cheap_distance(dx, dy);
+
+ // shift down dist (it is currently in dot6)
+ // down by 3 should give us 1/8 pixel accuracy (assuming our dist is accurate...)
+ // this is chosen by heuristic: make it as big as possible (to minimize segments)
+ // ... but small enough so that our curves still look smooth
+ // When shift > 0, we're using AA and everything is scaled up so we can
+ // lower the accuracy.
+ dist = (dist + (1 << 4)) >> (3 + shiftAA);
+
+ // each subdivision (shift value) cuts this dist (error) by 1/4
+ return (32 - SkCLZ(dist)) >> 1;
+}
+
+bool SkQuadraticEdge::setQuadraticWithoutUpdate(const SkPoint pts[3], int shift) {
+ SkFDot6 x0, y0, x1, y1, x2, y2;
+
+ {
+#ifdef SK_RASTERIZE_EVEN_ROUNDING
+ x0 = SkScalarRoundToFDot6(pts[0].fX, shift);
+ y0 = SkScalarRoundToFDot6(pts[0].fY, shift);
+ x1 = SkScalarRoundToFDot6(pts[1].fX, shift);
+ y1 = SkScalarRoundToFDot6(pts[1].fY, shift);
+ x2 = SkScalarRoundToFDot6(pts[2].fX, shift);
+ y2 = SkScalarRoundToFDot6(pts[2].fY, shift);
+#else
+ float scale = float(1 << (shift + 6));
+ x0 = int(pts[0].fX * scale);
+ y0 = int(pts[0].fY * scale);
+ x1 = int(pts[1].fX * scale);
+ y1 = int(pts[1].fY * scale);
+ x2 = int(pts[2].fX * scale);
+ y2 = int(pts[2].fY * scale);
+#endif
+ }
+
+ int winding = 1;
+ if (y0 > y2)
+ {
+ using std::swap;
+ swap(x0, x2);
+ swap(y0, y2);
+ winding = -1;
+ }
+ SkASSERT(y0 <= y1 && y1 <= y2);
+
+ int top = SkFDot6Round(y0);
+ int bot = SkFDot6Round(y2);
+
+ // are we a zero-height quad (line)?
+ if (top == bot)
+ return 0;
+
+ // compute number of steps needed (1 << shift)
+ {
+ SkFDot6 dx = (SkLeftShift(x1, 1) - x0 - x2) >> 2;
+ SkFDot6 dy = (SkLeftShift(y1, 1) - y0 - y2) >> 2;
+ // This is a little confusing:
+ // before this line, shift is the scale up factor for AA;
+ // after this line, shift is the fCurveShift.
+ shift = diff_to_shift(dx, dy, shift);
+ SkASSERT(shift >= 0);
+ }
+ // need at least 1 subdivision for our bias trick
+ if (shift == 0) {
+ shift = 1;
+ } else if (shift > MAX_COEFF_SHIFT) {
+ shift = MAX_COEFF_SHIFT;
+ }
+
+ fWinding = SkToS8(winding);
+ //fCubicDShift only set for cubics
+ fEdgeType = kQuad_Type;
+ fCurveCount = SkToS8(1 << shift);
+
+ /*
+ * We want to reformulate into polynomial form, to make it clear how we
+ * should forward-difference.
+ *
+ * p0 (1 - t)^2 + p1 t(1 - t) + p2 t^2 ==> At^2 + Bt + C
+ *
+ * A = p0 - 2p1 + p2
+ * B = 2(p1 - p0)
+ * C = p0
+ *
+ * Our caller must have constrained our inputs (p0..p2) to all fit into
+ * 16.16. However, as seen above, we sometimes compute values that can be
+ * larger (e.g. B = 2*(p1 - p0)). To guard against overflow, we will store
+ * A and B at 1/2 of their actual value, and just apply a 2x scale during
+ * application in updateQuadratic(). Hence we store (shift - 1) in
+ * fCurveShift.
+ */
+
+ fCurveShift = SkToU8(shift - 1);
+
+ SkFixed A = SkFDot6ToFixedDiv2(x0 - x1 - x1 + x2); // 1/2 the real value
+ SkFixed B = SkFDot6ToFixed(x1 - x0); // 1/2 the real value
+
+ fQx = SkFDot6ToFixed(x0);
+ fQDx = B + (A >> shift); // biased by shift
+ fQDDx = A >> (shift - 1); // biased by shift
+
+ A = SkFDot6ToFixedDiv2(y0 - y1 - y1 + y2); // 1/2 the real value
+ B = SkFDot6ToFixed(y1 - y0); // 1/2 the real value
+
+ fQy = SkFDot6ToFixed(y0);
+ fQDy = B + (A >> shift); // biased by shift
+ fQDDy = A >> (shift - 1); // biased by shift
+
+ fQLastX = SkFDot6ToFixed(x2);
+ fQLastY = SkFDot6ToFixed(y2);
+
+ return true;
+}
+
+int SkQuadraticEdge::setQuadratic(const SkPoint pts[3], int shift) {
+ if (!setQuadraticWithoutUpdate(pts, shift)) {
+ return 0;
+ }
+ return this->updateQuadratic();
+}
+
+int SkQuadraticEdge::updateQuadratic()
+{
+ int success;
+ int count = fCurveCount;
+ SkFixed oldx = fQx;
+ SkFixed oldy = fQy;
+ SkFixed dx = fQDx;
+ SkFixed dy = fQDy;
+ SkFixed newx, newy;
+ int shift = fCurveShift;
+
+ SkASSERT(count > 0);
+
+ do {
+ if (--count > 0)
+ {
+ newx = oldx + (dx >> shift);
+ dx += fQDDx;
+ newy = oldy + (dy >> shift);
+ dy += fQDDy;
+ }
+ else // last segment
+ {
+ newx = fQLastX;
+ newy = fQLastY;
+ }
+ success = this->updateLine(oldx, oldy, newx, newy);
+ oldx = newx;
+ oldy = newy;
+ } while (count > 0 && !success);
+
+ fQx = newx;
+ fQy = newy;
+ fQDx = dx;
+ fQDy = dy;
+ fCurveCount = SkToS8(count);
+ return success;
+}
+
+/////////////////////////////////////////////////////////////////////////
+
+static inline int SkFDot6UpShift(SkFDot6 x, int upShift) {
+ SkASSERT((SkLeftShift(x, upShift) >> upShift) == x);
+ return SkLeftShift(x, upShift);
+}
+
+/* f(1/3) = (8a + 12b + 6c + d) / 27
+ f(2/3) = (a + 6b + 12c + 8d) / 27
+
+ f(1/3)-b = (8a - 15b + 6c + d) / 27
+ f(2/3)-c = (a + 6b - 15c + 8d) / 27
+
+ use 16/512 to approximate 1/27
+*/
+static SkFDot6 cubic_delta_from_line(SkFDot6 a, SkFDot6 b, SkFDot6 c, SkFDot6 d)
+{
+ // since our parameters may be negative, we don't use << to avoid ASAN warnings
+ SkFDot6 oneThird = (a*8 - b*15 + 6*c + d) * 19 >> 9;
+ SkFDot6 twoThird = (a + 6*b - c*15 + d*8) * 19 >> 9;
+
+ return std::max(SkAbs32(oneThird), SkAbs32(twoThird));
+}
+
+bool SkCubicEdge::setCubicWithoutUpdate(const SkPoint pts[4], int shift, bool sortY) {
+ SkFDot6 x0, y0, x1, y1, x2, y2, x3, y3;
+
+ {
+#ifdef SK_RASTERIZE_EVEN_ROUNDING
+ x0 = SkScalarRoundToFDot6(pts[0].fX, shift);
+ y0 = SkScalarRoundToFDot6(pts[0].fY, shift);
+ x1 = SkScalarRoundToFDot6(pts[1].fX, shift);
+ y1 = SkScalarRoundToFDot6(pts[1].fY, shift);
+ x2 = SkScalarRoundToFDot6(pts[2].fX, shift);
+ y2 = SkScalarRoundToFDot6(pts[2].fY, shift);
+ x3 = SkScalarRoundToFDot6(pts[3].fX, shift);
+ y3 = SkScalarRoundToFDot6(pts[3].fY, shift);
+#else
+ float scale = float(1 << (shift + 6));
+ x0 = int(pts[0].fX * scale);
+ y0 = int(pts[0].fY * scale);
+ x1 = int(pts[1].fX * scale);
+ y1 = int(pts[1].fY * scale);
+ x2 = int(pts[2].fX * scale);
+ y2 = int(pts[2].fY * scale);
+ x3 = int(pts[3].fX * scale);
+ y3 = int(pts[3].fY * scale);
+#endif
+ }
+
+ int winding = 1;
+ if (sortY && y0 > y3)
+ {
+ using std::swap;
+ swap(x0, x3);
+ swap(x1, x2);
+ swap(y0, y3);
+ swap(y1, y2);
+ winding = -1;
+ }
+
+ int top = SkFDot6Round(y0);
+ int bot = SkFDot6Round(y3);
+
+ // are we a zero-height cubic (line)?
+ if (sortY && top == bot)
+ return 0;
+
+ // compute number of steps needed (1 << shift)
+ {
+ // Can't use (center of curve - center of baseline), since center-of-curve
+ // need not be the max delta from the baseline (it could even be coincident)
+ // so we try just looking at the two off-curve points
+ SkFDot6 dx = cubic_delta_from_line(x0, x1, x2, x3);
+ SkFDot6 dy = cubic_delta_from_line(y0, y1, y2, y3);
+ // add 1 (by observation)
+ shift = diff_to_shift(dx, dy) + 1;
+ }
+ // need at least 1 subdivision for our bias trick
+ SkASSERT(shift > 0);
+ if (shift > MAX_COEFF_SHIFT) {
+ shift = MAX_COEFF_SHIFT;
+ }
+
+ /* Since our in coming data is initially shifted down by 10 (or 8 in
+ antialias). That means the most we can shift up is 8. However, we
+ compute coefficients with a 3*, so the safest upshift is really 6
+ */
+ int upShift = 6; // largest safe value
+ int downShift = shift + upShift - 10;
+ if (downShift < 0) {
+ downShift = 0;
+ upShift = 10 - shift;
+ }
+
+ fWinding = SkToS8(winding);
+ fEdgeType = kCubic_Type;
+ fCurveCount = SkToS8(SkLeftShift(-1, shift));
+ fCurveShift = SkToU8(shift);
+ fCubicDShift = SkToU8(downShift);
+
+ SkFixed B = SkFDot6UpShift(3 * (x1 - x0), upShift);
+ SkFixed C = SkFDot6UpShift(3 * (x0 - x1 - x1 + x2), upShift);
+ SkFixed D = SkFDot6UpShift(x3 + 3 * (x1 - x2) - x0, upShift);
+
+ fCx = SkFDot6ToFixed(x0);
+ fCDx = B + (C >> shift) + (D >> 2*shift); // biased by shift
+ fCDDx = 2*C + (3*D >> (shift - 1)); // biased by 2*shift
+ fCDDDx = 3*D >> (shift - 1); // biased by 2*shift
+
+ B = SkFDot6UpShift(3 * (y1 - y0), upShift);
+ C = SkFDot6UpShift(3 * (y0 - y1 - y1 + y2), upShift);
+ D = SkFDot6UpShift(y3 + 3 * (y1 - y2) - y0, upShift);
+
+ fCy = SkFDot6ToFixed(y0);
+ fCDy = B + (C >> shift) + (D >> 2*shift); // biased by shift
+ fCDDy = 2*C + (3*D >> (shift - 1)); // biased by 2*shift
+ fCDDDy = 3*D >> (shift - 1); // biased by 2*shift
+
+ fCLastX = SkFDot6ToFixed(x3);
+ fCLastY = SkFDot6ToFixed(y3);
+
+ return true;
+}
+
+int SkCubicEdge::setCubic(const SkPoint pts[4], int shift) {
+ if (!this->setCubicWithoutUpdate(pts, shift)) {
+ return 0;
+ }
+ return this->updateCubic();
+}
+
+int SkCubicEdge::updateCubic()
+{
+ int success;
+ int count = fCurveCount;
+ SkFixed oldx = fCx;
+ SkFixed oldy = fCy;
+ SkFixed newx, newy;
+ const int ddshift = fCurveShift;
+ const int dshift = fCubicDShift;
+
+ SkASSERT(count < 0);
+
+ do {
+ if (++count < 0)
+ {
+ newx = oldx + (fCDx >> dshift);
+ fCDx += fCDDx >> ddshift;
+ fCDDx += fCDDDx;
+
+ newy = oldy + (fCDy >> dshift);
+ fCDy += fCDDy >> ddshift;
+ fCDDy += fCDDDy;
+ }
+ else // last segment
+ {
+ // SkDebugf("LastX err=%d, LastY err=%d\n", (oldx + (fCDx >> shift) - fLastX), (oldy + (fCDy >> shift) - fLastY));
+ newx = fCLastX;
+ newy = fCLastY;
+ }
+
+ // we want to say SkASSERT(oldy <= newy), but our finite fixedpoint
+ // doesn't always achieve that, so we have to explicitly pin it here.
+ if (newy < oldy) {
+ newy = oldy;
+ }
+
+ success = this->updateLine(oldx, oldy, newx, newy);
+ oldx = newx;
+ oldy = newy;
+ } while (count < 0 && !success);
+
+ fCx = newx;
+ fCy = newy;
+ fCurveCount = SkToS8(count);
+ return success;
+}
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