diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/core/SkEdge.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/core/SkEdge.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,129 @@
+
+/*
+ * 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.
+ */
+
+
+#ifndef SkEdge_DEFINED
+#define SkEdge_DEFINED
+
+#include "SkRect.h"
+#include "SkFDot6.h"
+#include "SkMath.h"
+
+// This correctly favors the lower-pixel when y0 is on a 1/2 pixel boundary
+#define SkEdge_Compute_DY(top, y0)  ((top << 6) + 32 - (y0))
+
+struct SkEdge {
+    enum Type {
+        kLine_Type,
+        kQuad_Type,
+        kCubic_Type
+    };
+
+    SkEdge* fNext;
+    SkEdge* fPrev;
+
+    SkFixed fX;
+    SkFixed fDX;
+    int32_t fFirstY;
+    int32_t fLastY;
+    int8_t fCurveCount;    // only used by kQuad(+) and kCubic(-)
+    uint8_t fCurveShift;    // appled to all Dx/DDx/DDDx except for fCubicDShift exception
+    uint8_t fCubicDShift;   // applied to fCDx and fCDy only in cubic
+    int8_t  fWinding;       // 1 or -1
+
+    int setLine(const SkPoint& p0, const SkPoint& p1, const SkIRect* clip,
+                int shiftUp);
+    // call this version if you know you don't have a clip
+    inline int setLine(const SkPoint& p0, const SkPoint& p1, int shiftUp);
+    inline int updateLine(SkFixed ax, SkFixed ay, SkFixed bx, SkFixed by);
+    void chopLineWithClip(const SkIRect& clip);
+
+    inline bool intersectsClip(const SkIRect& clip) const {
+        SkASSERT(fFirstY < clip.fBottom);
+        return fLastY >= clip.fTop;
+    }
+
+#ifdef SK_DEBUG
+    void dump() const {
+        SkDebugf("edge: firstY:%d lastY:%d x:%g dx:%g w:%d\n", fFirstY, fLastY, SkFixedToFloat(fX), SkFixedToFloat(fDX), fWinding);
+    }
+
+    void validate() const {
+        SkASSERT(fPrev && fNext);
+        SkASSERT(fPrev->fNext == this);
+        SkASSERT(fNext->fPrev == this);
+
+        SkASSERT(fFirstY <= fLastY);
+        SkASSERT(SkAbs32(fWinding) == 1);
+    }
+#endif
+};
+
+struct SkQuadraticEdge : public SkEdge {
+    SkFixed fQx, fQy;
+    SkFixed fQDx, fQDy;
+    SkFixed fQDDx, fQDDy;
+    SkFixed fQLastX, fQLastY;
+
+    int setQuadratic(const SkPoint pts[3], int shiftUp);
+    int updateQuadratic();
+};
+
+struct SkCubicEdge : public SkEdge {
+    SkFixed fCx, fCy;
+    SkFixed fCDx, fCDy;
+    SkFixed fCDDx, fCDDy;
+    SkFixed fCDDDx, fCDDDy;
+    SkFixed fCLastX, fCLastY;
+
+    int setCubic(const SkPoint pts[4], const SkIRect* clip, int shiftUp);
+    int updateCubic();
+};
+
+int SkEdge::setLine(const SkPoint& p0, const SkPoint& p1, int shift) {
+    SkFDot6 x0, y0, x1, y1;
+
+    {
+        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);
+    }
+
+    int winding = 1;
+
+    if (y0 > y1) {
+        SkTSwap(x0, x1);
+        SkTSwap(y0, y1);
+        winding = -1;
+    }
+
+    int top = SkFDot6Round(y0);
+    int bot = SkFDot6Round(y1);
+
+    // are we a zero-height line?
+    if (top == bot) {
+        return 0;
+    }
+
+    SkFixed slope = SkFDot6Div(x1 - x0, y1 - y0);
+    const int dy  = SkEdge_Compute_DY(top, y0);
+
+    fX          = SkFDot6ToFixed(x0 + SkFixedMul(slope, dy));   // + SK_Fixed1/2
+    fDX         = slope;
+    fFirstY     = top;
+    fLastY      = bot - 1;
+    fCurveCount = 0;
+    fWinding    = SkToS8(winding);
+    fCurveShift = 0;
+    return 1;
+}
+
+
+#endif