diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/pathops/SkPathOpsLine.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/src/pathops/SkPathOpsLine.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,201 @@
+/*
+ * Copyright 2012 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "SkPathOpsLine.h"
+
+SkDLine SkDLine::subDivide(double t1, double t2) const {
+    SkDVector delta = tangent();
+    SkDLine dst = {{{
+            fPts[0].fX - t1 * delta.fX, fPts[0].fY - t1 * delta.fY}, {
+            fPts[0].fX - t2 * delta.fX, fPts[0].fY - t2 * delta.fY}}};
+    return dst;
+}
+
+// may have this below somewhere else already:
+// copying here because I thought it was clever
+
+// Copyright 2001, softSurfer (www.softsurfer.com)
+// This code may be freely used and modified for any purpose
+// providing that this copyright notice is included with it.
+// SoftSurfer makes no warranty for this code, and cannot be held
+// liable for any real or imagined damage resulting from its use.
+// Users of this code must verify correctness for their application.
+
+// Assume that a class is already given for the object:
+//    Point with coordinates {float x, y;}
+//===================================================================
+
+// isLeft(): tests if a point is Left|On|Right of an infinite line.
+//    Input:  three points P0, P1, and P2
+//    Return: >0 for P2 left of the line through P0 and P1
+//            =0 for P2 on the line
+//            <0 for P2 right of the line
+//    See: the January 2001 Algorithm on Area of Triangles
+//    return (float) ((P1.x - P0.x)*(P2.y - P0.y) - (P2.x - P0.x)*(P1.y - P0.y));
+double SkDLine::isLeft(const SkDPoint& pt) const {
+    SkDVector p0 = fPts[1] - fPts[0];
+    SkDVector p2 = pt - fPts[0];
+    return p0.cross(p2);
+}
+
+SkDPoint SkDLine::ptAtT(double t) const {
+    if (0 == t) {
+        return fPts[0];
+    }
+    if (1 == t) {
+        return fPts[1];
+    }
+    double one_t = 1 - t;
+    SkDPoint result = { one_t * fPts[0].fX + t * fPts[1].fX, one_t * fPts[0].fY + t * fPts[1].fY };
+    return result;
+}
+
+double SkDLine::exactPoint(const SkDPoint& xy) const {
+    if (xy == fPts[0]) {  // do cheapest test first
+        return 0;
+    }
+    if (xy == fPts[1]) {
+        return 1;
+    }
+    return -1;
+}
+
+double SkDLine::nearPoint(const SkDPoint& xy) const {
+    if (!AlmostBetweenUlps(fPts[0].fX, xy.fX, fPts[1].fX)
+            || !AlmostBetweenUlps(fPts[0].fY, xy.fY, fPts[1].fY)) {
+        return -1;
+    }
+    // project a perpendicular ray from the point to the line; find the T on the line
+    SkDVector len = fPts[1] - fPts[0]; // the x/y magnitudes of the line
+    double denom = len.fX * len.fX + len.fY * len.fY;  // see DLine intersectRay
+    SkDVector ab0 = xy - fPts[0];
+    double numer = len.fX * ab0.fX + ab0.fY * len.fY;
+    if (!between(0, numer, denom)) {
+        return -1;
+    }
+    double t = numer / denom;
+    SkDPoint realPt = ptAtT(t);
+    double dist = realPt.distance(xy);   // OPTIMIZATION: can we compare against distSq instead ?
+    // find the ordinal in the original line with the largest unsigned exponent
+    double tiniest = SkTMin(SkTMin(SkTMin(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY);
+    double largest = SkTMax(SkTMax(SkTMax(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY);
+    largest = SkTMax(largest, -tiniest);
+    if (!AlmostEqualUlps(largest, largest + dist)) { // is the dist within ULPS tolerance?
+        return -1;
+    }
+    t = SkPinT(t);
+    SkASSERT(between(0, t, 1));
+    return t;
+}
+
+bool SkDLine::nearRay(const SkDPoint& xy) const {
+    // project a perpendicular ray from the point to the line; find the T on the line
+    SkDVector len = fPts[1] - fPts[0]; // the x/y magnitudes of the line
+    double denom = len.fX * len.fX + len.fY * len.fY;  // see DLine intersectRay
+    SkDVector ab0 = xy - fPts[0];
+    double numer = len.fX * ab0.fX + ab0.fY * len.fY;
+    double t = numer / denom;
+    SkDPoint realPt = ptAtT(t);
+    double dist = realPt.distance(xy);   // OPTIMIZATION: can we compare against distSq instead ?
+    // find the ordinal in the original line with the largest unsigned exponent
+    double tiniest = SkTMin(SkTMin(SkTMin(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY);
+    double largest = SkTMax(SkTMax(SkTMax(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY);
+    largest = SkTMax(largest, -tiniest);
+    return RoughlyEqualUlps(largest, largest + dist); // is the dist within ULPS tolerance?
+}
+
+// Returns true if a ray from (0,0) to (x1,y1) is coincident with a ray (0,0) to (x2,y2)
+// OPTIMIZE: a specialty routine could speed this up -- may not be called very often though
+bool SkDLine::NearRay(double x1, double y1, double x2, double y2) {
+    double denom1 = x1 * x1 + y1 * y1;
+    double denom2 = x2 * x2 + y2 * y2;
+    SkDLine line = {{{0, 0}, {x1, y1}}};
+    SkDPoint pt = {x2, y2};
+    if (denom2 > denom1) {
+        SkTSwap(line[1], pt);
+    }
+    return line.nearRay(pt);
+}
+
+double SkDLine::ExactPointH(const SkDPoint& xy, double left, double right, double y) {
+    if (xy.fY == y) {
+        if (xy.fX == left) {
+            return 0;
+        }
+        if (xy.fX == right) {
+            return 1;
+        }
+    }
+    return -1;
+}
+
+double SkDLine::NearPointH(const SkDPoint& xy, double left, double right, double y) {
+    if (!AlmostBequalUlps(xy.fY, y)) {
+        return -1;
+    }
+    if (!AlmostBetweenUlps(left, xy.fX, right)) {
+        return -1;
+    }
+    double t = (xy.fX - left) / (right - left);
+    t = SkPinT(t);
+    SkASSERT(between(0, t, 1));
+    double realPtX = (1 - t) * left + t * right;
+    SkDVector distU = {xy.fY - y, xy.fX - realPtX};
+    double distSq = distU.fX * distU.fX + distU.fY * distU.fY;
+    double dist = sqrt(distSq); // OPTIMIZATION: can we compare against distSq instead ?
+    double tiniest = SkTMin(SkTMin(y, left), right);
+    double largest = SkTMax(SkTMax(y, left), right);
+    largest = SkTMax(largest, -tiniest);
+    if (!AlmostEqualUlps(largest, largest + dist)) { // is the dist within ULPS tolerance?
+        return -1;
+    }
+    return t;
+}
+
+double SkDLine::ExactPointV(const SkDPoint& xy, double top, double bottom, double x) {
+    if (xy.fX == x) {
+        if (xy.fY == top) {
+            return 0;
+        }
+        if (xy.fY == bottom) {
+            return 1;
+        }
+    }
+    return -1;
+}
+
+double SkDLine::NearPointV(const SkDPoint& xy, double top, double bottom, double x) {
+    if (!AlmostBequalUlps(xy.fX, x)) {
+        return -1;
+    }
+    if (!AlmostBetweenUlps(top, xy.fY, bottom)) {
+        return -1;
+    }
+    double t = (xy.fY - top) / (bottom - top);
+    t = SkPinT(t);
+    SkASSERT(between(0, t, 1));
+    double realPtY = (1 - t) * top + t * bottom;
+    SkDVector distU = {xy.fX - x, xy.fY - realPtY};
+    double distSq = distU.fX * distU.fX + distU.fY * distU.fY;
+    double dist = sqrt(distSq); // OPTIMIZATION: can we compare against distSq instead ?
+    double tiniest = SkTMin(SkTMin(x, top), bottom);
+    double largest = SkTMax(SkTMax(x, top), bottom);
+    largest = SkTMax(largest, -tiniest);
+    if (!AlmostEqualUlps(largest, largest + dist)) { // is the dist within ULPS tolerance?
+        return -1;
+    }
+    return t;
+}
+
+#ifdef SK_DEBUG
+void SkDLine::dump() {
+    SkDebugf("{{");
+    fPts[0].dump();
+    SkDebugf(", ");
+    fPts[1].dump();
+    SkDebugf("}}\n");
+}
+#endif