1 files changed, 37 insertions, 0 deletions
diff --git a/include/core/SkGeometry.h b/include/core/SkGeometry.h
index 853a7c34a5..b8ab74caef 100644
--- a/include/core/SkGeometry.h
+++ b/include/core/SkGeometry.h
@@ -20,6 +20,17 @@
 
 #include "SkMatrix.h"
 
+/** An XRay is a half-line that runs from the specific point/origin to
+    +infinity in the X direction. e.g. XRay(3,5) is the half-line
+    (3,5)....(infinity, 5)
+ */
+typedef SkPoint SkXRay;
+
+/** Given a line segment from pts[0] to pts[1], and ax xray, return true if
+    they intersect.
+*/
+bool SkXRayCrossesLine(const SkXRay& pt, const SkPoint pts[2]);
+
 /** Given a quadratic equation Ax^2 + Bx + C = 0, return 0, 1, 2 roots for the
     equation.
 */
@@ -72,6 +83,12 @@ int SkChopQuadAtXExtrema(const SkPoint src[3], SkPoint dst[5]);
 */
 int SkChopQuadAtMaxCurvature(const SkPoint src[3], SkPoint dst[5]);
 
+/** Given 3 points on a quadratic bezier, use degree elevation to
+    convert it into the cubic fitting the same curve. The new cubic
+    curve is returned in dst[0..3].
+*/
+void SkConvertQuadToCubic(const SkPoint src[3], SkPoint dst[4]);
+
 ////////////////////////////////////////////////////////////////////////////////////////
 
 /** Convert from parametric from (pts) to polynomial coefficients
@@ -131,6 +148,26 @@ int SkChopCubicAtInflections(const SkPoint src[4], SkPoint dst[10]);
 int SkFindCubicMaxCurvature(const SkPoint src[4], SkScalar tValues[3]);
 int SkChopCubicAtMaxCurvature(const SkPoint src[4], SkPoint dst[13], SkScalar tValues[3] = NULL);
 
+/** Given a monotonic cubic bezier, determine whether an xray intersects the
+    cubic.
+    By definition the cubic is open at the starting point; in other
+    words, if pt.fY is equivalent to cubic[0].fY, and pt.fX is to the
+    left of the curve, the line is not considered to cross the curve,
+    but if it is equal to cubic[3].fY then it is considered to
+    cross.
+ */
+bool SkXRayCrossesMonotonicCubic(const SkXRay& pt, const SkPoint cubic[4]);
+
+/** Given an arbitrary cubic bezier, return the number of times an xray crosses
+    the cubic. Valid return values are [0..3]
+    By definition the cubic is open at the starting point; in other
+    words, if pt.fY is equivalent to cubic[0].fY, and pt.fX is to the
+    left of the curve, the line is not considered to cross the curve,
+    but if it is equal to cubic[3].fY then it is considered to
+    cross.
+ */
+int SkNumXRayCrossingsForCubic(const SkXRay& pt, const SkPoint cubic[4]);
+
 ///////////////////////////////////////////////////////////////////////////////////////////
 
 enum SkRotationDirection {