extract cubic classification from gpu into geometry

src/core/SkGeometry.h

 
 /*
  * 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 SkGeometry_DEFINED
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     but if it is equal to cubic[3].fY then it is considered to
     cross.
     Optional outgoing "ambiguous" argument indicates whether the answer is
     ambiguous because the query occurred exactly at one of the endpoints' y
     coordinates or at a tangent point, indicating that another query y
     coordinate is preferred for robustness.
  */
 int SkNumXRayCrossingsForCubic(const SkXRay& pt, const SkPoint cubic[4],
                                bool* ambiguous = NULL);
 
+enum SkCubicType {
+    kSerpentine_SkCubicType,
+    kCusp_SkCubicType,
+    kLoop_SkCubicType,
+    kQuadratic_SkCubicType,
+    kLine_SkCubicType,
+    kPoint_SkCubicType
+};
+
+/** Returns the cubic classification. Pass scratch storage for computing inflection data,
+    which can be used with additional work to find the loop intersections and so on.
+*/
+SkCubicType SkClassifyCubic(const SkPoint p[4], SkScalar inflection[3]);
+
 ///////////////////////////////////////////////////////////////////////////////
 
 enum SkRotationDirection {
     kCW_SkRotationDirection,
     kCCW_SkRotationDirection
 };
 
 /** Maximum number of points needed in the quadPoints[] parameter for
     SkBuildQuadArc()
 */
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 private:
     enum {
         kQuadCount = 8, // should handle most conics
         kPointCount = 1 + 2 * kQuadCount,
     };
     SkAutoSTMalloc<kPointCount, SkPoint> fStorage;
     int fQuadCount; // #quads for current usage
 };
 
 #endif