Move gpu conic calculations to GrPathUtils

src/gpu/GrPathUtils.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrPathUtils_DEFINED
 #define GrPathUtils_DEFINED
 
@@ skipping 79 matching lines @@
                 uv->fX = sx * xy->fX + kx * xy->fY + tx;
                 uv->fY = ky * xy->fX + sy * xy->fY + ty;
                 xyPtr += STRIDE;
                 uvPtr += STRIDE;
             }
         }
     private:
         float fM[6];
     };
 
+    // Input is 3 control points and a weight for a bezier conic. Calculates the
+    // three linear functionals (K,L,M) that represent the implicit equation of the
+    // conic, K^2 - LM.
+    //
+    // Output:
+    //  K = (klm[0], klm[1], klm[2])
+    //  L = (klm[3], klm[4], klm[5])
+    //  M = (klm[6], klm[7], klm[8])
+    void getConicKLM(const SkPoint p[3], const SkScalar weight, SkScalar klm[9]);
 
     // Converts a cubic into a sequence of quads. If working in device space
     // use tolScale = 1, otherwise set based on stretchiness of the matrix. The
     // result is sets of 3 points in quads (TODO: share endpoints in returned
     // array)
     // When we approximate a cubic {a,b,c,d} with a quadratic we may have to
     // ensure that the new control point lies between the lines ab and cd. The
     // convex path renderer requires this. It starts with a path where all the
     // control points taken together form a convex polygon. It relies on this
     // property and the quadratic approximation of cubics step cannot alter it.
@@ skipping 45 matching lines @@
     // K = (klm[0], klm[1], klm[2])
     // L = (klm[3], klm[4], klm[5])
     // M = (klm[6], klm[7], klm[8])
     //
     // Notice that the klm lines are calculated in the same space as the input control points.
     // If you transform the points the lines will also need to be transformed. This can be done
     // by mapping the lines with the inverse-transpose of the matrix used to map the points.
     void getCubicKLM(const SkPoint p[4], SkScalar klm[9]);
 };
 #endif