remove prototype pathops code

experimental/Intersection/QuadraticSubDivide.cpp

-/*
- * 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 "CurveIntersection.h"
-#include "IntersectionUtilities.h"
-#include "QuadraticUtilities.h"
-
-/*
-Given a quadratic q, t1, and t2, find a small quadratic segment.
-
-The new quadratic is defined by A, B, and C, where
- A = c[0]*(1 - t1)*(1 - t1) + 2*c[1]*t1*(1 - t1) + c[2]*t1*t1
- C = c[3]*(1 - t1)*(1 - t1) + 2*c[2]*t1*(1 - t1) + c[1]*t1*t1
-
-To find B, compute the point halfway between t1 and t2:
-
-q(at (t1 + t2)/2) == D
-
-Next, compute where D must be if we know the value of B:
-
-_12 = A/2 + B/2
-12_ = B/2 + C/2
-123 = A/4 + B/2 + C/4
-    = D
-
-Group the known values on one side:
-
-B   = D*2 - A/2 - C/2
-*/
-
-static double interp_quad_coords(const double* src, double t)
-{
-    double ab = interp(src[0], src[2], t);
-    double bc = interp(src[2], src[4], t);
-    double abc = interp(ab, bc, t);
-    return abc;
-}
-
-void sub_divide(const Quadratic& src, double t1, double t2, Quadratic& dst) {
-    double ax = dst[0].x = interp_quad_coords(&src[0].x, t1);
-    double ay = dst[0].y = interp_quad_coords(&src[0].y, t1);
-    double dx = interp_quad_coords(&src[0].x, (t1 + t2) / 2);
-    double dy = interp_quad_coords(&src[0].y, (t1 + t2) / 2);
-    double cx = dst[2].x = interp_quad_coords(&src[0].x, t2);
-    double cy = dst[2].y = interp_quad_coords(&src[0].y, t2);
-    /* bx = */ dst[1].x = 2*dx - (ax + cx)/2;
-    /* by = */ dst[1].y = 2*dy - (ay + cy)/2;
-}
-
-_Point sub_divide(const Quadratic& src, const _Point& a, const _Point& c, double t1, double t2) {
-    _Point b;
-    double dx = interp_quad_coords(&src[0].x, (t1 + t2) / 2);
-    double dy = interp_quad_coords(&src[0].y, (t1 + t2) / 2);
-    b.x = 2 * dx - (a.x + c.x) / 2;
-    b.y = 2 * dy - (a.y + c.y) / 2;
-    return b;
-}
-
-/* classic one t subdivision */
-static void interp_quad_coords(const double* src, double* dst, double t)
-{
-    double ab = interp(src[0], src[2], t);
-    double bc = interp(src[2], src[4], t);
-
-    dst[0] = src[0];
-    dst[2] = ab;
-    dst[4] = interp(ab, bc, t);
-    dst[6] = bc;
-    dst[8] = src[4];
-}
-
-void chop_at(const Quadratic& src, QuadraticPair& dst, double t)
-{
-    interp_quad_coords(&src[0].x, &dst.pts[0].x, t);
-    interp_quad_coords(&src[0].y, &dst.pts[0].y, t);
-}