remove prototype pathops code

experimental/Intersection/QuadraticBezierClip.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 "CurveUtilities.h"
-#include "LineParameters.h"
-
-#define DEBUG_BEZIER_CLIP 1
-
-// return false if unable to clip (e.g., unable to create implicit line)
-// caller should subdivide, or create degenerate if the values are too small
-bool bezier_clip(const Quadratic& q1, const Quadratic& q2, double& minT, double& maxT) {
-    minT = 1;
-    maxT = 0;
-    // determine normalized implicit line equation for pt[0] to pt[3]
-    //   of the form ax + by + c = 0, where a*a + b*b == 1
-
-    // find the implicit line equation parameters
-    LineParameters endLine;
-    endLine.quadEndPoints(q1);
-    if (!endLine.normalize()) {
-        printf("line cannot be normalized: need more code here\n");
-        SkASSERT(0);
-        return false;
-    }
-
-    double distance = endLine.controlPtDistance(q1);
-
-    // find fat line
-    double top = 0;
-    double bottom = distance / 2; // http://students.cs.byu.edu/~tom/557/text/cic.pdf (7.6)
-    if (top > bottom) {
-        SkTSwap(top, bottom);
-    }
-
-    // compute intersecting candidate distance
-    Quadratic distance2y; // points with X of (0, 1/2, 1)
-    endLine.quadDistanceY(q2, distance2y);
-
-    int flags = 0;
-    if (approximately_lesser_or_equal(distance2y[0].y, top)) {
-        flags |= kFindTopMin;
-    } else if (approximately_greater_or_equal(distance2y[0].y, bottom)) {
-        flags |= kFindBottomMin;
-    } else {
-        minT = 0;
-    }
-
-    if (approximately_lesser_or_equal(distance2y[2].y, top)) {
-        flags |= kFindTopMax;
-    } else if (approximately_greater_or_equal(distance2y[2].y, bottom)) {
-        flags |= kFindBottomMax;
-    } else {
-        maxT = 1;
-    }
-    // Find the intersection of distance convex hull and fat line.
-    int idx = 0;
-    do {
-        int next = idx + 1;
-        if (next == 3) {
-            next = 0;
-        }
-        x_at(distance2y[idx], distance2y[next], top, bottom, flags, minT, maxT);
-        idx = next;
-    } while (idx);
-#if DEBUG_BEZIER_CLIP
-    _Rect r1, r2;
-    r1.setBounds(q1);
-    r2.setBounds(q2);
-    _Point testPt = {0.487, 0.337};
-    if (r1.contains(testPt) && r2.contains(testPt)) {
-        printf("%s q1=(%1.9g,%1.9g %1.9g,%1.9g %1.9g,%1.9g)"
-                " q2=(%1.9g,%1.9g %1.9g,%1.9g %1.9g,%1.9g) minT=%1.9g maxT=%1.9g\n",
-                __FUNCTION__, q1[0].x, q1[0].y, q1[1].x, q1[1].y, q1[2].x, q1[2].y,
-                q2[0].x, q2[0].y, q2[1].x, q2[1].y, q2[2].x, q2[2].y, minT, maxT);
-    }
-#endif
-    return minT < maxT; // returns false if distance shows no intersection
-}