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diff --git a/include/2geom/crossing.h b/include/2geom/crossing.h
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+/**
+ * @file
+ * @brief Structure representing the intersection of two curves
+ *//*
+ * Authors:
+ *   Michael Sloan <mgsloan@gmail.com>
+ *   Marco Cecchetti <mrcekets at gmail.com>
+ * 
+ * Copyright 2006-2008  authors
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ */
+
+#ifndef LIB2GEOM_SEEN_CROSSING_H
+#define LIB2GEOM_SEEN_CROSSING_H
+
+#include <vector>
+#include <2geom/rect.h>
+#include <2geom/sweep-bounds.h>
+#include <optional>
+#include <2geom/pathvector.h>
+
+namespace Geom {
+
+//Crossing between one or two paths
+struct Crossing {
+    bool dir; //True: along a, a becomes outside.
+    double ta, tb;  //time on a and b of crossing
+    unsigned a, b;  //storage of indices
+    Crossing() : dir(false), ta(0), tb(1), a(0), b(1) {}
+    Crossing(double t_a, double t_b, bool direction) : dir(direction), ta(t_a), tb(t_b), a(0), b(1) {}
+    Crossing(double t_a, double t_b, unsigned ai, unsigned bi, bool direction) : dir(direction), ta(t_a), tb(t_b), a(ai), b(bi) {}
+    bool operator==(const Crossing & other) const { return a == other.a && b == other.b && dir == other.dir && ta == other.ta && tb == other.tb; }
+    bool operator!=(const Crossing & other) const { return !(*this == other); }
+
+    unsigned getOther(unsigned cur) const { return a == cur ? b : a; }
+    double getTime(unsigned cur) const { return a == cur ? ta : tb; }
+    double getOtherTime(unsigned cur) const { return a == cur ? tb : ta; }
+    bool onIx(unsigned ix) const { return a == ix || b == ix; }
+};
+
+typedef std::optional<Crossing> OptCrossing;
+
+
+/*
+struct Edge {
+    unsigned node, path;
+    double time;
+    bool reverse;
+    Edge(unsigned p, double t, bool r) : path(p), time(t), reverse(r) {}
+    bool operator==(Edge const &other) const { return other.path == path && other.time == time && other.reverse == reverse; }
+};
+
+struct CrossingNode {
+    std::vector<Edge> edges;
+    CrossingNode() : edges(std::vector<Edge>()) {}
+    explicit CrossingNode(std::vector<Edge> es) : edges(es) {}
+    void add_edge(Edge const &e) {
+    	if(std::find(edges.begin(), edges.end(), e) == edges.end())
+    	    edges.push_back(e);
+    }
+    double time_on(unsigned p) {
+    	for(unsigned i = 0; i < edges.size(); i++)
+    	    if(edges[i].path == p) return edges[i].time;
+    	std::cout << "CrossingNode time_on failed\n";
+    	return 0;
+    }
+};
+
+
+typedef std::vector<CrossingNode> CrossingGraph;
+
+struct TimeOrder {
+    bool operator()(Edge a, Edge b) {
+        return a.time < b.time;
+    }
+};
+
+class Path;
+CrossingGraph create_crossing_graph(PathVector const &p, Crossings const &crs);
+*/
+
+/*inline bool are_near(Crossing a, Crossing b) {
+    return are_near(a.ta, b.ta) && are_near(a.tb, b.tb);
+}
+
+struct NearF { bool operator()(Crossing a, Crossing b) { return are_near(a, b); } };
+*/
+
+struct CrossingOrder {
+    unsigned ix;
+    bool rev;
+    CrossingOrder(unsigned i, bool r = false) : ix(i), rev(r) {}
+    bool operator()(Crossing a, Crossing b) {
+        if(rev) 
+            return (ix == a.a ? a.ta : a.tb) <
+                   (ix == b.a ? b.ta : b.tb);
+        else
+            return (ix == a.a ? a.ta : a.tb) >
+                   (ix == b.a ? b.ta : b.tb);
+    }
+};
+
+typedef std::vector<Crossing> Crossings;
+
+typedef std::vector<Crossings> CrossingSet;
+
+template<typename C>
+std::vector<Rect> bounds(C const &a) {
+    std::vector<Rect> rs;
+    for (unsigned i = 0; i < a.size(); i++) {
+        OptRect bb = a[i].boundsFast();
+        if (bb) {
+            rs.push_back(*bb);
+        }
+    }
+    return rs;
+}
+// provide specific method for Paths because paths can be closed or open. Path::size() is named somewhat wrong...
+std::vector<Rect> bounds(Path const &a);
+
+inline void sort_crossings(Crossings &cr, unsigned ix) { std::sort(cr.begin(), cr.end(), CrossingOrder(ix)); }
+
+template <typename T>
+struct CrossingTraits {
+    typedef std::vector<T> VectorT;
+    static inline VectorT init(T const &x) { return VectorT(1, x); }
+};
+template <>
+struct CrossingTraits<Path> {
+    typedef PathVector VectorT;
+    static inline VectorT vector_one(Path const &x) { return VectorT(x); }
+};
+
+template<typename T>
+struct Crosser {
+    typedef typename CrossingTraits<T>::VectorT VectorT;
+    virtual ~Crosser() {}
+    virtual Crossings crossings(T const &a, T const &b) {
+        return crossings(CrossingTraits<T>::vector_one(a), CrossingTraits<T>::vector_one(b))[0]; }
+    virtual CrossingSet crossings(VectorT const &a, VectorT const &b) {
+        CrossingSet results(a.size() + b.size(), Crossings());
+    
+        std::vector<std::vector<unsigned> > cull = sweep_bounds(bounds(a), bounds(b));
+        for(unsigned i = 0; i < cull.size(); i++) {
+            for(unsigned jx = 0; jx < cull[i].size(); jx++) {
+                unsigned j = cull[i][jx];
+                unsigned jc = j + a.size();
+                Crossings cr = crossings(a[i], b[j]);
+                for(auto & k : cr) { k.a = i; k.b = jc; }
+                
+                //Sort & add A-sorted crossings
+                sort_crossings(cr, i);
+                Crossings n(results[i].size() + cr.size());
+                std::merge(results[i].begin(), results[i].end(), cr.begin(), cr.end(), n.begin(), CrossingOrder(i));
+                results[i] = n;
+                
+                //Sort & add B-sorted crossings
+                sort_crossings(cr, jc);
+                n.resize(results[jc].size() + cr.size());
+                std::merge(results[jc].begin(), results[jc].end(), cr.begin(), cr.end(), n.begin(), CrossingOrder(jc));
+                results[jc] = n;
+            }
+        }
+        return results;
+    }
+};
+void merge_crossings(Crossings &a, Crossings &b, unsigned i);
+void offset_crossings(Crossings &cr, double a, double b);
+
+Crossings reverse_ta(Crossings const &cr, std::vector<double> max);
+Crossings reverse_tb(Crossings const &cr, unsigned split, std::vector<double> max);
+CrossingSet reverse_ta(CrossingSet const &cr, unsigned split, std::vector<double> max);
+CrossingSet reverse_tb(CrossingSet const &cr, unsigned split, std::vector<double> max);
+
+void clean(Crossings &cr_a, Crossings &cr_b);
+void delete_duplicates(Crossings &crs);
+
+} // end namespace Geom
+
+#endif
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :