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diff --git a/src/3rdparty/libdepixelize/priv/curvature.h b/src/3rdparty/libdepixelize/priv/curvature.h
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+/*  This file is part of the libdepixelize project
+    Copyright (C) 2013 Vinícius dos Santos Oliveira <vini.ipsmaker@gmail.com>
+
+    GNU Lesser General Public License Usage
+    This library is free software; you can redistribute it and/or modify it
+    under the terms of the GNU Lesser General Public License as published by the
+    Free Software Foundation; either version 2.1 of the License, or (at your
+    option) any later version.
+    You should have received a copy of the GNU Lesser General Public License
+    along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+    GNU General Public License Usage
+    Alternatively, this library may be used under the terms of the GNU General
+    Public License as published by the Free Software Foundation, either version
+    2 of the License, or (at your option) any later version.
+    You should have received a copy of the GNU General Public License along with
+    this library.  If not, see <http://www.gnu.org/licenses/>.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+*/
+
+#ifndef LIBDEPIXELIZE_TRACER_CURVATURE_H
+#define LIBDEPIXELIZE_TRACER_CURVATURE_H
+
+#include "point.h"
+#include <cmath>
+
+namespace Tracer {
+
+/**
+ * Curvature function for a quadratic Bézier curve where the points are know.
+ * Its main use is to numerically integrate the curvature function and then
+ * smooth the B-Splines generated by the Kopf-Lischinski algorithm.
+ */
+template<class T>
+struct Curvature
+{
+    Curvature(Point<T> p0, Point<T> c1, Point<T> p2) :
+        p0(p0), c1(c1), p2(p2)
+    {}
+
+    T operator()(T t) const;
+
+    /**
+     * The derivative of x
+     */
+    T xPrime(T t) const;
+
+    /**
+     * The derivative of y
+     */
+    T yPrime(T t) const;
+
+    /**
+     * The second derivative of x
+     */
+    T xPrimePrime() const;
+
+    /**
+     * The second derivative of y
+     */
+    T yPrimePrime() const;
+
+    Point<T> p0, c1, p2;
+};
+
+template<class T>
+T Curvature<T>::operator()(T t) const
+{
+    T num = xPrime(t) * yPrimePrime() - yPrime(t) * xPrimePrime();
+    T den = std::pow(xPrime(t) * xPrime(t) + yPrime(t) * yPrime(t), T(3) / 2);
+    return num / den;
+}
+
+template<class T>
+T Curvature<T>::xPrime(T t) const
+{
+    return (1-t)*2*(c1.x-p0.x) + t*2*(p2.x-c1.x);
+}
+
+template<class T>
+T Curvature<T>::yPrime(T t) const
+{
+    return (1-t)*2*(c1.y-p0.y) + t*2*(p2.y-c1.y);
+}
+
+template<class T>
+T Curvature<T>::xPrimePrime() const
+{
+    return 2 * (p2.x - 2*c1.x + p0.x);
+}
+
+template<class T>
+T Curvature<T>::yPrimePrime() const
+{
+    return 2 * (p2.y - 2*c1.y + p0.y);
+}
+
+} // namespace Tracer
+
+#endif // LIBDEPIXELIZE_TRACER_CURVATURE_H
+
+/*
+  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:encoding=utf-8:textwidth=99 :