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+/**
+ * @file
+ * @brief Affine transformation classes
+ *//*
+ * Authors:
+ * ? <?@?.?>
+ * Krzysztof KosiƄski <tweenk.pl@gmail.com>
+ * Johan Engelen
+ *
+ * Copyright ?-2012 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.
+ */
+
+#include <boost/concept_check.hpp>
+#include <2geom/point.h>
+#include <2geom/transforms.h>
+#include <2geom/rect.h>
+
+namespace Geom {
+
+/** @brief Zoom between rectangles.
+ * Given two rectangles, compute a zoom that maps one to the other.
+ * Rectangles are assumed to have the same aspect ratio. */
+Zoom Zoom::map_rect(Rect const &old_r, Rect const &new_r)
+{
+ Zoom ret;
+ ret._scale = new_r.width() / old_r.width();
+ ret._trans = new_r.min() - old_r.min();
+ return ret;
+}
+
+// Point transformation methods.
+Point &Point::operator*=(Translate const &t)
+{
+ _pt[X] += t.vec[X];
+ _pt[Y] += t.vec[Y];
+ return *this;
+}
+Point &Point::operator*=(Scale const &s)
+{
+ _pt[X] *= s.vec[X];
+ _pt[Y] *= s.vec[Y];
+ return *this;
+}
+Point &Point::operator*=(Rotate const &r)
+{
+ double x = _pt[X], y = _pt[Y];
+ _pt[X] = x * r.vec[X] - y * r.vec[Y];
+ _pt[Y] = y * r.vec[X] + x * r.vec[Y];
+ return *this;
+}
+Point &Point::operator*=(HShear const &h)
+{
+ _pt[X] += h.f * _pt[X];
+ return *this;
+}
+Point &Point::operator*=(VShear const &v)
+{
+ _pt[Y] += v.f * _pt[Y];
+ return *this;
+}
+Point &Point::operator*=(Zoom const &z)
+{
+ _pt[X] += z._trans[X];
+ _pt[Y] += z._trans[Y];
+ _pt[X] *= z._scale;
+ _pt[Y] *= z._scale;
+ return *this;
+}
+
+// Affine multiplication methods.
+
+/** @brief Combine this transformation with a translation. */
+Affine &Affine::operator*=(Translate const &t) {
+ _c[4] += t[X];
+ _c[5] += t[Y];
+ return *this;
+}
+
+/** @brief Combine this transformation with scaling. */
+Affine &Affine::operator*=(Scale const &s) {
+ _c[0] *= s[X]; _c[1] *= s[Y];
+ _c[2] *= s[X]; _c[3] *= s[Y];
+ _c[4] *= s[X]; _c[5] *= s[Y];
+ return *this;
+}
+
+/** @brief Combine this transformation a rotation. */
+Affine &Affine::operator*=(Rotate const &r) {
+ // TODO: we just convert the Rotate to an Affine and use the existing operator*=()
+ // is there a better way?
+ *this *= (Affine) r;
+ return *this;
+}
+
+/** @brief Combine this transformation with horizontal shearing (skew). */
+Affine &Affine::operator*=(HShear const &h) {
+ _c[0] += h.f * _c[1];
+ _c[2] += h.f * _c[3];
+ _c[4] += h.f * _c[5];
+ return *this;
+}
+
+/** @brief Combine this transformation with vertical shearing (skew). */
+Affine &Affine::operator*=(VShear const &v) {
+ _c[1] += v.f * _c[0];
+ _c[3] += v.f * _c[2];
+ _c[5] += v.f * _c[4];
+ return *this;
+}
+
+Affine &Affine::operator*=(Zoom const &z) {
+ _c[0] *= z._scale; _c[1] *= z._scale;
+ _c[2] *= z._scale; _c[3] *= z._scale;
+ _c[4] += z._trans[X]; _c[5] += z._trans[Y];
+ _c[4] *= z._scale; _c[5] *= z._scale;
+ return *this;
+}
+
+Affine Rotate::around(Point const &p, Coord angle)
+{
+ Affine result = Translate(-p) * Rotate(angle) * Translate(p);
+ return result;
+}
+
+Affine reflection(Point const & vector, Point const & origin)
+{
+ Geom::Point vn = unit_vector(vector);
+ Coord cx2 = vn[X] * vn[X];
+ Coord cy2 = vn[Y] * vn[Y];
+ Coord c2xy = 2 * vn[X] * vn[Y];
+ Affine mirror ( cx2 - cy2, c2xy,
+ c2xy, cy2 - cx2,
+ 0, 0 );
+ return Translate(-origin) * mirror * Translate(origin);
+}
+
+// this checks whether the requirements of TransformConcept are satisfied for all transforms.
+// if you add a new transform type, include it here!
+void check_transforms()
+{
+#ifdef BOOST_CONCEPT_ASSERT
+ BOOST_CONCEPT_ASSERT((TransformConcept<Translate>));
+ BOOST_CONCEPT_ASSERT((TransformConcept<Scale>));
+ BOOST_CONCEPT_ASSERT((TransformConcept<Rotate>));
+ BOOST_CONCEPT_ASSERT((TransformConcept<HShear>));
+ BOOST_CONCEPT_ASSERT((TransformConcept<VShear>));
+ BOOST_CONCEPT_ASSERT((TransformConcept<Zoom>));
+ BOOST_CONCEPT_ASSERT((TransformConcept<Affine>)); // Affine is also a transform
+#endif
+
+ // check inter-transform multiplication
+ Affine m;
+ Translate t(Translate::identity());
+ Scale s(Scale::identity());
+ Rotate r(Rotate::identity());
+ HShear h(HShear::identity());
+ VShear v(VShear::identity());
+ Zoom z(Zoom::identity());
+
+ // notice that the first column is always the same and enumerates all transform types,
+ // while the second one changes to each transform type in turn.
+ // cppcheck-suppress redundantAssignment
+ m = t * t; m = t * s; m = t * r; m = t * h; m = t * v; m = t * z;
+ m = s * t; m = s * s; m = s * r; m = s * h; m = s * v; m = s * z;
+ m = r * t; m = r * s; m = r * r; m = r * h; m = r * v; m = r * z;
+ m = h * t; m = h * s; m = h * r; m = h * h; m = h * v; m = h * z;
+ m = v * t; m = v * s; m = v * r; m = v * h; m = v * v; m = v * z;
+ m = z * t; m = z * s; m = z * r; m = z * h; m = z * v; m = z * z;
+}
+
+} // namespace Geom
+
+/*
+ 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 :