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Diffstat (limited to 'src/2geom/transforms.cpp')
| -rw-r--r-- | src/2geom/transforms.cpp | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/src/2geom/transforms.cpp b/src/2geom/transforms.cpp new file mode 100644 index 0000000..41d3952 --- /dev/null +++ b/src/2geom/transforms.cpp @@ -0,0 +1,205 @@ +/** + * @file + * @brief Affine transformation classes + *//* + * Authors: + * ? <?@?.?> + * Krzysztof Kosiński <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 : |