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Diffstat (limited to 'include/2geom/coord.h')
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1 files changed, 208 insertions, 0 deletions
diff --git a/include/2geom/coord.h b/include/2geom/coord.h new file mode 100644 index 0000000..40db84e --- /dev/null +++ b/include/2geom/coord.h @@ -0,0 +1,208 @@ +/** @file + * @brief Integral and real coordinate types and some basic utilities + *//* + * Authors: + * Nathan Hurst <njh@mail.csse.monash.edu.au> + * Krzysztof Kosiński <tweenk.pl@gmail.com> + * Copyright 2006-2015 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_COORD_H +#define LIB2GEOM_SEEN_COORD_H + +#include <cmath> +#include <limits> +#include <string> +#include <functional> +#include <boost/operators.hpp> +#include <2geom/forward.h> + +namespace Geom { + +/** @brief 2D axis enumeration (X or Y). + * @ingroup Primitives */ +enum Dim2 { X=0, Y=1 }; + +/** @brief Get the other (perpendicular) dimension. + * @ingroup Primitives */ +inline constexpr Dim2 other_dimension(Dim2 d) { return Dim2(int(d) ^ 1); } + +// TODO: make a smarter implementation with C++11 +template <typename T> +struct D2Traits { + using D1Value = typename T::D1Value; + using D1Reference = typename T::D1Reference; + using D1ConstReference = typename T::D1ConstReference; +}; + +/** @brief Axis extraction functor. + * For use with things such as Boost's transform_iterator. + * @ingroup Utilities */ +template <Dim2 D, typename T> +struct GetAxis { + using result_type = typename D2Traits<T>::D1Value; + using argument_type = T; + typename D2Traits<T>::D1Value operator()(T const &a) const { + return a[D]; + } +}; + +/** @brief Floating point type used to store coordinates. + * @ingroup Primitives */ +using Coord = double; + +/** @brief Type used for integral coordinates. + * @ingroup Primitives */ +using IntCoord = int; + +/** @brief Default "acceptably small" value. + * @ingroup Primitives */ +constexpr Coord EPSILON = 1e-6; + +/** @brief Get a value representing infinity. + * @ingroup Primitives */ +inline constexpr Coord infinity() { return std::numeric_limits<Coord>::infinity(); } + +/** @brief Nearness predicate for values. + * @ingroup Primitives */ +inline constexpr bool are_near(Coord a, Coord b, double eps=EPSILON) { return std::abs(a-b) <= eps; } +inline constexpr bool rel_error_bound(Coord a, Coord b, double eps=EPSILON) { return std::abs(a) <= eps*b; } + +/** @brief Numerically stable linear interpolation. + * @ingroup Primitives */ +inline constexpr Coord lerp(Coord t, Coord a, Coord b) { + return (1 - t) * a + t * b; +} + +/** @brief Traits class used with coordinate types. + * Defines point, interval and rectangle types for the given coordinate type. + * @ingroup Utilities */ +template <typename C> +struct CoordTraits { + using PointType = D2<C>; + using IntervalType = GenericInterval<C>; + using OptIntervalType = GenericOptInterval<C>; + using RectType = GenericRect<C>; + using OptRectType = GenericOptRect<C>; + + using IntervalOps = + boost::equality_comparable< IntervalType + , boost::orable< IntervalType + >>; + + using RectOps = + boost::equality_comparable< RectType + , boost::orable< RectType + , boost::orable< RectType, OptRectType + >>>; +}; + +// NOTE: operator helpers for Rect and Interval are defined here. +// This is to avoid increasing their size through multiple inheritance. + +template<> +struct CoordTraits<IntCoord> { + using PointType = IntPoint; + using IntervalType = IntInterval; + using OptIntervalType = OptIntInterval; + using RectType = IntRect; + using OptRectType = OptIntRect; + + using IntervalOps = + boost::equality_comparable< IntInterval + , boost::additive< IntInterval + , boost::additive< IntInterval, IntCoord + , boost::orable< IntInterval + >>>>; + + using RectOps = + boost::equality_comparable< IntRect + , boost::orable< IntRect + , boost::orable< IntRect, OptIntRect + , boost::additive< IntRect, IntPoint + >>>>; +}; + +template<> +struct CoordTraits<Coord> { + using PointType = Point; + using IntervalType = Interval; + using OptIntervalType = OptInterval; + using RectType = Rect; + using OptRectType = OptRect; + + using IntervalOps = + boost::equality_comparable< Interval + , boost::equality_comparable< Interval, IntInterval + , boost::additive< Interval + , boost::multipliable< Interval + , boost::orable< Interval + , boost::arithmetic< Interval, Coord + >>>>>>; + + using RectOps = + boost::equality_comparable< Rect + , boost::equality_comparable< Rect, IntRect + , boost::orable< Rect + , boost::orable< Rect, OptRect + , boost::additive< Rect, Point + , boost::multipliable< Rect, Affine + >>>>>>; +}; + +/** @brief Convert coordinate to shortest possible string. + * @return The shortest string that parses back to the original value. + * @relates Coord */ +std::string format_coord_shortest(Coord x); + +/** @brief Convert coordinate to human-readable string. + * Unlike format_coord_shortest, this function will not omit a leading zero + * before a decimal point or use small negative exponents. The output format + * is similar to Javascript functions. + * @relates Coord */ +std::string format_coord_nice(Coord x); + +/** @brief Parse coordinate string. + * When using this function in conjunction with format_coord_shortest() + * or format_coord_nice(), the value is guaranteed to be preserved exactly. + * @relates Coord */ +Coord parse_coord(std::string const &s); + +} // namespace Geom + +#endif // LIB2GEOM_SEEN_COORD_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:fileencoding=utf-8:textwidth=99 : |