libcruft-util/region.cpp

/*
 * This file is part of libgim.
 *
 * libgim is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 *
 * libgim 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 General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright 2010 Danny Robson <danny@nerdcruft.net>
 */


#include "region.hpp"

#include "debug.hpp"
#include "types/casts.hpp"

#include <cmath>
#include <type_traits>

using namespace util;


template <typename T>
region<T>::region (T _x, T _y, size_type _w, size_type _h):
    x (_x),
    y (_y),
    w (_w),
    h (_h)
{
}


template <typename T>
region<T>&
region<T>::operator+= (const vector<2> &rhs) {
    x += rhs.x;
    y += rhs.y;

    return *this;
}


template <typename T>
typename region<T>::size_type
region<T>::area (void) const
    { return w * h; }


template <typename T>
typename region<T>::size_type
region<T>::diameter (void) const {
    return static_cast<size_type> (sqrt (w * w + h * h));
}


template <typename T>
bool 
region<T>::empty (void) const
    { return almost_equal (area (), 0); }


template <typename T>
point<2>
region<T>::base (void) const {
    return { static_cast<double> (x), static_cast<double> (y) };
}


template <typename T>
point<2>
region<T>::centre (void) const {
    double cx = x + static_cast<T>(w / 2.0),
           cy = y + static_cast<T>(h / 2.0);

    return { cx, cy };
}


template <typename T>
bool
region<T>::includes (const point<2> &p) const {
    return p.x >= x &&
           p.y >= y &&
           p.x - x <= w &&
           p.y - y <= h;
}


template <typename T>
bool
region<T>::contains (const point<2> &p) const {
    return p.x > x &&
           p.y > y &&
           p.x - x < w &&
           p.y - y < h;
}


template <typename T>
bool
region<T>::overlaps (const region<T> &rhs) const {
    //return !overlap (rhs).empty ();
    
    return x     < sign_cast<T> (rhs.w) + rhs.x && 
           rhs.x < sign_cast<T> (    w) +     x &&
           y     < sign_cast<T> (rhs.h) + rhs.y &&
           rhs.y < sign_cast<T> (    h) +     y;
}


template<typename T>
region<T>
region<T>::overlap (const region<T> &rhs) const {
    T newx1 = max (x, rhs.x),
      newy1 = max (y, rhs.y),
      newx2 = min (x + sign_cast<T> (w), rhs.x + sign_cast<T> (rhs.w)),
      newy2 = min (y + sign_cast<T> (h), rhs.y + sign_cast<T> (rhs.h));

    if (newx2 < newx1 || newy2 < newy1)
        throw std::logic_error ("No overlap");

    size_type nw = sign_cast<size_type> (newx2 - newx1);
    size_type nh = sign_cast<size_type> (newy2 - newy1);
    return region<T> (newx1, newy1, nw, nh);
    
}


template <typename T>
bool
region<T>::operator ==(const region& rhs) const
    { return almost_equal (x, rhs.x) &&
             almost_equal (y, rhs.y) &&
             almost_equal (w, rhs.w) &&
             almost_equal (h, rhs.h); }


template <typename T>
void
region<T>::sanity (void) const {
    static_assert(!std::is_floating_point<T>::value,
                  "Floating point types need width and height checks");
}


namespace util {
    template <>
    void region<double>::sanity (void) const {
        CHECK (w >= 0 && h >= 0);
    }


    template <>
    void region<float>::sanity (void) const {
        CHECK (w >= 0 && h >= 0);
    }
}


template <typename T>
std::ostream&
util::operator<< (std::ostream &os, const region<T> &rhs) {
    os << "region(" << rhs.x << ", " << rhs.y << ", " << rhs.w << ", " << rhs.h << ")";
    return os;
}


namespace util {
    template struct region<int32_t>;
    template struct region<int64_t>;
    template struct region<uint32_t>;
    template struct region<uint64_t>;
    template struct region<double>;

    template std::ostream& operator<< (std::ostream&, const region<unsigned int>&);
    template std::ostream& operator<< (std::ostream&, const region<double>&);
}