libcruft-util/region.cpp
Danny Robson f256f4d0e9 Add a point constrain method to region
Force a point to not exceed the region boundaries.
2013-08-05 16:38:05 +10:00

305 lines
7.7 KiB
C++

/*
* 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)
{
DEBUG_ONLY (sanity ());
}
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>
void
region<T>::scale (double factor) {
x -= (w * factor - w) / 2.0;
y -= (h * factor - h) / 2.0;
w *= factor;
h *= factor;
}
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;
}
// FIXME: This will fail with an actual infinite range (NaNs will be generated
// in the conditionals).
template <typename T>
bool
region<T>::overlaps (const region<T> &rhs) const {
return x < rhs.x + rhs.w &&
rhs.x < x + w &&
y < rhs.y + rhs.h &&
rhs.y < y + h;
}
//-----------------------------------------------------------------------------
template <typename T>
void
region<T>::constrain (point2 &p) const {
p.x = std::min (std::max (static_cast<T> (p.x), x), x + w);
p.y = std::min (std::max (static_cast<T> (p.y), y), y + h);
}
template <typename T>
point2
region<T>::constrained (const point2 &p) const {
point2 v;
v.x = std::min (std::max (static_cast<T> (p.x), x), x + w);
v.y = std::min (std::max (static_cast<T> (p.y), y), y + h);
return v;
}
//-----------------------------------------------------------------------------
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 {
CHECK_SOFT (w > 0);
CHECK_SOFT (h > 0);
static_assert(!std::is_floating_point<T>::value,
"Floating point types need width and height checks");
}
//-----------------------------------------------------------------------------
// The desired iterator semantics have been difficult to nail down; is it
// edge-inclusive, left-bottom inclusive, purely exclusive, integral only?
// The code has been left here because it was a little annoying to write and
// we're likely to need it again some day.
#if 0
template <typename T>
typename region<T>::iterator&
region<T>::iterator::operator++ (void) {
if (++x > static_cast<T> (w)) {
x = a;
++y;
}
return *this;
}
template <typename T>
typename region<T>::iterator&
region<T>::iterator::operator* (void) {
return *this;
}
template <typename T>
bool
region<T>::iterator::operator== (const iterator &rhs) const {
return almost_equal (rhs.x, x) && almost_equal (rhs.y, y);
}
template <typename T>
bool
region<T>::iterator::operator!= (const iterator &rhs) const {
return !(*this == rhs);
}
template <typename T>
typename region<T>::iterator
region<T>::begin (void) {
return { x, y, x, w, h };
}
template <typename T>
typename region<T>::iterator
region<T>::end (void) {
return { x, y + sign_cast<T> (h) + 1, x, w, h };
}
#endif
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>
const region<T>
region<T>::MAX (std::numeric_limits<T>::lowest (),
std::numeric_limits<T>::lowest (),
std::numeric_limits<T>::has_infinity ? std::numeric_limits<T>::infinity () :
std::numeric_limits<T>::max (),
std::numeric_limits<T>::has_infinity ? std::numeric_limits<T>::infinity () :
std::numeric_limits<T>::max ());
template <typename T>
const region<T>
region<T>::UNIT (0, 0, 1, 1);
//-----------------------------------------------------------------------------
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<float>;
template struct region<double>;
template std::ostream& operator<< (std::ostream&, const region< int32_t>&);
template std::ostream& operator<< (std::ostream&, const region< int64_t>&);
template std::ostream& operator<< (std::ostream&, const region<uint32_t>&);
template std::ostream& operator<< (std::ostream&, const region<uint64_t>&);
template std::ostream& operator<< (std::ostream&, const region< double>&);
}