mirror of
https://github.com/mapbox/tippecanoe.git
synced 2025-02-08 20:10:15 +00:00
86 lines
2.5 KiB
C++
86 lines
2.5 KiB
C++
#pragma once
|
|
|
|
#include <cmath>
|
|
|
|
#include <mapbox/geometry/point.hpp>
|
|
#include <mapbox/geometry/polygon.hpp>
|
|
#include <mapbox/geometry/wagyu/point.hpp>
|
|
|
|
namespace mapbox {
|
|
namespace geometry {
|
|
namespace wagyu {
|
|
|
|
template <typename T>
|
|
double area(mapbox::geometry::linear_ring<T> const& poly) {
|
|
std::size_t size = poly.size();
|
|
if (size < 3) {
|
|
return 0.0;
|
|
}
|
|
|
|
double a = 0.0;
|
|
auto itr = poly.begin();
|
|
auto itr_prev = poly.end();
|
|
--itr_prev;
|
|
a += static_cast<double>(itr_prev->x + itr->x) * static_cast<double>(itr_prev->y - itr->y);
|
|
++itr;
|
|
itr_prev = poly.begin();
|
|
for (; itr != poly.end(); ++itr, ++itr_prev) {
|
|
a += static_cast<double>(itr_prev->x + itr->x) * static_cast<double>(itr_prev->y - itr->y);
|
|
}
|
|
return -a * 0.5;
|
|
}
|
|
|
|
inline bool value_is_zero(double val) {
|
|
return std::fabs(val) < (5.0 * std::numeric_limits<double>::epsilon());
|
|
}
|
|
|
|
inline bool values_are_equal(double x, double y) {
|
|
return value_is_zero(x - y);
|
|
}
|
|
|
|
inline bool greater_than_or_equal(double x, double y) {
|
|
return x > y || values_are_equal(x, y);
|
|
}
|
|
|
|
template <typename T>
|
|
bool slopes_equal(mapbox::geometry::point<T> const& pt1,
|
|
mapbox::geometry::point<T> const& pt2,
|
|
mapbox::geometry::point<T> const& pt3) {
|
|
return (pt1.y - pt2.y) * (pt2.x - pt3.x) == (pt1.x - pt2.x) * (pt2.y - pt3.y);
|
|
}
|
|
|
|
template <typename T>
|
|
bool slopes_equal(mapbox::geometry::wagyu::point<T> const& pt1,
|
|
mapbox::geometry::wagyu::point<T> const& pt2,
|
|
mapbox::geometry::point<T> const& pt3) {
|
|
return (pt1.y - pt2.y) * (pt2.x - pt3.x) == (pt1.x - pt2.x) * (pt2.y - pt3.y);
|
|
}
|
|
|
|
template <typename T>
|
|
bool slopes_equal(mapbox::geometry::wagyu::point<T> const& pt1,
|
|
mapbox::geometry::wagyu::point<T> const& pt2,
|
|
mapbox::geometry::wagyu::point<T> const& pt3) {
|
|
return (pt1.y - pt2.y) * (pt2.x - pt3.x) == (pt1.x - pt2.x) * (pt2.y - pt3.y);
|
|
}
|
|
|
|
template <typename T>
|
|
bool slopes_equal(mapbox::geometry::point<T> const& pt1,
|
|
mapbox::geometry::point<T> const& pt2,
|
|
mapbox::geometry::point<T> const& pt3,
|
|
mapbox::geometry::point<T> const& pt4) {
|
|
return (pt1.y - pt2.y) * (pt3.x - pt4.x) == (pt1.x - pt2.x) * (pt3.y - pt4.y);
|
|
}
|
|
|
|
template <typename T>
|
|
inline T wround(double value) {
|
|
return static_cast<T>(::llround(value));
|
|
}
|
|
|
|
template <>
|
|
inline std::int64_t wround<std::int64_t>(double value) {
|
|
return ::llround(value);
|
|
}
|
|
}
|
|
}
|
|
}
|