Program Listing for File linesegment2d.cpp

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#include "tuw_geometry/linesegment2d.hpp"

using namespace tuw;
LineSegment2D::LineSegment2D() {}
LineSegment2D::LineSegment2D(const LineSegment2D & l)
: Line2D(l.line()), p0_(l.p0()), p1_(l.p1())
{
}
LineSegment2D::LineSegment2D(const Point2D & p0, const Point2D & p1)
: Line2D(p0, p1, true), p0_(p0), p1_(p1)
{
}
LineSegment2D::LineSegment2D(
  const double & x0, const double & y0, const double & x1, const double & y1)
: Line2D(x0, y0, x1, y1, true), p0_(x0, y0), p1_(x1, y1)
{
}
const double & LineSegment2D::x0() const {return p0_.x();}
const double & LineSegment2D::y0() const {return p0_.y();}
const double & LineSegment2D::x1() const {return p1_.x();}
const double & LineSegment2D::y1() const {return p1_.y();}
double LineSegment2D::angle() const
{
  double dx = p1_.x() - p0_.x();
  double dy = p1_.y() - p0_.y();
  return atan2(dy, dx);
}
Point2D LineSegment2D::pc() const
{
  double dx = p1_.x() - p0_.x();
  double dy = p1_.y() - p0_.y();
  return Point2D(p0_.x() + dx / 2., p0_.y() + dy / 2.);
}
const Point2D & LineSegment2D::p0() const {return p0_;}
const Point2D & LineSegment2D::p1() const {return p1_;}
const Line2D & LineSegment2D::line() const {return *this;}
double LineSegment2D::length() const {return p0_.distanceTo(p1_);}
bool LineSegment2D::operator==(const LineSegment2D & o) const
{
  return p0() == o.p0() && p1() == o.p1();
}
LineSegment2D & LineSegment2D::set(
  const double & x0, const double & y0, const double & x1, const double & y1)
{
  Line2D::set(x0, y0, x1, y1, true);
  p0_.set(x0, y0), p1_.set(x1, y1);
  return *this;
}
LineSegment2D & LineSegment2D::set(const Point2D & p0, const Point2D & p1)
{
  set(p0.x(), p0.y(), p1.x(), p1.y());
  return *this;
}
double LineSegment2D::distanceTo(const Point2D & p, double & dx, double & dy) const
{
  return sqrt(distanceSqrTo(p, dx, dy));
}
double LineSegment2D::distanceSqrTo(const Point2D & p, double & dx, double & dy) const
{
  const double px = x1() - x0();
  const double py = y1() - y0();
  const double l2 = px * px + py * py;
  double u = ((p.x() - x0()) * px + (p.y() - y0()) * py) / l2;
  if (u > 1) {
    u = 1;
  } else if (u < 0) {
    u = 0;
  }
  const double xk = x0() + u * px;
  const double yk = y0() + u * py;
  dx = xk - p.x();
  dy = yk - p.y();
  return dx * dx + dy * dy;
}

double LineSegment2D::closestPointLineSegmentRatio(const Point2D & p) const
{
  double px = x1() - x0();
  double py = y1() - y0();
  double l2 = px * px + py * py;
  double u = ((p.x() - x0()) * px + (p.y() - y0()) * py) / l2;
  if (u > 1) {
    u = 1;
  } else if (u < 0) {
    u = 0;
  }
  return u;
}
Point2D LineSegment2D::closestPointTo(const Point2D & p) const
{
  double px = x1() - x0();
  double py = y1() - y0();
  const double u = closestPointLineSegmentRatio(p);
  return Point2D(x0() + u * px, y0() + u * py);
}

double LineSegment2D::distanceTo(const Point2D & p) const
{
  double dx, dy;
  return distanceTo(p, dx, dy);
}