// returns true if left belongs above right in ascending order
bool LineSegment::yasc(const LineSegment& left, const LineSegment& right) {
// both vertical
if(left.isVertical() && right.isVertical()) {
if(left.getBottomEndPoint().y < right.getBottomEndPoint().y)
return true;
if(left.getBottomEndPoint().y > right.getBottomEndPoint().y)
return false;
return left.getTopEndPoint().y < right.getTopEndPoint().y;
}
// left is vertical
if(left.isVertical())
return left.getBottomEndPoint().y < right.getLeftEndPoint().y;
// left.left, left.right, right.left colinear
if(Point2D::colinear(left.getLeftEndPoint(),
left.getRightEndPoint(),
right.getLeftEndPoint())) {
// all points colinear
if(Point2D::colinear(left.getLeftEndPoint(),
left.getRightEndPoint(),
right.getRightEndPoint())) {
return left.getBottomEndPoint().y < right.getBottomEndPoint().y;
}
// only 3 colinear
return Point2D::leftTurn(left.getLeftEndPoint(),
left.getRightEndPoint(),
right.getRightEndPoint());
}
// normal case
return Point2D::leftTurn(left.getLeftEndPoint(),
left.getRightEndPoint(),
right.getLeftEndPoint());
}
bool LineSegment::xasc(const LineSegment& bottom, const LineSegment& top) {
// both horizontal
if(bottom.isHorizontal() && top.isHorizontal())
return bottom.getLeftEndPoint().x < top.getLeftEndPoint().x;
// left is vertical
if(bottom.isHorizontal())
return bottom.getLeftEndPoint().x < top.getBottomEndPoint().x;
// left.left, left.right, right.left colinear
if(Point2D::colinear(bottom.getBottomEndPoint(),
bottom.getTopEndPoint(),
top.getBottomEndPoint()))
return Point2D::leftTurn(bottom.getBottomEndPoint(),
bottom.getTopEndPoint(),
top.getTopEndPoint());
// normal case
return Point2D::leftTurn(bottom.getBottomEndPoint(),
bottom.getTopEndPoint(),
top.getBottomEndPoint());
}