public void Contains_Point()
{
var sut = new LineSegment(new Point(0, 0), new Point(2, 2));
Assert.IsTrue(sut.Contains(new Point(0, 0)));
Assert.IsTrue(sut.Contains(new Point(1, 1)));
Assert.IsTrue(sut.Contains(new Point(2, 2)));
}
public void Does_Not_Contain_Point()
{
var sut = new LineSegment(new Point(0, 0), new Point(2, 2));
Assert.IsFalse(sut.Contains(new Point(-1, -1)));
Assert.IsFalse(sut.Contains(new Point(3, 3)));
Assert.IsFalse(sut.Contains(new Point(3, 0)));
Assert.IsFalse(sut.Contains(new Point(1, 2)));
}
public Point Intersect(LineSegment segment)
{
if (Start.Equals(segment.End))
return Start;
if (End.Equals(segment.Start))
return End;
if ( Gradient == segment.Gradient)
return null;
if (Gradient == null)
return intersectWithVertical(Start.X, segment);
if (segment.Gradient == null)
return intersectWithVertical(segment.Start.X, this);
if (Gradient == 0)
return intersectWithHorizontal(Start.Y, segment);
if (segment.Gradient == 0)
return intersectWithHorizontal(segment.Start.Y, this);
var b1 = Start.Y - Start.X * Gradient.Value;
var b2 = segment.Start.Y - segment.Start.X * segment.Gradient.Value;
var x = (b1 - b2)/(segment.Gradient.Value - Gradient.Value);
var y = Gradient.Value*x + b1;
var point = new Point(x, y);
if (Contains(point) && segment.Contains(point))
return point;
return null;
}