public override double Distance(PointF2D point)
{
VectorF2D vectorF2D = point - this._a;
double num1 = VectorF2D.Cross(this.Direction, vectorF2D);
double length = this.Length;
double num2 = point.Distance(this._a);
double num3 = point.Distance(this._b);
double num4 = System.Math.Abs(num1 / length);
if (this.IsSegment)
{
if (VectorF2D.Dot(vectorF2D, this.Direction) < 0.0 && num1 != 0.0)
{
num4 = this._a.Distance(point);
}
else if (num1 == 0.0 && (num2 >= length || num3 >= length))
{
num4 = num2 <= num3?this._a.Distance(point) : this._b.Distance(point);
}
if (VectorF2D.Dot(point - this._b, this.Direction.Inverse) < 0.0 && num1 != 0.0)
{
num4 = this._b.Distance(point);
}
}
return(num4);
}
/// <summary>
/// Returns the distance from the point to this line.
/// </summary>
/// <param name="point"></param>
/// <returns></returns>
public override double Distance(PointF2D point)
{
double distance = 0.0f;
// get the second vector for the cross product.
VectorF2D a_point = point - _a;
// get the cross product.
double cross = VectorF2D.Cross(this.Direction, a_point);
// distances between a, b and point.
double distance_a_b = this.Length;
double distance_a = point.Distance(_a);
double distance_b = point.Distance(_b);
// calculate distance to line as if it were no segment.
distance = System.Math.Abs(cross / distance_a_b);
// if this line is a segment.
if (this.IsSegment)
{
double dot1 = VectorF2D.Dot(a_point, this.Direction);
if (dot1 < 0 && cross != 0)
{
distance = _a.Distance(point);
}
else if (cross == 0 &&
(distance_a >= distance_a_b ||
distance_b >= distance_a_b))
{ // check if the point is between the points.
if (distance_a > distance_b)
{ // if the distance to a is greater then the point is at the b-side.
distance = _b.Distance(point);
}
else
{// if the distance to b is greater then the point is at the a-side.
distance = _a.Distance(point);
}
}
VectorF2D b_point = point - _b;
double dot2 = VectorF2D.Dot(b_point, this.Direction.Inverse);
if (dot2 < 0 && cross != 0)
{
distance = _b.Distance(point);
}
}
return(distance);
}
public void Vector2DTest()
{
// create the test cases.
VectorF2D a_b = new VectorF2D(1, 1);
VectorF2D b_a = new VectorF2D(-1, -1);
VectorF2D a_c = new VectorF2D(-1, 1);
VectorF2D a_d = new VectorF2D(0, 1);
VectorF2D a_e = new VectorF2D(-1, 0);
VectorF2D a_f = new VectorF2D(0, 1);
VectorF2D a_g = new VectorF2D(0, -1);
// calculate the results
double sqrt_2 = (double)System.Math.Sqrt(2);
// check the sizes.
Assert.AreEqual(a_b.Size, sqrt_2, string.Format("Size should be {0}!", sqrt_2));
Assert.AreEqual(b_a.Size, sqrt_2, string.Format("Size should be {0}!", sqrt_2));
// check the equality.
Assert.IsTrue(a_b.Inverse == b_a, "The inverse of ab should be ba!");
// check the cross product.
Assert.AreEqual(VectorF2D.Cross(a_b, b_a), 0, "Cross product of two parallel vectors should be 0!");
Assert.AreEqual(VectorF2D.Cross(a_b, a_c), 2, string.Format("Cross product of two perpendicular vectors should be maximized; in this case {0}!", 2));
Assert.AreEqual(VectorF2D.Cross(b_a, a_b), 0, "Cross product of two parallel vectors should be 0!");
Assert.AreEqual(VectorF2D.Cross(a_c, a_b), -2, string.Format("Cross product of two perpendicular vectors should be maximized; in this case {0}!", -2));
// check the dot product.
Assert.AreEqual(VectorF2D.Dot(a_b, b_a), -2, string.Format("Cross product of two parallel vectors should be maximized (absolute value); in this case {0}!", -2));
Assert.AreEqual(VectorF2D.Dot(a_b, a_c), 0, string.Format("Cross product of two perpendicular vectors should be {0}!", 0));
Assert.AreEqual(VectorF2D.Dot(a_b, a_d), 1);
Assert.AreEqual(VectorF2D.Dot(a_b, a_e), -1);
Assert.AreEqual(VectorF2D.Dot(a_b, a_f), 1);
Assert.AreEqual(VectorF2D.Dot(a_b, a_g), -1);
Assert.AreEqual(VectorF2D.Dot(b_a, a_b), -2, string.Format("Cross product of two parallel vectors should be maximized; in this case {0}!", -2));
Assert.AreEqual(VectorF2D.Dot(a_c, a_b), 0, string.Format("Cross product of two perpendicular vectors should be {0}!", 0));
}
