/// <summary>
/// computes orientation of three vectors with a common source
/// (compare polar angles of v1 and v2 with respect to v0)
/// </summary>
/// <returns>
/// -1 if the orientation is v0 v1 v2
/// 1 if the orientation is v0 v2 v1
/// 0 if v1 and v2 are collinear and codirectinal
/// </returns>
static public int GetOrientationOf3Vectors(Point vector0, Point vector1, Point vector2)
{
const double multiplier = 1000; //TODO, need to fix it?
vector0 *= multiplier;
vector1 *= multiplier;
vector2 *= multiplier;
double xp2 = Point.CrossProduct(vector0, vector2);
double dotp2 = vector0 * vector2;
double xp1 = Point.CrossProduct(vector0, vector1);
double dotp1 = vector0 * vector1;
// v1 is collinear with v0
if (ApproximateComparer.Close(xp1, 0.0) && ApproximateComparer.GreaterOrEqual(dotp1, 0.0))
{
if (ApproximateComparer.Close(xp2, 0.0) && ApproximateComparer.GreaterOrEqual(dotp2, 0.0))
{
return(0);
}
return(1);
}
// v2 is collinear with v0
if (ApproximateComparer.Close(xp2, 0.0) && ApproximateComparer.GreaterOrEqual(dotp2, 0.0))
{
return(-1);
}
if (ApproximateComparer.Close(xp1, 0.0) || ApproximateComparer.Close(xp2, 0.0) || xp1 * xp2 > 0.0)
{
// both on same side of v0, compare to each other
return(ApproximateComparer.Compare(Point.CrossProduct(vector2, vector1), 0.0));
}
// vectors "less than" zero degrees are actually large, near 2 pi
return(-ApproximateComparer.Compare(Math.Sign(xp1), 0.0));
}
/// <summary>
/// returns true if the rectangle contains the point
/// </summary>
/// <param name="point"></param>
/// <returns></returns>
public bool Contains(Point point)
{
return((ApproximateComparer.Compare(left, point.X) <= 0) && (ApproximateComparer.Compare(right, point.X) >= 0) &&
(ApproximateComparer.Compare(top, point.Y) >= 0) && (ApproximateComparer.Compare(bottom, point.Y) <= 0));
}