public LineEquation(Coordinate point1, Coordinate point2)
{
if (point1 == null)
{
throw new ArgumentNullException("point1");
}
if (point2 == null)
{
throw new ArgumentNullException("point2");
}
try
{
if (point1.Equals(point2))
{
string errMsg = "The input points are the same";
InvalidInputGeometryDataException ex = new
InvalidInputGeometryDataException(errMsg);
throw ex;
}
//Point1 and Point2 are different points:
if (Math.Abs(point1.X - point2.X)
< ConstantValue.SmallValue) //vertical line
{
Initialize(Math.PI / 2, point1);
}
else if (Math.Abs(point1.Y - point2.Y)
< ConstantValue.SmallValue) //Horizontal line
{
Initialize(0, point1);
}
else //normal line
{
double m = (point2.Y - point1.Y) / (point2.X - point1.X);
double alphaInRad = Math.Atan(m);
Initialize(alphaInRad, point1);
}
}
catch (Exception ex)
{
ExceptionManager.Publish(ex);
throw;
}
}
private void Initialize(Double angleInRad, Coordinate point)
{
//angleInRad should be between 0-Pi
try
{
//if ((angleInRad<0) ||(angleInRad>Math.PI))
if (angleInRad > 2 * Math.PI)
{
string errMsg = string.Format(
CultureInfo.InvariantCulture.NumberFormat,
"The input line angle" +
" {0} is wrong. It should be between 0-2*PI.",
angleInRad);
InvalidInputGeometryDataException ex = new
InvalidInputGeometryDataException(errMsg);
throw ex;
}
if (Math.Abs(angleInRad - Math.PI / 2) <
ConstantValue.SmallValue) //vertical line
{
a = 1;
b = 0;
c = -point.X;
}
else //not vertical line
{
a = -Math.Tan(angleInRad);
b = 1;
c = -a * point.X - b * point.Y;
}
}
catch (Exception ex)
{
ExceptionManager.Publish(ex);
throw;
}
}