main/src/georegression/geometry/UtilLine2D_F64.java
public static LineGeneral2D_F64 convert( Point2D_F64 a , Point2D_F64 b , LineGeneral2D_F64 ret )
	{
		if( ret == null )
			ret = new LineGeneral2D_F64();

		ret.A = a.y - b.y;
		ret.B = b.x - a.x;
		ret.C = -(ret.A*a.x + ret.B*a.y);

		return ret;
	}
public static LineGeneral2D_F64 convert( Point2D_F64 a , Point2D_F64 b , LineGeneral2D_F64 ret )
	{
		if( ret == null )
			ret = new LineGeneral2D_F64();

		ret.A = a.y - b.y;
		ret.B = b.x - a.x;
		ret.C = -(ret.A*a.x + ret.B*a.y);

		return ret;
	}
Converts a line segment into a general line. Line segment is defined by two points.

@param a (Input) End point of line segment
@param b (Input) End point of line segment
@param ret (output) line in general notation. If null a new instance will be created.
@return Line in general notation