CL_Line2d::CL_Line2d(); CL_Line2d::CL_Line2d( const CL_Line2x < dle > &amp; copy); CL_Line2d::CL_Line2d( const CL_Vec2 < dle > &amp; point_p, const CL_Vec2 < dle > &amp; point_q); CL_Line2d::CL_Line2d( const CL_Vec2 < dle > &amp; point_p, double gradient);