{ If EndDate_YYMMDD = 0, this indicator inserts a lin reg line ending at the last bar
  on the chart at the time the indicator is applied to the chart (flag-1 line).  
  Otherwise, it inserts a lin reg line ending at the bar with the specified date and
  time (flag-2 line).  The flag-1 line is updated at each new real time bar; the
  flag-2 line is not updated - it is drawn only once. }
// TS's LinRegLine code modified by John Hudson to draw channel boundaries at standard error distance from centerline and set colors and linestyles for different length channels.
inputs:
        Length( 100),
        EndDate_YYMMDD(  0), { 0 or YYMMDD, constant; if EndDate_YYMMDD = 0,
         EndTime_HHMM ignored and last bar on chart used }
        EndTime_HHMM(  0), { 0 or HHMM, constant; EndTime_HHMM ignored if 0 }
         
        ExtRight(true) ,
        Linewidth(0),
        Linestyle(3),
        NumDevs(2);
variables:
        EndDate( iff( EndDate_YYMMDD < 500000, EndDate_YYMMDD + 1000000,
         EndDate_YYMMDD ) ),
        LRV( 0 ),
        LRVAgo( 0 ),
        TLLRV( 0 ),
        TLLRVHI(0),
        TLLRVLO(0),
        StdErrEnv(0),
        CumStdErr(0),
        AvgStdErr(0),
        EnvWidth(0),
        Flag( 0 ) ;

StdErrEnv=NumDevs*StdError(C,Length);
CumStdErr=CumStdErr + StdErrEnv;
AvgStdErr=CumStdErr/Barnumber;
   
if Flag = 0 then

{ Insert a lin reg line for the first time and set it's color and extents }

        begin
        if EndDate = 1000000 and LastBarOnChart then
                begin
               
                LRV = LinearRegValue( C, Length, 0 ) ;
                LRVAgo = LinearRegValue( C, Length, Length - 1 ) ;
                TLLRV = TL_New( Date[ Length - 1 ], Time[ Length - 1 ], LRVAgo, Date, Time, LRV ) ;
                TLLRVHI = TL_New(Date[Length - 1], Time[Length-1],LRVAgo+IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr),Date,Time,LRV+IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr));
                TLLRVLO = TL_New(Date[Length - 1], Time[Length-1],LRVAgo-IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr),Date,Time,LRV-IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr));
                Flag = 1 ;
                end
        else if Date = EndDate and ( Time = EndTime_HHMM or EndTime_HHMM = 0 ) then
                begin
                LRV = LinearRegValue( C, Length, 0 ) ;
                LRVAgo = LinearRegValue( C, Length, Length - 1 ) ;
                TLLRV = TL_New( Date[ Length - 1 ], Time[ Length - 1 ], LRVAgo, Date, Time, LRV ) ;
        TLLRVHI = TL_New(Date[Length - 1], Time[Length-1],LRVAgo+IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr),Date,Time,LRV+IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr));
                TLLRVLO = TL_New(Date[Length - 1], Time[Length-1],LRVAgo-IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr),Date,Time,LRV-IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr));
                Flag = 2 ;
                end ;
        if Flag = 1 or Flag = 2 then
                begin
                if Length <= 50 then TL_SetColor( TLLRV, Red ) ;
                if Length > 50 and Length <=100 then TL_SetColor( TLLRV, Green);
                if Length > 100 and Length <=200 then TL_SetColor(TLLRV, Cyan);
                if Length > 200 and Length <=400 then TL_SetColor(TLLRV, BLUE);
                if Length > 400 and Length <=800 then TL_SetColor(TLLRV, Yellow);
                if Length > 800 then TL_SetColor(TLLRV, White);
                TL_SetColor( TLLRVHI, Green );
                TL_SetColor( TLLRVLO, Red );
                TL_SetSize(TLLRV, Linewidth);
                TL_SetSize(TLLRVHI, Linewidth);
                TL_SetSize(TLLRVLO, Linewidth);
                TL_SetStyle(TLLRVHI, Linestyle);
                TL_SetStyle(TLLRVLO, Linestyle);
                TL_SetExtLeft( TLLRV, false ) ;
                TL_SetExtLeft( TLLRVHI, false );
                TL_SetExtLeft( TLLRVLO, false );
                if ExtRight then
                        begin
                        TL_SetExtRight( TLLRV, true );
                        TL_SetExtRight( TLLRVHI, true );
                        TL_SetExtRight( TLLRVLO, true );
                        end
                else begin
                        TL_SetExtRight( TLLRV, false ) ;
                        TL_SetExtRight( TLLRVHI, false ) ;
                        TL_SetExtRight( TLLRVLO, false ) ;
                        end;
                end;
        end
else if Flag = 1 then

{ Reset the end-points of the flag-1 LRLine at each new bar after it has been drawn
  for the first time; this effectively results in a new LRLine each time. }

        begin
        LRV = LinearRegValue( C, Length, 0 ) ;
        LRVAgo = LinearRegValue( C, Length, Length - 1 ) ;
        TL_SetBegin( TLLRV, Date[ Length - 1 ], Time[ Length - 1 ], LRVAgo ) ;
        TL_SetBegin( TLLRVHI, Date[ Length - 1 ], Time[ Length - 1 ], LRVAgo+IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr) ) ;
        TL_SetBegin( TLLRVLO, Date[ Length - 1 ], Time[ Length - 1 ], LRVAgo-IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr) ) ;
        TL_SetEnd( TLLRV, Date, Time, LRV ) ;
        TL_SetEnd( TLLRVHI, Date, Time, LRV+IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr) ) ;
        TL_SetEnd( TLLRVLO, Date, Time, LRV-IFF(StdErrEnv<AvgStdErr,StdErrEnv,AvgStdErr) ) ;
        end ;