SetLine example

[nasdorq]

I'm trying to use SetLine to plot multiple horizontal lines from a single paintbar.  The code is below.

What I'm struggling with is the SetLine ID and X axis values.

ID, I'm not sure what to put, so I copied TradingDay.DayNumber from the support example

X1 and X2, I put CandleNumber -15, Candle Number, to at least see if it would plot.

The result is, it only plots the 4th (blue) SetLine.

 

Do you have any suggestions for the proper ID and X values, so that all 4 lines plot, and starts from the beginning of 3 sessions ago?

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Edited August 14, 2021 by nasdorq

[nasdorq]

public void MainCalculation()
{
    var TS     = GetTradingSessionInfo(Timestamp);

    if (DateTime.UtcNow>TS.DayStart.AddDays(3))     // only plot last 3 days
        return;
    
    var Line1 = 4460;    //  prices for horizontal lines
    var Line2 = 4455;
    var Line3 = 4450;
    var Line4 = 4445;

    Color Orange = (Color.Orange);
    SetLine(TradingDay.DayNumber, Orange, CandleNumber - 15, Line1, CandleNumber, Line1, 2, null);
    
    Color Red = (Color.Red);
    SetLine(TradingDay.DayNumber, Red, CandleNumber - 15, Line2, CandleNumber, Line2, 2, null);
    
    Color Yellow = (Color.Yellow);
    SetLine(TradingDay.DayNumber, Yellow, CandleNumber - 15, Line3, CandleNumber, Line3, 2, null);
    
    Color Blue = (Color.Blue);
    SetLine(TradingDay.DayNumber, Blue, CandleNumber - 15, Line4, CandleNumber, Line4, 2, null);

[Mike Medved]

The ID is the unique ID of the line. What that means is that each SetLine that you are showing in your code is setting the same line - that is, it is re-setting the line to the new values. Because the ID of the line does not change.

For example, If you have a line which starts at a particular candle number, AND you know that it's the only line that will start at that candlenumber AND you know that the line, once started, will stay at that candle number, then it would be logical to use the candle number as the line's ID.

What your code above does is, for each day of the last few days, it draws a blue line (the last SetLine in your code) from the last candle of the day to the 15th candle prior to that. At 4445 - because that is the value have in the last SetLine.

 

 

 

[nasdorq]

Thanks Mike.  I set the line ID's to simply #s 1 through 4.  I tried giving them names but that returned an error, so numbered will work.  One last follow up if I may?

1)  I seem to remember reading that paintbars, at least a while back, can't plot beyond the current candle into the future.  I tried entering "CandleNumber 5" for x2, and got a bunch of errors.  However if I put "CandleNumber -(-5)", with the double negative becoming a positive, it does plot to the right of the current candle.  It goes infinitely right, regardless of whether it's -(-1) or -(-100).  You can see the example with the red line in the attached chart and the code.

Do you think having them plot beyond the current candle will cause issues with regards to stability or resource use?  I was hoping to have a bunch of these on different charts.

2)  To have the x1 value start plotting from the open 3 sessions ago, is there an easy way to reference the CandleNumber for the opening bar 3 sessions ago?  (I was hoping to use this on charts with different timeframes, otherwise I could just count the # of bars).  I figure I could save it as a var, and then reference it in the SetLine as CandleNumber -(var).

__________________________________________

public void MainCalculation()
{
    var TS     = GetTradingSessionInfo(Timestamp);

    if (DateTime.UtcNow>TS.DayStart.AddDays(3))     // only plot last 3 days
        return;
    
    var Line1 = 4460;    //  prices for horizontal lines
    var Line2 = 4455;
    var Line3 = 4450;
    var Line4 = 4445;
    var test  = 10;

    Color Orange = (Color.Orange);
    SetLine(1, Orange, CandleNumber -15, Line1, CandleNumber, Line1, 2, null);
    
    Color Red = (Color.Red);
    SetLine(2, Red, CandleNumber -15, Line2, CandleNumber -(-5), Line2, 2, null);
    
    Color Yellow = (Color.Yellow);
    SetLine(3, Yellow, CandleNumber -15, Line3, CandleNumber, Line3, 2, null);
    
    Color Blue = (Color.Blue);
    SetLine(4, Blue, CandleNumber -15, Line4, CandleNumber, Line4, 2, null);
    
}

[Mike Medved]

1. CandleNumber+5 will work. Not "CandleNumber 5" . And yes you can just do +whatever, it will just go far to the right.

2. In order to start at a particular candle, you have to remember the number of the candle. Since the paintbar evaluates looking at all candles, from the earliest to the latest, in the code you can see whether the candle being looked at is at start of session, and if it is, remember its number to be used later.

 

[nasdorq]

Sorry one more quick follow up.   Almost there   

I'm not quite sure how to reference and save particular candles within the code.

I figured I'd just set x1 to "-1000".  That way it would cover several days on a 1min chart, and all available data on the 60min chart.  However, -1000 bars on the 60min goes way beyond the # of bars on the chart, and causes the paintbar to stop working.

Is there an easy way to reference the furthest left candle on any chart, so I could use this on multiple timeframes?  If not, I can make do and try to find workarounds.

 

Thanks for your help with this.

 

[Mike Medved]

Well the leftmost candle is 0. If you draw from candle 0, it will just go to the left side of the chart, no matter what period you're showing.

[nasdorq]

"CandleNumber -15" plots 15 bars back, and "CandleNumber +1" plots to the right, as in the code/chart below.  "CandleNumber 0" produces an error.

Perhaps you mean referencing Candle 0 outside of the "CandleNumber" function, which behaves differently?

 

[Mike Medved]

Yes. Just use 0 as a coordinate. You're getting errors 'cuz you're putting in "CandleNumber 0". That's wrong syntax for C#.
 

SetLine(2, Red, 0, Line2, CandleNumber, Line2, 2, null);

This will draw a line from left side of the chart to current candle.