Draw Line or Make Plot? Can I do NaN stuff in Ninjascript?

[noevictorian]

I'm a convert to NinjaTrader, coming over from Thinkorswim after months of frustrating workarounds in their Thinkscript language. It's a tragically stunted scripting language that doesn't include basic things like loops or all but the most basic math functions.

But one thing it did that I haven't figured out in NinjaScript yet relates to drawing horizontal lines.

I'd like to draw lines on my chart to mark certain levels of support/resistance but be able to turn the lines off if certain conditions aren't met.

In thinkscript this was done with an if statement whose ELSE section returned Nan (not a number). So you'd have something that went:

if (mycondition) then 140 else Nan;

That sort of statement would draw a line if the condition was met and nothing if it wasn't met. Is there a way to do this in NinjaScript?

I'm not so sure when to use static number plots to draw horizontal lines and when to draw line objects, or whether either of these could do this for me.

[NinjaTrader_JoshP]

noevictorian,

To draw horizontal lines in NT, you can use the method DrawHorizontalLine(). When you want to get rid of the lines you can use RemoveDrawObject().

It really is up to you what your preference is between Plots vs draw object lines. Plots cannot be moved, but draw object lines can be dragged and dropped by the user.

[noevictorian]

Thanks josh... I guess what's confusing me is that DrawHorizontalLine specifies a start and a stop point but I want to have a start point and have the stop point continually moving along with each current bar until the condition that's drawing it changes. So if the line starts drawing on bar 50 it would keep extending along with bar 51, 52, 53, 54, 55, 56, 57, 58, etc. But if conditions change on bar 78, the line would stop drawing.

To do that with DrawHorizontal line would require removing the drawing each bar and redrawing it, yes?

Or can I do it more easily with a plot? I'd prefer a plot so users can move it. Thanks!

[NinjaTrader_JoshP]

noevictorian,

Not sure what you mean. DrawHorizontalLine() does not take two points. http://www.ninjatrader-support.com/H...ontalLine.html

Once you draw a horizontal line it extends left and right indefinitely.

[noevictorian]

Sorry I was thinking DrawLine(). Well I don't want the line extending forever. I want to be able to terminate it at some point. So how would I do that?

Is there a way to terminate a horizontal line X bars away from its start point?

[NinjaTrader_Bertrand]

Yes, just specify endBars in relation to your startBars setting - http://www.ninjatrader-support.com/H.../DrawLine.html

Just add / subtract the bars needed to the bars paramter in startBars.

[outsource]

hello,guys,

any examples on how to convert drawline into plot?any examples, technics,guidance are appreciated!

[NinjaTrader_JessicaP]

Hello outsource, and thank you for your questions. When an existing thread is over a year old, please create a new thread instead of replying to an old thread, as our system will not automatically track replies to very old threads.

Can you clarify our goals? If you have enough information to draw an object on a chart, you should have enough information to instead assign the same values to a plot. One of our techs will be happy to assist further.

[fx.practic]

Hello, outsource.

It isn't possible to convert drawline into plot.
And You have to decide beforehand what You prefer to use.

When using DrawLine() You need to set coordinates of 2 dots: begin and end of the desired line. One command, 2 dots.

When using Plot You need to set coordinates of each dot between begin and end of Your line (look at attached image).

I, personally, trying to avoid using DrawLine() and use indicator plot instead.

Here my simple function that plot line by 2 coordinates:

public static void Connect_2_Points( DataSeries ds, int x1, double y1, int x2, double y2, ref string errorMsg )
		{
			if( x1 < x2 ){ errorMsg = "Common_class.Connect_2_points.i_Lib_Common: x1 must be greater then x2"; return; }
			double d = (y2 - y1) / ( x1 - x2 );
			
			double y = y1;
			for( int x = x1; x >= x2; x-- )
			{
				ds.Set( x, y );
				y += d;
			}
		}

[outsource]

Hello outsource, and thank you for your questions. When an existing thread is over a year old, please create a new thread instead of replying to an old thread, as our system will not automatically track replies to very old threads.

Can you clarify our goals? If you have enough information to draw an object on a chart, you should have enough information to instead assign the same values to a plot. One of our techs will be happy to assist further.

Hi Jessica,

the problem that i have an indicator that i`m trying to get into strategy,but it doesn`t work properly.I`m not sure,but i think it`s because Drawline method,that used to draw trend lines.I tried everything ILine,bools,convert double to dataseries but it just shoots entries randomly.I attached the indicator in case someone would want to assist.

[outsource]

Hello, outsource.

It isn't possible to convert drawline into plot.
And You have to decide beforehand what You prefer to use.

When using DrawLine() You need to set coordinates of 2 dots: begin and end of the desired line. One command, 2 dots.

When using Plot You need to set coordinates of each dot between begin and end of Your line (look at attached image).

I, personally, trying to avoid using DrawLine() and use indicator plot instead.

Here my simple function that plot line by 2 coordinates:

public static void Connect_2_Points( DataSeries ds, int x1, double y1, int x2, double y2, ref string errorMsg )
		{
			if( x1 < x2 ){ errorMsg = "Common_class.Connect_2_points.i_Lib_Common: x1 must be greater then x2"; return; }
			double d = (y2 - y1) / ( x1 - x2 );
			
			double y = y1;
			for( int x = x1; x >= x2; x-- )
			{
				ds.Set( x, y );
				y += d;
			}
		}

Thanks,Fx.Drawline is just a pain in the neck when it comes to use it with strategies.

[NinjaTrader_JessicaP]

I am attaching a copy of your source where a single line's current Y value is added as a plot value. Look for my initials (JDP) in your code. Code samples we provide are for educational purposes, and are not intended for live trading, and are not guaranteed to accomplish any user goal or to be maintained. Please let us know if there are any other ways we can help.

[outsource]

I am attaching a copy of your source where a single line's current Y value is added as a plot value. Look for my initials (JDP) in your code. Code samples we provide are for educational purposes, and are not intended for live trading, and are not guaranteed to accomplish any user goal or to be maintained. Please let us know if there are any other ways we can help.

Jessica,do i have to do the same with the other instacies and the call it via strategy?

[NinjaTrader_JessicaP]

Yes, it was intended that you do the same with other instances. From a strategy you will need to use

AddChartIndicator(TrendSpotter(STPeriod, LTPeriod, STUTbool, LTUTbool, STDTbool, LTDTbool, STUTColor, LTUTColor, STDTColor, LTDTColor))

In your Initialize routine.