DrawRectangle and scrolling

[ETFVoyageur]

When I draw a rectangle in an indicator panel, and then scroll backward, I very soon run out of rectangle. F5 will cause it to be drawn where I am, but if I scroll back the same thing happens.

My best guess is that the left-most rectangle data is not kept, and as I scroll left OnBarUpdate() is not called, so the rectangle does not get updated.

How do I fix this?

(I'm sure I have seen this answered before, but I cannot find that now that I need it.)

One thing I can think of that might work is to override Plot(), draw the rectangle there, and then call base.Plot(). Or maybe in the other order.

--EV

[NinjaTrader_RyanM1]

ETFVoyageur,

Yes, if you're trying to draw a rectangle in a fixed position on the chart, it's required to override the plot method.

Our support for this is to point to the built in CustomPlotSample, but unfortunately we can't assist with the exact implementation. You may get some help searching these forums to see what others have done in this area.

[ETFVoyageur]

What I am trying to do is to shade the area between two horizontal lines.

Does that require overriding Plot(), or is there a more mainstream way to go?

If I do override Plot(), I presume that my idea to just draw the rectangle and have base.Plot() is the way to do?

--EV

[NinjaTrader_RyanM1]

Have you tried DrawRegion() for this?

http://www.ninjatrader-support.com/vb/showthread.php?t=4331

[ETFVoyageur]

No, I forgot all about that.

I did not go that way in the first place because I need to create a DataSeries for both the top and bottom lines, which seemed heavier weight.

Am I right that I do need to create those DataSeries, and cannot just use the Line objects as parameters to DrawRegion?

--EV

[NinjaTrader_RyanM1]

Yes, that's correct. You will have to use a data series for at least one of the y values, but can use an overload that offers double as input for the other y value. You can then type in the same value used is the line rather than creating a series for it.

[ETFVoyageur]

Thanks for the suggestion -- sounds like a winner.

--EV

[ETFVoyageur]

RyanM,

Done. Works fine. Thanks.

The irony is that I had DrawRegion in there to begin with. I took it out because DrawRectangle seemed cleaner and lighter weight. Only after that did I note the problem.

Oh, well, at least putting it back was fast.

--EV

[NinjaTrader_RyanM1]

Glad to hear this function suits your needs. Thanks for the follow - up.

[koganam]

What I am trying to do is to shade the area between two horizontal lines.

Does that require overriding Plot(), or is there a more mainstream way to go?

If I do override Plot(), I presume that my idea to just draw the rectangle and have base.Plot() is the way to do?

--EV

Why not use DrawRegion() then?

[ETFVoyageur]

Why not use DrawRegion() then?

That's what I am doing now.