Dynamically updating Plots[0].Width in OnRender

[swcooke]

I am trying to get the Width of one of my plots to match the width of another minus 1 pixel. I am trying to confirm that OnRender is the right place to do that and also inquire as to why this isn't working:

namespace NinjaTrader.NinjaScript.Indicators
{
    public class BarWidthTest : Indicator
    {

        protected override void OnStateChange()
        {
            if (State == State.SetDefaults)
            {
                Description                                    = @"Displays the Average Volume for a particular time based on N previous days.";
                Name                                        = "BarWidthTest";
                Calculate                                    = Calculate.OnBarClose;
                IsOverlay                                    = false;
                DisplayInDataBox                            = true;
                DrawOnPricePanel                            = true;
                DrawHorizontalGridLines                        = true;
                DrawVerticalGridLines                        = true;
                PaintPriceMarkers                            = true;
                ScaleJustification                            = NinjaTrader.Gui.Chart.ScaleJustification.Right;
                //Disable this property if your indicator requires custom values that cumulate with each new market data event. 
                //See Help Guide for additional information.
                IsSuspendedWhileInactive                    = true;
                AddPlot(new Stroke(Brushes.Black), PlotStyle.Bar, "AverageVolume");
                AddPlot(new Stroke(Brushes.Red,5), PlotStyle.Bar, "VolumeIndicator");
                Plots[0].AutoWidth = true;

            }
            else if (State == State.DataLoaded)
            {

            }
            else if (State == State.Configure)
            {
            }
        }

        protected override void OnBarUpdate()
        {
            if(CurrentBar < 0) return;

            AverageVolume[0] = Volume[0]/2;
            VolumeIndicator[0] = Volume[0];
        }
        protected override void OnRender(ChartControl chartControl, ChartScale chartScale) {
            Plots[1].Width = Plots[0].Width - 1;
        }        



        #region Properties
        [Browsable(false)]
        [XmlIgnore]
        public Series<double> VolumeIndicator
        {
            get { return Values[1]; }
        }
        [Browsable(false)]
        [XmlIgnore]
        public Series<double> AverageVolume
        {
            get { return Values[0]; }
        }        
        #endregion

    }
}

[NinjaTrader_PaulH]

Hello swcooke,

Thanks for your post.

You would not need Onrender() for this.

You can move your plot width coding into State.DataLoaded so it is only executed once.

I highly recommend you also add code to prevent setting a value smaller than 1.

[swcooke]

Paul,

Plot[0] is set by this line:

Plots[0].AutoWidth = true;

Since that is a dynamic width, I don't think your suggestion would do the trick. That is why I was trying to use OnRender.

[NinjaTrader_PaulH]

Hello swcooke,

Thanks for your reply.

Yes, I missed that, thanks.

In OnRender() you would need to use base.OnRender(chartControl, chartScale); See the 2nd tip here: https://ninjatrader.com/support/help.../?onrender.htm

In OnRender you can obtain the current bar width from BarWidth: https://ninjatrader.com/support/help...l_barwidth.htm which is a double so just convert to int type and subtract 1 and set Plots[1].width to that value.

[swcooke]

Thank you Paul. Here is the code I went with in case it helps anyone else:

        protected override void OnRender(ChartControl chartControl, ChartScale chartScale) {
            base.OnRender(chartControl, chartScale);
            Plots[1].Width = Math.Max((float)chartControl.BarWidth - 3,2);
        }