RenderTarget.DrawLine question...

[funk101]

In my custom DrawingTool, I've successfully gotten to the point where my startPoint is created on mouse hit, and the endPoint is calculated. What I would like to happen is a line get's drawn automatically. So far, I have to actually move the mouse in order to draw the line (for example). I'm missing something. Do I further look into OnRender()? or is there somewhere else that would make this happen. I understand it's like drawing a Horizontal, or Vertical line, and I've reverse engineered that to give me the points I desire, it's just the auto drawing of the line that eludes me. Any sort of help what be great, thanks.

[NinjaTrader_MichaelM]

Hello funk101,

Thank you for writing in. I created an extremely basic drawing tool to test this. I was able to create a drawing tool which you click once on the chart and it draws a line from the point you clicked to a calculated point elsewhere on the chart. This was accomplished in the OnRender() method. Here is the example:

namespace NinjaTrader.NinjaScript.DrawingTools
{
	public class AutomaticLineTest : DrawingTool
	{
		protected override void OnStateChange()
		{
			if (State == State.SetDefaults)
			{
				Description	= @"";
				Name		= "AutomaticLineTest";
			}
		}
		Point point;
		public override Cursor GetCursor(ChartControl chartControl, ChartPanel chartPanel, ChartScale chartScale, Point point)
		{
			return Cursors.Arrow;
		}
		public override Point[] GetSelectionPoints(ChartControl chartControl, ChartScale chartScale)
		{
			return new Point[0];
		}
		public override void OnMouseDown(ChartControl chartControl, ChartPanel chartPanel, ChartScale chartScale, ChartAnchor dataPoint)
		{
			point = dataPoint.GetPoint(chartControl, chartPanel, chartScale); //Get the start point
		}
		public override void OnRender(ChartControl chartControl, ChartScale chartScale)
		{
			RenderTarget.DrawLine(point.ToVector2(), new Point(point.X + 200, point.Y).ToVector2(), Brushes.Aqua.ToDxBrush(RenderTarget)); //Draw the line from the start point to a new end point
		}
	}
}

If you have questions that are specific to your code, please feel free to send in the relevant code you are working with so we can better assist.

Thank you in advance.

[funk101]

Ok, thanks for your reply. I now am able to select a bar, a startAnchor/startPoint, and endAnchor/endPoint are created at the desired location,and a line auto-draws now, however, if I move my mouse the endAnchor moves still, and the line stays the same(which is ok). It's not until I mouse down again that the start and end anchors disappear and I'm left with the desired line intact.

[NinjaTrader_MichaelM]

Hello funk101,

Thank you for the update. To better illustrate this behavior could you please create a quick video or send in the drawing tool code?

You can make a quick video using the free tool provided by TechSmith: https://www.techsmith.com/jing-features.html

If you would like to send in your drawing tool code you can attach it in an email to platformsupport[AT]ninjatrader[DOT]com with the subject line: "ATTN: Michael M http://www.ninjatrader.com/support/forum/showthread.php?t=79106"

Thank you in advance.