ChartAnchor.UpdateFromPoint() returns unequal Y coordinates?

[SmartArtsStudio]

Hello

I am trying to use ChartAnchor.UpdateFromPoint() to draw perfectly horizontal ray cast price lines from a drawing tool using an endAnchor set to the same price as the startAnchor point. I am also rounding the excessive decimal places off.. So same times in should be same times out - perfect horizontal line right?

Both anchor.GetPoint()s come back with equal Y values DrawingTool.GetExtendedPoint() returns a point with equal Y values. But once you use endAnchor.UpdateFromPoint() to copy it the new endAnchor extended out in time are not perfectly straight their prices come back at least 0.00002 different?

Thus crooked ray casts. I have to manually correct endAnchor.UpdateFromPoint() result... is there a bug in ChartAnchor.UpdateFromPoint()?

protected void syncEdgeAnchor() {
    // "Tool" is a direct reference to a DrawingTool extended class.
    var startAnchor = Tool.StartAnchor;
    var endAnchor = Tool.EndAnchor;
    var chartControl = Tool.ChartControl;
    var chartPanel = Tool.ChartPanel;
    var chartScale = Tool.ChartScale;

    roundPrice( startAnchor );
    endAnchor.Price = startAnchor.Price;

    var startPoint = startAnchor.GetPoint( chartControl, chartPanel, chartScale );
    var endPoint = endAnchor.GetPoint( chartControl, chartPanel, chartScale );
    var edgePoint = /*Drawing*/Tool.GetExtendedPoint( startPoint, endPoint );
    var hideAnchor = IsRight() ? anchorWidth : -anchorWidth;
          edgePoint.X = edgePoint.X + hideAnchor;

    endAnchor.UpdateFromPoint( edgePoint, chartControl, chartScale );
[B]// endAnchor.Price = startAnchor.Price; <--- I have to add this line to render perfectly straight lines.[/B]
}

protected static void roundPrice( ChartAnchor anchor ) {
    anchor.Price = Math.Round( anchor.Price, 5 );
}

[NinjaTrader_ChelseaB]

Hello SmartArtsStudio,

Do you have a simplified test script that can demonstrate?

Also, print the values after each of these lines to the output window, save these to a text file, and attach with your post so we can see at which point the numbers are becoming incorrect.
https://ninjatrader.com/support/foru...121#post791121

To confirm, you are expecting the startAnchor.GetPoint() and endAnchor.GetPoint() to be exactly the same, and these are not the same?

Or is GetExtendedPoint() specifically returning different values for each of these?

The Horizontal Drawing tool only uses one anchor point. So what logic is setting a second anchor point to the y value of the first anchor point? Is this being manually set with mouse clicks?

Does your drawing tool need two anchor points? Could this instead be a horizontal line that extends only left or only right?


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[SmartArtsStudio]

Hello Chelsea

Similar Horizontal Drawing tool which takes the mouse click as the first startAnchor point copies the price to endAnchor then gives it the panel width for its X. I was copying this method originally but for some reason worked fine for for dragging but not for scrolling.
This code does basically the same, takes the mouse click as the first startAnchor point copies the price to endAnchor, its X default 0 now makes 2 points on the same Y axis.

I'm not using the NT8 editor while an excellent addition. I use Jetbrains Rider to debug so I can see everything at once.

So it is ChartAnchor.UpdateFromPoint() specifically that takes in a price I have specifically rounded to 5 decimal places and returns a close price but also not rounded. The additional decimal places multiplied by time shows up not straight surprisingly quickly.

I'm not too concerned about it because its fixed with one extra line of code and it just occurs to me now that it name is updateFromPoint not copyFromPoint but I do think the most peoples expectation will be copyFromPoint and thought I'd let you know in case that was the intended behavior.

I am happy to use the provided export instructions to email it to you with the specific file name and line number to set your break point, and brief instructions that will have you trigger it in 3 clicks.

Thanks

[NinjaTrader_ChelseaB]

Hello SmartArtsStudio,

The HorizontalLine class does not use the EndAnchor and sets the IsBrowsable of this to false. Only one anchor is used for the logic with this.

UpdateFromPoint() is not used at all in the @Lines.cs file. Is this absolutely necessary for your script?

Are you certain that the rounding is not causing the issue as this is changing the values?

Please add prints for the behalf of sharing information.

Print these values to the output window along with labels as demonstrated in the video linked in the post on using prints to understand behavior, and save this to a text file and post the text file with your reply.

[SmartArtsStudio]

Hello Chelsea

Yes you are correct about Horizontal Line. I was thinking start/endAnchor Points but typing anchors. 2 Points are used in render method cast of 1 anchor using panel width for second X..

As I mentioned it is not a big concern because I can correct UpdateFromPoint() result once I have its X, and there are other ways to do this.
I am just letting you guys know that I was surprised to find it does not copyFromPoint which is the implication of the name in case that was the intended behavior... it is doing something else

Below you can follow the progress all the Y coordinates are equal. This isn't a particularly bad variation it fluctuates I have seen a larger and also a smaller variations.
They may look insignificant in numbers but plot them against time they are not insignificant..

Of course I am assuming GetPoint() is accurate... I have no way to compare Price to Co-ordinates.

[NinjaTrader_ChelseaB]

Hello SmartArtsStudio,

In the logic I am seeing edgePoint is used for the UpdateFromPoint() call. This is a different object created with Tool.GetExtendedPoint() and may have a different value than startAnchor price.

If the second Y value is not necessary, and the line is extended from a single point to the edge of the chart. Perhaps use only one anchor?

Coordinate values can be converted to and from price with:

https://ninjatrader.com/support/helpGuides/nt8/getvaluebyy.htm

https://ninjatrader.com/support/helpGuides/nt8/getybyvalue.htm