LightningChart Support Forums

I have several samplelineseries (line only, no points) with several million points on the chart.

I'd like to show any kind of indicator when my mouse goes over a trace point (or nearest point, i'm not very picky there). Here is how our old graphing package looked:



I know in the example application its sets points=true (or in some cases puts annotations on every single point). Both of those will cause memory usage to spike and immediately get an OutOfMemoryException.

I think the best bet is to handle the mouse-over event, and manually put something there at that point. Maybe an annotation, which is just a dot or something? What do you recommend?

Thanks!

SampleDataSeries has SolveNearestSampleByCoord method. In chart.MouseMove event handler, use that, and place a SeriesEventMarker or Annotation on the location of the solved point.

This is one approach

Thanks, I'll give the series event markers a try today

This method works very well, but I have a followup.

I have code in my mousemove, and foreach series (3 series, for example), I find the closest point to my cursor, and plop an event marker there.

I would liek to know the X\Y coordinate of the point that I found. I only want to show an event marker if there is one found within some distance (20px) of the mouse cursor.;


Is there a way to convert an X\Y value or samplenumber to XY screen coordinates?

Thanks!

You can do that with xAxis.ValueToCoord and yAxis.ValueToCoord method.