Snap to closest graph point

[PauldePaor]

I have an xy graph with multiple points. The graph is controlled by a mouse down event, when the user clicks on the graph it draws a red circle at the click point. My question is how I would get this to snap to the nearest point?

[GerdW]

Hi Paul,

I would look for the nearest plot data using Pythagoras formula c²=b²+a²…

[altenbach]

What is the datatype of the xy graph? If you use complex numbers (recommended!), convert the click point to a complex point in the data scale, subtract it from the complex array of points, take the absolute value, and use array min&max. The index of the min is the index of the closest point.

Can you attach your VI?

[PauldePaor]

Please see my attached VI

[altenbach]

That's just a subVI, there is no xy graph. Also your subVI is missing.

[J-M]

Maybe this:

http://www.ni.com/example/25477/en/

[altenbach]

Here's what I had in mind.

(just showing how to find the closest point. Now simply tranform the value back to pixel coordinates and draw the circle. Not shown.)

[PauldePaor]

Sorry about that please see attached the updated VI

[altenbach]

You shold be able to use my code with minimal changes. As I said, simply transform the position of the closest point back to pixels and draw the circle.

[PauldePaor]

I have tried implementing your method but I am not having much luck?