Getting Y-value corresponding to a given X-value

Hi Jhonatan,

We tried to reproduce this but could not. I’ve created the codepen showing how to get the y-value to a corresponding x-value here.

Here’s my code.

After creating a FastLineRenderableSeries and XyDataSeries I use xyDataSeries.findIndex to find the nearest index to the xValue of 70. I then find the yValue that corresponds to this xValue:

// For the x-value at 70, find the Y-value
const xValue = 70;
const index = xyDataSeries.findIndex(xValue, ESearchMode.Nearest);
const yValue = xyDataSeries.getNativeYValues().get(index);

I also place some annotations onto the chart to show the intersection:

// Add an annotation to the line showing the X-Y intersection
sciChartSurface.annotations.add(new VerticalLineAnnotation({ 
    x1: xValue,
    y1: yValue,
    showLabel: true,
    strokeDashArray: [2, 2],
    stroke: "Orange"
}), new HorizontalLineAnnotation({
    x1: xValue,
    y1: yValue,
    showLabel: true,
    strokeDashArray: [2, 2],
    stroke: "Orange"
}));  

This results in the following output

Other methods are possible in scichart, for example, how to get the Y-Value at a x-y mouse coordinate using the HitTest API.

Let me know if this helps