Line chart with String X-Axis data, starting closer to Y-Axis

I'm trying to make a line chart with String values in the X-Axis.
XYChart doesn't work because "Series data must be either Number or Date type" (as an exception message told me).
So I tried to use a CategoryChart with line rendering (as in your example).
This way it works, but the offset of the line's starting point is a bit too large for my taste.
This is how it looks:

And this is what I'd like:

I checked the API and also did some debugging, and there seems to be no way to configure this.
I found the xOffset variable in:
org.knowm.xchart.internal.chartpart.PlotContent_Category_Line_Area_Scatter.doPaint(Graphics2D)
As far as I can tell, we always add half a gridStep at the beginning.

If you don't have time for that, I would try to change this myself and then send a pull request, but I'd like your opinion.

1. Should we try and alter the aforementioned part of the code (PlotContent_Category_Line_Area_Scatter)? Maybe that half gridStep makes sense for bar charts, but for lines maybe it could be different.
2. Should we change the XYChart to accept Strings for the X-Axis? I'm thinking of using the index of the String array for the values, and the actual String only as a label.

Which variant makes more sense to you?

Or do you see another way of doing it?

[timmolter]

Option one would be better. You could make it a configurable style parameter.

[hakantkn]

You can use custom axis tick calculator.
Here is an example:

    List<Integer> xData = new ArrayList<Integer>();
    List<Double> yData = new ArrayList<Double>();
    xData.add(1);
    xData.add(2);
    yData.add(50.0);
    yData.add(49.9995);
    
    // Create Chart
    XYChart chart =
        new XYChartBuilder()
            .width(800)
            .height(600)
            .title("Test")
            .xAxisTitle("Power")
            .yAxisTitle("Value")
            .build();

    // Customize Chart
    chart.getStyler().setChartTitleVisible(true);
    chart.getStyler().setLegendVisible(false);
    
    chart.getStyler().setXAxisLabelRotation(45);


    // Series
    chart.addSeries("10^x", xData, yData);

    Map<Double, Object> xMarkMap = new TreeMap<Double, Object>();
    xMarkMap.put(1.0, "initial value");
    xMarkMap.put(2.0, "2016-01");

    chart.setXAxisLabelOverrideMap(xMarkMap);

Here is the screenshot:

@hakantkn, this is exactly what I needed, thank you very much!
I guess I didn't see the setXAxisLabelOverrideMap method because I was still using 3.5.0.

In this case I don't think we need a parameter for the CategoryChart anymore.