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javascalejfreechartyaxis

JFreeChart: how to scale Y-axis when time axis is reduced?

I have created a plot in JFreeChart, consisting of a TimeSeriesCollection and XYPlot. The horizontal axis uses a DateAxis, and the vertical (Y) axis is using a NumberAxis. If the horizontal axis is using all dates for which I have data points I get a proper Y-axis scale when using:

Y1axis.setAutoRangeIncludesZero(false);
Y1axis.setRangeWithMargins(LeftSeries.getRangeBounds(true));

Now I want to create a plot from only a portion of the available time data. For example: I have data points covering four years, but want to create a plot of only the second year. For this I create a date range (MinDate is the oldest data point I want to show, MaxDate the most recent data point I want to show):

dateAxis.setMinimumDate(MinDate);
dateAxis.setMaximumDate(MaxDate);

This scales the horizontal axis as desired. However, if I now use the same code to scale the Y axis (Y1axis.setRangeWithMargins(LeftSeries.getRangeBounds(true))) I get the entire vertical range, suitable for the entire data set. What I want is a vertical scale which suits the date range MinDate~MaxDate. I have tried a few things to get the vertical axis to scale correctly, but none of my attempts was any good. For example:

double LowValue = Y1axis.getLowerBound();
double HighValue = Y1axis.getUpperBound();
Y1axis.setRange(LowValue, HighValue);

did not work. What code should I use to adjust the scale on the vertical (Y) axis to adapt itself to the horizontal time axis data points which are shown in the plot?

Solution

  • You just have to enable auto range for the Y1axis axis:

    Y1axis.setAutoRangeIncludesZero(false);
Y1axis.setAutoRange(true);

    Example:

    All data:

    enter image description here

    Subset of values with auto range disabled:

    enter image description here

    Subset of values with auto range enabled:

    enter image description here