Package limn.components.chart

Class ChartAxis

java.lang.Object
limn.components.chart.ChartAxis
public final class ChartAxis extends Object
One axis of a CartesianChart: the value axis that carries the numbers, or the category axis that carries the labels. Reach them with CartesianChart.valueAxis() and CartesianChart.categoryAxis(); both are created with the chart and live as long as it does.

An axis is automatic until told otherwise: it reads the data, rounds the range outward to values a human would have chosen, and picks a tick spacing near setTickCount(int). setMin(Double) and setMax(Double) pin either end; whichever end stays null keeps following the data.

Four settings apply only to the value axis and are ignored on the category axis, which has no numbers to place: min, max, tickCount and beginAtZero. format is likewise a value-axis setting; category labels come from Chart.setLabels(java.util.List).

  • Method Details

    • min

      public @Nullable Double min()
      The pinned lower bound, or null while it follows the data.

    • setMin

      public ChartAxis setMin(@Nullable Double value)
      Pins the lower bound; null hands it back to the data.

    • max

      public @Nullable Double max()
      The pinned upper bound, or null while it follows the data.

    • setMax

      public ChartAxis setMax(@Nullable Double value)
      Pins the upper bound; null hands it back to the data.

    • beginsAtZero

      public boolean beginsAtZero()
      Whether the automatic range always reaches zero.

    • setBeginAtZero

      public ChartAxis setBeginAtZero(boolean value)
      Whether the automatic range must include zero. On by default for bars, off for lines, and that difference is not a preference: the length of a bar is the value, so a bar axis that starts anywhere else draws a ratio that is not the data's. A line encodes value as position, so it may zoom into the range that matters.

    • tickCount

      public int tickCount()
      The tick count the automatic scale aims for.

    • setTickCount

      public ChartAxis setTickCount(int value)
      Sets how many ticks the automatic scale aims for (clamped to [2, 20]). It is a target, not a promise: the scale rounds the spacing to 1, 2 or 5 times a power of ten first, and honours that over the count.

    • format

      public DoubleFunction<String> format()
      How tick values are turned into text: the format set, or the default, which the ticks write with more decimals when their spacing needs them (see setFormat(java.util.function.DoubleFunction<java.lang.String>)).

    • setFormat

      public ChartAxis setFormat(DoubleFunction<String> value)
      Sets the tick text format. Defaults to NumberFormats.number(), written with as many more decimals as the tick spacing needs: ticks a thousandth apart read 0.001, 0.002, 0.003 rather than four zeros. A format set here is used as it is. The chart's own Chart.setValueFormat(DoubleFunction) does not reach here, so an axis and its tooltips can read differently (compact ticks, exact tooltips).

    • hasGrid

      public boolean hasGrid()
      Whether this axis draws grid lines across the plot.

    • setGrid

      public ChartAxis setGrid(boolean value)
      Shows or hides this axis' grid lines (value axis on, category axis off by default).

    • isVisible

      public boolean isVisible()
      Whether this axis draws its labels at all.

    • setVisible

      public ChartAxis setVisible(boolean value)
      Shows or hides the axis labels. Hiding them gives the plot their gutter back, the shape a sparkline wants.

    • title

      public @Nullable String title()
      The axis title, or null for none.

    • setTitle

      public ChartAxis setTitle(@Nullable String value)
      Sets a title drawn beside the axis (null for none).