Module platform
Package org.jfree.chart.axis

Class LogAxis

java.lang.Object
org.jfree.chart.axis.Axis
org.jfree.chart.axis.ValueAxis
org.jfree.chart.axis.LogAxis
All Implemented Interfaces:
Serializable, Cloneable, PublicCloneable
public class LogAxis extends ValueAxis
A numerical axis that uses a logarithmic scale. The class is an alternative to the LogarithmicAxis class.
See Also:

  • Constructor Details

    • LogAxis

      public LogAxis()
      Creates a new LogAxis with no label.

    • LogAxis

      public LogAxis(String label)
      Creates a new LogAxis with the given label.
      Parameters:
      label - the axis label (null permitted).

  • Method Details

    • getBase

      public double getBase()
      Returns the base for the logarithm calculation. The default value is 10.0.
      Returns:
      The base for the logarithm calculation.
      See Also:

    • setBase

      public void setBase(double base)
      Sets the base for the logarithm calculation and sends a change event to all registered listeners.
      Parameters:
      base - the base value (must be > 1.0).
      See Also:

    • getBaseSymbol

      public String getBaseSymbol()
      Returns the symbol used to represent the base of the logarithmic scale for the axis. If this is null (the default) then the numerical value of the base is displayed.
      Returns:
      The base symbol (possibly null).

    • setBaseSymbol

      public void setBaseSymbol(String symbol)
      Sets the symbol used to represent the base value of the logarithmic scale and sends a change event to all registered listeners.
      Parameters:
      symbol - the symbol (null permitted).

    • getBaseFormatter

      public Format getBaseFormatter()
      Returns the formatter used to format the base value of the logarithmic scale when it is displayed numerically. The default value is new DecimalFormat("0").
      Returns:
      The base formatter (never null).

    • setBaseFormatter

      public void setBaseFormatter(Format formatter)
      Sets the formatter used to format the base value of the logarithmic scale when it is displayed numerically and sends a change event to all registered listeners.
      Parameters:
      formatter - the formatter (null not permitted).

    • getSmallestValue

      public double getSmallestValue()
      Returns the smallest value represented by the axis.
      Returns:
      The smallest value represented by the axis.
      See Also:

    • setSmallestValue

      public void setSmallestValue(double value)
      Sets the smallest value represented by the axis and sends a change event to all registered listeners.
      Parameters:
      value - the value.
      See Also:

    • getTickUnit

      public NumberTickUnit getTickUnit()
      Returns the current tick unit.
      Returns:
      The current tick unit.
      See Also:

    • setTickUnit

      public void setTickUnit(NumberTickUnit unit)
      Sets the tick unit for the axis and sends an AxisChangeEvent to all registered listeners. A side effect of calling this method is that the "auto-select" feature for tick units is switched off (you can restore it using the ValueAxis.setAutoTickUnitSelection(boolean) method).
      Parameters:
      unit - the new tick unit (null not permitted).
      See Also:

    • setTickUnit

      public void setTickUnit(NumberTickUnit unit, boolean notify, boolean turnOffAutoSelect)
      Sets the tick unit for the axis and, if requested, sends an AxisChangeEvent to all registered listeners. In addition, an option is provided to turn off the "auto-select" feature for tick units (you can restore it using the ValueAxis.setAutoTickUnitSelection(boolean) method).
      Parameters:
      unit - the new tick unit (null not permitted).
      notify - notify listeners?
      turnOffAutoSelect - turn off the auto-tick selection?
      See Also:

    • getNumberFormatOverride

      public NumberFormat getNumberFormatOverride()
      Returns the number format override. If this is non-null, then it will be used to format the numbers on the axis.
      Returns:
      The number formatter (possibly null).
      See Also:

    • setNumberFormatOverride

      public void setNumberFormatOverride(NumberFormat formatter)
      Sets the number format override and sends a change event to all registered listeners. If this is non-null, then it will be used to format the numbers on the axis.
      Parameters:
      formatter - the number formatter (null permitted).
      See Also:

    • calculateLog

      public double calculateLog(double value)
      Calculates the log of the given value, using the current base.
      Parameters:
      value - the value.
      Returns:
      The log of the given value.
      See Also:

    • calculateValue

      public double calculateValue(double log)
      Calculates the value from a given log.
      Parameters:
      log - the log value.
      Returns:
      The value with the given log.
      See Also:

    • java2DToValue

      public double java2DToValue(double java2DValue, Rectangle2D area, RectangleEdge edge)
      Converts a Java2D coordinate to an axis value, assuming that the axis is aligned to the specified edge of the area.
      Specified by:
      java2DToValue in class ValueAxis
      Parameters:
      java2DValue - the Java2D coordinate.
      area - the area for plotting data (null not permitted).
      edge - the edge that the axis is aligned to (null not permitted).
      Returns:
      A value along the axis scale.
      See Also:

    • valueToJava2D

      public double valueToJava2D(double value, Rectangle2D area, RectangleEdge edge)
      Converts a value on the axis scale to a Java2D coordinate relative to the given area, based on the axis running along the specified edge.
      Specified by:
      valueToJava2D in class ValueAxis
      Parameters:
      value - the data value.
      area - the area (null not permitted).
      edge - the edge (null not permitted).
      Returns:
      The Java2D coordinate corresponding to value.
      See Also:

    • configure

      public void configure()
      Configures the axis. This method is typically called when an axis is assigned to a new plot.
      Specified by:
      configure in class Axis

    • autoAdjustRange

      protected void autoAdjustRange()
      Adjusts the axis range to match the data range that the axis is required to display.
      Specified by:
      autoAdjustRange in class ValueAxis

    • draw

      public AxisState draw(Graphics2D g2, double cursor, Rectangle2D plotArea, Rectangle2D dataArea, RectangleEdge edge, PlotRenderingInfo plotState)
      Draws the axis on a Java 2D graphics device (such as the screen or a printer).
      Specified by:
      draw in class Axis
      Parameters:
      g2 - the graphics device (null not permitted).
      cursor - the cursor location (determines where to draw the axis).
      plotArea - the area within which the axes and plot should be drawn.
      dataArea - the area within which the data should be drawn.
      edge - the axis location (null not permitted).
      plotState - collects information about the plot (null permitted).
      Returns:
      The axis state (never null).

    • refreshTicks

      public List refreshTicks(Graphics2D g2, AxisState state, Rectangle2D dataArea, RectangleEdge edge)
      Calculates the positions of the tick labels for the axis, storing the results in the tick label list (ready for drawing).
      Specified by:
      refreshTicks in class Axis
      Parameters:
      g2 - the graphics device.
      state - the axis state.
      dataArea - the area in which the plot should be drawn.
      edge - the location of the axis.
      Returns:
      A list of ticks.

    • refreshTicksHorizontal

      protected List refreshTicksHorizontal(Graphics2D g2, Rectangle2D dataArea, RectangleEdge edge)
      Returns a list of ticks for an axis at the top or bottom of the chart.
      Parameters:
      g2 - the graphics device (null not permitted).
      dataArea - the data area (null not permitted).
      edge - the edge (null not permitted).
      Returns:
      A list of ticks.

    • refreshTicksVertical

      protected List refreshTicksVertical(Graphics2D g2, Rectangle2D dataArea, RectangleEdge edge)
      Returns a list of ticks for an axis at the left or right of the chart.
      Parameters:
      g2 - the graphics device (null not permitted).
      dataArea - the data area (null not permitted).
      edge - the edge that the axis is aligned to (null not permitted).
      Returns:
      A list of ticks.

    • selectAutoTickUnit

      protected void selectAutoTickUnit(Graphics2D g2, Rectangle2D dataArea, RectangleEdge edge)
      Selects an appropriate tick value for the axis. The strategy is to display as many ticks as possible (selected from an array of 'standard' tick units) without the labels overlapping.
      Parameters:
      g2 - the graphics device (null not permitted).
      dataArea - the area defined by the axes (null not permitted).
      edge - the axis location (null not permitted).

    • selectHorizontalAutoTickUnit

      protected void selectHorizontalAutoTickUnit(Graphics2D g2, Rectangle2D dataArea, RectangleEdge edge)
      Selects an appropriate tick value for the axis. The strategy is to display as many ticks as possible (selected from an array of 'standard' tick units) without the labels overlapping.
      Parameters:
      g2 - the graphics device.
      dataArea - the area defined by the axes.
      edge - the axis location.

    • exponentLengthToJava2D

      public double exponentLengthToJava2D(double length, Rectangle2D area, RectangleEdge edge)
      Converts a length in data coordinates into the corresponding length in Java2D coordinates.
      Parameters:
      length - the length.
      area - the plot area.
      edge - the edge along which the axis lies.
      Returns:
      The length in Java2D coordinates.

    • selectVerticalAutoTickUnit

      protected void selectVerticalAutoTickUnit(Graphics2D g2, Rectangle2D dataArea, RectangleEdge edge)
      Selects an appropriate tick value for the axis. The strategy is to display as many ticks as possible (selected from an array of 'standard' tick units) without the labels overlapping.
      Parameters:
      g2 - the graphics device.
      dataArea - the area in which the plot should be drawn.
      edge - the axis location.

    • createTickLabel

      protected AttributedString createTickLabel(double value)
      Creates a tick label for the specified value based on the current tick unit (used for formatting the exponent).
      Parameters:
      value - the value.
      Returns:
      The label.

    • estimateMaximumTickLabelHeight

      protected double estimateMaximumTickLabelHeight(Graphics2D g2)
      Estimates the maximum tick label height.
      Parameters:
      g2 - the graphics device.
      Returns:
      The maximum height.

    • estimateMaximumTickLabelWidth

      protected double estimateMaximumTickLabelWidth(Graphics2D g2, TickUnit unit)
      Estimates the maximum width of the tick labels, assuming the specified tick unit is used.

      Rather than computing the string bounds of every tick on the axis, we just look at two values: the lower bound and the upper bound for the axis. These two values will usually be representative.

      Parameters:
      g2 - the graphics device.
      unit - the tick unit to use for calculation.
      Returns:
      The estimated maximum width of the tick labels.

    • zoomRange

      public void zoomRange(double lowerPercent, double upperPercent)
      Zooms in on the current range.
      Overrides:
      zoomRange in class ValueAxis
      Parameters:
      lowerPercent - the new lower bound.
      upperPercent - the new upper bound.

    • pan

      public void pan(double percent)
      Slides the axis range by the specified percentage.
      Overrides:
      pan in class ValueAxis
      Parameters:
      percent - the percentage.

    • resizeRange

      public void resizeRange(double percent)
      Increases or decreases the axis range by the specified percentage about the central value and sends an AxisChangeEvent to all registered listeners.

      To double the length of the axis range, use 200% (2.0). To halve the length of the axis range, use 50% (0.5).

      Overrides:
      resizeRange in class ValueAxis
      Parameters:
      percent - the resize factor.
      See Also:

    • resizeRange

      public void resizeRange(double percent, double anchorValue)
      Description copied from class: ValueAxis
      Increases or decreases the axis range by the specified percentage about the specified anchor value and sends an AxisChangeEvent to all registered listeners.

      To double the length of the axis range, use 200% (2.0). To halve the length of the axis range, use 50% (0.5).

      Overrides:
      resizeRange in class ValueAxis
      Parameters:
      percent - the resize factor.
      anchorValue - the new central value after the resize.
      See Also:

    • resizeRange2

      public void resizeRange2(double percent, double anchorValue)
      Resizes the axis length to the specified percentage of the current range and sends a change event to all registered listeners. If percent is greater than 1.0 (100 percent) then the axis range is increased (which has the effect of zooming out), while if the percent is less than 1.0 the axis range is decreased (which has the effect of zooming in). The resize occurs around an anchor value (which may not be in the center of the axis). This is used to support mouse wheel zooming around an arbitrary point on the plot.

      This method is overridden to perform the percentage calculations on the log values (which are linear for this axis).
      Overrides:
      resizeRange2 in class ValueAxis
      Parameters:
      percent - the percentage (must be greater than zero).
      anchorValue - the anchor value.
      See Also:

    • equals

      public boolean equals(Object obj)
      Tests this axis for equality with an arbitrary object.
      Overrides:
      equals in class ValueAxis
      Parameters:
      obj - the object (null permitted).
      Returns:
      A boolean.

    • hashCode

      public int hashCode()
      Returns a hash code for this instance.
      Overrides:
      hashCode in class Axis
      Returns:
      A hash code.