Module org.jfree.chart

Package org.jfree.chart.swing

Interface Overlay

All Known Implementing Classes:

CrosshairOverlay

public interface Overlay

An Overlay is anything that can be drawn over top of a chart to add additional information to the chart. This interface defines the operations that must be supported for an overlay that can be added to a ChartPanel in Swing.

Note: if you are using JavaFX rather than Swing, then you need to look at the OverlayFX interface in the JFreeChart-FX project.

Method Summary

Modifier and Type	Method	Description
void	addChangeListener(OverlayChangeListener listener)	Registers a change listener with the overlay.
void	paintOverlay(Graphics2D g2, ChartPanel chartPanel)	Paints the visual representation of the overlay.
void	removeChangeListener(OverlayChangeListener listener)	Deregisters a listener from the overlay.

Method Detail

paintOverlay

void paintOverlay(Graphics2D g2,
                  ChartPanel chartPanel)

Paints the visual representation of the overlay. This method will be called by the ChartPanel after the underlying chart has been fully rendered. When implementing this method, the chartPanel argument can be used to get state information from the chart (you can, for example, extract the axis ranges for the chart).

Parameters:

g2 - the graphics target (never null).

chartPanel - the chart panel (never null).

addChangeListener

void addChangeListener(OverlayChangeListener listener)

Registers a change listener with the overlay. Typically this method not be called by user code, it exists so that the ChartPanel can register and receive notification of changes to the overlay (such changes will trigger an automatic repaint of the chart).

Parameters:

listener - the listener (null not permitted).

See Also:

removeChangeListener(org.jfree.chart.event.OverlayChangeListener)

removeChangeListener

void removeChangeListener(OverlayChangeListener listener)

Deregisters a listener from the overlay.

Parameters:

listener - the listener (null not permitted).

See Also:

addChangeListener(org.jfree.chart.event.OverlayChangeListener)