org.jfree.chart.plot
Class CrosshairState

java.lang.Object
  extended byorg.jfree.chart.plot.CrosshairState

public class CrosshairState
extends java.lang.Object

Maintains state information about crosshairs on a plot.


Constructor Summary
CrosshairState()
          Default constructor.
CrosshairState(boolean calculateDistanceInDataSpace)
          Creates a new info object.
 
Method Summary
 double getCrosshairX()
          Get the x-value for the crosshair point.
 double getCrosshairY()
          Get the y-value for the crosshair point.
 void setAnchor(java.awt.geom.Point2D anchor)
          Sets the anchor point.
 void setCrosshairDistance(double distance)
          Sets the distance between the anchor point and the current crosshair point.
 void setCrosshairX(double x)
          Sets the x coordinate for the crosshair.
 void setCrosshairY(double y)
          Sets the y coordinate for the crosshair.
 void updateCrosshairPoint(double x, double y, double transX, double transY, PlotOrientation orientation)
          Evaluates a data point and if it is the closest to the anchor point it becomes the new crosshair point.
 void updateCrosshairX(double candidateX)
          Evaluates an x-value and if it is the closest to the anchor point it becomes the new crosshair point.
 void updateCrosshairY(double candidateY)
          Evaluates a y-value and if it is the closest to the anchor point it becomes the new crosshair point.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

CrosshairState

public CrosshairState()
Default constructor.


CrosshairState

public CrosshairState(boolean calculateDistanceInDataSpace)
Creates a new info object.

Parameters:
calculateDistanceInDataSpace - a flag that controls whether the distance is calculated in data space or Java2D space.
Method Detail

setCrosshairDistance

public void setCrosshairDistance(double distance)
Sets the distance between the anchor point and the current crosshair point. As each data point is processed, its distance to the anchor point is compared with this value and, if it is closer, the data point becomes the new crosshair point.

Parameters:
distance - the distance.

updateCrosshairPoint

public void updateCrosshairPoint(double x,
                                 double y,
                                 double transX,
                                 double transY,
                                 PlotOrientation orientation)
Evaluates a data point and if it is the closest to the anchor point it becomes the new crosshair point.

To understand this method, you need to know the context in which it will be called. An instance of this class is passed to an XYItemRenderer as each data point is plotted. As the point is plotted, it is passed to this method to see if it should be the new crosshair point.

Parameters:
x - x coordinate (measured against the domain axis).
y - y coordinate (measured against the range axis).
transX - x translated into Java2D space.
transY - y translated into Java2D space.
orientation - the plot orientation.

updateCrosshairX

public void updateCrosshairX(double candidateX)
Evaluates an x-value and if it is the closest to the anchor point it becomes the new crosshair point.

Used in cases where only the x-axis is numerical.

Parameters:
candidateX - x position of the candidate for the new crosshair point.

updateCrosshairY

public void updateCrosshairY(double candidateY)
Evaluates a y-value and if it is the closest to the anchor point it becomes the new crosshair point.

Used in cases where only the y-axis is numerical.

Parameters:
candidateY - y position of the candidate for the new crosshair point.

setAnchor

public void setAnchor(java.awt.geom.Point2D anchor)
Sets the anchor point. This is usually the mouse click point in a chart panel, and the crosshair point will often be the data item that is closest to the anchor point.

Parameters:
anchor - the anchor point.

getCrosshairX

public double getCrosshairX()
Get the x-value for the crosshair point.

Returns:
the x position of the crosshair point.

setCrosshairX

public void setCrosshairX(double x)
Sets the x coordinate for the crosshair. This is the coordinate in data space measured against the domain axis.

Parameters:
x - the coordinate.

getCrosshairY

public double getCrosshairY()
Get the y-value for the crosshair point. This is the coordinate in data space measured against the range axis.

Returns:
the y position of the crosshair point.

setCrosshairY

public void setCrosshairY(double y)
Sets the y coordinate for the crosshair.

Parameters:
y - the y coordinate.