org.jdesktop.animation.timing.interpolation
Class SplineInterpolator

java.lang.Object
  org.jdesktop.animation.timing.interpolation.SplineInterpolator

All Implemented Interfaces:

Interpolator

public final class SplineInterpolator
extends Object
implements Interpolator

This class interpolates fractional values using Bezier splines. The anchor points * for the spline are assumed to be (0, 0) and (1, 1). Control points should all be in the range [0, 1].

For more information on how splines are used to interpolate, refer to the SMIL specification at http://w3c.org.

This class provides one simple built-in facility for non-linear interpolation. Applications are free to define their own Interpolator implementation and use that instead when particular non-linear effects are desired.

Constructor Summary

SplineInterpolator(float x1, float y1, float x2, float y2)
Creates a new instance of SplineInterpolator with the control points defined by (x1, y1) and (x2, y2).

Method Summary

float

interpolate(float lengthFraction) Given a fraction of time along the spline (which we can interpret as the length along a spline), return the interpolated value of the spline.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SplineInterpolator

public SplineInterpolator(float x1,
                          float y1,
                          float x2,
                          float y2)

Creates a new instance of SplineInterpolator with the control points defined by (x1, y1) and (x2, y2). The anchor points are implicitly defined as (0, 0) and (1, 1).

Throws:

IllegalArgumentException - This exception is thrown when values beyond the allowed [0,1] range are passed in

Method Detail

interpolate

public float interpolate(float lengthFraction)

Given a fraction of time along the spline (which we can interpret as the length along a spline), return the interpolated value of the spline. We first calculate the t value for the length (by doing a lookup in our array of previousloy calculated values and then linearly interpolating between the nearest values) and then calculate the Y value for this t.

Specified by:

interpolate in interface Interpolator

Parameters:

lengthFraction - Fraction of time in a given time interval.

Returns:

interpolated fraction between 0 and 1