Class Interpolator

java.lang.Object

javafx.animation.Interpolator

public abstract class Interpolator extends Object

The abstract class defines several interpolate methods, which are used to calculate interpolated values. Various built-in implementations of this class are offered. Applications may choose to implement their own Interpolator to get custom interpolation behavior.

A custom Interpolator has to be defined in terms of a " curve()".

Since:: JavaFX 2.0

Nested Class Summary

Modifier and Type	Class	Description
`static enum`	`Interpolator.StepPosition`	Specifies the step position of a step interpolator.

Field Summary

Modifier and Type	Field	Description
`static final Interpolator`	`DISCRETE`	Built-in interpolator that provides discrete time interpolation.
`static final Interpolator`	`EASE_BOTH`	Built-in interpolator instance that provides ease in/out behavior.
`static final Interpolator`	`EASE_IN`	Built-in interpolator instance that provides ease in behavior.
`static final Interpolator`	`EASE_OUT`	Built-in interpolator instance that provides ease out behavior.
`static final Interpolator`	`LINEAR`	Built-in interpolator that provides linear time interpolation.
`static final Interpolator`	`STEP_END`	Built-in interpolator instance that is equivalent to `STEPS(1, StepPosition.END)`.
`static final Interpolator`	`STEP_START`	Built-in interpolator instance that is equivalent to `STEPS(1, StepPosition.START)`.

Constructor Summary

Interpolator()

Modifier	Constructor	Description
`protected`	The constructor of `Interpolator`.

Method Summary

Modifier and Type	Method	Description
`protected abstract double`	`curve(double t)`	Mapping from [0.0..1.0] to itself.
`boolean`	`interpolate(boolean startValue, boolean endValue, double fraction)`	This method takes two `boolean` values along with a `fraction` between `0.0` and `1.0` and returns the interpolated value.
`double`	`interpolate(double startValue, double endValue, double fraction)`	This method takes two `double` values along with a `fraction` between `0.0` and `1.0` and returns the interpolated value.
`int`	`interpolate(int startValue, int endValue, double fraction)`	This method takes two `int` values along with a `fraction` between `0.0` and `1.0` and returns the interpolated value.
`long`	`interpolate(long startValue, long endValue, double fraction)`	This method takes two `int` values along with a `fraction` between `0.0` and `1.0` and returns the interpolated value.
`Object`	`interpolate(Object startValue, Object endValue, double fraction)`	This method takes two `Objects` along with a `fraction` between `0.0` and `1.0` and returns the interpolated value.
`static Interpolator`	`SPLINE(double x1, double y1, double x2, double y2)`	Creates an `Interpolator`, which `curve()` is shaped using the spline control points defined by (`x1`, `y1` ) and (`x2`, `y2`).
`static Interpolator`	`STEPS(int intervalCount, Interpolator.StepPosition position)`	Creates a step interpolator that divides the input time into a series of intervals, each interval being equal in length, where each interval maps to a constant output time value.
`static Interpolator`	`TANGENT(Duration t, double v)`	Creates a tangent interpolator, for which in-tangent and out-tangent are identical.
`static Interpolator`	`TANGENT(Duration t1, double v1, Duration t2, double v2)`	Create a tangent interpolator.

Methods declared in class java.lang.Object

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

Field Details

DISCRETE

public static final Interpolator DISCRETE

Built-in interpolator that provides discrete time interpolation. The return value of interpolate() is endValue only when the input fraction is 1.0, and startValue otherwise.

LINEAR

public static final Interpolator LINEAR

Built-in interpolator that provides linear time interpolation. The return value of interpolate() is startValue + (endValue - startValue) * fraction.

EASE_BOTH

public static final Interpolator EASE_BOTH

Built-in interpolator instance that provides ease in/out behavior.

An ease-both interpolator will make an animation start slow, then accelerate and slow down again towards the end, all in a smooth manner.

The implementation uses the algorithm for easing defined in SMIL 3.0 with an acceleration and deceleration factor of 0.2, respectively.

EASE_IN

public static final Interpolator EASE_IN

Built-in interpolator instance that provides ease in behavior.

An ease-in interpolator will make an animation start slow and then accelerate smoothly.

The implementation uses the algorithm for easing defined in SMIL 3.0 with an acceleration factor of 0.2.

EASE_OUT

public static final Interpolator EASE_OUT

Built-in interpolator instance that provides ease out behavior.

An ease-out interpolator will make an animation slow down toward the end smoothly.

The implementation uses the algorithm for easing defined in SMIL 3.0 with an deceleration factor of 0.2.

STEP_START

public static final Interpolator STEP_START

Built-in interpolator instance that is equivalent to STEPS(1, StepPosition.START).

Since:: 23

STEP_END

public static final Interpolator STEP_END

Built-in interpolator instance that is equivalent to STEPS(1, StepPosition.END).

Since:: 23

Constructor Details

Interpolator

protected Interpolator()

The constructor of Interpolator.

Method Details

SPLINE

public static Interpolator SPLINE(double x1, double y1, double x2, double y2)

Creates an Interpolator, which curve() is shaped using the spline control points defined by (x1, y1 ) and (x2, y2). The anchor points of the spline are implicitly defined as (0.0, 0.0) and (1.0, 1.0).

Parameters:: x1 - x coordinate of the first control point; y1 - y coordinate of the first control point; x2 - x coordinate of the second control point; y2 - y coordinate of the second control point
Returns:: A spline interpolator

TANGENT

public static Interpolator TANGENT(Duration t1, double v1, Duration t2, double v2)

Create a tangent interpolator. A tangent interpolator allows to define the behavior of an animation curve very precisely by defining the tangents close to a key frame. A tangent interpolator defines the behavior to the left and to the right of a key frame, therefore it is only useful within a Timeline. If used in a KeyFrame after a KeyFrame that has different interpolator, it's treated as if the out-tangent of that KeyFrame was equal to the value in the KeyFrame.

A tangent interpolator
defines the behavior to the left and to the right of a key frame,
therefore it is only useful within a Timeline

The parameters define the tangent of the animation curve for the in tangent (before a key frame) and out tangent (after a key frame). Each tangent is specified with a pair, the distance to the key frame and the value of the tangent at this moment.

The interpolation then follows a bezier curve, with 2 control points defined by the specified tangent and positioned at 1/3 of the duration before the second KeyFrame or after the first KeyFrame. See the picture above.

Parameters:: t1 - The delta time of the in-tangent, relative to the KeyFrame; v1 - The value of the in-tangent; t2 - The delta time of the out-tangent, relative to the KeyFrame; v2 - The value of the out-tangent
Returns:: the new tangent interpolator

TANGENT

public static Interpolator TANGENT(Duration t, double v)

Creates a tangent interpolator, for which in-tangent and out-tangent are identical. This is especially useful for the first and the last key frame of a Timeline, because for these key frames only one tangent is used.

Parameters:

t - The delta time of the tangent

v - The value of the tangent

Returns:

the new Tangent interpolator

See Also:

STEPS

public static Interpolator STEPS(int intervalCount, Interpolator.StepPosition position)

Creates a step interpolator that divides the input time into a series of intervals, each interval being equal in length, where each interval maps to a constant output time value. The output time value is determined by the Interpolator.StepPosition.

Parameters:: intervalCount - the number of intervals in the step interpolator; position - the StepPosition of the step interpolator
Returns:: a new step interpolator
Throws:: IllegalArgumentException - if intervals is less than 1, or if intervals is less than 2 when position is Interpolator.StepPosition.NONE; NullPointerException - if position is null
Since:: 23

interpolate

public Object interpolate(Object startValue, Object endValue, double fraction)

This method takes two Objects along with a fraction between 0.0 and 1.0 and returns the interpolated value.

If both Objects implement Number, their values are interpolated. If startValue implements Interpolatable the calculation defined in interpolate() is used. If neither of these conditions are met, a discrete interpolation is used, i.e. endValue is returned if and only if fraction is 1.0, otherwise startValue is returned.