Class 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
    • Field Summary

      Fields 
      Modifier and Type Field Description
      static Interpolator DISCRETE
      Built-in interpolator that provides discrete time interpolation.
      static Interpolator EASE_BOTH
      Built-in interpolator instance that provides ease in/out behavior.
      static Interpolator EASE_IN
      Built-in interpolator instance that provides ease in behavior.
      static Interpolator EASE_OUT
      Built-in interpolator instance that provides ease out behavior.
      static Interpolator LINEAR
      Built-in interpolator that provides linear time interpolation.
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
      protected Interpolator()
      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 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.
    • Field Detail

      • 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.

    • Constructor Detail

      • Interpolator

        protected Interpolator()
        The constructor of Interpolator.
    • Method Detail

      • 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:
        TANGENT(Duration, double, Duration, double)
      • 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.

        Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

        Parameters:
        startValue - start value
        endValue - end value
        fraction - a value between 0.0 and 1.0
        Returns:
        interpolated value
      • interpolate

        public 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.

        Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

        Parameters:
        startValue - the first data point
        endValue - the second data point
        fraction - the fraction in [0.0...1.0]
        Returns:
        the interpolated value
      • interpolate

        public 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.

        Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

        Parameters:
        startValue - the first data point
        endValue - the second data point
        fraction - the fraction in [0.0...1.0]
        Returns:
        the interpolated value
      • interpolate

        public 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.

        Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

        Parameters:
        startValue - the first data point
        endValue - the second data point
        fraction - the fraction in [0.0...1.0]
        Returns:
        the interpolated value
      • interpolate

        public 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.

        Before calculating the interpolated value, the fraction is altered according to the function defined in curve().

        Parameters:
        startValue - the first data point
        endValue - the second data point
        fraction - the fraction in [0.0...1.0]
        Returns:
        the interpolated value
      • curve

        protected abstract double curve​(double t)
        Mapping from [0.0..1.0] to itself.
        Parameters:
        t - time, but normalized to the range [0.0..1.0], where 0.0 is the start of the current interval, while 1.0 is the end of the current interval. Usually a function that increases monotonically.
        Returns:
        the curved value