javafx.animation.Interpolator Maven / Gradle / Ivy
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package javafx.animation;
import javafx.util.Duration;
import com.sun.scenario.animation.NumberTangentInterpolator;
import com.sun.scenario.animation.SplineInterpolator;
/**
* The abstract class defines several {@code 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
* {@code Interpolator} to get custom interpolation behavior.
*
* A custom {@code Interpolator} has to be defined in terms of a "
* {@link #curve(double) curve()}".
* @since JavaFX 2.0
*/
public abstract class Interpolator {
private static final double EPSILON = 1e-12;
/**
* The constructor of {@code Interpolator}.
*/
protected Interpolator() {
}
/**
* Built-in interpolator that provides discrete time interpolation. The
* return value of {@code interpolate()} is {@code endValue} only when the
* input {@code fraction} is 1.0, and {@code startValue} otherwise.
*/
public static final Interpolator DISCRETE = new Interpolator() {
@Override
protected double curve(double t) {
return (Math.abs(t - 1.0) < EPSILON) ? 1.0 : 0.0;
}
@Override
public String toString() {
return "Interpolator.DISCRETE";
}
};
/**
* Built-in interpolator that provides linear time interpolation. The return
* value of {@code interpolate()} is {@code startValue} + ({@code endValue}
* - {@code startValue}) * {@code fraction}.
*/
public static final Interpolator LINEAR = new Interpolator() {
@Override
protected double curve(double t) {
return t;
}
@Override
public String toString() {
return "Interpolator.LINEAR";
}
};
/*
* Easing is calculated with the following algorithm (taken from SMIL 3.0
* specs). The result is clamped because of possible rounding errors.
*
* double runRate = 1.0 / (1.0 - acceleration/2.0 - deceleration/2.0); if
* (fraction < acceleration) { double averageRunRate = runRate * (fraction /
* acceleration) / 2; fraction *= averageRunRate; } else if (fraction > (1.0
* - deceleration)) { // time spent in deceleration portion double tdec =
* fraction - (1.0 - deceleration); // proportion of tdec to total
* deceleration time double pdec = tdec / deceleration; fraction = runRate *
* (1.0 - ( acceleration / 2) - deceleration + tdec * (2 - pdec) / 2); }
* else { fraction = runRate * (fraction - (acceleration / 2)); }
*/
/**
* 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.
*/
public static final Interpolator EASE_BOTH = new Interpolator() {
@Override
protected double curve(double t) {
// See the SMIL 3.1 specification for details on this calculation
// acceleration = 0.2, deceleration = 0.2
return Interpolator.clamp((t < 0.2) ? 3.125 * t * t
: (t > 0.8) ? -3.125 * t * t + 6.25 * t - 2.125
: 1.25 * t - 0.125);
}
@Override
public String toString() {
return "Interpolator.EASE_BOTH";
}
};
/**
* 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.
*/
public static final Interpolator EASE_IN = new Interpolator() {
private static final double S1 = 25.0 / 9.0;
private static final double S3 = 10.0 / 9.0;
private static final double S4 = 1.0 / 9.0;
@Override
protected double curve(double t) {
// See the SMIL 3.1 specification for details on this calculation
// acceleration = 0.2, deceleration = 0.0
return Interpolator.clamp((t < 0.2) ? S1 * t * t : S3 * t - S4);
}
@Override
public String toString() {
return "Interpolator.EASE_IN";
}
};
/**
* 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.
*/
public static final Interpolator EASE_OUT = new Interpolator() {
private static final double S1 = -25.0 / 9.0;
private static final double S2 = 50.0 / 9.0;
private static final double S3 = -16.0 / 9.0;
private static final double S4 = 10.0 / 9.0;
@Override
protected double curve(double t) {
// See the SMIL 3.1 specification for details on this calculation
// acceleration = 0.2, deceleration = 0.0
return Interpolator.clamp((t > 0.8) ? S1 * t * t + S2 * t + S3 : S4
* t);
}
@Override
public String toString() {
return "Interpolator.EASE_OUT";
}
};
/**
* Creates an {@code Interpolator}, which {@link #curve(double) curve()} is
* shaped using the spline control points defined by ({@code x1}, {@code y1}
* ) and ({@code x2}, {@code y2}). The anchor points of the spline are
* implicitly defined as ({@code 0.0}, {@code 0.0}) and ({@code 1.0},
* {@code 1.0}).
*
* @param x1
* x coordinate of the first control point
* @param y1
* y coordinate of the first control point
* @param x2
* x coordinate of the second control point
* @param y2
* y coordinate of the second control point
* @return A spline interpolator
*/
public static Interpolator SPLINE(double x1, double y1, double x2, double y2) {
return new SplineInterpolator(x1, y1, x2, y2);
}
/**
* 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 {@link Timeline}.
* If used in a {@link 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.
*
*
* 
*
*
* 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.
*
* @param t1
* The delta time of the in-tangent, relative to the KeyFrame
* @param v1
* The value of the in-tangent
* @param t2
* The delta time of the out-tangent, relative to the KeyFrame
* @param v2
* The value of the out-tangent
* @return the new tangent interpolator
*/
public static Interpolator TANGENT(Duration t1, double v1, Duration t2,
double v2) {
return new NumberTangentInterpolator(t1, v1, t2, v2);
}
/**
* 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 {@link Timeline}, because for these key frames only one tangent is
* used.
*
* @see #TANGENT(Duration, double, Duration, double)
*
* @param t
* The delta time of the tangent
* @param v
* The value of the tangent
* @return the new Tangent interpolator
*/
public static Interpolator TANGENT(Duration t, double v) {
return new NumberTangentInterpolator(t, v);
}
/**
* This method takes two {@code Objects} along with a {@code fraction}
* between {@code 0.0} and {@code 1.0} and returns the interpolated value.
*
* If both {@code Objects} implement {@code Number}, their values are
* interpolated. If {@code startValue} implements {@link Interpolatable} the
* calculation defined in {@link Interpolatable#interpolate(Object, double)
* interpolate()} is used. If neither of these conditions are met, a
* discrete interpolation is used, i.e. {@code endValue} is returned if and
* only if {@code fraction} is {@code 1.0}, otherwise {@code startValue} is
* returned.
*
* Before calculating the interpolated value, the fraction is altered
* according to the function defined in {@link #curve(double) curve()}.
*
* @param startValue
* start value
* @param endValue
* end value
* @param fraction
* a value between 0.0 and 1.0
* @return interpolated value
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public Object interpolate(Object startValue, Object endValue,
double fraction) {
if ((startValue instanceof Number) && (endValue instanceof Number)) {
final double start = ((Number) startValue).doubleValue();
final double end = ((Number) endValue).doubleValue();
final double val = start + (end - start) * curve(fraction);
if ((startValue instanceof Double) || (endValue instanceof Double)) {
return Double.valueOf(val);
}
if ((startValue instanceof Float) || (endValue instanceof Float)) {
return Float.valueOf((float) val);
}
if ((startValue instanceof Long) || (endValue instanceof Long)) {
return Long.valueOf(Math.round(val));
}
return Integer.valueOf((int) Math.round(val));
} else if ((startValue instanceof Interpolatable) && (endValue instanceof Interpolatable)) {
return ((Interpolatable) startValue).interpolate(endValue,
curve(fraction));
} else {
// discrete
return (curve(fraction) == 1.0) ? endValue : startValue;
}
}
/**
* This method takes two {@code boolean} values along with a
* {@code fraction} between {@code 0.0} and {@code 1.0} and returns the
* interpolated value.
*
* Before calculating the interpolated value, the fraction is altered
* according to the function defined in {@link #curve(double) curve()}.
*
* @param startValue
* the first data point
* @param endValue
* the second data point
* @param fraction
* the fraction in {@code [0.0...1.0]}
* @return the interpolated value
*/
public boolean interpolate(boolean startValue, boolean endValue,
double fraction) {
return (Math.abs(curve(fraction) - 1.0) < EPSILON) ? endValue
: startValue;
}
/**
* This method takes two {@code double} values along with a {@code fraction}
* between {@code 0.0} and {@code 1.0} and returns the interpolated value.
*
* Before calculating the interpolated value, the fraction is altered
* according to the function defined in {@link #curve(double) curve()}.
*
* @param startValue
* the first data point
* @param endValue
* the second data point
* @param fraction
* the fraction in {@code [0.0...1.0]}
* @return the interpolated value
*/
public double interpolate(double startValue, double endValue,
double fraction) {
return startValue + (endValue - startValue) * curve(fraction);
}
/**
* This method takes two {@code int} values along with a {@code fraction}
* between {@code 0.0} and {@code 1.0} and returns the interpolated value.
*
* Before calculating the interpolated value, the fraction is altered
* according to the function defined in {@link #curve(double) curve()}.
*
* @param startValue
* the first data point
* @param endValue
* the second data point
* @param fraction
* the fraction in {@code [0.0...1.0]}
* @return the interpolated value
*/
public int interpolate(int startValue, int endValue, double fraction) {
return startValue
+ (int) Math.round((endValue - startValue) * curve(fraction));
}
/**
* This method takes two {@code int} values along with a {@code fraction}
* between {@code 0.0} and {@code 1.0} and returns the interpolated value.
*
* Before calculating the interpolated value, the fraction is altered
* according to the function defined in {@link #curve(double) curve()}.
*
* @param startValue
* the first data point
* @param endValue
* the second data point
* @param fraction
* the fraction in {@code [0.0...1.0]}
* @return the interpolated value
*/
public long interpolate(long startValue, long endValue,
double fraction) {
return startValue
+ Math.round((endValue - startValue) * curve(fraction));
}
private static double clamp(double t) {
return (t < 0.0) ? 0.0 : (t > 1.0) ? 1.0 : t;
}
/**
* Mapping from [0.0..1.0] to itself.
*
* @param 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.
* @return the curved value
*/
protected abstract double curve(double t);
}