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package javafx.animation;

import javafx.beans.property.DoubleProperty;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.ObjectPropertyBase;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.scene.Node;
import javafx.util.Duration;

This Transition creates a fade effect animation that spans its duration. This is done by updating the opacity variable of the node at regular interval. 
 It starts from the fromValue if provided else uses the node's opacity value. 
 It stops at the toValue value if provided else it will use start value plus byValue. 
 The toValue takes precedence if both toValue and byValue are specified. 

Code Segment Example:


import javafx.scene.shape.*;
import javafx.animation.*;
...
    Rectangle rect = new Rectangle (100, 40, 100, 100);
    rect.setArcHeight(50);
    rect.setArcWidth(50);
    rect.setFill(Color.VIOLET);
    FadeTransition ft = new FadeTransition(Duration.millis(3000), rect);
    ft.setFromValue(1.0);
    ft.setToValue(0.3);
    ft.setCycleCount(4);
    ft.setAutoReverse(true);
    ft.play();
...


See Also:
Transition
Animation
Since:
JavaFX 2.0/**
 * This {@code Transition} creates a fade effect animation that spans its
 * {@code duration}. This is done by updating the {@code opacity} variable of
 * the {@code node} at regular interval.
 * <p>
 * It starts from the {@code fromValue} if provided else uses the {@code node}'s
 * {@code opacity} value.
 * <p>
 * It stops at the {@code toValue} value if provided else it will use start
 * value plus {@code byValue}.
 * <p>
 * The {@code toValue} takes precedence if both {@code toValue} and
 * {@code byValue} are specified.
 *
 * <p>
 * Code Segment Example:
 * </p>
 *
 * <pre>
 * <code>
 * import javafx.scene.shape.*;
 * import javafx.animation.*;
 *
 * ...
 *
 *     Rectangle rect = new Rectangle (100, 40, 100, 100);
 *     rect.setArcHeight(50);
 *     rect.setArcWidth(50);
 *     rect.setFill(Color.VIOLET);
 *
 *     FadeTransition ft = new FadeTransition(Duration.millis(3000), rect);
 *     ft.setFromValue(1.0);
 *     ft.setToValue(0.3);
 *     ft.setCycleCount(4);
 *     ft.setAutoReverse(true);
 *
 *     ft.play();
 *
 * ...
 *
 * </code>
 * </pre>
 *
 * @see Transition
 * @see Animation
 *
 * @since JavaFX 2.0
 */
public final class FadeTransition extends Transition {
    private static final double EPSILON = 1e-12;

    private double start;
    private double delta;

    
The target node of this Transition. 
 It is not possible to change the target node of a running FadeTransition. If the value of node is changed for a running FadeTransition, the animation has to be stopped and started again to pick up the new value. /**
     * The target node of this {@code Transition}.
     * <p>
     * It is not possible to change the target {@code node} of a running
     * {@code FadeTransition}. If the value of {@code node} is changed for a
     * running {@code FadeTransition}, the animation has to be stopped and
     * started again to pick up the new value.
     */
    private ObjectProperty<Node> node;
    private static final Node DEFAULT_NODE = null;

    public final void setNode(Node value) {
        if ((node != null) || (value != null /* DEFAULT_NODE */)) {
            nodeProperty().set(value);
        }
    }

    public final Node getNode() {
        return (node == null)? DEFAULT_NODE : node.get();
    }

    public final ObjectProperty<Node> nodeProperty() {
        if (node == null) {
            node = new SimpleObjectProperty<Node>(this, "node", DEFAULT_NODE);
        }
        return node;
    }

    private Node cachedNode;

    
The duration of this FadeTransition. 
 It is not possible to change the duration of a running FadeTransition. If the value of duration is changed for a running FadeTransition, the animation has to be stopped and started again to pick up the new value. 
 Note: While the unit of duration is a millisecond, the granularity depends on the underlying operating system and will in general be larger. For example animations on desktop systems usually run with a maximum of 60fps which gives a granularity of ~17 ms. Setting duration to value lower than Duration.ZERO will result in IllegalArgumentException. 
@defaultValue
400ms/**
     * The duration of this {@code FadeTransition}.
     * <p>
     * It is not possible to change the {@code duration} of a running
     * {@code FadeTransition}. If the value of {@code duration} is changed for a
     * running {@code FadeTransition}, the animation has to be stopped and
     * started again to pick up the new value.
     * <p>
     * Note: While the unit of {@code duration} is a millisecond, the
     * granularity depends on the underlying operating system and will in
     * general be larger. For example animations on desktop systems usually run
     * with a maximum of 60fps which gives a granularity of ~17 ms.
     *
     * Setting duration to value lower than {@link Duration#ZERO} will result
     * in {@link IllegalArgumentException}.
     *
     * @defaultValue 400ms
     */
    private ObjectProperty<Duration> duration;
    private static final Duration DEFAULT_DURATION = Duration.millis(400);

    public final void setDuration(Duration value) {
        if ((duration != null) || (!DEFAULT_DURATION.equals(value))) {
            durationProperty().set(value);
        }
    }

    public final Duration getDuration() {
        return (duration == null)? DEFAULT_DURATION : duration.get();
    }

    public final ObjectProperty<Duration> durationProperty() {
        if (duration == null) {
            duration = new ObjectPropertyBase<Duration>(DEFAULT_DURATION) {

                @Override
                public void invalidated() {
                    try {
                        setCycleDuration(getDuration());
                    } catch (IllegalArgumentException e) {
                        if (isBound()) {
                            unbind();
                        }
                        set(getCycleDuration());
                        throw e;
                    }
                }

                @Override
                public Object getBean() {
                    return FadeTransition.this;
                }

                @Override
                public String getName() {
                    return "duration";
                }
            };
        }
        return duration;
    }

    
Specifies the start opacity value for this FadeTransition. 
 It is not possible to change fromValue of a running FadeTransition. If the value of fromValue is changed for a running FadeTransition, the animation has to be stopped and started again to pick up the new value. 
@defaultValue
Double.NaN/**
     * Specifies the start opacity value for this {@code FadeTransition}.
     * <p>
     * It is not possible to change {@code fromValue} of a running
     * {@code FadeTransition}. If the value of {@code fromValue} is changed for
     * a running {@code FadeTransition}, the animation has to be stopped and
     * started again to pick up the new value.
     *
     * @defaultValue {@code Double.NaN}
     */
    private DoubleProperty fromValue;
    private static final double DEFAULT_FROM_VALUE = Double.NaN;

    public final void setFromValue(double value) {
        if ((fromValue != null) || (!Double.isNaN(value) /* DEFAULT_FROM_VALUE */ )) {
            fromValueProperty().set(value);
        }
    }

    public final double getFromValue() {
        return (fromValue == null)? DEFAULT_FROM_VALUE : fromValue.get();
    }

    public final DoubleProperty fromValueProperty() {
        if (fromValue == null) {
            fromValue = new SimpleDoubleProperty(this, "fromValue", DEFAULT_FROM_VALUE);
        }
        return fromValue;
    }

    
Specifies the stop opacity value for this FadeTransition. 
 It is not possible to change toValue of a running FadeTransition. If the value of toValue is changed for a running FadeTransition, the animation has to be stopped and started again to pick up the new value. 
@defaultValue
Double.NaN/**
     * Specifies the stop opacity value for this {@code FadeTransition}.
     * <p>
     * It is not possible to change {@code toValue} of a running
     * {@code FadeTransition}. If the value of {@code toValue} is changed for a
     * running {@code FadeTransition}, the animation has to be stopped and
     * started again to pick up the new value.
     *
     * @defaultValue {@code Double.NaN}
     */
    private DoubleProperty toValue;
    private static final double DEFAULT_TO_VALUE = Double.NaN;

    public final void setToValue(double value) {
        if ((toValue != null) || (!Double.isNaN(value))) {
            toValueProperty().set(value);
        }
    }

    public final double getToValue() {
        return (toValue == null)? DEFAULT_TO_VALUE : toValue.get();
    }

    public final DoubleProperty toValueProperty() {
        if (toValue == null) {
            toValue = new SimpleDoubleProperty(this, "toValue", DEFAULT_TO_VALUE);
        }
        return toValue;
    }

    
Specifies the incremented stop opacity value, from the start, of this FadeTransition. 
 It is not possible to change byValue of a running FadeTransition. If the value of byValue is changed for a running FadeTransition, the animation has to be stopped and started again to pick up the new value. /**
     * Specifies the incremented stop opacity value, from the start, of this
     * {@code FadeTransition}.
     * <p>
     * It is not possible to change {@code byValue} of a running
     * {@code FadeTransition}. If the value of {@code byValue} is changed for a
     * running {@code FadeTransition}, the animation has to be stopped and
     * started again to pick up the new value.
     */
    private DoubleProperty byValue;
    private static final double DEFAULT_BY_VALUE = 0.0;

    public final void setByValue(double value) {
        if ((byValue != null) || (Math.abs(value - DEFAULT_BY_VALUE) > EPSILON)) {
            byValueProperty().set(value);
        }
    }

    public final double getByValue() {
        return (byValue == null)? DEFAULT_BY_VALUE : byValue.get();
    }

    public final DoubleProperty byValueProperty() {
        if (byValue == null) {
            byValue = new SimpleDoubleProperty(this, "byValue", DEFAULT_BY_VALUE);
        }
        return byValue;
    }

    
The constructor of FadeTransition 
Params:
duration –  The duration of the FadeTransition
node –  The node which opacity will be animated/**
     * The constructor of {@code FadeTransition}
     *
     * @param duration
     *            The duration of the {@code FadeTransition}
     * @param node
     *            The {@code node} which opacity will be animated
     */
    public FadeTransition(Duration duration, Node node) {
        setDuration(duration);
        setNode(node);
        setCycleDuration(duration);
    }

    
The constructor of FadeTransition 
Params:
duration –  The duration of the FadeTransition/**
     * The constructor of {@code FadeTransition}
     *
     * @param duration
     *            The duration of the {@code FadeTransition}
     */
    public FadeTransition(Duration duration) {
        this(duration, null);
    }

    
The constructor of FadeTransition /**
     * The constructor of {@code FadeTransition}
     */
    public FadeTransition() {
        this(DEFAULT_DURATION, null);
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    protected void interpolate(double frac) {
        final double newOpacity = Math.max(0.0,
                Math.min(start + frac * delta, 1.0));
        cachedNode.setOpacity(newOpacity);
    }

    private Node getTargetNode() {
        final Node node = getNode();
        return (node != null) ? node : getParentTargetNode();
    }

    @Override
    boolean startable(boolean forceSync) {
        return super.startable(forceSync)
                && ((getTargetNode() != null) || (!forceSync && (cachedNode != null)));
    }

    @Override
    void sync(boolean forceSync) {
        super.sync(forceSync);
        if (forceSync || (cachedNode == null)) {
            cachedNode = getTargetNode();
            final double _fromValue = getFromValue();
            final double _toValue = getToValue();
            start = (!Double.isNaN(_fromValue)) ? Math.max(0,
                    Math.min(_fromValue, 1)) : cachedNode.getOpacity();
            delta = (!Double.isNaN(_toValue)) ? _toValue - start : getByValue();
            if (start + delta > 1.0) {
                delta = 1.0 - start;
            } else if (start + delta < 0.0) {
                delta = -start;
            }
        }
    }
}