// ===== pom.xml =====
<project xmlns="http://maven.apache.org/POM/4.0.0" …>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.example</groupId>
  <artifactId>fade-animation</artifactId>
  <version>1.0.0</version>
</project>
 
// ===== src/main/java/com/example/fade/EasingFunction.java =====
package com.example.fade;
 
/** 緩動(dòng)函數(shù)接口 */
public interface EasingFunction {
    /** @param t 進(jìn)度 [0,1], @return eased 進(jìn)度 */
    double apply(double t);
}
 
// ===== src/main/java/com/example/fade/Easings.java =====
package com.example.fade;
 
/** 常用緩動(dòng)函數(shù)實(shí)現(xiàn) */
public class Easings {
    public static final EasingFunction LINEAR = t -> t;
    public static final EasingFunction EASE_IN_QUAD = t -> t * t;
    public static final EasingFunction EASE_OUT_QUAD = t -> t * (2 - t);
    public static final EasingFunction EASE_IN_OUT_CUBIC = t ->
        t < 0.5 ? 4 * t * t * t : 1 - Math.pow(-2 * t + 2, 3) / 2;
    // 更多...
}
 
// ===== src/main/java/com/example/fade/FadeListener.java =====
package com.example.fade;
 
/** 動(dòng)畫監(jiān)聽器 */
public interface FadeListener {
    void onStart();
    void onFrame(double progress);
    void onPause();
    void onResume();
    void onComplete();
}
 
// ===== src/main/java/com/example/fade/FadeAnimation.java =====
package com.example.fade;
 
public interface FadeAnimation {
    void fadeIn();
    void fadeOut();
    void pause();
    void resume();
    void stop();
    void setDuration(long millis);
    void setEasing(EasingFunction easing);
    void addListener(FadeListener listener);
    boolean isRunning();
}
 
// ===== src/main/java/com/example/fade/SwingFadeLabel.java =====
package com.example.fade;
 
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
 
/**
 * Swing 實(shí)現(xiàn)的淡入淡出組件，繼承 JLabel
 */
public class SwingFadeLabel extends JLabel implements FadeAnimation {
    private BufferedImage image;
    private long duration = 1000;
    private EasingFunction easing = Easings.LINEAR;
    private javax.swing.Timer timer;
    private long startTime;
    private boolean fadeInMode;
    private List<FadeListener> listeners = new ArrayList<>();
 
    public SwingFadeLabel(BufferedImage img) {
        this.image = img;
        setPreferredSize(new Dimension(img.getWidth(), img.getHeight()));
        setOpaque(false);
        initTimer();
    }
 
    private void initTimer() {
        timer = new javax.swing.Timer(16, new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                long now = System.currentTimeMillis();
                double t = (now - startTime) / (double) duration;
                if (t >= 1) t = 1;
                double progress = easing.apply(fadeInMode ? t : (1 - t));
                for (FadeListener l : listeners) l.onFrame(progress);
                repaint();
                if (t >= 1) {
                    timer.stop();
                    for (FadeListener l : listeners) {
                        if (fadeInMode) l.onComplete(); else l.onComplete();
                    }
                }
            }
        });
    }
 
    @Override protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g.create();
        float alpha = 1f;
        if (timer.isRunning()) {
            long now = System.currentTimeMillis();
            double t = (now - startTime) / (double) duration;
            if (t > 1) t = 1;
            alpha = (float) (fadeInMode ? easing.apply(t) : easing.apply(1 - t));
        }
        g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, alpha));
        g2.drawImage(image, 0, 0, null);
        g2.dispose();
    }
 
    @Override public void fadeIn() {
        fadeInMode = true; startTime = System.currentTimeMillis();
        for (FadeListener l : listeners) l.onStart(); timer.start();
    }
    @Override public void fadeOut() {
        fadeInMode = false; startTime = System.currentTimeMillis();
        for (FadeListener l : listeners) l.onStart(); timer.start();
    }
    @Override public void pause() { timer.stop(); listeners.forEach(FadeListener::onPause); }
    @Override public void resume() { startTime = System.currentTimeMillis() - (long)(duration * getCurrentProgress()); timer.start(); listeners.forEach(FadeListener::onResume); }
    @Override public void stop() { timer.stop(); listeners.forEach(FadeListener::onComplete); }
    @Override public void setDuration(long millis) { this.duration = millis; }
    @Override public void setEasing(EasingFunction easing) { this.easing = easing; }
    @Override public void addListener(FadeListener listener) { this.listeners.add(listener); }
    @Override public boolean isRunning() { return timer.isRunning(); }
 
    private double getCurrentProgress() {
        long now = System.currentTimeMillis();
        double t = (now - startTime) / (double) duration;
        if (t < 0) t = 0; if (t > 1) t = 1;
        return easing.apply(fadeInMode ? t : (1 - t));
    }
}
 
// ===== src/main/java/com/example/fade/FxFadeImageView.java =====
package com.example.fade;
 
import javafx.animation.AnimationTimer;
import javafx.scene.image.ImageView;
import javafx.scene.image.Image;
import java.util.ArrayList;
import java.util.List;
 
/**
 * JavaFX 實(shí)現(xiàn)的淡入淡出組件，基于 ImageView
 */
public class FxFadeImageView extends ImageView implements FadeAnimation {
    private long duration = 1000_000_000; // 納秒
    private EasingFunction easing = Easings.LINEAR;
    private List<FadeListener> listeners = new ArrayList<>();
    private AnimationTimer timer;
    private long startTime;
    private boolean fadeInMode;
 
    public FxFadeImageView(Image img) {
        super(img);
        initAnimation();
    }
 
    private void initAnimation() {
        timer = new AnimationTimer() {
            @Override public void handle(long now) {
                double t = (now - startTime) / (double) duration;
                if (t >= 1) t = 1;
                double p = easing.apply(fadeInMode ? t : (1 - t));
                setOpacity(p);
                listeners.forEach(l -> l.onFrame(p));
                if (t >= 1) {
                    stop();
                    listeners.forEach(FadeListener::onComplete);
                }
            }
        };
    }
 
    @Override public void fadeIn() {
        fadeInMode = true; startTime = System.nanoTime();
        listeners.forEach(FadeListener::onStart); timer.start();
    }
    @Override public void fadeOut() {
        fadeInMode = false; startTime = System.nanoTime();
        listeners.forEach(FadeListener::onStart); timer.start();
    }
    @Override public void pause() { timer.stop(); listeners.forEach(FadeListener::onPause); }
    @Override public void resume() { startTime = System.nanoTime() - (long)(duration * getCurrentProgress()); timer.start(); listeners.forEach(FadeListener::onResume); }
    @Override public void stop() { timer.stop(); listeners.forEach(FadeListener::onComplete); }
    @Override public void setDuration(long ms) { this.duration = ms * 1_000_000L; }
    @Override public void setEasing(EasingFunction easing) { this.easing = easing; }
    @Override public void addListener(FadeListener listener) { this.listeners.add(listener); }
    @Override public boolean isRunning() { return timer != null; }
 
    private double getCurrentProgress() {
        double t = (System.nanoTime() - startTime) / (double) duration;
        if (t < 0) t = 0; if (t > 1) t = 1;
        return easing.apply(fadeInMode ? t : (1 - t));
    }
}
 
// ===== src/main/java/com/example/ui/SwingDemo.java =====
package com.example.ui;
 
import com.example.fade.*;
import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.image.BufferedImage;
import java.io.File;
 
/** Swing 演示 */
public class SwingDemo {
    public static void main(String[] args) throws Exception {
        BufferedImage img = ImageIO.read(new File("demo.png"));
        SwingFadeLabel fadeLabel = new SwingFadeLabel(img);
        fadeLabel.setDuration(2000);
        fadeLabel.setEasing(Easings.EASE_IN_OUT_CUBIC);
        fadeLabel.addListener(new FadeListener() {
            public void onStart()   { System.out.println("Swing Start"); }
            public void onFrame(double p) { /* 可更新進(jìn)度條 */ }
            public void onPause()   { System.out.println("Swing Pause"); }
            public void onResume()  { System.out.println("Swing Resume"); }
            public void onComplete(){ System.out.println("Swing Complete"); }
        });
 
        JFrame f = new JFrame("Swing 淡入淡出示例");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(fadeLabel);
        f.pack(); f.setLocationRelativeTo(null); f.setVisible(true);
        fadeLabel.fadeIn();
    }
}
 
// ===== src/main/java/com/example/ui/FxDemo.java =====
package com.example.ui;
 
import com.example.fade.*;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.stage.Stage;
 
/** JavaFX 演示 */
public class FxDemo extends Application {
    @Override public void start(Stage stage) throws Exception {
        Image img = new Image("file:demo.png");
        FxFadeImageView fadeView = new FxFadeImageView(img);
        fadeView.setDuration(2000);
        fadeView.setEasing(Easings.EASE_OUT_QUAD);
        fadeView.addListener(new FadeListener() {
            public void onStart()   { System.out.println("FX Start"); }
            public void onFrame(double p) { /* 更新 UI */ }
            public void onPause()   { System.out.println("FX Pause"); }
            public void onResume()  { System.out.println("FX Resume"); }
            public void onComplete(){ System.out.println("FX Complete"); }
        });
 
        Scene scene = new Scene(new StackPane(fadeView), img.getWidth(), img.getHeight());
        stage.setTitle("JavaFX 淡入淡出示例");
        stage.setScene(scene); stage.show();
        fadeView.fadeIn();
    }
    public static void main(String[] args){ launch(); }
}