Question

我正在使用Java的JFrame来显示.jpeg图片。选中复选框时，我需要对图像启动水平滑动效果。因此，基本上选中复选框后，图像将从左向右滑动，花费几秒钟，完成后，将永远重新开始，直到取消选中该复选框。如何添加此功能？

编辑：其实我并不是说图片本身在移动;我的意思是图片是稳定和静态的，但是图像将从左到右开始以水平滑动效果显示并重新启动。我希望它足够清楚。

这里假设我的代码是显示图像和复选框（来自Java教程）：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/*
 * CheckBoxDemo.java requires 16 image files in the images/geek
 * directory: 
 * geek-----.gif, geek-c---.gif, geek--g--.gif, geek---h-.gif, geek----t.gif,
 * geek-cg--.gif, ..., geek-cght.gif.
 */
public class CheckBoxDemo extends JPanel
                          implements ItemListener {
    JCheckBox chinButton;
    JCheckBox glassesButton;
    JCheckBox hairButton;
    JCheckBox teethButton;

    /*
     * Four accessory choices provide for 16 different
     * combinations. The image for each combination is
     * contained in a separate image file whose name indicates
     * the accessories. The filenames are "geek-XXXX.gif"
     * where XXXX can be one of the following 16 choices.
     * The "choices" StringBuffer contains the string that
     * indicates the current selection and is used to generate
     * the file name of the image to display.

       ----             //zero accessories

       c---             //one accessory
       -g--
       --h-
       ---t

       cg--             //two accessories
       c-h-
       c--t
       -gh-
       -g-t
       --ht

       -ght             //three accessories
       c-ht
       cg-t
       cgh-

       cght             //all accessories
     */

    StringBuffer choices;
    JLabel pictureLabel;

    public CheckBoxDemo() {
        super(new BorderLayout());

        //Create the check boxes.
        chinButton = new JCheckBox("Chin");
        chinButton.setMnemonic(KeyEvent.VK_C);
        chinButton.setSelected(true);

        glassesButton = new JCheckBox("Glasses");
        glassesButton.setMnemonic(KeyEvent.VK_G);
        glassesButton.setSelected(true);

        hairButton = new JCheckBox("Hair");
        hairButton.setMnemonic(KeyEvent.VK_H);
        hairButton.setSelected(true);

        teethButton = new JCheckBox("Teeth");
        teethButton.setMnemonic(KeyEvent.VK_T);
        teethButton.setSelected(true);

        //Register a listener for the check boxes.
        chinButton.addItemListener(this);
        glassesButton.addItemListener(this);
        hairButton.addItemListener(this);
        teethButton.addItemListener(this);

        //Indicates what's on the geek.
        choices = new StringBuffer("cght");

        //Set up the picture label
        pictureLabel = new JLabel();
        pictureLabel.setFont(pictureLabel.getFont().deriveFont(Font.ITALIC));
        updatePicture();

        //Put the check boxes in a column in a panel
        JPanel checkPanel = new JPanel(new GridLayout(0, 1));
        checkPanel.add(chinButton);
        checkPanel.add(glassesButton);
        checkPanel.add(hairButton);
        checkPanel.add(teethButton);

        add(checkPanel, BorderLayout.LINE_START);
        add(pictureLabel, BorderLayout.CENTER);
        setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
    }

    /** Listens to the check boxes. */
    public void itemStateChanged(ItemEvent e) {
        int index = 0;
        char c = '-';
        Object source = e.getItemSelectable();

        if (source == chinButton) {
            index = 0;
            c = 'c';
        } else if (source == glassesButton) {
            index = 1;
            c = 'g';
        } else if (source == hairButton) {
            index = 2;
            c = 'h';
        } else if (source == teethButton) {
            index = 3;
            c = 't';
        }

        //Now that we know which button was pushed, find out
        //whether it was selected or deselected.
        if (e.getStateChange() == ItemEvent.DESELECTED) {
            c = '-';
        }

        //Apply the change to the string.
        choices.setCharAt(index, c);

        updatePicture();
    }

    protected void updatePicture() {
        //Get the icon corresponding to the image.
        ImageIcon icon = createImageIcon(
                                    "images/geek/geek-"
                                    + choices.toString()
                                    + ".gif");
        pictureLabel.setIcon(icon);
        pictureLabel.setToolTipText(choices.toString());
        if (icon == null) {
            pictureLabel.setText("Missing Image");
        } else {
            pictureLabel.setText(null);
        }
    }

    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) {
        java.net.URL imgURL = CheckBoxDemo.class.getResource(path);
        if (imgURL != null) {
            return new ImageIcon(imgURL);
        } else {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("CheckBoxDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        JComponent newContentPane = new CheckBoxDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

Answer 1

最简单的解决方案是使用类似javax.swing.Timer之类的东西来推动自己...

Fly baby, fly

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class SlidingAnimation {

    public static void main(String[] args) {
        new SlidingAnimation();
    }

    public SlidingAnimation() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private BufferedImage img;
        private int x = 0;

        private Timer timer;
        private long startTime = -1;
        private int playTime = 4000;

        public TestPane() {
            try {
                img = ImageIO.read(new File("..."));
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            timer = new Timer(40, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    float progress = 0f;
                    if (startTime == -1) {
                        startTime = System.currentTimeMillis();
                    } else {
                        long currentTime = System.currentTimeMillis();
                        long diff = currentTime - startTime;

                        if (diff >= playTime) {
                            diff = 0;
                            startTime = -1;
                        }
                        progress = diff / (float)playTime;
                    }

                    x = (int)((getWidth() - img.getWidth()) * progress);
                    repaint();
                }
            });
            timer.start();
        }

        @Override
        public Dimension getPreferredSize() {
            return img == null ? new Dimension(200, 200) : new Dimension(img.getWidth() * 2, img.getHeight());
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (img != null) {
                Graphics2D g2d = (Graphics2D) g.create();
                int y = (getHeight() - img.getHeight()) / 2;
                g2d.drawImage(img, x, y, this);
                g2d.dispose();
            }
        }

    }

}

这是一个两秒循环，它根据开始时间和当前时间之间的差异以及动画需要移动的总面积来计算当前位置。这确实使它变得灵活，但它是一个直线动画，它没有很好的轻松和轻松，这给动画带来了更逼真的动作......

对于更高级的动画效果，我强烈建议您查看

The Timing Framework。提供对核心的良好访问以执行不寻常的事情，但也能够随时间更改对象属性
Trident。提供随时间更改对象属性的功能
Universal Tween Engine我还没有使用但看起来非常好。

您可能还想查看Performing Custom Painting，了解有关如何在Swing中完成自定义绘制的详细信息

<强>更新

所以，如果我理解你的评论，你想要做一个交叉淡入淡出效果。现在有几种方法可以做到这一点，你可以使用BufferedImage#subImage来获得＆＃34;裁剪＆＃34;原始图像的版本并显示，但是，恕我直言，并没有产生如此好的效果...

相反，你可以使用一种遮蔽技术，让你产生褪色效果......

enter image description here

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.LinearGradientPaint;
import java.awt.Rectangle;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Point2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class SlidingAnimation {

    public static void main(String[] args) {
        new SlidingAnimation();
    }

    public SlidingAnimation() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private BufferedImage img;

        private Timer timer;
        private long startTime = -1;
        private int playTime = 4000;

        private float progress;

        public TestPane() {
            try {
                img = ImageIO.read(new File("..."));
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            timer = new Timer(40, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    if (startTime == -1) {
                        startTime = System.currentTimeMillis();
                    } else {
                        long currentTime = System.currentTimeMillis();
                        long diff = currentTime - startTime;

                        if (diff >= playTime) {
                            diff = 0;
                            startTime = -1;
                        }
                        progress = diff / (float) playTime;
                    }

                    repaint();
                }
            });
            timer.start();
        }

        @Override
        public Dimension getPreferredSize() {
            return img == null ? new Dimension(200, 200) : new Dimension(img.getWidth(), img.getHeight());
        }

        protected BufferedImage generateImage() {

            BufferedImage buffer = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_INT_ARGB);
            Graphics2D g2d = buffer.createGraphics();
            g2d.setBackground(new Color(0, 0, 0, 0));
            g2d.clearRect(0, 0, buffer.getWidth(), buffer.getHeight());
            g2d.drawImage(img, 0, 0, this);

            float startAt = progress - 0.05f;
            float endAt = progress + 0.05f;

            if (endAt <= 0.1f) {
                startAt = 0;
                endAt = Math.max(0.1f, progress);
            } else if (endAt >= 1f) {
                endAt = 1f;
                startAt = progress;
            }

            LinearGradientPaint lgp = new LinearGradientPaint(
                    new Point2D.Float(0, 0),
                    new Point2D.Float(img.getWidth(), 0),
                    new float[]{startAt, endAt},
                    new Color[]{new Color(0, 0, 0, 0), Color.RED});

            g2d.setPaint(lgp);

            g2d.setComposite(AlphaComposite.DstOut.derive(1f));
            g2d.fill(new Rectangle(0, 0, img.getWidth(), img.getHeight()));
            g2d.dispose();

            return buffer;

        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (img != null) {
                Graphics2D g2d = (Graphics2D) g.create();
                int y = (getHeight() - img.getHeight()) / 2;
                int x = (getWidth() - img.getWidth()) / 2;
                g2d.drawImage(generateImage(), x, y, this);

                g2d.dispose();
            }
        }

    }

}

在Java JFrame中为图像添加可见性效果

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