java - 在 Java Swing 中显示运动图像

Question

我正在尝试在 Java Swing 中显示高宽度图像(例如 2000x100，如心率条)。当它稍微向左移动时，我只需要显示一个 500 宽度的窗口。我目前的代码(有点复杂，它也有不必要的动画)做到了，但我需要添加的功能是:图像的结尾应该与图像的开头连接起来。所以它总是一遍又一遍地重复显示。

总之，我需要加入图像的两端!我该怎么做？

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);
                JPanel j = new JPanel();
                j.add(new AnimatedBar(true));
                frame.add(j);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }
}

class AnimatedBar extends JPanel {

    private BufferedImage img;

    private Timer timer;
    private long startTime = -1;
    private int playTime = 4000;
    private int window = 500;
    private int moveX=0;
    public static boolean keepRunning=true;

    private float progress;

    public AnimatedBar(boolean x) {
        try {
            if(x)
                img = ImageIO.read(new File("strip2.jpg"));
            else
                img=null;
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        if(x){
            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(50, 50) : new Dimension(img.getWidth()/3, 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, 500, 0, this);
        g2d.drawImage(img,0,0,500,100,(moveX++),0,window+moveX,100,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;

    }

    public void setImg(BufferedImage img) {
        this.img = img;
    }

    @Override
    protected void paintComponent(Graphics g) {
        if(keepRunning==false){
            img=null;
        }
        else{
            try {
                img = ImageIO.read(new File("strip2.jpg"));
            } catch (IOException e) {
            }
        }
            super.paintComponent(g);
            if (img != null) {
                Graphics2D g2d = (Graphics2D) g.create();
                int y = (getHeight() - img.getHeight()) / 2;
                int x = (getWidth() - img.getWidth()/3) / 2;
                g2d.drawImage(generateImage(), x, y, this);

                g2d.dispose();
        }
    }

}

Answer 1

要连接两端，将图像绘制两次，如 this answer 中所示.第一次绘画将是图像的结尾。第二次绘制将是图像的开始，偏移到结束的宽度。

例如

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

import java.net.URL;
import javax.imageio.ImageIO;

public class HeartBeat {

    public static void main(String[] args) throws Exception {
        URL url = new URL("http://i.stack.imgur.com/i8UJD.jpg");
        final BufferedImage bi = ImageIO.read(url);
        Runnable r = new Runnable() {

            @Override
            public void run() {
                final BufferedImage canvas = new BufferedImage(
                        bi.getWidth(), bi.getHeight(),
                        BufferedImage.TYPE_INT_RGB);
                final JLabel animationLabel = new JLabel(new ImageIcon(canvas));
                ActionListener animator = new ActionListener() {

                    int x = 0;

                    @Override
                    public void actionPerformed(ActionEvent e) {
                        Graphics2D g = canvas.createGraphics();

                        // paint last part of image in left of canvas
                        g.drawImage(bi, x, 0, null);
                        // paint first part of image immediately to the right
                        g.drawImage(bi, x + bi.getWidth(), 0, null);

                        // reset x to prevent hitting integer overflow
                        if (x%bi.getWidth()==0) x = 0;

                        g.dispose();
                        animationLabel.repaint();
                        x--;
                    }
                };
                Timer timer = new Timer(40, animator);
                timer.start();
                JOptionPane.showMessageDialog(null, animationLabel);
                timer.stop();
            }
        };
        // Swing GUIs should be created and updated on the EDT
        // http://docs.oracle.com/javase/tutorial/uiswing/concurrency
        SwingUtilities.invokeLater(r);
    }
}