如何用 Graphics2D 创建的形状裁剪 BufferedImage？(Java)

Question

目前，我正在开发我的第一个 Java 应用程序，用户可以使用它浏览照片、剪切照片和旋转照片。我在裁剪图像时遇到问题。我想要实现的是：

用户点击 "Cut" 选项
重绘方法调用的矩形出现在图像上
通过拉伸矩形用户选择切割区域
当用户释放鼠标（停止拉伸矩形）时，矩形包围的区域将保留下来，图像的其余部分将被剪切。

目前我有几个问题：

我的图像集中在 JLabel 上，它又被添加到 JPanel，最后一个被添加到 JFrame，所以现在，当我想在 JLable 上方添加一个矩形时（因此它位于图片上）它是不可见的，只能直接添加到 JPanel 上。
我用 paintComponent 画了一个图像，但不知道如何移动和拉伸它并重新绘制矩形。

下面是我的代码部分（我希望）能更准确地描述我的问题：

public class GraphicalUserInterface {


static JPanel background;
static JLabel labelIcon;

public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
        @Override
        public void run() {
            new GraphicalUserInterface().go();
        }
    });
}


public void go() {
    buildGui();
}

public void buildGui() {

    frame = new JFrame("PicMove");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    BorderLayout layout = new BorderLayout();
    background = new JPanel(layout);

   /**To center picture on the background**/
    labelIcon = new JLabel();
    labelIcon.setHorizontalAlignment(JLabel.CENTER);
    labelIcon.setVerticalAlignment(JLabel.CENTER);

    background.add(BorderLayout.SOUTH, bottom);
    background.add(BorderLayout.PAGE_START, bar);
    background.add(BorderLayout.CENTER, labelIcon);
    background.add(BorderLayout.EAST, chatPanel);

    frame.getContentPane().add(BorderLayout.CENTER, background);
    frame.setJMenuBar(menuBar);
    frame.setVisible(true);
    frame.setSize(1300, 1200);}


static class CutImage extends JPanel implements Runnable {
    boolean clip;

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);

        Graphics2D g2d = (Graphics2D) g;

        if (clip) {
            BasicStroke bs = new BasicStroke(50, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER,
                    10, null, 0);
            g2d.setStroke(bs);
            QuadCurve2D.Float qc = new QuadCurve2D.Float(20, 50, 100, 140, 460, 170);
            g2d.setClip(qc);
        }
        BasicStroke bs = new BasicStroke(5, BasicStroke.CAP_BUTT, BasicStroke.JOIN_MITER,
                10, new float[]{10}, 0);
        g2d.setStroke(bs);
        g2d.drawRect(260, 50, 80, 120);

    }

    @Override
    public void run() {
        CutImage cutPanel = new CutImage();
        GraphicalUserInterface.background.add(cutPanel).repaint();
    }
}
public class PicChanges implements Runnable{

static BufferedImage newImage;
static File [] selectedFile;
static int currentImage;



FileNameExtensionFilter filter;
JFileChooser fileChooser;

public void openPic() {
    currentImage = 0;
    try {
        fileChooser = new JFileChooser();
        fileChooser.setCurrentDirectory(new java.io.File((System.getProperty("user.home"))));
        filter = new FileNameExtensionFilter("*.images", "jpg", "gif", "png");
        fileChooser.addChoosableFileFilter(filter);
        fileChooser.setMultiSelectionEnabled(true);
        int result = fileChooser.showOpenDialog(null);
        if (result == JFileChooser.OPEN_DIALOG) {
            selectedFile = fileChooser.getSelectedFiles();
            for (File image : selectedFile) {
                if ((image.isFile()) && (selectedFile.length > 0)){
                    newImage = ImageIO.read(selectedFile[0]);
                    GraphicalUserInterface.labelIcon.setIcon(new ImageIcon(
                            new ImageIcon(newImage).getImage().getScaledInstance(
                                    450, 620, Image.SCALE_DEFAULT)));
                } else if (result == JFileChooser.CANCEL_OPTION) {
                    System.out.println("No Pics Selected");
                }
            }
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}
@Override
public void run() {
    Thread.currentThread().interrupt();
    openPic();
}

public static void nextPic() {
    currentImage++;
    try {
        newImage = ImageIO.read(selectedFile[currentImage]);
    } catch (IOException e) {
        e.printStackTrace();
        System.out.println("No pictures left");
        System.out.println("next"+currentImage);
    }
    GraphicalUserInterface.labelIcon.setIcon(new ImageIcon(
            new ImageIcon(newImage).getImage().getScaledInstance(
                    450, 620, Image.SCALE_DEFAULT)));
}

static class NextPicture implements Runnable{
    @Override
    public void run() {
        Thread.currentThread().interrupt();
        nextPic();
    }
}

public static void previousPic () {
    currentImage--;
    try {
        newImage = ImageIO.read(selectedFile[currentImage]);
    } catch (IOException e) {
        e.printStackTrace();
        System.out.println("previous "+currentImage);
    }
    GraphicalUserInterface.labelIcon.setIcon(new ImageIcon(
            new ImageIcon(newImage).getImage().getScaledInstance(
                    450, 620, Image.SCALE_DEFAULT)));
}

static class PreviousPic implements Runnable{
    @Override
    public void run() {
        Thread.currentThread().interrupt();
        previousPic();
    }
}
}

我的想法是添加 MouseListeners，但我可以将它添加到使用 Graphics2D 创建的形状吗？我将不胜感激 :) 谢谢

Answer 1

在寻找这个问题的解决方案时，我又问了两个问题（也许对某人有帮助）：

1)

2)

这进一步帮助我找到了出路。我的解决方案是创建一个单独的框架，用于在其中显示复制的 BufferedImage，并在此框架上借助 MouseListeners 绘制一个矩形。这是一段代码：

public class ImageScreenShot extends JFrame implements MouseListener, MouseMotionListener {

@Override
public Dimension getPreferredSize() {
    return super.getPreferredSize();
}

private static Thread screenShotThread;

public static Thread getScreenShotThread() {
    return screenShotThread;
}

public static void setScreenShotThread(Thread screenShot) {
    ImageScreenShot.screenShotThread = screenShot;
}

private int drag_status = 0, c1, c2, c3, c4;

public int getC1() {
    return c1;
}

public int getC2() {
    return c2;
}

public int getC3() {
    return c3;
}

public int getC4() {
    return c4;
}

class AdditionalPanel extends JLabel {
    private BufferedImage img;

    public BufferedImage getImg() {
        return img;
    }

    public AdditionalPanel(BufferedImage img) {
        this.img = img;
        setPreferredSize(new Dimension(2560, 1600));
        getPreferredSize();
        setLayout(null);
    }

    @Override
    public Dimension getPreferredSize() {
        return super.getPreferredSize();
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(img, 0, 0, null);
        System.out.println("Additional panel class paint method was invoked");
    }
}

public void cut() {
    AdditionalPanel apanel = new AdditionalPanel(PicChanges.getNewImage());
    JScrollPane scrollPane = new JScrollPane(apanel);
    scrollPane.addMouseMotionListener(this);
    scrollPane.addMouseListener(this);
    getContentPane().add(scrollPane, BorderLayout.CENTER);
    setPreferredSize(new Dimension(2560, 1600));
    getPreferredSize();
    pack();
    setVisible(true);
}

private void draggedScreen() throws Exception {
    int w = c1 - c3;
    int h = c2 - c4;
    w = w * -1;
    h = h * -1;
    Robot robot = new Robot();
    BufferedImage img = robot.createScreenCapture(new Rectangle(c1, c2, w, h));
    File save_path = new File("screen1.jpg");
    ImageIO.write(img, "JPG", save_path);
    GraphicalUserInterface.getLabelIcon().setIcon(new ImageIcon(new ImageIcon(img).getImage().getScaledInstance(img.getWidth(), img.getHeight(), Image.SCALE_SMOOTH)));
    JOptionPane.showConfirmDialog(this, "Would you like to save your cropped Pic?");
    System.out.println("Cropped image saved successfully.");
}

@Override
public void mouseClicked(MouseEvent arg0) {
}

@Override
public void mouseEntered(MouseEvent arg0) {
}

@Override
public void mouseExited(MouseEvent arg0) {
}

@Override
public void mousePressed(MouseEvent arg0) {
    repaint();
    c1 = arg0.getXOnScreen();
    c2 = arg0.getYOnScreen();
    System.out.println("pressed");
}

@Override
public void mouseReleased(MouseEvent arg0) {
    repaint();
    if (drag_status == 1) {
        c3 = arg0.getXOnScreen();
        c4 = arg0.getYOnScreen();
        try {
            repaint();
            draggedScreen();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

@Override
public void mouseDragged(MouseEvent arg0) {
    repaint();
    drag_status = 1;
    c3 = arg0.getXOnScreen();
    c4 = arg0.getYOnScreen();
}

@Override
public void mouseMoved(MouseEvent arg0) {
}

@Override
public void paint(Graphics g) {
    super.paint(g);
    int w = c1 - c3;
    int h = c2 - c4;
    w = w * -1;
    h = h * -1;
    if (w < 0)
        w = w * -1;
    g.setColor(Color.RED);
    g.drawRect(c1, c2, w, h);
    System.out.println("Paint component was invoked in imagescreenshot class");
}

P.S。我知道添加 JFrame 不是最好的解决方案，但我仍在寻找实现它的最佳方法，所以请不要犹豫，对我的代码发表评论并指出什么是错的或什么是好的）

如何用 Graphics2D 创建的形状裁剪 BufferedImage？(Java)

How to clip a BufferedImage with a shape created with Graphics2D?(Java)

java

graphics2d

image-clipping