Java Canvas从BufferedImage绘制图像。

I am currently working on my personal project. The idea is to import a picture and crop it into n-pieces of bufferedimage then draw them with random sequence to a java canvas. After that save the canvas to image file. Right now iam stuck at saving the canvas and i have searching for the solutions but none of them work. Here my save procedure. Please help, thanks in advance

我目前正在做我的个人项目。其想法是导入图片并将其裁剪成n块，然后将其随机序列绘制到java画布中。然后将画布保存到图像文件中。现在我还在保存画布，我在寻找解决方案，但是没有一个能工作。在这里我保存过程。请帮忙，谢谢。

 private void save() {    
    int r = jFileChooser1.showSaveDialog(this);
    File file2 = null; 
    if(r == jFileChooser1.APPROVE_OPTION){
    file2 = jFileChooser1.getSelectedFile();

    Graphics g2d = canvas.getGraphics();    
    BufferedImage bi = new BufferedImage(300, 300, BufferedImage.TYPE_INT_RGB);  
    Graphics2D g2 = bi.createGraphics();
    canvas.paint(g2);  
    g2.dispose();  
    g2d.dispose();
    try  
    {  
        ImageIO.write(bi, "jpg", file2);  
    }  
    catch (Exception ex) {
        System.out.println("Error saving");
    }
    }
}

Update : Now i get it, after using paintComponents now i can save the picture. Thanks @madProgrammer

更新:现在我明白了，在使用了paintComponents之后，现在我可以保存图片了。由于@madProgrammer

public class CaptureImage extends javax.swing.JFrame {

MyPanel canvas;
BufferedImage[] processedImage;


public CaptureImage(BufferedImage[] proc) {
    processedImage = proc;
    SwingUtilities.invokeLater(new Runnable() {

        public void run() {
            createAndShowGUI();
        }
    });

}

private void createAndShowGUI() {
    System.out.println("Created GUI on EDT? "
            + SwingUtilities.isEventDispatchThread());
    JFrame f = new JFrame("Output Picture");
    f.addWindowListener(new WindowAdapter(){
            public void windowClosing(WindowEvent e){
                save();
                System.exit(0);//cierra aplicacion
            }
        });
    canvas = new MyPanel(processedImage);
    f.add(canvas);
    f.setSize(400, 400);
    f.setVisible(true);
}

public void save() {
    JFileChooser jFileChooser1 = new JFileChooser();
    int r = jFileChooser1.showSaveDialog(this);
    File file2 = null;
    if (r == jFileChooser1.APPROVE_OPTION) {
        file2 = jFileChooser1.getSelectedFile();

        BufferedImage bi = new BufferedImage(300, 300, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = bi.createGraphics();
        canvas.print(g2);

        try {
            ImageIO.write(bi, "jpg", file2);
            g2.dispose();
        } catch (Exception ex) {
            System.out.println("Error saving");
        }
    }
}
}


 class MyPanel extends JPanel {

private Image[] processedImage;

public MyPanel(Image[] processedImage) {
    this.processedImage = processedImage;

    addMouseListener(new MouseAdapter() {

        public void mousePressed(MouseEvent e) {
            repaint();
        }
    });

}

public Dimension getPreferredSize() {
    return new Dimension(300, 300);
}

public void paintComponent(Graphics g) {
    super.paintComponent(g);
    int loopj = 10;
    int loopi = 10;
    int l = 0;
    int jPieces = 100;
    int[] r = new int[jPieces];
    int rand = 0;
    for (int i = 0; i < r.length; i++) {
        rand = (int) (Math.random() * (r.length));
        if (Arrays.binarySearch(r, 0, r.length, rand) <= -1) {
            r[i] = rand;
        }
    }
    Graphics2D g2d = (Graphics2D) g;
    for (int i = 0; i < loopi; i++) {
        for (int j = 0; j < loopj; j++) {
            g2d.drawImage(processedImage[r[l]], i * 30, j * 30, this);
            l++;
        }
    }
}
}

1 个解决方案

#1

There's no need to use getGraphics and you certainly shouldn't be disposing of it.

没有必要使用getGraphics，当然也不应该处理它。

Instead of using paint, which could include double buffering, you should try using printAll

您应该尝试使用printAll，而不是使用可以包含双缓冲的油漆。

BufferedImage bi = new BufferedImage(canvas.getWidth(), canvas.getHeight(), BufferedImage.TYPE_INT_RGB);  
Graphics2D g2 = bi.createGraphics();
canvas.printAll(g2);  
g2.dispose();

See Component#printAll for more details.

有关详细信息，请参阅组件#printAll。

You should also be using the size of the canvas to determine the size of the image. The above example assumes that the canvas has already been sized appropriately...

您还应该使用画布的大小来确定图像的大小。上面的例子假设画布已经适当地大小了…

#1