BufferedImage 在旋转后被切断

Question

我的代码每次“更新”将图像旋转 0.4 度，图像在 [-10,+10] 范围内连续旋转。 问题是缓冲图像在旋转时在边缘被切断，似乎旋转改变了 bufferedImage 需要的大小但大小永远不会更新，有什么想法可以让它工作吗？

    protected double rotation = 0;
    private   double rotDir = 0.4;

    private BufferedImage getRotatedSprite(){
        if(Math.abs(rotation)>10)
            rotDir=rotDir*(-1);
        rotation+=rotDir;
        ImageIcon icon = new ImageIcon(bImage);
        BufferedImage bImg = new BufferedImage(icon.getIconWidth(), 
                   icon.getIconHeight(), BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2d= (Graphics2D)bImg.getGraphics();
        g2d.rotate(Math.toRadians(rotation), icon.getIconWidth()/2, icon.getIconHeight()/2);
        g2d.drawImage(bImage, 0, 0, null);
        return bImg;
}
   public void drawSprite(Graphics g) { 
        BufferedImage image = getRotatedSprite();

        if(customWidth != -1 && customHeight != -1){
            g.drawImage(image, (int)locX, (int)locY, customWidth, customHeight, this);
    }else
        g.drawImage(image, (int)locX, (int)locY, this);
}

Answer 1

似乎旋转改变了缓冲图像的大小

是的，大小会根据旋转角度而变化。

您可能会发现使用Rotated Icon 更容易。它为您进行旋转并重新计算大小（如有必要）。无需创建新的 BufferedImages，您只需设置旋转度数即可。

简单的例子。使用滑动条旋转图标：

import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;
import javax.swing.event.*;

public class Rotation3 extends JPanel
{
    private Icon icon;
    private RotatedIcon rotated;
    private int degrees;

    public Rotation3(Image image)
    {
        icon = new ImageIcon( image );
        rotated = new RotatedIcon(icon, 0);
//      rotated.setCircularIcon( true );
        setDegrees( 0 );
        setPreferredSize( new Dimension(600, 600) );
    }

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

        // translate x/y so Icon rotated around a specific point (300, 300)

        int x = 300 - (rotated.getIconWidth() / 2);
        int y = 300 - (rotated.getIconHeight() / 2);
        rotated.paintIcon(this, g, x, y);

        g.setColor(Color.RED);
        g.fillOval(295, 295, 10, 10);
    }

    public void setDegrees(int degrees)
    {
        this.degrees = degrees;
        rotated.setDegrees(degrees);
        repaint();
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                try
                {
//                  String path = "dukewavered.gif";
                    String path = "lunch75.jpg";
                    BufferedImage bi = ImageIO.read(Rotation3.class.getResourceAsStream(path));
                    final Rotation3 r = new Rotation3(bi);

                    final JSlider slider = new JSlider(JSlider.HORIZONTAL, 0, 360, 0);
                    slider.addChangeListener(new ChangeListener()
                    {
                        public void stateChanged(ChangeEvent e)
                        {
                            int value = slider.getValue();
                            r.setDegrees( value );
                        }
                    });

                    JFrame f = new JFrame();
                    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    f.add(new JScrollPane(r));
                    f.add(slider, BorderLayout.SOUTH);
                    f.pack();
                    f.setLocationRelativeTo(null);
                    f.setVisible(true);
                }
                catch(IOException e)
                {
                    System.out.println(e);
                }
            }
        });
    }
}