在 Java 中旋转 BufferedImage 而不改变大小

Question

我正在尝试在 Java 中旋转 BufferedImage 而不改变大小。宽度 = 232 高度 = 174

宽度 = 232 高度 = 174

我使用此代码，但我的图像不旋转：

AffineTransform at = new AffineTransform();
at.translate(four2.getWidth() / 2, four2.getHeight() / 2);
at.rotate(Math.PI/2);
at.scale(0.5, 0.5);
at.translate(-four2.getWidth()/2, -four2.getHeight()/2);
Graphics2D g2d = (Graphics2D) four2.getGraphics();
g2d.drawImage(four2, at, null);
g2d.dispose();

Answer 1

在相同边界内旋转非正方形图像将裁剪图像。

您可以更改 Graphics 裁剪边界，但这是危险的，因为您实际上最终可能会在 Graphics 上下文可用的可见边界之外进行绘制，这会导致一些非常奇怪的结果并且通常不受欢迎的结果。

一个更简单的解决方案可能是从原始图像生成新图像并在其自身范围内旋转它，例如...

import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
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.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Test {

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

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

                try {
                    JFrame frame = new JFrame("Testing");
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    frame.add(new TestPane());
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException iOException) {
                    iOException.printStackTrace();
                }
            }
        });
    }

    public class TestPane extends JPanel {

        private BufferedImage master;
        private BufferedImage rotated;

        public TestPane() throws IOException {
            master = ImageIO.read(new File("/Volumes/Disk02/Dropbox/MegaTokyo/issue142.jpg"));
            rotated = new BufferedImage(master.getWidth(), master.getHeight(), BufferedImage.TYPE_INT_ARGB);
            Graphics2D g2d = rotated.createGraphics();
            AffineTransform at = new AffineTransform();
            at.rotate(Math.PI / 2, master.getWidth() / 2, master.getHeight() / 2);
            g2d.setTransform(at);
            g2d.drawImage(master, 0, 0, this);
            g2d.dispose();
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(master.getWidth() * 2, master.getHeight());
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            int x = (getWidth() - (master.getWidth() * 2)) / 2;
            int y = (getHeight() - master.getHeight()) / 2;
            g2d.drawImage(master, x, y, this);
            g2d.drawImage(rotated, x + master.getWidth(), y, this);
            g2d.dispose();
        }

    }

}

在 Java 中旋转 BufferedImage 而不改变大小

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