在 Java 中旋转缓冲图像 [英] Rotate a buffered image in Java

问题描述

我正在尝试在 java 中旋转缓冲图像.这是我正在使用的代码:

public static BufferedImage rotate(BufferedImage bimg, double angle) {int w = bimg.getWidth();int h = bimg.getHeight();Graphics2D 图形 = bimg.createGraphics();图形.旋转(Math.toRadians(角度)，w/2，h/2)；图形.drawImage(bimg, null, 0, 0);图形.dispose();返回 bimg；}

我查看了有关此主题的大量堆栈溢出问题和答案，但无法弄清楚为什么图像会像我尝试旋转它时那样被切碎.这是一个显示加载图像的示例:

还有这段代码……

package javaapplication1.pkg040;导入 java.awt.Color；导入 java.awt.Dimension；导入 java.awt.EventQueue；导入 java.awt.Graphics；导入 java.awt.Graphics2D；导入 java.awt.event.ActionEvent；导入 java.awt.event.ActionListener；导入 java.awt.geom.AffineTransform；导入 java.awt.image.BufferedImage；导入java.io.File；导入 java.io.IOException；导入 javax.imageio.ImageIO；导入 javax.swing.JFrame；导入 javax.swing.JPanel；导入 javax.swing.Timer；导入 javax.swing.UIManager；导入 javax.swing.UnsupportedLookAndFeelException;公共类测试{公共静态无效主要(字符串[]参数){新测试()；}公共测试(){EventQueue.invokeLater(new Runnable() {@覆盖公共无效运行(){尝试 {UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());} 捕捉(ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex){ex.printStackTrace();}JFrame frame = new JFrame("Testing");frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.add(new TestPane());框架.pack();frame.setLocationRelativeTo(null);frame.setVisible(true);}});}公共类 TestPane 扩展 JPanel {私有 BufferedImage 主控；私有 BufferedImage 旋转；公共TestPane(){尝试 {master = ImageIO.read(new File("/Volumes/Disk02/Dropbox/MegaTokyo/Miho_Small.png"));旋转 = rotateImageByDegrees(master, 0.0);} 捕捉(IOException ex){ex.printStackTrace();}定时器 timer = new Timer(40, new ActionListener() {私人双角= 0；私人双三角洲= 1.0；@覆盖公共无效actionPerformed(ActionEvent e){角度 += 增量；旋转 = rotateImageByDegrees(主，角度)；重绘()；}});计时器.start();}@覆盖公共维度 getPreferredSize() {返回大师==空?新维度(200, 200):新维度(master.getWidth()，master.getHeight())；}@覆盖受保护的无效paintComponent(图形g){super.paintComponent(g);如果(旋转！= null){Graphics2D g2d = (Graphics2D) g.create();int x = (getWidth() - rotate.getWidth())/2;int y = (getHeight() - rotate.getHeight())/2;g2d.drawImage(旋转，x，y，这个)；g2d.dispose();}}公共 BufferedImage rotateImageByDegrees(BufferedImage img，双角){双弧度 = Math.toRadians(角度);双罪 = Math.abs(Math.sin(rads)), cos = Math.abs(Math.cos(rads));int w = img.getWidth();int h = img.getHeight();int newWidth = (int) Math.floor(w * cos + h * sin);int newHeight = (int) Math.floor(h * cos + w * sin);BufferedImage 旋转 = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_ARGB);Graphics2D g2d = 旋转的.createGraphics();AffineTransform at = new AffineTransform();at.translate((newWidth - w)/2, (newHeight - h)/2);整数 x = w/2;整数 y = h/2;at.rotate(rads, x, y);g2d.setTransform(at);g2d.drawImage(img, 0, 0, 这个);g2d.dispose();旋转返回；}}}

我可以生成类似...

I am trying to rotate a buffered image in java. Here is the code I am using:

public static BufferedImage rotate(BufferedImage bimg, double angle) {
    int w = bimg.getWidth();
    int h = bimg.getHeight();
    Graphics2D graphic = bimg.createGraphics();
    graphic.rotate(Math.toRadians(angle), w / 2, h / 2);
    graphic.drawImage(bimg, null, 0, 0);
    graphic.dispose();
    return bimg;
}

I have looked a numerous stack overflow questions and answers on this topic and not been able to figure out why the image is chopped up the way it is when I try to rotate it. Here is an example showing a loaded image: loaded image

After I click the rotate button which calls the above function with the buffered image and a 90.0 for the angle: chopped up image

Can someone help me understand what is happening and how to fix it?

解决方案

As always, the Internet to the rescue. So, this is some code which I hobbled together from other resources/post/blogs which will return a new image which is sized so it will contain the rotated image

public BufferedImage rotateImageByDegrees(BufferedImage img, double angle) {
    double rads = Math.toRadians(angle);
    double sin = Math.abs(Math.sin(rads)), cos = Math.abs(Math.cos(rads));
    int w = img.getWidth();
    int h = img.getHeight();
    int newWidth = (int) Math.floor(w * cos + h * sin);
    int newHeight = (int) Math.floor(h * cos + w * sin);

    BufferedImage rotated = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_ARGB);
    Graphics2D g2d = rotated.createGraphics();
    AffineTransform at = new AffineTransform();
    at.translate((newWidth - w) / 2, (newHeight - h) / 2);

    int x = w / 2;
    int y = h / 2;

    at.rotate(rads, x, y);
    g2d.setTransform(at);
    g2d.drawImage(img, 0, 0, this);
    g2d.setColor(Color.RED);
    g2d.drawRect(0, 0, newWidth - 1, newHeight - 1);
    g2d.dispose();

    return rotated;
}

Updated

So, using this PNG:

And this code...

package javaapplication1.pkg040;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
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.Timer;
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();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private BufferedImage master;
        private BufferedImage rotated;

        public TestPane() {
            try {
                master = ImageIO.read(new File("/Volumes/Disk02/Dropbox/MegaTokyo/Miho_Small.png"));
                rotated = rotateImageByDegrees(master, 0.0);
            } catch (IOException ex) {
                ex.printStackTrace();
            }

            Timer timer = new Timer(40, new ActionListener() {
                private double angle = 0;
                private double delta = 1.0;

                @Override
                public void actionPerformed(ActionEvent e) {
                    angle += delta;
                    rotated = rotateImageByDegrees(master, angle);
                    repaint();
                }
            });
            timer.start();
        }

        @Override
        public Dimension getPreferredSize() {
            return master == null
                         ? new Dimension(200, 200)
                         : new Dimension(master.getWidth(), master.getHeight());
        }

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

        public BufferedImage rotateImageByDegrees(BufferedImage img, double angle) {

            double rads = Math.toRadians(angle);
            double sin = Math.abs(Math.sin(rads)), cos = Math.abs(Math.cos(rads));
            int w = img.getWidth();
            int h = img.getHeight();
            int newWidth = (int) Math.floor(w * cos + h * sin);
            int newHeight = (int) Math.floor(h * cos + w * sin);

            BufferedImage rotated = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_ARGB);
            Graphics2D g2d = rotated.createGraphics();
            AffineTransform at = new AffineTransform();
            at.translate((newWidth - w) / 2, (newHeight - h) / 2);

            int x = w / 2;
            int y = h / 2;

            at.rotate(rads, x, y);
            g2d.setTransform(at);
            g2d.drawImage(img, 0, 0, this);
            g2d.dispose();

            return rotated;
        }
    }

}

I can generate something like...

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