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java 如何旋转图片

2026-02-05 07:32:11Java

旋转图片的方法

在Java中旋转图片可以通过多种方式实现，以下是几种常见的方法：

java 如何旋转图片

使用`AffineTransform`和`Graphics2D`

Java的Graphics2D类结合AffineTransform可以实现图片旋转。以下是一个示例代码：

java 如何旋转图片

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;

public class ImageRotator {
    public static BufferedImage rotateImage(BufferedImage image, double angle) {
        double radians = Math.toRadians(angle);
        double sin = Math.abs(Math.sin(radians));
        double cos = Math.abs(Math.cos(radians));
        int newWidth = (int) Math.round(image.getWidth() * cos + image.getHeight() * sin);
        int newHeight = (int) Math.round(image.getHeight() * cos + image.getWidth() * sin);

        BufferedImage rotated = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g2d = rotated.createGraphics();
        AffineTransform transform = new AffineTransform();
        transform.translate((newWidth - image.getWidth()) / 2, (newHeight - image.getHeight()) / 2);
        transform.rotate(radians, image.getWidth() / 2, image.getHeight() / 2);
        g2d.setTransform(transform);
        g2d.drawImage(image, 0, 0, null);
        g2d.dispose();
        return rotated;
    }

    public static void main(String[] args) throws Exception {
        BufferedImage original = ImageIO.read(new File("input.jpg"));
        BufferedImage rotated = rotateImage(original, 45);
        ImageIO.write(rotated, "jpg", new File("output.jpg"));
    }
}

使用`Thumbnailator`库

Thumbnailator是一个简化图像处理的库，可以轻松实现旋转功能：

import net.coobird.thumbnailator.Thumbnails;
import java.io.File;

public class ThumbnailatorRotate {
    public static void main(String[] args) throws Exception {
        Thumbnails.of(new File("input.jpg"))
            .scale(1)
            .rotate(90)
            .toFile(new File("output.jpg"));
    }
}

使用OpenCV

如果项目已集成OpenCV，可以使用其旋转功能：

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;

public class OpenCVRotate {
    public static void main(String[] args) {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
        Mat src = Imgcodecs.imread("input.jpg");
        Mat dst = new Mat();
        Mat rotationMatrix = Imgproc.getRotationMatrix2D(
            new org.opencv.core.Point(src.cols()/2, src.rows()/2), 45, 1);
        Imgproc.warpAffine(src, dst, rotationMatrix, src.size());
        Imgcodecs.imwrite("output.jpg", dst);
    }
}