java 图片水印工具

package com.cajc.common.utils;

import com.cajctech.common.exception.CajctechException;
import org.springframework.mock.web.MockMultipartFile;
import org.springframework.web.multipart.MultipartFile;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

/**
 * @author 图片水印工具类
 */
public class WatermarkUtils {
    // 水印透明度
    private static final float alpha = 1f;
    // 水印文字大小
    public static final int FONT_SIZE = 60; // 适中的大小
    // 水印文字字体
    private static final Font font = new Font("宋体", Font.PLAIN, FONT_SIZE);
    // 水印文字颜色
    private static final Color color = Color.white;
    // 水印之间的间隔
    private static final int XMOVE = 100; // 增加水平间距
    // 水印之间的间隔
    private static final int YMOVE = 100; // 增加垂直间距
    // 错开的距离
    private static final int OFFSET_X = 120; // 每行错开的水平距离
    // 固定的水印文字
    public static final String FIXED_WATERMARK_TEXT = "水印";

    /**
     * 获取文本长度。汉字为1:1，英文和数字为2:1
     */
    private static int getTextLength(String text) {
        int length = text.length();
        for (int i = 0; i < text.length(); i++) {
            String s = String.valueOf(text.charAt(i));
            if (s.getBytes().length > 1) {
                length++;
            }
        }
        length = length % 2 == 0 ? length / 2 : length / 2 + 1;
        return length;
    }

    /**
     * 给图片添加固定水印文字，默认旋转角度为-15度，并返回带有水印的 MultipartFile 对象
     *
     * @param multipartFile 源图片的MultipartFile对象
     * @return 带有水印的 MultipartFile 对象
     */
    public static MultipartFile addFixedWatermark(MultipartFile multipartFile) {
//        String logoText = "水印"; // 固定水印文本
        int degree = -15; // 默认旋转角度

        try (InputStream inputStream = multipartFile.getInputStream()) {
            // 读取原始图像
            BufferedImage srcImg = ImageIO.read(inputStream);
            if (srcImg == null) {
                throw new CajctechException("无法读取图像");
            }

            int width = srcImg.getWidth(); // 原图宽度
            int height = srcImg.getHeight(); // 原图高度
            BufferedImage buffImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics2D g = buffImg.createGraphics();

            // 设置图像处理选项
            g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            g.drawImage(srcImg, 0, 0, null);

            // 设置水印旋转
            g.rotate(Math.toRadians(degree), (double) buffImg.getWidth() / 2, (double) buffImg.getHeight() / 2);

            // 设置水印属性
            g.setColor(color);
            g.setFont(font);
            g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));

            // 循环添加水印
            int x = -width / 2;
            int y = -height / 2;
            int markWidth = FONT_SIZE * getTextLength(FIXED_WATERMARK_TEXT); // 字体长度
            int markHeight = FONT_SIZE; // 字体高度

            while (x < width * 1.5) {
                y = -height / 2;
                while (y < height * 1.5) {
                    int offsetY = (int) (Math.random() * 40) - 20;
                    g.drawString(FIXED_WATERMARK_TEXT, x, y + offsetY);
                    y += markHeight + YMOVE;
                }
                x += markWidth + XMOVE;
            }

            g.dispose();

            // 将带有水印的图像写入字节数组
            ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
            ImageIO.write(buffImg, "JPG", outputStream);
            byte[] watermarkedImageBytes = outputStream.toByteArray();

            // 创建并返回带有水印的 MultipartFile 对象
            return new MockMultipartFile(
                    multipartFile.getName(),
                    multipartFile.getOriginalFilename(),
                    multipartFile.getContentType(),
                    watermarkedImageBytes
            );

        } catch (Exception e) {
            e.printStackTrace();
            throw new CajctechException("添加水印失败");
        }
    }

    public static void main(String[] args) {
        try {
            // 设置输入和输出路径
            String inputImagePath = "D:\\photo\\20241030164805.jpg";
            String outputImagePath = "D:\\photo\\20241030164805.jpg";


            Path path = Paths.get(inputImagePath);
            byte[] fileContent = Files.readAllBytes(path);

            MultipartFile multipartFile = new MockMultipartFile(
                    "file",
                    new File(inputImagePath).getName(),
                    "image/jpeg",
                    fileContent
            );

            MultipartFile watermarkedMultipartFile = WatermarkUtils.addFixedWatermark(multipartFile);

            saveToFile(watermarkedMultipartFile.getBytes(), outputImagePath);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void saveToFile(byte[] bytes, String filePath) throws IOException {
        try (FileOutputStream fos = new FileOutputStream(filePath)) {
            fos.write(bytes);
        }
    }
}