给图片加水印的工具类 以及 使用方法

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/yswKnight/article/details/80656554

给图片加水印的工具类 以及 使用方法

---

工具类代码

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;

/**
 * WaterMarkUtil
 * @Description 图片加水印工具类
 * @Date 2018-06-11 下午4:45
 */
public class WaterMarkUtil {
    private static final String FONT_FAMILY = "微软雅黑";//字体
    private static final int FONT_STYLE = Font.BOLD;//字体加粗
    private static final int FONT_SIZE = 40;//字体大小
    private static final float ALPHA = 0.2F;//水印透明度

    private static final int LOGO_WIDTH = 200;//图片水印大小

    //添加文字水印
    /*tarPath:图片保存路径
     *contents:文字水印内容* */
    public static void generateWithTextMark(File srcFile,
                                            String tarPath, String contents) throws Exception {
        Image srcImage = ImageIO.read(srcFile);
        int width = srcImage.getWidth(null);
        int height = srcImage.getHeight(null);

        BufferedImage tarBuffImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = tarBuffImage.createGraphics();
        g.drawImage(srcImage, 0, 0, width, height, null);

        //计算
        int strWidth = FONT_SIZE * getTextLength(contents);
        int strHeight = FONT_SIZE;

        //水印位置
//      int x=width-strWidth;
//      int y=height-strHeight;

        int x = 0, y = 0;

        //设置水印颜色
        g.setColor(Color.red);
        //设置水印字体
        g.setFont(new Font(FONT_FAMILY, FONT_STYLE, FONT_SIZE));
        //设置水印透明度
        g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA));
//      g.drawString(contents, x, y);
        //旋转图片
        g.rotate(Math.toRadians(-30), width / 2, height / 2);
        while (x < width * 1.5) {
            y = -height / 2;
            while (y < height * 1.5) {
                g.drawString(contents, x, y);
                y += strHeight + 200;
            }
            x += strWidth + 500; //水印之间的间隔设为200
        }
        g.dispose();

        JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(new FileOutputStream(tarPath));
        en.encode(tarBuffImage);
    }

    //添加图片水印
    /*
     * tarPath:图片保存路径
     * logoPath:logo文件路径
     * */
    public static void generateWithImageMark(File srcFile,
                                             String tarPath, String logoPath) throws Exception {
        Image srcImage = ImageIO.read(srcFile);
        int width = srcImage.getWidth(null);
        int height = srcImage.getHeight(null);

        BufferedImage tarBuffImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
        Graphics2D g = tarBuffImage.createGraphics();
        g.drawImage(srcImage, 0, 0, width, height, null);

        Image logoImage = ImageIO.read(new File(logoPath));
        int logoWidth = LOGO_WIDTH;
        int logoHeight = (LOGO_WIDTH * logoImage.getHeight(null)) / logoImage.getWidth(null);

        int x = width - logoWidth;
        int y = height - logoHeight;

        g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, ALPHA));
        g.drawImage(logoImage, x, y, logoWidth, logoHeight, null);
        g.dispose();

        JPEGImageEncoder en = JPEGCodec.createJPEGEncoder(new FileOutputStream(tarPath));
        en.encode(tarBuffImage);
    }

    //文本长度的处理：文字水印的中英文字符的宽度转换
    public 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) {  //中文字符
                length++;
            }
        }
        length = length % 2 == 0 ? length / 2 : length / 2 + 1;  //中文和英文字符的转换
        return length;
    }
}

---

使用方法

//文件路径+文件名
String pathName = path+fileName;
//根据上面文件，创建一个file对象
File targetfile = new File(pathName);
//保存上面文件
file.transferTo(targetfile);
//添加水印
WaterMarkUtil.generateWithTextMark(targetfile, pathName, "我是水印文字");

---

预览