Java implements adding watermarks to pictures (text watermarks or picture watermarks)

Language 2023-04-10 03:01:55 views: null

This article introduces the method of adding text watermark on the picture in java. The watermark can be a picture or text, which is easy to operate.

Table of contents

Implementation steps of adding watermark to pictures in java:
(1) Get original picture object information (local picture or network picture)
(2) Add watermark (set watermark color, font, coordinates, etc.)
(3) Process output target picture

1. Java realizes adding text watermark to pictures

1. Obtain the object information of the original image

The first step: get the picture that needs to be processed

There are usually two ways to obtain pictures:

  1. One is by downloading to the local and reading from the local (local picture);

  2. The other is to read through the network address (network picture)

1.1 Read local pictures

insert image description here
Through the code to read the pictures in the local directory (F:\image\1.png), the code is as follows:

// 读取原图片信息 得到文件
File srcImgFile = new File("F:/image/1.png");
//将文件对象转化为图片对象
Image srcImg = ImageIO.read(srcImgFile);
//获取图片的宽
int srcImgWidth = srcImg.getWidth(null);
//获取图片的高
int srcImgHeight = srcImg.getHeight(null);
System.out.println("图片的宽:"+srcImgWidth);
System.out.println("图片的高:"+srcImgHeight);

The code effect is as follows:
insert image description here

1.2 Read network pictures

//创建一个URL对象,获取网络图片的地址信息
URL url = new URL("https://pngimg.com/distr/img/ukraine.png");
//将URL对象输入流转化为图片对象 (url.openStream()方法，获得一个输入流)
Image srcImg = ImageIO.read(url.openStream());
//获取图片的宽
int srcImgWidth = srcImg.getWidth(null);
//获取图片的高
int srcImgHeight = srcImg.getHeight(null);
System.out.println("图片的宽:"+srcImgWidth);
System.out.println("图片的高:"+srcImgHeight);

The code effect is as follows:
insert image description here

2. Add watermark

Through the above steps, we have obtained the original image information, and we need to create a brush to add watermarks. Watermarks include text watermarks and image watermarks.

The brush can set the watermark color, font size, font style, etc.

BufferedImage bufImg = new BufferedImage(srcImgWidth, srcImgHeight, BufferedImage.TYPE_INT_RGB);
// 加水印
//创建画笔
Graphics2D g = bufImg.createGraphics();
//srcImg 为上面获取到的原始图片的图片对象
g.drawImage(srcImg, 0, 0, srcImgWidth, srcImgHeight, null);
//根据图片的背景设置水印颜色
g.setColor(new Color(255,255,255,128));
//设置字体  画笔字体样式为微软雅黑，加粗，文字大小为60pt
g.setFont(new Font("微软雅黑", Font.BOLD, 60));
//设置水印的坐标
//int x=200;
//int y=200;
int x=(srcImgWidth - getWatermarkLength(waterMarkContent, g)) / 2;
int y=srcImgHeight / 2;
//画出水印 第一个参数是水印内容，第二个参数是x轴坐标，第三个参数是y轴坐标
g.drawString("图片来源：https://image.baidu.com/", x, y);
g.dispose();

The getWatermarkLength method is used to calculate the length of the watermark content :

    /**
     * 获取水印文字的长度
     * @param waterMarkContent
     * @param g
     * @return
     */
    public static int getWatermarkLength(String waterMarkContent, Graphics2D g) {
    
    
        return g.getFontMetrics(g.getFont()).charsWidth(waterMarkContent.toCharArray(), 0, waterMarkContent.length());
    }

Font Description of fonts:

The constructor of the Font class is: public Font(String familyName, int style, int size)
参数说明：第一个参数为字体类型，第二个参数为字体风格，第三个参数为字体大小

The font styles are:

  • Font.PLAIN (plain)
  • Font.BOLD (bold)
  • Font.ITALIC (italics)
  • Font.BOLD+Font.ITALIC (bold italics)

size The default unit of font size is pt (pound), the larger the number, the larger the character

Note that yes 水印坐标位置. If the setting is not proper, the watermark effect will not be visible.

How to determine the watermark position?
Method 1: Set a fixed value

① First of all, we need to know the representation of the coordinates on the picture. The details are as follows:
insert image description here
②Save the picture locally, then select the picture and right-click, edit, and select the "Paint" software to open
insert image description here
③Move the mouse to the position where you want to add a watermark, and you can see the coordinate value corresponding to the mouse click position in the lower left corner. Write the program to this coordinate value.
insert image description here
Method 2: Set according to the size of the original image, such as placing it in the middle of the original image.
X-axis coordinate: (width of original image - width of watermark) / 2
Y-axis coordinate: (original image height - height of watermark) / 2

3. Get the target image

After the above operations, our picture adding text has been processed. But he is still stored in the Java object.
If we want to see the effect, we need to process it and save the picture locally.

//待存储的地址
String tarImgPath="F:/image/t.png";
// 输出图片
FileOutputStream outImgStream = new FileOutputStream(tarImgPath);
ImageIO.write(bufImg, "png", outImgStream);
System.out.println("添加水印完成");
outImgStream.flush();
outImgStream.close();

Execution effect:
Execution, there is an additional t.png image in the target directory:
insert image description here

Open t.png and you can see the added text watermark, the watermark is added successfully:
insert image description here

4. Complete the code

package com.example.listdemo.utils;

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

/**
 * 图片添加水印
 * @author qzz
 */
public class ImageUtils {
    
    

    public static void main(String[] args) throws IOException {
    
    
        // 读取原图片信息 得到文件（本地图片）
        File srcImgFile = new File("F:/image/1.png");
        //将文件对象转化为图片对象
        Image srcImg = ImageIO.read(srcImgFile);
        //获取图片的宽
        int srcImgWidth = srcImg.getWidth(null);
        //获取图片的高
        int srcImgHeight = srcImg.getHeight(null);
        System.out.println("图片的宽:"+srcImgWidth);
        System.out.println("图片的高:"+srcImgHeight);

        //创建一个URL对象,获取网络图片的地址信息（网络图片）
//        URL url = new URL("https://pngimg.com/distr/img/ukraine.png");
//        //将URL对象输入流转化为图片对象 (url.openStream()方法，获得一个输入流)
//        Image srcImg = ImageIO.read(url.openStream());
//        //获取图片的宽
//        int srcImgWidth = srcImg.getWidth(null);
//        //获取图片的高
//        int srcImgHeight = srcImg.getHeight(null);
//        System.out.println("图片的宽:"+srcImgWidth);
//        System.out.println("图片的高:"+srcImgHeight);



        BufferedImage bufImg = new BufferedImage(srcImgWidth, srcImgHeight, BufferedImage.TYPE_INT_RGB);
        // 加水印
        //创建画笔
        Graphics2D g = bufImg.createGraphics();
        //绘制原始图片
        g.drawImage(srcImg, 0, 0, srcImgWidth, srcImgHeight, null);
        //-------------------------文字水印 start----------------------------
        //根据图片的背景设置水印颜色
        g.setColor(new Color(255,255,255,128));
        //设置字体  画笔字体样式为微软雅黑，加粗，文字大小为60pt
        g.setFont(new Font("微软雅黑", Font.BOLD, 60));
        //水印内容
        String waterMarkContent="图片来源：https://image.baidu.com/";
        //设置水印的坐标(为原图片中间位置)
        int x=(srcImgWidth - getWatermarkLength(waterMarkContent, g)) / 2;
        int y=srcImgHeight / 2;
        //画出水印 第一个参数是水印内容，第二个参数是x轴坐标，第三个参数是y轴坐标
        g.drawString(waterMarkContent, x, y);
        g.dispose();
        //-------------------------文字水印 end----------------------------
        //待存储的地址
        String tarImgPath="F:/image/t.png";
        // 输出图片
        FileOutputStream outImgStream = new FileOutputStream(tarImgPath);
        ImageIO.write(bufImg, "png", outImgStream);
        System.out.println("添加水印完成");
        outImgStream.flush();
        outImgStream.close();

    }
    
    /**
     * 获取水印文字的长度
     * @param waterMarkContent
     * @param g
     * @return
     */
    public static int getWatermarkLength(String waterMarkContent, Graphics2D g) {
    
    
        return g.getFontMetrics(g.getFont()).charsWidth(waterMarkContent.toCharArray(), 0, waterMarkContent.length());
    }
}

Two, java implements adding image watermarks to images

Download the watermark image to the local:
watermark image location: F:\image\s.png
insert image description here

1. Add image watermark method:

// 水印文件
String waterMarkImage="F:/image/s.png";
Image srcWaterMark = ImageIO.read(new File(waterMarkImage));
//获取水印图片的宽度
int widthWaterMark= srcWaterMark.getWidth(null);
//获取水印图片的高度
int heightWaterMark = srcWaterMark.getHeight(null);
//设置 alpha 透明度：alpha 必须是范围 [0.0, 1.0] 之内（包含边界值）的一个浮点数字
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 0.9f));
//绘制水印图片  坐标为中间位置
g.drawImage(srcWaterMark, (srcImgWidth - widthWaterMark) / 2,
        (srcImgHeight - heightWaterMark) / 2, widthWaterMark, heightWaterMark, null);
// 水印文件结束
g.dispose();

2. Complete the code

package com.example.listdemo.utils;

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

/**
 * 图片添加水印
 * @author qzz
 */
public class ImageUtils {
    
    

    public static void main(String[] args) throws IOException {
    
    
        // 读取原图片信息 得到文件（本地图片）
        File srcImgFile = new File("F:/image/1.png");
        //将文件对象转化为图片对象
        Image srcImg = ImageIO.read(srcImgFile);
        //获取图片的宽
        int srcImgWidth = srcImg.getWidth(null);
        //获取图片的高
        int srcImgHeight = srcImg.getHeight(null);
        System.out.println("图片的宽:"+srcImgWidth);
        System.out.println("图片的高:"+srcImgHeight);

        //创建一个URL对象,获取网络图片的地址信息（网络图片）
//        URL url = new URL("https://pngimg.com/distr/img/ukraine.png");
//        //将URL对象输入流转化为图片对象 (url.openStream()方法，获得一个输入流)
//        Image srcImg = ImageIO.read(url.openStream());
//        //获取图片的宽
//        int srcImgWidth = srcImg.getWidth(null);
//        //获取图片的高
//        int srcImgHeight = srcImg.getHeight(null);
//        System.out.println("图片的宽:"+srcImgWidth);
//        System.out.println("图片的高:"+srcImgHeight);



        BufferedImage bufImg = new BufferedImage(srcImgWidth, srcImgHeight, BufferedImage.TYPE_INT_RGB);
        // 加水印
        //创建画笔
        Graphics2D g = bufImg.createGraphics();
        //绘制原始图片
        g.drawImage(srcImg, 0, 0, srcImgWidth, srcImgHeight, null);
        //-------------------------文字水印 start----------------------------
//        //根据图片的背景设置水印颜色
//        g.setColor(new Color(255,255,255,128));
//        //设置字体  画笔字体样式为微软雅黑，加粗，文字大小为60pt
//        g.setFont(new Font("微软雅黑", Font.BOLD, 60));
//        String waterMarkContent="图片来源：https://image.baidu.com/";
//        //设置水印的坐标(为原图片中间位置)
//        int x=(srcImgWidth - getWatermarkLength(waterMarkContent, g)) / 2;
//        int y=srcImgHeight / 2;
//        //画出水印 第一个参数是水印内容，第二个参数是x轴坐标，第三个参数是y轴坐标
//        g.drawString(waterMarkContent, x, y);
//        g.dispose();
        //-------------------------文字水印 end----------------------------

        //-------------------------图片水印 start----------------------------
        // 水印文件
        String waterMarkImage="F:/image/s.png";
        Image srcWaterMark = ImageIO.read(new File(waterMarkImage));
        //获取水印图片的宽度
        int widthWaterMark= srcWaterMark.getWidth(null);
        //获取水印图片的高度
        int heightWaterMark = srcWaterMark.getHeight(null);
        //设置 alpha 透明度：alpha 必须是范围 [0.0, 1.0] 之内（包含边界值）的一个浮点数字
        g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 0.9f));
        //绘制水印图片  坐标为中间位置
        g.drawImage(srcWaterMark, (srcImgWidth - widthWaterMark) / 2,
                (srcImgHeight - heightWaterMark) / 2, widthWaterMark, heightWaterMark, null);
        // 水印文件结束
        g.dispose();
        //-------------------------图片水印 end----------------------------

        //待存储的地址
        String tarImgPath="F:/image/t.png";
        // 输出图片
        FileOutputStream outImgStream = new FileOutputStream(tarImgPath);
        ImageIO.write(bufImg, "png", outImgStream);
        System.out.println("添加水印完成");
        outImgStream.flush();
        outImgStream.close();

    }
    
    /**
     * 获取水印文字的长度
     * @param waterMarkContent
     * @param g
     * @return
     */
    public static int getWatermarkLength(String waterMarkContent, Graphics2D g) {
    
    
        return g.getFontMetrics(g.getFont()).charsWidth(waterMarkContent.toCharArray(), 0, waterMarkContent.length());
    }
}

3. Code execution effect

insert image description here
The t.png image file contains a watermark image, indicating that the image watermark has been successfully added!

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Origin blog.csdn.net/qq_26383975/article/details/125996277
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