Java批量向PDF文件中添加图像水印实现细节

<repositories>
    <repository>
        <id>com.e-iceblue</id>
        <name>e-iceblue</name>
        <url>https://repo.e-iceblue.cn/repository/maven-public/</url>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <groupId>e-iceblue</groupId>
        <artifactId>spire.pdf.free</artifactId>
        <version>5.1.0</version>
    </dependency>
</dependencies>

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;
import com.spire.pdf.graphics.PdfImage;
public class insertSingleImageWatermark {
    public static void main(String[] args) {
        //创建PdfDocument类的对象
        PdfDocument pdf = new PdfDocument();
        //载入PDF文档
        pdf.loadFromFile("sample.pdf");
        //载入图片
        PdfImage image = PdfImage.fromFile("image.png");
        //获取图片的宽度和高度用于计算插入水印的初始坐标
        int imageWidth = image.getWidth();
        int imageHeight = image.getHeight();
        //循环遍历所有页面以插入水印
        for (int i = 0; i < pdf.getPages().getCount(); i++) {
            //获取一个页面
            PdfPageBase page = pdf.getPages().get(i);
            //获取该页面的宽度和高度，用于计算插入水印的初始坐标
            float pageWidth = (float) (page.getActualSize().getWidth());
            float pageHeight = (float) (page.getActualSize().getHeight());
            //设置水印图片的透明度
            page.getCanvas().setTransparency(0.3f);
            //在页面的中间位置绘制水印图片
            page.getCanvas().drawImage(image, pageWidth/2 - imageWidth/2, pageHeight/2 - imageHeight/2, imageWidth, imageHeight);
        }
        //保存文档
        pdf.saveToFile("result1.pdf");
    }
}

import com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;
import com.spire.pdf.graphics.PdfImage;
import com.spire.pdf.graphics.PdfTilingBrush;
import java.awt.*;
public class insertTiledImageWatermark {
    public static void main(String[] args) {
        //创建PdfDocument类的对象
        PdfDocument pdf = new PdfDocument();
        //载入PDF文档
        pdf.loadFromFile("sample.pdf");
        //载入图片
        PdfImage image = PdfImage.fromFile("image.png");
        //循环遍历文档页面以插入水印
        for (int i = 0; i < pdf.getPages().getCount(); i++ ) {
            //获取一个页面
            PdfPageBase page = pdf.getPages().get(i);
            //使用自定义方法插入平铺图片水印
            insertImageWatermark(page, image, 3, 3);
        }
        //保存文档
        pdf.saveToFile("result2.pdf");
    }
    static void insertImageWatermark(PdfPageBase page, PdfImage image, int row, int column) {
        //创建一个平铺笔刷
        PdfTilingBrush brush = new PdfTilingBrush(new Dimension((int) (page.getActualSize().getWidth()/column), (int) (page.getActualSize().getHeight()/row)));
        brush.getGraphics().setTransparency(0.3f);
        brush.getGraphics().save();
        brush.getGraphics().translateTransform(brush.getSize().getWidth()/2 - image.getWidth()/2, brush.getSize().getHeight()/2 - image.getHeight()/2);
        //将图片绘制于笔刷
        brush.getGraphics().drawImage(image, 0, 0);
        brush.getGraphics().restore();
        //使用该平铺笔刷绘制水印图片
        page.getCanvas().drawRectangle(brush, new Rectangle(new Point(0, 0), new Dimension((int) (page.getActualSize().getWidth()), (int) (page.getActualSize().getHeight()))));
    }
}