使用pdfbox Java

Question

我正在尝试使用pdfbox将图像添加到pdf的中心。下面是我的代码，但我无法在pdf中获得正确的图像位置。我按照以下链接In PDFBox, how to change the origin (0,0) point of a PDRectangle object?来获取正确的位置，但静止图像是从中点位置关闭的？

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDPageContentStream;
import org.apache.pdfbox.pdmodel.common.PDRectangle;
import org.apache.pdfbox.pdmodel.graphics.image.LosslessFactory;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
import org.apache.pdfbox.util.Matrix;

public class imageAppend {
     public static void main (String[] args){

            File file = new File("...pdf file location");
            PDDocument doc = null;
            try 
            {
                doc = PDDocument.load(file);
                PDImageXObject pdImage = PDImageXObject.createFromFile("image file location", doc);

                PDPage page = doc.getPage(0);
                PDPageContentStream contentStream = new PDPageContentStream(doc, page, PDPageContentStream.AppendMode.APPEND, true);

               float x_pos = page.getCropBox().getWidth();
               float y_pos = page.getCropBox().getHeight();

                float x_adjusted = ( x_pos - w ) / 2;
                float y_adjusted = ( y_pos - h ) / 2;

                Matrix mt = new Matrix(1f, 0f, 0f, -1f, page.getCropBox().getLowerLeftX(), page.getCropBox().getUpperRightY());
            contentStream.transform(mt);
            contentStream.drawImage(pdImage, x_adjusted, y_adjusted, w, h);

                doc.save("new pdf file location");
                doc.close();

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

Answer 1

我用我的测试数据（不幸的是你没有与你分享）重现了你的问题我得到了

修复很简单，我删除了两行

float64

现在得到

对于一般情况，您还应将裁剪框左下角的坐标添加到Matrix mt = new Matrix(1f, 0f, 0f, -1f, page.getCropBox().getLowerLeftX(), page.getCropBox().getUpperRightY()); contentStream.transform(mt); 和x_adjusted

y_adjusted

（AddImage测试方法float x_adjusted = ( x_pos - w ) / 2 + page.getCropBox().getLowerLeftX(); float y_adjusted = ( y_pos - h ) / 2 + page.getCropBox().getLowerLeftY(); ）