ApachePOI和iTextPDF。将.ppt转换为PDF时，每张PDF幻灯片的边框都很大

我生成的pdf在pdf的左侧、底部和右侧都有很大的空白。我已经通过将我的BuffereImage写入JPEG来确认，我从powerpoint中提取的图像中不存在这些白色边框

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我正在缩放图像，否则我会得到一张低分辨率的540图像，我会将1080图像缩放2

因为我们已经通过电子邮件进行了沟通（它变成垃圾邮件了吗？），我想知道你为什么不直接在POI中使用新的PDF功能？它应该比PDF中的位图有更好的效果

import com.itextpdf.text.Document;
import com.itextpdf.text.Rectangle;
import com.itextpdf.text.Image;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import com.itextpdf.text.pdf.PdfPCell;
import com.itextpdf.text.pdf.PdfPTable;
import com.itextpdf.text.pdf.PdfWriter;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.hslf.usermodel.HSLFSlide;
import org.apache.poi.hslf.usermodel.HSLFSlideShow;
import org.apache.poi.xslf.usermodel.XMLSlideShow;
import org.apache.poi.xslf.usermodel.XSLFSlide;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.stream.FileImageOutputStream;

@Service
@Slf4j
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class FileConverterService {
  public void convertPptToImages(Double scaling, float compression) throws Exception {
    String path = "convert" + scaling + "-compression" + compression + "-";
    ClassLoader classLoader = getClass().getClassLoader();
    File theDir = new File("convert" + scaling + "-compression" + compression + "/");
    theDir.mkdirs();
    File file = new File(classLoader.getResource("myppt.ppt").getFile());
    Document pdfDocument = new Document();
    PdfWriter pdfWriter = PdfWriter.getInstance(pdfDocument, new FileOutputStream(theDir + "/"  + path + "converted.pdf"));
    PdfPTable table = new PdfPTable(1);
    FileInputStream is = new FileInputStream(file);
    HSLFSlideShow ppt = new HSLFSlideShow(is);
    is.close();
    Dimension pgsize = ppt.getPageSize();
    Double scaledPageSizeHeightDouble = pgsize.height * scaling;
    Double scaledPageSizeWidthDouble = pgsize.width * scaling;
    pdfDocument.setPageSize(new Rectangle(scaledPageSizeWidthDouble.floatValue(),scaledPageSizeHeightDouble.floatValue()));
    pdfDocument.setMargins(0f,0f,0f,0f);
    pdfWriter.open();
    pdfDocument.open();
    Image slideImage = null;
    // convert to images
    int idx = 1;
    for (HSLFSlide slide : ppt.getSlides()) {

      BufferedImage img =
          new BufferedImage(pgsize.width * scaling.intValue(), pgsize.height * scaling.intValue(), BufferedImage.TYPE_INT_RGB);
      Graphics2D graphics = img.createGraphics();
      // these settings make it higher quality
      // without it text is very hard to read
      graphics.setRenderingHint(
          RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
      graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
      graphics.setRenderingHint(
          RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_GASP);
      graphics.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
      graphics.setRenderingHint(
          RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
      graphics.setRenderingHint(
          RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
      // clear the drawing area
      graphics.setPaint(Color.white);
      graphics.scale(scaling ,scaling);
      graphics.fill(new Rectangle2D.Float(0, 0, scaledPageSizeWidthDouble.floatValue(), scaledPageSizeHeightDouble.floatValue()));
      // render
      slide.draw(graphics);
      // save the output
      var pdfCell = new PdfPCell(slideImage,true);
      //tried setting these to make borders go away
      pdfCell.setPaddingBottom(0f);
      pdfCell.setPaddingTop(0f);
      pdfCell.setPaddingLeft(0f);
      pdfCell.setPaddingRight(0f);
      pdfCell.setBorderWidthBottom(0f);
      pdfCell.setBorderWidthTop(0f);
      pdfCell.setBorderWidthLeft(0f);
      pdfCell.setBorderWidthRight(0f);
      pdfCell.setBorderWidth(0f);
      table.addCell(pdfCell);
      idx++;
    }
    pdfDocument.add(table);
    pdfDocument.close();
    pdfWriter.close();
  }