Remove the margins in the header using Apache POI in Java

Question

I am using Apache POI version 4.1.2. When, I try to create a document with an image in the header, there is some default margins allocated for the header on the 4 sides of the image.

How can I remove the default margins in the header portion and place the image fully occupied in the header portion?

XWPFDocument document = new XWPFDocument();
CTSectPr sectPr = document.getDocument().getBody().addNewSectPr();
XWPFHeaderFooterPolicy headerFooterPolicy = new XWPFHeaderFooterPolicy(document, sectPr);
XWPFHeader header = document.createHeader(HeaderFooterType.FIRST);
XWPFParagraph paragraph = header.createParagraph();
XWPFRun run = paragraph.createRun();

//Adding the image using run.addPicture() method.

The output document is looking like below,

I would like to remove the margins and make that image fully occupied in the header.

Answer 1

Using XWPFRun.addPicture the image is inline with text so the paragraph settings matters. Word paragraphs have spacing after it per default. Using XWPFParagraph.setSpacingAfter it can be set 0. Also Word paragraphs have spacing between lines in paragraph per default. Using XWPFParagraph.setSpacingBetween it can be set to single, so there is no spacing between the lines in paragraph.

To make the picture in the header appear at absolute top of the page, the top page margin needs to be 0. Also the distance between header and page margin needs to be 0. Unfortunately setting the page size and page margins is not yet implemented in XWPF . So we need using the org.openxmlformats.schemas.wordprocessingml.x2006.main.* classes.

The gaps at left and right of the picture are the distances between the picture's left edge and the left page margin respective the picture's right edge and the right page margin. It depends on the picture's width. But I cannot see how this gaps shall be removed without violating the picture's aspect ratio and so distort the picture. If that is the wanted, then set the picture's width appropriate.

Complete example:

import java.io.FileOutputStream;
import java.io.FileInputStream;
import java.io.IOException;

import org.apache.poi.util.Units;

import org.apache.poi.xwpf.usermodel.*;

import org.apache.poi.xwpf.model.XWPFHeaderFooterPolicy;

import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTSectPr;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTPageSz;
import org.openxmlformats.schemas.wordprocessingml.x2006.main.CTPageMar;

import java.math.BigInteger;

public class CreateWordHeaderFooter {

 public static void main(String[] args) throws Exception {

  XWPFDocument document = new XWPFDocument();

  // the body content
  XWPFParagraph paragraph = document.createParagraph();
  XWPFRun run=paragraph.createRun();  
  run.setText("The Body:");

  paragraph = document.createParagraph();
  run=paragraph.createRun();  
  run.setText("Lorem ipsum....");

  // create header start
  CTSectPr sectPr = document.getDocument().getBody().addNewSectPr();
  XWPFHeaderFooterPolicy headerFooterPolicy = new XWPFHeaderFooterPolicy(document, sectPr);

  XWPFHeader header = headerFooterPolicy.createHeader(XWPFHeaderFooterPolicy.DEFAULT);

  paragraph = header.getParagraphArray(0);
  if (paragraph == null) paragraph = header.createParagraph();
  paragraph.setAlignment(ParagraphAlignment.CENTER);
  
  // set spacing after paragraph 0
  paragraph.setSpacingAfter(0);
  // set spacing between lines in paragraph to 1 (single)
  paragraph.setSpacingBetween(1d, LineSpacingRule.AUTO);

  // the image is inline with text so the paragraph settings matters
  run = paragraph.createRun();  
  String imgFile="./laptop.jpg";
  run.addPicture(new FileInputStream(imgFile), XWPFDocument.PICTURE_TYPE_JPEG, imgFile, Units.toEMU(300), Units.toEMU(200));

  // create footer start
  XWPFFooter footer = headerFooterPolicy.createFooter(XWPFHeaderFooterPolicy.DEFAULT);

  paragraph = footer.createParagraph();
  paragraph.setAlignment(ParagraphAlignment.CENTER);

  run = paragraph.createRun();  
  run.setText("The Footer:");
  
  // create page margins
  sectPr = document.getDocument().getBody().getSectPr();
  if (sectPr == null) sectPr = document.getDocument().getBody().addNewSectPr();
  CTPageSz pageSz = sectPr.addNewPgSz(); // paper format letter
  pageSz.setW(BigInteger.valueOf(12240)); //12240 Twips = 12240/20 = 612 pt = 612/72 = 8.5"
  pageSz.setH(BigInteger.valueOf(15840)); //15840 Twips = 15840/20 = 792 pt = 792/72 = 11"
  CTPageMar pageMar = sectPr.getPgMar();
  if (pageMar == null) pageMar = sectPr.addNewPgMar();
  pageMar.setLeft(BigInteger.valueOf(720)); //720 TWentieths of an Inch Point (Twips) = 720/20 = 36 pt = 36/72 = 0.5"
  pageMar.setRight(BigInteger.valueOf(720));
  // set top page margin 0, so header can be at absolute top
  pageMar.setTop(BigInteger.valueOf(0));
  //pageMar.setBottom(BigInteger.valueOf(0));
  //pageMar.setFooter(BigInteger.valueOf(0));
  // set distance between header and page margin 0, so header starts at absolute top
  pageMar.setHeader(BigInteger.valueOf(0));
  //pageMar.setGutter(BigInteger.valueOf(0));

  FileOutputStream out = new FileOutputStream("./test.docx");
  document.write(out);
  out.close();
  document.close();

 }
}

Result:

To make the picture full width, one need to know the needed width in points ( pt ). That would be the inner width of the page between the page margins. In my example 8.5" page width - 0.5" left margin - 0.5" right margin = 7.5". That would be

...
  long pageInnerWidthPt = Math.round(7.5 * 72d); //8.5" page width - 0.5" left margin - 0.5" right margin = 7.5"
  run.addPicture(new FileInputStream(imgFile), XWPFDocument.PICTURE_TYPE_JPEG, imgFile, Units.toEMU(pageInnerWidthPt), Units.toEMU(200));
...

in the code.