com.aspose.words

Example:

Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);

// By default, the image is inline
Shape shape = builder.insertImage(getImageDir() + "Logo.jpg");

// Make the image float, put it behind text and center on the page
shape.setWrapType(WrapType.NONE);
shape.setBehindText(true);
shape.setRelativeHorizontalPosition(RelativeHorizontalPosition.PAGE);
shape.setRelativeVerticalPosition(RelativeVerticalPosition.PAGE);
shape.setHorizontalAlignment(HorizontalAlignment.CENTER);
shape.setVerticalAlignment(VerticalAlignment.CENTER);

doc.save(getArtifactsDir() + "Image.CreateFloatingPageCenter.docx");

Example:

Document doc = new Document();
DocumentBuilder builder = new DocumentBuilder(doc);

// Insert the image into the header so that it will be visible on every page.
BufferedImage image = ImageIO.read(new File(getImageDir() + "Transparent background logo.png"));
builder.moveToHeaderFooter(HeaderFooterType.HEADER_PRIMARY);
Shape shape = builder.insertImage(image);
shape.setWrapType(WrapType.NONE);
shape.setBehindText(true);

// Place the image at the center of the page.
shape.setRelativeHorizontalPosition(RelativeHorizontalPosition.PAGE);
shape.setRelativeVerticalPosition(RelativeVerticalPosition.PAGE);
shape.setLeft((builder.getPageSetup().getPageWidth() - shape.getWidth()) / 2.0);
shape.setTop((builder.getPageSetup().getPageHeight() - shape.getHeight()) / 2.0);

doc.save(getArtifactsDir() + "DocumentBuilder.InsertWatermark.docx");