想知道这是否可能。看到很多关于在PDF创建并保存到磁盘后添加水印的帖子。但是在创建文档期间,如何添加图像水印?我知道如何向文档中添加图像,但如何定位它以使其出现在页面末尾呢。
对于C#,使用以下代码...
//new Document
Document DOC = new Document();
// open Document
DOC.Open();
//create New FileStream with image "WM.JPG"
FileStream fs1 = new FileStream("WM.JPG", FileMode.Open);
iTextSharp.text.Image JPG = iTextSharp.text.Image.GetInstance(System.Drawing.Image.FromStream(fs1), ImageFormat.Jpeg);
//Scale image
JPG.ScalePercent(35f);
//Set position
JPG.SetAbsolutePosition(130f,240f);
//Close Stream
fs1.Close();
DOC.Add(JPG);
PdfPageEvent
的类,在 OnPageEnd
中获取页面的 PdfContentByte
,并在那里绘制您的图像。使用绝对位置。PdfPageEventHelper
派生,它具有所有页面事件的空实现,因此您只需要编写实际关心的方法。OnStartPage()
。Image watermarkImage = new Image(imgPath);
watermarkImage.setAbsolutePosition(x, y);
writer.setPageEvent( new MyPageEvent(watermarkImage) );
public MyPageEvent extends PdfPageEventHelper {
private Image waterMark;
public MyPageEvent(Image img) {
waterMark = img;
}
public void OnEndPage/*OnStartPage*/(PdfWriter writer, Document doc) {
PdfContentByte content = writer.getContent();
content.addImage( waterMark );
}
}
public class BackgroundImagePdfPageEvent : PdfPageEventHelper
{
private readonly Image watermark;
public BackgroundImagePdfPageEvent(string imagePath)
{
using (var fs = new FileStream(imagePath, FileMode.Open))
{
watermark = Image.GetInstance(System.Drawing.Image.FromStream(fs), ImageFormat.Jpeg);
watermark.SetAbsolutePosition(0, 0);
watermark.ScaleAbsolute(PageSize.A4.Width, PageSize.A4.Height);
watermark.Alignment = Image.UNDERLYING;
}
}
public override void OnStartPage(PdfWriter writer, Document document)
{
document.Add(watermark);
}
}
然后,在创建您的文档时:
var doc = new Document(PageSize.A4);
doc.SetMargins(60f, 60f, 120f, 60f);
var outputStream = new MemoryStream();
var writer = PdfWriter.GetInstance(doc, outputStream);
var imagePath = "PATH_TO_YOUR_IMAGE";
writer.PageEvent = new BackgroundImagePdfPageEvent(imagePath);