Add watermarks to PDF documents Leave feedback

The watermarking API allows you to add watermarks to PDF documents. Adding watermarks to a particular page or adding watermarks on all images or attachments of a particular page is possible.

GroupDocs.Watermark API allows you to add watermark to a particular page of a PDF document. Adding watermark to a PDF document using GroupDocs.Watermark consists of following steps.

1. Load the document
2. Create and initialize watermark object
3. Set watermark properties
4. Add watermark to the page of the document using property PageIndex of PdfArtifactWatermarkOptions
5. Save the document

Following code performs this functionality.

AdvancedUsage.AddingWatermarks.AddWatermarksToPdf.PdfAddWatermarks

PdfLoadOptions loadOptions = new PdfLoadOptions();
// Specify an absolute or relative path to your document. Ex: @"C:\Docs\document.pdf"
using (Watermarker watermarker = new Watermarker("document.pdf", loadOptions))
{
    // Add text watermark to the first page
    TextWatermark textWatermark = new TextWatermark("This is a test watermark", new Font("Arial", 8));
    PdfArtifactWatermarkOptions textWatermarkOptions = new PdfArtifactWatermarkOptions();
    textWatermarkOptions.PageIndex = 0;

    watermarker.Add(textWatermark, textWatermarkOptions);

    // Add image watermark to the second page
    using (ImageWatermark imageWatermark = new ImageWatermark("protect.jpg"))
    {
        PdfArtifactWatermarkOptions imageWatermarkOptions = new PdfArtifactWatermarkOptions();
        imageWatermarkOptions.PageIndex = 1;
        watermarker.Add(imageWatermark, imageWatermarkOptions);
    }

    watermarker.Save("document.pdf");
}

The API also allows you to add watermark to the images inside a particular page of the PDF document. Following code snippet shows how to add watermark to all images in a particular page of a PDF document.

AdvancedUsage.AddingWatermarks.AddWatermarksToPdf.PdfAddWatermarkToImages

PdfLoadOptions loadOptions = new PdfLoadOptions();
// Specify an absolute or relative path to your document. Ex: @"C:\Docs\document.pdf"
using (Watermarker watermarker = new Watermarker("document.pdf", loadOptions))
{
    // Initialize image or text watermark
    TextWatermark watermark = new TextWatermark("Protected image", new Font("Arial", 8));
    watermark.HorizontalAlignment = HorizontalAlignment.Center;
    watermark.VerticalAlignment = VerticalAlignment.Center;
    watermark.RotateAngle = 45;
    watermark.SizingType = SizingType.ScaleToParentDimensions;
    watermark.ScaleFactor = 1;

    PdfContent pdfContent = watermarker.GetContent<PdfContent>();

    // Get all images from the first page
    WatermarkableImageCollection images = pdfContent.Pages[0].FindImages();

    // Add watermark to all found images
    foreach (WatermarkableImage image in images)
    {
        image.Add(watermark);
    }

    watermarker.Save("document.pdf");
}

If for some reasons you want to use absolute sizing and positioning, you may also need to determine page size. GroupDocs.Watermark also provides the feature to get the dimensions of the page in a PDF document. Below example shows how to get width and height of a particular page.

AdvancedUsage.AddingWatermarks.AddWatermarksToPdf.PdfGetDimensions

PdfLoadOptions loadOptions = new PdfLoadOptions();
// Specify an absolute or relative path to your document. Ex: @"C:\Docs\document.pdf"
using (Watermarker watermarker = new Watermarker("document.pdf", loadOptions))
{
    PdfContent pdfContent = watermarker.GetContent<PdfContent>();
    Console.WriteLine(pdfContent.Pages[0].Width);
    Console.WriteLine(pdfContent.Pages[0].Height);
}

Note

PDF Reference 1.7

A PDF page may be prepared either for a finished medium, such as a sheet of paper, or as part of a prepress process in which the content of the page is placed on an intermediate medium, such as film or an imposed reproduction plate. In the latter case, it is important to distinguish between the intermediate page and the finished page. The intermediate page may often include additional production-related content, such as bleeds or printer marks, that falls outside the boundaries of the finished page. To handle such cases, a PDF page can define as many as five separate boundaries to control various aspects of the imaging process:

• The media box defines the boundaries of the physical medium on which the page is to be printed. It may include any extended area surrounding the finished page for bleed, printing marks, or other such purposes. It may also include areas close to the edges of the medium that cannot be marked because of physical limitations of the output device. Content falling outside this boundary can safely be discarded without affecting the meaning of the PDF file.
• The crop box defines the region to which the contents of the page are to be clipped (cropped) when displayed or printed. Unlike the other boxes, the crop box has no defined meaning in terms of physical page geometry or intended use; it merely imposes clipping on the page contents. However, in the absence of additional information (such as imposition instructions specified in a JDF or PJTF job ticket), the crop box determines how the page’s contents are to be positioned on the output medium. The default value is the page’s media box.
• The bleed box (PDF 1.3) defines the region to which the contents of the page should be clipped when output in a production environment. This may include any extra bleed area needed to accommodate the physical limitations of cutting, folding, and trimming equipment. The actual printed page may include printing marks that fall outside the bleed box. The default value is the page’s crop box.
• The trim box (PDF 1.3) defines the intended dimensions of the finished page after trimming. It may be smaller than the media box to allow for production-related content, such as printing instructions, cut marks, or color bars. The default value is the page’s crop box.
• The art box (PDF 1.3) defines the extent of the page’s meaningful content (including potential white space) as intended by the page’s creator. The default value is the page’s crop box.

If a PDF document contains a crop box definition, Adobe Acrobat uses it for screen display and printing. That’s why GroupDocs.Watermark uses crop box by default to calculate relative watermark size and position. When you set Watermark.ConsiderParentMargins property to true, trim box rectangle is used instead. But what if you want to get watermark aligned to bleed box or art box? In this case, you need to set the appropriate value to PdfContent.PageMarginType property as shown in the below example.

AdvancedUsage.AddingWatermarks.AddWatermarksToPdf.PdfAddWatermarkWithPageMarginType

PdfLoadOptions loadOptions = new PdfLoadOptions();
// Specify an absolute or relative path to your document. Ex: @"C:\Docs\document.pdf"
using (Watermarker watermarker = new Watermarker("document.pdf", loadOptions))
{
    TextWatermark watermark = new TextWatermark("Test watermark", new Font("Arial", 42));
    watermark.HorizontalAlignment = HorizontalAlignment.Right;
    watermark.VerticalAlignment = VerticalAlignment.Top;
    watermark.SizingType = SizingType.ScaleToParentDimensions;
    watermark.ScaleFactor = 1;

    PdfContent pdfContent = watermarker.GetContent<PdfContent>();
    pdfContent.PageMarginType = PdfPageMarginType.BleedBox;
    watermark.ConsiderParentMargins = true;

    watermarker.Add(watermark);
    watermarker.Save("document.pdf");
}

GroupDocs.Watermark also provides the feature to add watermark to supported files in all attachments in a PDF document. Below example shows how to add watermark to all supported attachments.

AdvancedUsage.AddingWatermarks.AddWatermarksToPdf.PdfAddWatermarkToAllAttachments

TextWatermark watermark = new TextWatermark("This is WaterMark on Attachment", new Font("Arial", 19));
PdfLoadOptions loadOptions = new PdfLoadOptions();
// Specify an absolute or relative path to your document. Ex: @"C:\Docs\document.pdf"
using (Watermarker watermarker = new Watermarker("document.pdf", loadOptions))
{
    PdfContent pdfContent = watermarker.GetContent<PdfContent>();
    foreach (PdfAttachment attachment in pdfContent.Attachments)
    {
        // Check if the attached file is supported by GroupDocs.Watermark
        IDocumentInfo info = attachment.GetDocumentInfo();
        if (info.FileType != FileType.Unknown && !info.IsEncrypted)
        {
            // Load the attached document
            using (Watermarker attachedWatermarker = attachment.CreateWatermarker())
            {
                // Add wateramrk
                attachedWatermarker.Add(watermark);

                // Save changes in the attached file
                attachedWatermarker.Save();
            }
        }
    }

    watermarker.Save("document.pdf");
}

• Attachments in PDF document
• Existing objects in PDF document
• Rasterize document or page
• Watermarks in PDF document