1. GroupDocs Documentation
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    3. GroupDocs.Watermark Product Family
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    5. GroupDocs.Watermark for .NET
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    7. Developer guide
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    9. Advanced usage
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    11. Adding watermarks
    12. /
    13. To PDF documents
    14. /
    15. Rasterize document or page

    Rasterize document or page

    How to remove a watermark from a pdf

    The watermark can be removed from the PDF documents using third-party tools. However, if you want to remove a watermark that is almost impossible to remove, you can rasterize pdf documents. GroupDocs.Watermark provides the feature to convert all the pages of a PDF document to raster images with only one line of code.

    Rasterize PDF document

    Following code snippet is used to rasterize the PDF document to protect added watermarks.

    AdvancedUsage.AddingWatermarks.AddWatermarksToPdf.PdfRasterizeDocument

    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("Do not copy", new Font("Arial", 8));
    watermark.HorizontalAlignment = HorizontalAlignment.Center;
    watermark.VerticalAlignment = VerticalAlignment.Center;
    watermark.RotateAngle = 45;
    watermark.SizingType = SizingType.ScaleToParentDimensions;
    watermark.ScaleFactor = 1;
    watermark.Opacity = 0.5;

    // Add watermark of any type first
    watermarker.Add(watermark);
    PdfContent pdfContent = watermarker.GetContent<PdfContent>();

    // Rasterize all pages
    pdfContent.Rasterize(100, 100, PdfImageConversionFormat.Png);

    // Content of all pages is replaced with raster images
    watermarker.Save("document.pdf");
}
    Warning
    You can’t restore document content after saving the document. Rasterization significantly increases the size of the resultant PDF file.

    Rasterize particular page of the PDF document

    The API also allows you to rasterize any particular page of the PDF document. Following code snippet is used to rasterize a page of the PDF document.

    AdvancedUsage.AddingWatermarks.AddWatermarksToPdf.PdfRasterizePage

    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("Do not copy", new Font("Arial", 8));
    watermark.HorizontalAlignment = HorizontalAlignment.Center;
    watermark.VerticalAlignment = VerticalAlignment.Center;
    watermark.RotateAngle = 45;
    watermark.SizingType = SizingType.ScaleToParentDimensions;
    watermark.ScaleFactor = 1;
    watermark.Opacity = 0.5;

    // Add watermark of any type first
    PdfArtifactWatermarkOptions options = new PdfArtifactWatermarkOptions();
    options.PageIndex = 0;
    watermarker.Add(watermark, options);

    // Rasterize the first page
    PdfContent pdfContent = watermarker.GetContent<PdfContent>();
    pdfContent.Pages[0].Rasterize(100, 100, PdfImageConversionFormat.Png);

    // Content of the first page is replaced with raster image
    watermarker.Save("document.pdf");
}
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