Watermark

[DIZ]

How to add watermark to pdf document and make it appear behind the text of the document?

[Loïc]

Hello,

Here a proposal. Let me know if you need special explanations.

Code: Select all

        Const text As String = "WATERMARK"
        Const textSize As Integer = 100
        Const rotation As Single = 320 'Note: rotation is anti-clockwise
        Const font As String = "Arial"

        Using gdPicturePDF As New GdPicturePDF
            gdPicturePDF.LoadFromFile("c:\input.pdf", False)
            gdPicturePDF.SetMeasurementUnit(PdfMeasurementUnit.PdfMeasurementUnitPoint)
            gdPicturePDF.SelectPage(1)
            Using gdpicturePDFBack As New GdPicturePDF
                gdpicturePDFBack.NewPDF()
                Dim pageWidth As Single = gdPicturePDF.GetPageWidth()
                Dim pageHeight As Single = gdPicturePDF.GetPageHeight()

                gdpicturePDFBack.ClonePage(gdPicturePDF, 1)

                gdPicturePDF.SetOrigin(PdfOrigin.PdfOriginTopLeft)
                gdPicturePDF.ClearPageContent()

                Dim fontResName As String = gdPicturePDF.AddTrueTypeFont(font, True, False, False)
                gdPicturePDF.SetTextSize(textSize)
                gdPicturePDF.DrawRotatedText(fontResName, 0, gdPicturePDF.GetTextHeight(fontResName, textSize), text, rotation)
                gdPicturePDF.SaveGraphicsState()
                gdPicturePDF.SetBlendMode(PdfBlendMode.PdfBlendModeNormal)
                gdPicturePDF.SetFillAlpha(200)

                Dim status As GdPictureStatus = gdPicturePDF.DrawPage(gdpicturePDFBack, 1, 0, pageHeight, pageWidth, pageHeight)

                gdPicturePDF.ResetGraphicsState()

                gdPicturePDF.SaveToFile("c:\output.pdf")
            End Using
        End Using

Kind regards,

Loïc