The sample demonstrates how to draw text as watermark in PDF document.

Download TextWaterMark.pdf

using System;
using System.Drawing;
using Spire.Pdf;
using Spire.Pdf.Graphics;
using Spire.Pdf.Tables;

namespace TextWaterMark
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a pdf document.
            PdfDocument doc = new PdfDocument();

            //margin
            PdfUnitConvertor unitCvtr = new PdfUnitConvertor();
            PdfMargins margin = new PdfMargins();
            margin.Top = unitCvtr.ConvertUnits(2.54f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point);
            margin.Bottom = margin.Top;
            margin.Left = unitCvtr.ConvertUnits(3.17f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point);
            margin.Right = margin.Left;

            // Create one page
            PdfPageBase page = doc.Pages.Add(PdfPageSize.A4, margin);

            PdfTilingBrush brush
                = new PdfTilingBrush(new SizeF(page.Canvas.ClientSize.Width / 2, page.Canvas.ClientSize.Height / 3));
            brush.Graphics.SetTransparency(0.3f);
            brush.Graphics.Save();
            brush.Graphics.TranslateTransform(brush.Size.Width / 2, brush.Size.Height / 2);
            brush.Graphics.RotateTransform(-45);
            brush.Graphics.DrawString("Spire.Pdf Demo",
                new PdfFont(PdfFontFamily.Helvetica, 24), PdfBrushes.Violet, 0, 0,
                new PdfStringFormat(PdfTextAlignment.Center));
            brush.Graphics.Restore();
            brush.Graphics.SetTransparency(1);
            page.Canvas.DrawRectangle(brush, new RectangleF(new PointF(0, 0), page.Canvas.ClientSize));

            //Draw the page
            DrawPage(page);

            //Save pdf file.
            doc.SaveToFile("TextWaterMark.pdf");
            doc.Close();

            //Launching the Pdf file.
            System.Diagnostics.Process.Start("TextWaterMark.pdf");
        }

        private static void DrawPage(PdfPageBase page)
        {
            float y = 10;

            //title
            PdfBrush brush1 = PdfBrushes.Black;
            PdfTrueTypeFont font1 = new PdfTrueTypeFont(new Font("Arial", 16f, FontStyle.Bold));
            PdfStringFormat format1 = new PdfStringFormat(PdfTextAlignment.Center);
            page.Canvas.DrawString("Category Sales by Year", font1, brush1, page.Canvas.ClientSize.Width / 2, y, format1);
            y = y + font1.MeasureString("Category Sales by Year", format1).Height;
            y = y + 5;

            String[][] data
                = {
                    new String[]{"Category Name", "1994 Sale Amount", "1995 Sale Amount", "1996 Sale Amount"},
                    new String[]{"Beverages", "38,487.20", "102,479.46", "126,901.53"},
                    new String[]{"Condiments", "16,402.95", "51,041.83", "38,602.31"},
                    new String[]{"Confections", "23,812.90", "79,752.25", "63,792.07"},
                    new String[]{"Dairy Products", "30,027.79", "116,495.45", "87,984.05"},
                    new String[]{"Grains/Cereals", "7,313.92", "53,823.48", "34,607.19"},
                    new String[]{"Meat/Poultry", "19,856.86", "77,164.75", "66,000.75"},
                    new String[]{"Produce", "10,694.96", "45,973.69", "43,315.93"},
                    new String[]{"Seafood", "16,247.77", "64,195.51", "50,818.46"}
                };

            PdfTable table = new PdfTable();
            table.Style.CellPadding = 2;
            table.Style.BorderPen = new PdfPen(brush1, 0.75f);
            table.Style.DefaultStyle.BackgroundBrush = PdfBrushes.SkyBlue;
            table.Style.DefaultStyle.Font = new PdfTrueTypeFont(new Font("Arial", 10f));
            table.Style.HeaderSource = PdfHeaderSource.Rows;
            table.Style.HeaderRowCount = 1;
            table.Style.HeaderStyle.BackgroundBrush = PdfBrushes.CadetBlue;
            table.Style.HeaderStyle.Font = new PdfTrueTypeFont(new Font("Arial", 11f, FontStyle.Bold));
            table.Style.HeaderStyle.StringFormat = new PdfStringFormat(PdfTextAlignment.Center);
            table.Style.ShowHeader = true;
            table.DataSource = data;

            PdfLayoutResult result = table.Draw(page, new PointF(0, y));
            y = y + result.Bounds.Height + 5;

            PdfBrush brush2 = PdfBrushes.LightGray;
            PdfTrueTypeFont font2 = new PdfTrueTypeFont(new Font("Arial", 9f));
            page.Canvas.DrawString("* All data from NorthWind", font2, brush2, 5, y);
        }                
    }
}

Imports System.Drawing
Imports Spire.Pdf
Imports Spire.Pdf.Graphics
Imports Spire.Pdf.Tables

Namespace TextWaterMark
    Friend Class Program
        Shared Sub Main(ByVal args() As String)
            'Create a pdf document.
            Dim doc As New PdfDocument()

            'margin
            Dim unitCvtr As New PdfUnitConvertor()
            Dim margin As New PdfMargins()
            margin.Top = unitCvtr.ConvertUnits(2.54F, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point)
            margin.Bottom = margin.Top
            margin.Left = unitCvtr.ConvertUnits(3.17F, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point)
            margin.Right = margin.Left

            ' Create one page
            Dim page As PdfPageBase = doc.Pages.Add(PdfPageSize.A4, margin)

            Dim brush As New PdfTilingBrush(New SizeF(page.Canvas.ClientSize.Width \ 2, page.Canvas.ClientSize.Height \ 3))
            brush.Graphics.SetTransparency(0.3F)
            brush.Graphics.Save()
            brush.Graphics.TranslateTransform(brush.Size.Width \ 2, brush.Size.Height \ 2)
            brush.Graphics.RotateTransform(-45)
            brush.Graphics.DrawString("Spire.Pdf Demo", New PdfFont(PdfFontFamily.Helvetica, 24), _
                                      PdfBrushes.Violet, 0, 0, New PdfStringFormat(PdfTextAlignment.Center))
            brush.Graphics.Restore()
            brush.Graphics.SetTransparency(1)
            page.Canvas.DrawRectangle(brush, New RectangleF(New PointF(0, 0), page.Canvas.ClientSize))

            'Draw the page
            DrawPage(page)

            'Save pdf file.
            doc.SaveToFile("TextWaterMark.pdf")
            doc.Close()

            'Launching the Pdf file.
            Process.Start("TextWaterMark.pdf")
        End Sub

        Private Shared Sub DrawPage(ByVal page As PdfPageBase)
            Dim y As Single = 10

            'title
            Dim brush1 As PdfBrush = PdfBrushes.Black
            Dim font1 As New PdfTrueTypeFont(New Font("Arial", 16.0F, FontStyle.Bold))
            Dim format1 As New PdfStringFormat(PdfTextAlignment.Center)
            page.Canvas.DrawString("Category Sales by Year", font1, brush1, _
                                   page.Canvas.ClientSize.Width \ 2, y, format1)
            y = y + font1.MeasureString("Category Sales by Year", format1).Height
            y = y + 5

            Dim data()() As String _
                = {New String() {"Category Name", "1994 Sale Amount", "1995 Sale Amount", "1996 Sale Amount"}, _
                   New String() {"Beverages", "38,487.20", "102,479.46", "126,901.53"}, _
                   New String() {"Condiments", "16,402.95", "51,041.83", "38,602.31"}, _
                   New String() {"Confections", "23,812.90", "79,752.25", "63,792.07"}, _
                   New String() {"Dairy Products", "30,027.79", "116,495.45", "87,984.05"}, _
                   New String() {"Grains/Cereals", "7,313.92", "53,823.48", "34,607.19"}, _
                   New String() {"Meat/Poultry", "19,856.86", "77,164.75", "66,000.75"}, _
                   New String() {"Produce", "10,694.96", "45,973.69", "43,315.93"}, _
                   New String() {"Seafood", "16,247.77", "64,195.51", "50,818.46"}}

            Dim table As New PdfTable()
            table.Style.CellPadding = 2
            table.Style.BorderPen = New PdfPen(brush1, 0.75F)
            table.Style.DefaultStyle.BackgroundBrush = PdfBrushes.SkyBlue
            table.Style.DefaultStyle.Font = New PdfTrueTypeFont(New Font("Arial", 10.0F))
            table.Style.HeaderSource = PdfHeaderSource.Rows
            table.Style.HeaderRowCount = 1
            table.Style.HeaderStyle.BackgroundBrush = PdfBrushes.CadetBlue
            table.Style.HeaderStyle.Font = New PdfTrueTypeFont(New Font("Arial", 11.0F, FontStyle.Bold))
            table.Style.HeaderStyle.StringFormat = New PdfStringFormat(PdfTextAlignment.Center)
            table.Style.ShowHeader = True
            table.DataSource = data

            Dim result As PdfLayoutResult = table.Draw(page, New PointF(0, y))
            y = y + result.Bounds.Height + 5

            Dim brush2 As PdfBrush = PdfBrushes.LightGray
            Dim font2 As New PdfTrueTypeFont(New Font("Arial", 9.0F))
            page.Canvas.DrawString("* All data from NorthWind", font2, brush2, 5, y)
        End Sub
    End Class
End Namespace

The sample demonstrates how to draw an image as watermark in PDF document.

Download ImageWaterMark.pdf

using System;
using System.Drawing;
using Spire.Pdf;
using Spire.Pdf.Graphics;

namespace ImageWaterMark
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a pdf document.
            PdfDocument doc = new PdfDocument();

            //margin
            PdfUnitConvertor unitCvtr = new PdfUnitConvertor();
            PdfMargins margin = new PdfMargins();
            margin.Top = unitCvtr.ConvertUnits(2.54f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point);
            margin.Bottom = margin.Top;
            margin.Left = unitCvtr.ConvertUnits(3.17f, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point);
            margin.Right = margin.Left;

            // Create one page
            PdfPageBase page = doc.Pages.Add(PdfPageSize.A4, margin);
            Image img = Image.FromFile(@"Background.png");
            page.BackgroundImage = img;

            //Draw page
            DrawPage(page);

            //Save pdf file.
            doc.SaveToFile("ImageWaterMark.pdf");
            doc.Close();

            //Launching the Pdf file.
            System.Diagnostics.Process.Start("ImageWaterMark.pdf");
        }

        private static void DrawPage(PdfPageBase page)
        {
            float pageWidth = page.Canvas.ClientSize.Width;
            float y = 0;

            //page header
            PdfPen pen1 = new PdfPen(Color.LightGray, 1f);
            PdfBrush brush1 = new PdfSolidBrush(Color.LightGray);
            PdfTrueTypeFont font1 = new PdfTrueTypeFont(new Font("Arial", 8f, FontStyle.Italic));
            PdfStringFormat format1 = new PdfStringFormat(PdfTextAlignment.Right);
            String text = "Demo of Spire.Pdf";
            page.Canvas.DrawString(text, font1, brush1, pageWidth, y, format1);
            SizeF size = font1.MeasureString(text, format1);
            y = y + size.Height + 1;
            page.Canvas.DrawLine(pen1, 0, y, pageWidth, y);

            //title
            y = y + 5;
            PdfBrush brush2 = new PdfSolidBrush(Color.Black);
            PdfTrueTypeFont font2 = new PdfTrueTypeFont(new Font("Arial", 16f, FontStyle.Bold));
            PdfStringFormat format2 = new PdfStringFormat(PdfTextAlignment.Center);
            format2.CharacterSpacing = 1f;
            text = "Summary of Science";
            page.Canvas.DrawString(text, font2, brush2, pageWidth / 2, y, format2);
            size = font2.MeasureString(text, format2);
            y = y + size.Height + 6;

            //icon
            PdfImage image = PdfImage.FromFile(@"Wikipedia_Science.png");
            page.Canvas.DrawImage(image, new PointF(pageWidth - image.PhysicalDimension.Width, y));
            float imageLeftSpace = pageWidth - image.PhysicalDimension.Width - 2;
            float imageBottom = image.PhysicalDimension.Height + y;

            //refenrence content
            PdfTrueTypeFont font3 = new PdfTrueTypeFont(new Font("Arial", 9f));
            PdfStringFormat format3 = new PdfStringFormat();
            format3.ParagraphIndent = font3.Size * 2;
            format3.MeasureTrailingSpaces = true;
            format3.LineSpacing = font3.Size * 1.5f;
            String text1 = "(All text and picture from ";
            String text2 = "Wikipedia";
            String text3 = ", the free encyclopedia)";
            page.Canvas.DrawString(text1, font3, brush2, 0, y, format3);

            size = font3.MeasureString(text1, format3);
            float x1 = size.Width;
            format3.ParagraphIndent = 0;
            PdfTrueTypeFont font4 = new PdfTrueTypeFont(new Font("Arial", 9f, FontStyle.Underline));
            PdfBrush brush3 = PdfBrushes.Blue;
            page.Canvas.DrawString(text2, font4, brush3, x1, y, format3);
            size = font4.MeasureString(text2, format3);
            x1 = x1 + size.Width;

            page.Canvas.DrawString(text3, font3, brush2, x1, y, format3);
            y = y + size.Height;

            //content
            PdfStringFormat format4 = new PdfStringFormat();
            text = System.IO.File.ReadAllText(@"Summary_of_Science.txt");
            PdfTrueTypeFont font5 = new PdfTrueTypeFont(new Font("Arial", 10f));
            format4.LineSpacing = font5.Size * 1.5f;
            PdfStringLayouter textLayouter = new PdfStringLayouter();
            float imageLeftBlockHeight = imageBottom - y;
            PdfStringLayoutResult result
                = textLayouter.Layout(text, font5, format4, new SizeF(imageLeftSpace, imageLeftBlockHeight));
            if (result.ActualSize.Height < imageBottom - y)
            {
                imageLeftBlockHeight = imageLeftBlockHeight + result.LineHeight;
                result = textLayouter.Layout(text, font5, format4, new SizeF(imageLeftSpace, imageLeftBlockHeight));
            }
            foreach (LineInfo line in result.Lines)
            {
                page.Canvas.DrawString(line.Text, font5, brush2, 0, y, format4);
                y = y + result.LineHeight;
            }
            PdfTextWidget textWidget = new PdfTextWidget(result.Remainder, font5, brush2);
            PdfTextLayout textLayout = new PdfTextLayout();
            textLayout.Break = PdfLayoutBreakType.FitPage;
            textLayout.Layout = PdfLayoutType.Paginate;
            RectangleF bounds = new RectangleF(new PointF(0, y), page.Canvas.ClientSize);
            textWidget.StringFormat = format4;
            textWidget.Draw(page, bounds, textLayout);
        }
    }
}

Imports System.Drawing
Imports Spire.Pdf
Imports Spire.Pdf.Graphics

Namespace ImageWaterMark
    Friend Class Program
        Shared Sub Main(ByVal args() As String)
            'Create a pdf document.
            Dim doc As New PdfDocument()

            'margin
            Dim unitCvtr As New PdfUnitConvertor()
            Dim margin As New PdfMargins()
            margin.Top = unitCvtr.ConvertUnits(2.54F, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point)
            margin.Bottom = margin.Top
            margin.Left = unitCvtr.ConvertUnits(3.17F, PdfGraphicsUnit.Centimeter, PdfGraphicsUnit.Point)
            margin.Right = margin.Left

            ' Create one page
            Dim page As PdfPageBase = doc.Pages.Add(PdfPageSize.A4, margin)
            Dim img As Image = Image.FromFile("Background.png")
            page.BackgroundImage = img

            'Draw table
            DrawPage(page)

            'Save pdf file.
            doc.SaveToFile("ImageWaterMark.pdf")
            doc.Close()

            'Launching the Pdf file.
            Process.Start("ImageWaterMark.pdf")
        End Sub

        Private Shared Sub DrawPage(ByVal page As PdfPageBase)
            Dim pageWidth As Single = page.Canvas.ClientSize.Width
            Dim y As Single = 0

            'page header
            Dim pen1 As New PdfPen(Color.LightGray, 1.0F)
            Dim brush1 As PdfBrush = New PdfSolidBrush(Color.LightGray)
            Dim font1 As New PdfTrueTypeFont(New Font("Arial", 8.0F, FontStyle.Italic))
            Dim format1 As New PdfStringFormat(PdfTextAlignment.Right)
            Dim text As String = "Demo of Spire.Pdf"
            page.Canvas.DrawString(text, font1, brush1, pageWidth, y, format1)
            Dim size As SizeF = font1.MeasureString(text, format1)
            y = y + size.Height + 1
            page.Canvas.DrawLine(pen1, 0, y, pageWidth, y)

            'title
            y = y + 5
            Dim brush2 As PdfBrush = New PdfSolidBrush(Color.Black)
            Dim font2 As New PdfTrueTypeFont(New Font("Arial", 16.0F, FontStyle.Bold))
            Dim format2 As New PdfStringFormat(PdfTextAlignment.Center)
            format2.CharacterSpacing = 1.0F
            text = "Summary of Science"
            page.Canvas.DrawString(text, font2, brush2, pageWidth / 2, y, format2)
            size = font2.MeasureString(text, format2)
            y = y + size.Height + 6

            'icon
            Dim image As PdfImage = PdfImage.FromFile("Wikipedia_Science.png")
            page.Canvas.DrawImage(image, New PointF(pageWidth - image.PhysicalDimension.Width, y))
            Dim imageLeftSpace As Single = pageWidth - image.PhysicalDimension.Width - 2
            Dim imageBottom As Single = image.PhysicalDimension.Height + y

            'refenrence content
            Dim font3 As New PdfTrueTypeFont(New Font("Arial", 9.0F))
            Dim format3 As New PdfStringFormat()
            format3.ParagraphIndent = font3.Size * 2
            format3.MeasureTrailingSpaces = True
            format3.LineSpacing = font3.Size * 1.5F
            Dim text1 As String = "(All text and picture from "
            Dim text2 As String = "Wikipedia"
            Dim text3 As String = ", the free encyclopedia)"
            page.Canvas.DrawString(text1, font3, brush2, 0, y, format3)

            size = font3.MeasureString(text1, format3)
            Dim x1 As Single = size.Width
            format3.ParagraphIndent = 0
            Dim font4 As New PdfTrueTypeFont(New Font("Arial", 9.0F, FontStyle.Underline))
            Dim brush3 As PdfBrush = PdfBrushes.Blue
            page.Canvas.DrawString(text2, font4, brush3, x1, y, format3)
            size = font4.MeasureString(text2, format3)
            x1 = x1 + size.Width

            page.Canvas.DrawString(text3, font3, brush2, x1, y, format3)
            y = y + size.Height

            'content
            Dim format4 As New PdfStringFormat()
            text = System.IO.File.ReadAllText("Summary_of_Science.txt")
            Dim font5 As New PdfTrueTypeFont(New Font("Arial", 10.0F))
            format4.LineSpacing = font5.Size * 1.5F
            Dim textLayouter As New PdfStringLayouter()
            Dim imageLeftBlockHeight As Single = imageBottom - y
            Dim result As PdfStringLayoutResult _
                = textLayouter.Layout(text, font5, format4, New SizeF(imageLeftSpace, imageLeftBlockHeight))
            If result.ActualSize.Height < imageBottom - y Then
                imageLeftBlockHeight = imageLeftBlockHeight + result.LineHeight
                result = textLayouter.Layout(text, font5, format4, New SizeF(imageLeftSpace, imageLeftBlockHeight))
            End If
            For Each line As LineInfo In result.Lines
                page.Canvas.DrawString(line.Text, font5, brush2, 0, y, format4)
                y = y + result.LineHeight
            Next line
            Dim textWidget As New PdfTextWidget(result.Remainder, font5, brush2)
            Dim textLayout As New PdfTextLayout()
            textLayout.Break = PdfLayoutBreakType.FitPage
            textLayout.Layout = PdfLayoutType.Paginate
            Dim bounds As New RectangleF(New PointF(0, y), page.Canvas.ClientSize)
            textWidget.StringFormat = format4
            textWidget.Draw(page, bounds, textLayout)
        End Sub
    End Class
End Namespace