The sample demonstrates how to convert HTML to PDF document.

Download FromHTML.pdf

using System;
using Spire.Pdf;

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

            String url = "http://www.e-iceblue.com/";
            doc.LoadFromHTML(url, false, true, true);

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

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

    }
}

Imports Spire.Pdf

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

            Dim url As String = "http://www.e-iceblue.com/"
            doc.LoadFromHTML(url, False, True, True)

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

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

    End Class
End Namespace

The sample demonstrates how to sign PDF document with digital certificate.

Download DigitalSignature.pdf

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

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

            // Create one page
            PdfPageBase page = doc.Pages.Add();

            //Draw the page
            DrawPage(page);

            String pfxPath = @"Demo.pfx";
            PdfCertificate cert = new PdfCertificate(pfxPath, "e-iceblue");
            PdfSignature signature = new PdfSignature(doc, page, cert, "demo");
            signature.ContactInfo = "Harry Hu";
            signature.Certificated = true;
            signature.DocumentPermissions = PdfCertificationFlags.AllowFormFill;

            //Save pdf file.
            doc.Save("DigitalSignature.pdf");
            doc.Close();

            //Launching the Pdf file.
            System.Diagnostics.Process.Start("DigitalSignature.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
Imports Spire.Pdf.Security

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

            ' Create one page
            Dim page As PdfPageBase = doc.Pages.Add()

            'Draw the page
            DrawPage(page)

            Dim pfxPath As String = "Demo.pfx"
            Dim cert As New PdfCertificate(pfxPath, "e-iceblue")
            Dim signature As New PdfSignature(doc, page, cert, "demo")
            signature.ContactInfo = "Harry Hu"
            signature.Certificated = True
            signature.DocumentPermissions = PdfCertificationFlags.AllowFormFill

            'Save pdf file.
            doc.Save("DigitalSignature.pdf")
            doc.Close()

            'Launching the Pdf file.
            Process.Start("DigitalSignature.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

The sample demonstrates how to decrypt an encrypted PDF document and extract the embedded picture.

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

namespace Decryption
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a pdf document.
            String encryptedPdf = @"Encrypted.pdf";
            PdfDocument doc = new PdfDocument(encryptedPdf, "test");

            //extract image
            Image image = doc.Pages[0].ImagesInfo[0].Image;

            doc.Close();

            //Save image file.
            image.Save("Wikipedia_Science.png", System.Drawing.Imaging.ImageFormat.Png);

            //Launching the image file.
            System.Diagnostics.Process.Start("Wikipedia_Science.png");
        }
    }
}

Imports System.Drawing
Imports Spire.Pdf

Namespace Decryption
    Friend Class Program
        Shared Sub Main(ByVal args() As String)
            'Create a pdf document.
            Dim encryptedPdf As String = "Encrypted.pdf"
            Dim doc As New PdfDocument(encryptedPdf, "test")

            'extract image
            Dim image As Image = doc.Pages(0).ImagesInfo(0).Image

            doc.Close()

            'Save image file.
            image.Save("Wikipedia_Science.png", System.Drawing.Imaging.ImageFormat.Png)

            'Launching the image file.
            Process.Start("Wikipedia_Science.png")
        End Sub
    End Class
End Namespace