Digital signature

PdfSharpCore.sln

@@ -1,7 +1,7 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio Version 16
-VisualStudioVersion = 16.0.29911.84
+# Visual Studio Version 17
+VisualStudioVersion = 17.2.32519.379
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "PdfSharpCore", "PdfSharpCore\PdfSharpCore.csproj", "{4005DEBC-75F8-48DA-BBCC-353E17872B3E}"
 EndProject
@@ -18,6 +18,11 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "PdfSharpCore.Test", "PdfSharpCore.Test\PdfSharpCore.Test.csproj", "{A862C0CE-C095-459C-A32B-8FCDD15A93BF}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SignatureTestConsole", "SignatureTestConsole\SignatureTestConsole.csproj", "{272E99C1-3210-497B-8CCE-D561E353FC13}"
+	ProjectSection(ProjectDependencies) = postProject
+		{4005DEBC-75F8-48DA-BBCC-353E17872B3E} = {4005DEBC-75F8-48DA-BBCC-353E17872B3E}
+	EndProjectSection
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -44,6 +49,10 @@ Global
 		{A862C0CE-C095-459C-A32B-8FCDD15A93BF}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{A862C0CE-C095-459C-A32B-8FCDD15A93BF}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{A862C0CE-C095-459C-A32B-8FCDD15A93BF}.Release|Any CPU.Build.0 = Release|Any CPU
+		{272E99C1-3210-497B-8CCE-D561E353FC13}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{272E99C1-3210-497B-8CCE-D561E353FC13}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{272E99C1-3210-497B-8CCE-D561E353FC13}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{272E99C1-3210-497B-8CCE-D561E353FC13}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

PdfSharpCore/Pdf.AcroForms/PdfAcroField.cs

@@ -300,6 +300,10 @@ public sealed class PdfAcroFieldCollection : PdfArray
                 : base(array)
             { }
 
+            PdfAcroFieldCollection(PdfDocument document)
+                : base(document)
+            { }
+
             /// <summary>
             /// Gets the names of all fields in the collection.
             /// </summary>
@@ -553,7 +557,27 @@ public class Keys : KeysBase
             [KeyInfo(KeyType.Integer | KeyType.Optional)]
             public const string Q = "/Q";
 
-            // ReSharper restore InconsistentNaming
+            /// <summary>
+            /// (Optional) The type of PDF object that this dictionary describes; if present,
+            /// must be Sig for a signature dictionary.
+            /// </summary>
+            [KeyInfo(KeyType.Name | KeyType.Optional)]
+            public const string Type = "/Type";
+
+            /// <summary>
+            /// 
+            /// </summary>
+            [KeyInfo(KeyType.Name | KeyType.Required)]
+            public const string Subtype = "/Subtype";
+
+            /// <summary>
+            /// 
+            /// </summary>
+            [KeyInfo(KeyType.Rectangle | KeyType.Required)]
+            public const string Rect = "/Rect";
+
+            [KeyInfo(KeyType.Rectangle | KeyType.Required)]
+            public const string P = "/P";
         }
     }
 }

PdfSharpCore/Pdf.AcroForms/PdfSignatureField.cs

@@ -27,36 +27,157 @@
 // DEALINGS IN THE SOFTWARE.
 #endregion
 
+using PdfSharpCore.Drawing;
+using PdfSharpCore.Pdf.Annotations;
+using PdfSharpCore.Pdf.Signatures;
+using System;
+
 namespace PdfSharpCore.Pdf.AcroForms
 {
     /// <summary>
     /// Represents the signature field.
     /// </summary>
     public sealed class PdfSignatureField : PdfAcroField
     {
+        private bool visible;
+
+        public string Reason
+        {
+            get
+            {
+                return Elements.GetDictionary(Keys.V).Elements.GetString(Keys.Reason);
+            }
+            set
+            {
+                Elements.GetDictionary(Keys.V).Elements[Keys.Reason] = new PdfString(value);
+            }
+        }
+
+        public string Location
+        {
+            get
+            {
+                return Elements.GetDictionary(Keys.V).Elements.GetString(Keys.Location);
+            }
+            set
+            {
+                Elements.GetDictionary(Keys.V).Elements[Keys.Location] = new PdfString(value);
+            }
+        }
+
+        public PdfItem Contents
+        {
+            get
+            {
+                return Elements.GetDictionary(Keys.V).Elements[Keys.Contents];
+            }
+            set
+            {
+                Elements.GetDictionary(Keys.V).Elements.Add(Keys.Contents, value);
+            }
+        }
+
+
+        public PdfItem ByteRange
+        {
+            get
+            {
+                return Elements.GetDictionary(Keys.V).Elements[Keys.ByteRange];
+            }
+            set
+            {
+                Elements.GetDictionary(Keys.V).Elements.Add(Keys.ByteRange, value);
+            }
+        }
+
+
+        public PdfRectangle Rectangle
+        {
+            get
+            {
+                return (PdfRectangle)Elements[Keys.Rect];
+            }
+            set
+            {                
+                Elements.Add(Keys.Rect, value);
+                this.visible = !(value.X1 + value.X2 + value.Y1 + value.Y2 == 0);   
+
+            }
+        }
+
+
+        public ISignatureAppearanceHandler AppearanceHandler { get; internal set; }
+
         /// <summary>
         /// Initializes a new instance of PdfSignatureField.
         /// </summary>
-        internal PdfSignatureField(PdfDocument document)
-            : base(document)
-        { }
+        internal PdfSignatureField(PdfDocument document) : base(document)
+        {
+
+
+            Elements.Add(Keys.FT, new PdfName("/Sig"));
+            Elements.Add(Keys.T, new PdfString("Signature1"));
+            Elements.Add(Keys.Ff, new PdfInteger(132));
+            Elements.Add(Keys.DR, new PdfDictionary());
+            Elements.Add(Keys.Type, new PdfName("/Annot"));
+            Elements.Add(Keys.Subtype, new PdfName("/Widget"));
+            Elements.Add(Keys.P, document.Pages[0]);
+
+
+            PdfDictionary sign = new PdfDictionary(document);
+            sign.Elements.Add(Keys.Type, new PdfName("/Sig"));
+            sign.Elements.Add(Keys.Filter, new PdfName("/Adobe.PPKLite"));
+            sign.Elements.Add(Keys.SubFilter, new PdfName("/adbe.pkcs7.detached"));
+            sign.Elements.Add(Keys.M, new PdfDate(DateTime.Now));
+
+            document._irefTable.Add(sign);
+            document._irefTable.Add(this);
+
+            Elements.Add(Keys.V, sign);
+
+        }
 
         internal PdfSignatureField(PdfDictionary dict)
             : base(dict)
         { }
 
+
+        internal override void PrepareForSave()
+        {
+            if (!this.visible)
+                return;
+
+            if (this.AppearanceHandler == null)
+                throw new Exception("AppearanceHandler is null");
+
+
+
+            PdfRectangle rect = Elements.GetRectangle(PdfAnnotation.Keys.Rect);
+            XForm form = new XForm(this._document, rect.Size);
+            XGraphics gfx = XGraphics.FromForm(form);
+
+            this.AppearanceHandler.DrawAppearance(gfx, rect.ToXRect());
+
+            form.DrawingFinished();
+
+            // Get existing or create new appearance dictionary
+            PdfDictionary ap = Elements[PdfAnnotation.Keys.AP] as PdfDictionary;
+            if (ap == null)
+            {
+                ap = new PdfDictionary(this._document);
+                Elements[PdfAnnotation.Keys.AP] = ap;
+            }
+
+            // Set XRef to normal state
+            ap.Elements["/N"] = form.PdfForm.Reference;
+        }
+
         /// <summary>
         /// Predefined keys of this dictionary.
         /// The description comes from PDF 1.4 Reference.
         /// </summary>
         public new class Keys : PdfAcroField.Keys
-        {
-            /// <summary>
-            /// (Optional) The type of PDF object that this dictionary describes; if present,
-            /// must be Sig for a signature dictionary.
-            /// </summary>
-            [KeyInfo(KeyType.Name | KeyType.Optional)]
-            public const string Type = "/Type";
+        {          
 
             /// <summary>
             /// (Required; inheritable) The name of the signature handler to be used for
@@ -113,6 +234,12 @@ internal PdfSignatureField(PdfDictionary dict)
             [KeyInfo(KeyType.TextString | KeyType.Optional)]
             public const string Reason = "/Reason";
 
+            /// <summary>
+            /// (Optional)
+            /// </summary>
+            [KeyInfo(KeyType.TextString | KeyType.Optional)]
+            public const string ContactInfo = "/ContactInfo";
+
             /// <summary>
             /// Gets the KeysMeta for these keys.
             /// </summary>

PdfSharpCore/Pdf.Advanced/PdfCatalog.cs

@@ -160,14 +160,15 @@ internal PdfOutlineCollection Outlines
         /// </summary>
         public PdfAcroForm AcroForm
         {
-            get
+            get { return (PdfAcroForm)Elements.GetValue(Keys.AcroForm); }
+            set
             {
-                if (_acroForm == null)
-                    _acroForm = (PdfAcroForm)Elements.GetValue(Keys.AcroForm);
-                return _acroForm;
+                if (Elements.ContainsKey(Keys.AcroForm))
+                    Elements[Keys.AcroForm] = value;
+                else
+                    Elements.Add(Keys.AcroForm, value);
             }
         }
-        PdfAcroForm _acroForm;
 
         /// <summary>
         /// Gets or sets the language identifier specifying the natural language for all text in the document.

PdfSharpCore/Pdf.Advanced/PdfContents.cs

@@ -200,7 +200,7 @@ internal override void WriteObject(PdfWriter writer)
         {
             // Save two bytes in PDF stream...
             if (Elements.Count == 1)
-                Elements[0].WriteObject(writer);
+                Elements[0].Write(writer);
             else
                 base.WriteObject(writer);
         }

PdfSharpCore/Pdf.Advanced/PdfInternals.cs

@@ -268,7 +268,7 @@ public void WriteObject(Stream stream, PdfItem item)
             // Never write an encrypted object
             PdfWriter writer = new PdfWriter(stream, null);
             writer.Options = PdfWriterOptions.OmitStream;
-            item.WriteObject(writer);
+            item.Write(writer);
         }
 
         /// <summary>

PdfSharpCore/Pdf.IO/PdfWriter.cs

@@ -199,7 +199,7 @@ public void Write(PdfString value)
             PdfStringEncoding encoding = (PdfStringEncoding)(value.Flags & PdfStringFlags.EncodingMask);
             string pdf = (value.Flags & PdfStringFlags.HexLiteral) == 0 ?
                 PdfEncoders.ToStringLiteral(value.Value, encoding, SecurityHandler) :
-                PdfEncoders.ToHexStringLiteral(value.Value, encoding, SecurityHandler);
+                PdfEncoders.ToHexStringLiteral(value.Value, encoding, SecurityHandler, value.PaddingLeft);
             WriteRaw(pdf);
 
             _lastCat = CharCat.Delimiter;

PdfSharpCore/Pdf.Internal/PdfEncoders.cs

@@ -245,9 +245,9 @@ public static string ToStringLiteral(byte[] bytes, bool unicode, PdfStandardSecu
         /// <summary>
         /// Converts a raw string into a raw hexadecimal string literal, possibly encrypted.
         /// </summary>
-        public static string ToHexStringLiteral(string text, PdfStringEncoding encoding, PdfStandardSecurityHandler securityHandler)
+        public static string ToHexStringLiteral(string text, PdfStringEncoding encoding, PdfStandardSecurityHandler securityHandler, int paddingLeft)
         {
-            if (String.IsNullOrEmpty(text))
+            if (String.IsNullOrEmpty(text) && paddingLeft == 0)
                 return "<>";
 
             byte[] bytes;
@@ -274,6 +274,13 @@ public static string ToHexStringLiteral(string text, PdfStringEncoding encoding,
                     throw new NotImplementedException(encoding.ToString());
             }
 
+            if (bytes.Length < paddingLeft)
+            {
+                byte[] tmp = new byte[paddingLeft];
+                Array.Copy(bytes, tmp, bytes.Length);
+                bytes = tmp;
+            }
+
             byte[] agTemp = FormatStringLiteral(bytes, encoding == PdfStringEncoding.Unicode, true, true, securityHandler);
             return RawEncoding.GetString(agTemp, 0, agTemp.Length);
         }

PdfSharpCore/Pdf.Signatures/DefaultAppearanceHandler.cs

@@ -0,0 +1,32 @@
+using System;
+using PdfSharpCore.Drawing;
+using PdfSharpCore.Drawing.Layout;
+
+namespace PdfSharpCore.Pdf.Signatures
+{
+    internal class DefaultAppearanceHandler : ISignatureAppearanceHandler
+    {
+        public string Location { get; set; }
+        public string Reason { get; set; }
+        public string Signer { get; set; }
+
+
+        public void DrawAppearance(XGraphics gfx, XRect rect)
+        {
+            var backColor = XColor.Empty;
+            var defaultText = string.Format("Signed by: {0}\nLocation: {1}\nReason: {2}\nDate: {3}", Signer, Location, Reason, DateTime.Now);            
+
+            XFont font = new XFont("Verdana", 7, XFontStyle.Regular);                     
+
+            XTextFormatter txtFormat = new XTextFormatter(gfx); 
+
+            var currentPosition = new XPoint(0, 0);
+
+            txtFormat.DrawString(defaultText, 
+                font, 
+                new XSolidBrush(XColor.FromKnownColor(XKnownColor.Black)), 
+                new XRect(currentPosition.X, currentPosition.Y, rect.Width - currentPosition.X, rect.Height),  
+                XStringFormats.TopLeft);           
+        }
+    }
+}