Complete rewrite with better low-level support

Directory.Build.props

@@ -48,16 +48,6 @@
   </PropertyGroup>
 
   <Choose>
-    <When Condition="'$(TargetFramework)' == 'net472'">
-      <PropertyGroup>
-        <DefineConstants>$(DefineConstants);SUPPORTS_CODECOVERAGE</DefineConstants>
-      </PropertyGroup>
-    </When>
-    <When Condition="'$(TargetFramework)' == 'netstandard2.0'">
-      <PropertyGroup>
-        <DefineConstants>$(DefineConstants);SUPPORTS_CODECOVERAGE</DefineConstants>
-      </PropertyGroup>
-    </When>
     <When Condition="'$(TargetFramework)' == 'netstandard2.1'">
       <PropertyGroup>
         <DefineConstants>$(DefineConstants);SUPPORTS_MATHF</DefineConstants>
@@ -66,19 +56,6 @@
         <DefineConstants>$(DefineConstants);SUPPORTS_NULLABLEREFATTRIBUTES</DefineConstants>
       </PropertyGroup>
     </When>
-    <When Condition="'$(TargetFramework)' == 'netcoreapp2.0'">
-      <PropertyGroup>
-        <DefineConstants>$(DefineConstants);SUPPORTS_MATHF</DefineConstants>
-        <DefineConstants>$(DefineConstants);SUPPORTS_CODECOVERAGE</DefineConstants>
-      </PropertyGroup>
-    </When>
-    <When Condition="'$(TargetFramework)' == 'netcoreapp2.1'">
-      <PropertyGroup>
-        <DefineConstants>$(DefineConstants);SUPPORTS_MATHF</DefineConstants>
-        <DefineConstants>$(DefineConstants);SUPPORTS_HASHCODE</DefineConstants>
-        <DefineConstants>$(DefineConstants);SUPPORTS_CODECOVERAGE</DefineConstants>
-      </PropertyGroup>
-    </When>
     <When Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
       <PropertyGroup>
         <DefineConstants>$(DefineConstants);SUPPORTS_MATHF</DefineConstants>

samples/Synercoding.FileFormats.Pdf.ConsoleTester/Program.cs

@@ -1,4 +1,4 @@
-using Synercoding.FileFormats.Pdf.Primitives;
+using Synercoding.FileFormats.Pdf.Extensions;
 using Synercoding.Primitives;
 using Synercoding.Primitives.Extensions;
 using System.IO;

src/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project>
 
   <PropertyGroup>
-    <TargetFrameworks>net5.0;netcoreapp3.1;netcoreapp2.1;netstandard2.1;netstandard2.0;netstandard1.6</TargetFrameworks>
+    <TargetFrameworks>net5.0;netcoreapp3.1;netstandard2.1</TargetFrameworks>
     <MSBuildAllProjects>$(MSBuildAllProjects);$(MSBuildThisFileDirectory)..\Directory.Build.props</MSBuildAllProjects>
     <SynercodingProjectCategory>src</SynercodingProjectCategory>
   </PropertyGroup>

src/Synercoding.FileFormats.Pdf/DocumentInformation.cs

@@ -1,12 +1,21 @@
+using Synercoding.FileFormats.Pdf.LowLevel;
+using Synercoding.FileFormats.Pdf.LowLevel.Extensions;
 using System;
 
 namespace Synercoding.FileFormats.Pdf
 {
     /// <summary>
     /// This class contains information about the document
     /// </summary>
-    public class DocumentInformation
+    public class DocumentInformation : IPdfObject
     {
+        private bool _isWritten;
+
+        internal DocumentInformation(PdfReference id)
+        {
+            Reference = id;
+        }
+
         /// <summary>
         /// The document's title
         /// </summary>
@@ -46,5 +55,87 @@ public class DocumentInformation
         /// The date and time the document was most recently modified, in human-readable form.
         /// </summary>
         public DateTime? ModDate { get; set; }
+
+        /// <inheritdoc />
+        public PdfReference Reference { get; }
+
+        internal uint WriteToStream(PdfStream stream)
+        {
+            if (_isWritten)
+                throw new InvalidOperationException("Object is already written to stream.");
+
+            var position = (uint)stream.Position;
+
+            stream.IndirectDictionary(this, static (did, dictionary) =>
+            {
+                if (!string.IsNullOrWhiteSpace(did.Title))
+                    dictionary.Write(PdfName.Get("Title"), _toPdfHexadecimalString(did.Title!));
+                if (!string.IsNullOrWhiteSpace(did.Author))
+                    dictionary.Write(PdfName.Get("Author"), _toPdfHexadecimalString(did.Author!));
+                if (!string.IsNullOrWhiteSpace(did.Subject))
+                    dictionary.Write(PdfName.Get("Subject"), _toPdfHexadecimalString(did.Subject!));
+                if (!string.IsNullOrWhiteSpace(did.Keywords))
+                    dictionary.Write(PdfName.Get("Keywords"), _toPdfHexadecimalString(did.Keywords!));
+                if (!string.IsNullOrWhiteSpace(did.Creator))
+                    dictionary.Write(PdfName.Get("Creator"), _toPdfHexadecimalString(did.Creator!));
+                if (!string.IsNullOrWhiteSpace(did.Producer))
+                    dictionary.Write(PdfName.Get("Producer"), _toPdfHexadecimalString(did.Producer!));
+                if (did.CreationDate != null)
+                    dictionary.Write(PdfName.Get("CreationDate"), _toPdfDate(did.CreationDate.Value));
+                if (did.ModDate != null)
+                    dictionary.Write(PdfName.Get("ModDate"), _toPdfDate(did.ModDate.Value));
+            });
+
+            _isWritten = true;
+
+            return position;
+        }
+
+        private static string _toPdfHexadecimalString(string input)
+        {
+            var bytes = System.Text.Encoding.ASCII.GetBytes(input);
+            var builder = new System.Text.StringBuilder((bytes.Length * 2) + 2);
+            builder.Append('<');
+            foreach (var b in bytes)
+            {
+                builder.Append(b.ToString("X2"));
+            }
+            builder.Append('>');
+            return builder.ToString();
+        }
+
+        private static string _toPdfDate(DateTimeOffset input)
+        {
+            var datePart = input.ToString("yyyyMMddHHmmss");
+
+            var builder = new System.Text.StringBuilder(22);
+            builder.Append("(D:");
+            builder.Append(datePart);
+
+            var hours = input.Offset.Hours;
+            var minutes = input.Offset.Minutes;
+
+            if (hours == 0 && minutes == 0)
+            {
+                builder.Append("Z00'00");
+            }
+            else
+            {
+                if (hours > 0 || (hours == 0 && minutes > 0))
+                {
+                    builder.Append('+');
+                }
+                else
+                {
+                    builder.Append('-');
+                }
+                builder.Append(Math.Abs(hours).ToString().PadLeft(2, '0'));
+                builder.Append('\'');
+                builder.Append(minutes.ToString().PadLeft(2, '0'));
+            }
+            builder.Append(')');
+
+            return builder.ToString();
+        }
     }
 }

src/Synercoding.FileFormats.Pdf/Extensions/PdfPageExtensions.cs

@@ -0,0 +1,127 @@
+using Synercoding.Primitives;
+using System.IO;
+
+namespace Synercoding.FileFormats.Pdf.Extensions
+{
+    /// <summary>
+    /// Extension class for <see cref="PdfPage"/>
+    /// </summary>
+    public static class PdfPageExtensions
+    {
+        /// <summary>
+        /// Add an image to the pdf page
+        /// </summary>
+        /// <param name="page">The page to add the image to</param>
+        /// <param name="image">The image to add</param>
+        /// <param name="matrix">The placement matrix</param>
+        /// <returns>The same <see cref="PdfPage"/> to chain other calls.</returns>
+        public static PdfPage AddImage(this PdfPage page, Image image, Matrix matrix)
+        {
+            page.ContentStream
+                .SaveState()
+                .CTM(matrix)
+                .Paint(page.AddImageToResources(image))
+                .RestoreState();
+
+            return page;
+        }
+
+        /// <summary>
+        /// Add an image to the pdf page
+        /// </summary>
+        /// <param name="page">The page to add the image to</param>
+        /// <param name="image">The image to add</param>
+        /// <param name="rectangle">The placement rectangle</param>
+        /// <returns>The same <see cref="PdfPage"/> to chain other calls.</returns>
+        public static PdfPage AddImage(this PdfPage page, Image image, Rectangle rectangle)
+            => page.AddImage(image, rectangle.AsPlacementMatrix());
+
+        /// <summary>
+        /// Add an image to the pdf page
+        /// </summary>
+        /// <param name="page">The page to add the image to</param>
+        /// <param name="image">The image to add</param>
+        /// <param name="matrix">The placement matrix</param>
+        /// <returns>The same <see cref="PdfPage"/> to chain other calls.</returns>
+        public static PdfPage AddImage(this PdfPage page, SixLabors.ImageSharp.Image image, Matrix matrix)
+        {
+            page.ContentStream
+                .SaveState()
+                .CTM(matrix)
+                .Paint(page.AddImageToResources(image))
+                .RestoreState();
+
+            return page;
+        }
+
+        /// <summary>
+        /// Add an image to the pdf page
+        /// </summary>
+        /// <param name="page">The page to add the image to</param>
+        /// <param name="image">The image to add</param>
+        /// <param name="rectangle">The placement rectangle</param>
+        /// <returns>The same <see cref="PdfPage"/> to chain other calls.</returns>
+        public static PdfPage AddImage(this PdfPage page, SixLabors.ImageSharp.Image image, Rectangle rectangle)
+            => page.AddImage(image, rectangle.AsPlacementMatrix());
+
+        /// <summary>
+        /// Add an image to the pdf page
+        /// </summary>
+        /// <param name="page">The page to add the image to</param>
+        /// <param name="imageStream">The image to add</param>
+        /// <param name="matrix">The placement matrix</param>
+        /// <returns>The same <see cref="PdfPage"/> to chain other calls.</returns>
+        public static PdfPage AddImage(this PdfPage page, Stream imageStream, Matrix matrix)
+        {
+            page.ContentStream
+                .SaveState()
+                .CTM(matrix)
+                .Paint(page.AddImageToResources(imageStream))
+                .RestoreState();
+
+            return page;
+        }
+
+        /// <summary>
+        /// Add an image to the pdf page
+        /// </summary>
+        /// <param name="page">The page to add the image to</param>
+        /// <param name="imageStream">The image to add</param>
+        /// <param name="rectangle">The placement rectangle</param>
+        /// <returns>The same <see cref="PdfPage"/> to chain other calls.</returns>
+        public static PdfPage AddImage(this PdfPage page, Stream imageStream, Rectangle rectangle)
+            => page.AddImage(imageStream, rectangle.AsPlacementMatrix());
+
+        /// <summary>
+        /// Add an image to the pdf page
+        /// </summary>
+        /// <param name="page">The page to add the image to</param>
+        /// <param name="jpgStream">The image to add</param>
+        /// <param name="originalWidth">The original width of the image</param>
+        /// <param name="originalHeight">The original height of the image</param>
+        /// <param name="matrix">The placement matrix</param>
+        /// <returns>The same <see cref="PdfPage"/> to chain other calls.</returns>
+        public static PdfPage AddImage(this PdfPage page, Stream jpgStream, int originalWidth, int originalHeight, Matrix matrix)
+        {
+            page.ContentStream
+                .SaveState()
+                .CTM(matrix)
+                .Paint(page.AddImageToResources(jpgStream, originalWidth, originalHeight))
+                .RestoreState();
+
+            return page;
+        }
+
+        /// <summary>
+        /// Add an image to the pdf page
+        /// </summary>
+        /// <param name="page">The page to add the image to</param>
+        /// <param name="jpgStream">The image to add</param>
+        /// <param name="originalWidth">The original width of the image</param>
+        /// <param name="originalHeight">The original height of the image</param>
+        /// <param name="rectangle">The placement rectangle</param>
+        /// <returns>The same <see cref="PdfPage"/> to chain other calls.</returns>
+        public static PdfPage AddImage(this PdfPage page, Stream jpgStream, int originalWidth, int originalHeight, Rectangle rectangle)
+            => page.AddImage(jpgStream, originalWidth, originalHeight, rectangle.AsPlacementMatrix());
+    }
+}

src/Synercoding.FileFormats.Pdf/Extensions/PrimitiveExtensions.cs

@@ -0,0 +1,16 @@
+using Synercoding.Primitives;
+
+namespace Synercoding.FileFormats.Pdf.Extensions
+{
+    public static class PrimitiveExtensions
+    {
+        public static Matrix AsPlacementMatrix(this Rectangle rectangle)
+        {
+            rectangle = rectangle.ConvertTo(Unit.Points);
+            return new Matrix(
+                rectangle.URX.Raw - rectangle.LLX.Raw, 0,
+                0, rectangle.URY.Raw - rectangle.LLY.Raw,
+                rectangle.LLX.Raw, rectangle.LLY.Raw);
+        }
+    }
+}