[POC] Start refactoring to render pdf pages as images

src/UglyToad.PdfPig.Core/TransformationMatrix.cs

@@ -1,7 +1,6 @@
 namespace UglyToad.PdfPig.Core
 {
     using System;
-    using System.Collections;
     using System.Collections.Generic;
     using System.Diagnostics.Contracts;
     using System.Linq;
@@ -10,22 +9,22 @@
     /// <summary>
     /// Specifies the conversion from the transformed coordinate space to the original untransformed coordinate space.
     /// </summary>
-    public struct TransformationMatrix
+    public readonly struct TransformationMatrix
     {
         /// <summary>
         /// The default <see cref="TransformationMatrix"/>.
         /// </summary>
-        public static TransformationMatrix Identity = new TransformationMatrix(1,0,0,
-            0,1,0,
-            0,0,1);
-        
+        public static TransformationMatrix Identity = new TransformationMatrix(1, 0, 0,
+            0, 1, 0,
+            0, 0, 1);
+
         /// <summary>
         /// Create a new <see cref="TransformationMatrix"/> with the X and Y translation values set.
         /// </summary>
         public static TransformationMatrix GetTranslationMatrix(double x, double y) => new TransformationMatrix(1, 0, 0,
             0, 1, 0,
             x, y, 1);
-        
+
         /// <summary>
         /// Create a new <see cref="TransformationMatrix"/> with the X and Y scaling values set.
         /// </summary>
@@ -105,7 +104,7 @@ public static TransformationMatrix GetRotationMatrix(double degreesCounterclockw
         /// The value at (2, 1) - translation in Y.
         /// </summary>
         public readonly double F;
-        
+
         /// <summary>
         /// Get the value at the specific row and column.
         /// </summary>
@@ -224,10 +223,20 @@ public TransformationMatrix(double a, double b, double r1, double c, double d, d
         [Pure]
         public PdfPoint Transform(PdfPoint original)
         {
-            var x = A * original.X + C * original.Y + E;
-            var y = B * original.X + D * original.Y + F;
+            (double x, double y) xy = Transform(original.X, original.Y);
+            return new PdfPoint(xy.x, xy.y);
+        }
 
-            return new PdfPoint(x, y);
+        /// <summary>
+        /// Transform a point using this transformation matrix.
+        /// </summary>
+        /// <param name="x">The original point X coordinate.</param>
+        /// <param name="y">The original point Y coordinate.</param>
+        /// <returns>A new point which is the result of applying this transformation matrix.</returns>
+        [Pure]
+        public (double x, double y) Transform(double x, double y)
+        {
+            return new(A * x + C * y + E, B * x + D * y + F);
         }
 
         /// <summary>
@@ -353,7 +362,7 @@ public static TransformationMatrix FromValues(double a, double b, double c, doub
         /// <param name="values">Either all 9 values of the matrix, 6 values in the default PDF order or the 4 values of the top left square.</param>
         /// <returns></returns>
         public static TransformationMatrix FromArray(decimal[] values)
-            => FromArray(values.Select(x => (double) x).ToArray());
+            => FromArray(values.Select(x => (double)x).ToArray());
 
         /// <summary>
         /// Create a new <see cref="TransformationMatrix"/> from the values.
@@ -404,8 +413,8 @@ public TransformationMatrix Multiply(TransformationMatrix matrix)
             var f = (E * matrix.B) + (F * matrix.D) + (row3 * matrix.F);
             var r3 = (E * matrix.row1) + (F * matrix.row2) + (row3 * matrix.row3);
 
-            return new TransformationMatrix(a, b, r1, 
-                c, d, r2, 
+            return new TransformationMatrix(a, b, r1,
+                c, d, r2,
                 e, f, r3);
         }
 

src/UglyToad.PdfPig.Core/UglyToad.PdfPig.Core.csproj

@@ -7,6 +7,7 @@
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\pdfpig.snk</AssemblyOriginatorKeyFile>
+    <Nullable>annotations</Nullable>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netstandard2.0|AnyCPU'">
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>

src/UglyToad.PdfPig.DocumentLayoutAnalysis/UglyToad.PdfPig.DocumentLayoutAnalysis.csproj

@@ -7,6 +7,7 @@
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\pdfpig.snk</AssemblyOriginatorKeyFile>
+    <Nullable>annotations</Nullable>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netstandard2.0|AnyCPU'">
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>

src/UglyToad.PdfPig.Fonts/UglyToad.PdfPig.Fonts.csproj

@@ -7,6 +7,7 @@
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <SignAssembly>true</SignAssembly>
     <AssemblyOriginatorKeyFile>..\pdfpig.snk</AssemblyOriginatorKeyFile>
+    <Nullable>annotations</Nullable>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(TargetFramework)|$(Platform)'=='Debug|netstandard2.0|AnyCPU'">
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>

src/UglyToad.PdfPig.Rendering.Skia.Tests/Helpers.cs

@@ -0,0 +1,22 @@
+namespace UglyToad.PdfPig.Rendering.Skia.Tests
+{
+    internal static class Helpers
+    {
+        private static readonly string basePath = Path.GetFullPath("..\\..\\..\\..\\UglyToad.PdfPig.Tests\\Integration\\Documents");
+
+        public static string GetDocumentPath(string fileName)
+        {
+            if (!fileName.EndsWith(".pdf"))
+            {
+                fileName += ".pdf";
+            }
+
+            return Path.Combine(basePath, fileName);
+        }
+
+        public static string[] GetAllDocuments()
+        {
+            return Directory.GetFiles(basePath, "*.pdf");
+        }
+    }
+}

src/UglyToad.PdfPig.Rendering.Skia.Tests/RenderTests.cs

@@ -0,0 +1,97 @@
+using SkiaSharp;
+using UglyToad.PdfPig.Rendering.Skia.Parser;
+
+namespace UglyToad.PdfPig.Rendering.Skia.Tests
+{
+    public class RenderTests
+    {
+        // Image rotated bug
+
+        const float scale = 1.5f;
+
+        public RenderTests()
+        {
+            Directory.CreateDirectory("renders");
+        }
+
+        [Fact]
+        public void PigProductionHandbook()
+        {
+            RenderDocument("Pig Production Handbook");
+        }
+
+        [Fact]
+        public void d_68_1990_01_A()
+        {
+            RenderDocument("68-1990-01_A");
+        }
+
+        [Fact]
+        public void d_22060_A1_01_Plans_1()
+        {
+            RenderDocument("22060_A1_01_Plans-1");
+        }
+
+        [Fact]
+        public void cat_genetics_bobld()
+        {
+            RenderDocument("cat-genetics_bobld");
+        }
+
+        [Fact(Skip = "For debugging purpose")]
+        public void RenderAllDocuments()
+        {
+            foreach (string doc in Helpers.GetAllDocuments())
+            {
+                string fileName = Path.GetFileNameWithoutExtension(doc);
+
+                using (var document = PdfDocument.Open(doc))
+                {
+                    document.AddPageFactory<SKPicture, SkiaPageFactory>();
+
+                    for (int p = 1; p <= document.NumberOfPages; p++)
+                    {
+                        var page = document.GetPage(p);
+
+                        using (var picture = document.GetPage<SKPicture>(p))
+                        {
+                            Assert.NotNull(picture);
+
+                            using (var fs = new FileStream($"renders\\{fileName}_{p}.png", FileMode.Create))
+                            using (var image = SKImage.FromPicture(picture, new SKSizeI((int)(page.Width * scale), (int)(page.Height * scale)), SKMatrix.CreateScale(scale, scale)))
+                            using (SKData d = image.Encode(SKEncodedImageFormat.Png, 100))
+                            {
+                                d.SaveTo(fs);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        private static void RenderDocument(string path)
+        {
+            using (var document = PdfDocument.Open(Helpers.GetDocumentPath(path)))
+            {
+                document.AddPageFactory<SKPicture, SkiaPageFactory>();
+
+                for (int p = 1; p <= document.NumberOfPages; p++)
+                {
+                    var page = document.GetPage(p);
+
+                    using (var picture = document.GetPage<SKPicture>(p))
+                    {
+                        Assert.NotNull(picture);
+
+                        using (var fs = new FileStream($"renders\\{path}_{p}.png", FileMode.Create))
+                        using (var image = SKImage.FromPicture(picture, new SKSizeI((int)(page.Width * scale), (int)(page.Height * scale)), SKMatrix.CreateScale(scale, scale)))
+                        using (SKData d = image.Encode(SKEncodedImageFormat.Png, 100))
+                        {
+                            d.SaveTo(fs);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}

src/UglyToad.PdfPig.Rendering.Skia.Tests/UglyToad.PdfPig.Rendering.Skia.Tests.csproj

@@ -0,0 +1,29 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.5.0" />
+    <PackageReference Include="xunit" Version="2.4.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+    <PackageReference Include="coverlet.collector" Version="3.2.0">
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+      <PrivateAssets>all</PrivateAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\UglyToad.PdfPig.Rendering.Skia\UglyToad.PdfPig.Rendering.Skia.csproj" />
+  </ItemGroup>
+
+</Project>

src/UglyToad.PdfPig.Rendering.Skia.Tests/Usings.cs

@@ -0,0 +1 @@
+global using Xunit;