add support for extracting grayscale images and inline images

src/UglyToad.PdfPig/Content/InlineImage.cs

@@ -8,6 +8,7 @@
     using Graphics.Colors;
     using Graphics.Core;
     using Tokens;
+    using Images.Png;
 
     /// <inheritdoc />
     /// <summary>
@@ -112,11 +113,7 @@
         }
 
         /// <inheritdoc />
-        public bool TryGetPng(out byte[] bytes)
+        public bool TryGetPng(out byte[] bytes) => PngFromPdfImageFactory.TryGenerate(this, out bytes);
-        {
-            bytes = null;
-            return false;
-        }
 
         /// <inheritdoc />
         public override string ToString()

src/UglyToad.PdfPig/Images/Png/PngFromPdfImageFactory.cs

@@ -0,0 +1,61 @@
+namespace UglyToad.PdfPig.Images.Png
+{
+    using Content;
+    using Graphics.Colors;
+
+    internal static class PngFromPdfImageFactory
+    {
+        public static bool TryGenerate(IPdfImage image, out byte[] bytes)
+        {
+            bytes = null;
+
+            var isColorSpaceSupported = image.ColorSpace == ColorSpace.DeviceGray || image.ColorSpace == ColorSpace.DeviceRGB;
+            if (!isColorSpaceSupported || !image.TryGetBytes(out var bytesPure))
+            {
+                return false;
+            }
+
+            try
+            {
+                var is3Byte = image.ColorSpace == ColorSpace.DeviceRGB;
+                var multiplier = is3Byte ? 3 : 1;
+
+                var builder = PngBuilder.Create(image.WidthInSamples, image.HeightInSamples, false);
+
+                var isCorrectlySized = bytesPure.Count == (image.WidthInSamples * image.HeightInSamples * (image.BitsPerComponent / 8) * multiplier);
+
+                if (!isCorrectlySized)
+                {
+                    return false;
+                }
+
+                var i = 0;
+                for (var y = 0; y < image.HeightInSamples; y++)
+                {
+                    for (var x = 0; x < image.WidthInSamples; x++)
+                    {
+                        if (is3Byte)
+                        {
+                            builder.SetPixel(bytesPure[i++], bytesPure[i++], bytesPure[i++], x, y);
+                        }
+                        else
+                        {
+                            var pixel = bytesPure[i++];
+                            builder.SetPixel(pixel, pixel, pixel, x, y);
+                        }
+                    }
+                }
+
+                bytes = builder.Save();
+
+                return true;
+            }
+            catch
+            {
+                // ignored.
+            }
+
+            return false;
+        }
+    }
+}

src/UglyToad.PdfPig/UglyToad.PdfPig.csproj

@@ -38,7 +38,4 @@
     <ProjectReference Include="..\UglyToad.PdfPig.Tokenization\UglyToad.PdfPig.Tokenization.csproj" />
     <ProjectReference Include="..\UglyToad.PdfPig.Tokens\UglyToad.PdfPig.Tokens.csproj" />
   </ItemGroup>
-  <ItemGroup>
-    <Folder Include="Images\Png\" />
-  </ItemGroup>
 </Project>

src/UglyToad.PdfPig/Writer/PdfPageBuilder.cs

@@ -333,7 +333,13 @@
         /// </summary>
         /// <param name="image">An image previously added to this page or another page.</param>
         /// <param name="placementRectangle">The size and location to draw the image on this page.</param>
-        public void AddJpeg(AddedImage image, PdfRectangle placementRectangle)
+        public void AddJpeg(AddedImage image, PdfRectangle placementRectangle) => AddImage(image, placementRectangle);
+
+        /// <summary>
+        /// Adds the image previously added using <see cref="AddJpeg(byte[], PdfRectangle)"/>
+        /// or <see cref="AddPng(byte[], PdfRectangle)"/> sharing the same image to prevent duplication.
+        /// </summary>
+        public void AddImage(AddedImage image, PdfRectangle placementRectangle)
         {
             if (!resourcesDictionary.TryGetValue(NameToken.Xobject, out var xobjectsDict) 
                 || !(xobjectsDict is DictionaryToken xobjects))

src/UglyToad.PdfPig/XObjects/XObjectImage.cs

@@ -109,45 +109,7 @@
         }
 
         /// <inheritdoc />
-        public bool TryGetPng(out byte[] bytes)
+        public bool TryGetPng(out byte[] bytes) => PngFromPdfImageFactory.TryGenerate(this, out bytes);
-        {
-            bytes = null;
-            if (ColorSpace != Graphics.Colors.ColorSpace.DeviceRGB || !TryGetBytes(out var bytesPure))
-            {
-                return false;
-            }
-
-            try
-            {
-                var builder = PngBuilder.Create(WidthInSamples, HeightInSamples, false);
-
-                var isCorrectlySized = bytesPure.Count == (WidthInSamples * HeightInSamples * (BitsPerComponent / 8) * 3);
-
-                if (!isCorrectlySized)
-                {
-                    return false;
-                }
-
-                var i = 0;
-                for (var y = 0; y < HeightInSamples; y++)
-                {
-                    for (var x = 0; x < WidthInSamples; x++)
-                    {
-                        builder.SetPixel(bytesPure[i++], bytesPure[i++], bytesPure[i++], x, y);
-                    }
-                }
-
-                bytes = builder.Save();
-
-                return true;
-            }
-            catch
-            {
-                // ignored.
-            }
-
-            return false;
-        }
 
         /// <inheritdoc />
         public override string ToString()