feature: .dds image support (#1392)

* Added Pfim as 3rdparty lib

* Added support for parsing showing dds and tga images using Pfim

---------

Co-authored-by: Snimax <[email protected]>

Author: henrik-andersson-sus

src/Models/ImageDecoder.cs

@@ -4,5 +4,6 @@ public enum ImageDecoder
     {
         None = 0,
         Builtin,
+        Pfim
     }
 }

src/SourceGit.csproj

@@ -50,6 +50,7 @@
     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.4.0" />
     <PackageReference Include="LiveChartsCore.SkiaSharpView.Avalonia" Version="2.0.0-rc5.4" />
     <PackageReference Include="OpenAI" Version="2.2.0-beta.4" />
+    <PackageReference Include="Pfim" Version="0.11.3" />
     <PackageReference Include="TextMateSharp" Version="1.0.66" />
     <PackageReference Include="TextMateSharp.Grammars" Version="1.0.66" />
   </ItemGroup>

src/ViewModels/ImageSource.cs

@@ -1,5 +1,7 @@
 using System.IO;
+using System.Runtime.InteropServices;
 using Avalonia.Media.Imaging;
+using Pfim;
 
 namespace SourceGit.ViewModels
 {
@@ -27,6 +29,9 @@ public static Models.ImageDecoder GetDecoder(string file)
                 case ".png":
                 case ".webp":
                     return Models.ImageDecoder.Builtin;
+                case ".tga":
+                case ".dds":
+                    return Models.ImageDecoder.Pfim;
                 default:
                     return Models.ImageDecoder.None;
             }
@@ -70,9 +75,93 @@ private static ImageSource LoadFromStream(Stream stream, Models.ImageDecoder dec
                         // Just ignore.
                     }
                 }
+                else if (decoder == Models.ImageDecoder.Pfim)
+                {
+                    return new ImageSource(LoadWithPfim(stream), size);
+                }
             }
 
             return new ImageSource(null, 0);
         }
+
+        private static Bitmap LoadWithPfim(Stream stream)
+        {
+            var image = Pfim.Pfimage.FromStream(stream);
+            byte[] data;
+            int stride;
+            if (image.Format == ImageFormat.Rgba32)
+            {
+                data = image.Data;
+                stride = image.Stride;
+            }
+            else
+            {
+                int pixels = image.Width * image.Height;
+                data = new byte[pixels * 4];
+                stride = image.Width * 4;
+
+                switch (image.Format)
+                {
+                    case ImageFormat.Rgba16:
+                    case ImageFormat.R5g5b5a1:
+                        {
+                            for (int i = 0; i < pixels; i++)
+                            {
+                                data[i * 4 + 0] = image.Data[i * 4 + 2]; // B
+                                data[i * 4 + 1] = image.Data[i * 4 + 1]; // G
+                                data[i * 4 + 2] = image.Data[i * 4 + 0]; // R
+                                data[i * 4 + 3] = image.Data[i * 4 + 3]; // A
+                            }
+                        }
+                        break;
+                    case ImageFormat.R5g5b5:
+                    case ImageFormat.R5g6b5:
+                    case ImageFormat.Rgb24:
+                        {
+                            for (int i = 0; i < pixels; i++)
+                            {
+                                data[i * 4 + 0] = image.Data[i * 3 + 2]; // B
+                                data[i * 4 + 1] = image.Data[i * 3 + 1]; // G
+                                data[i * 4 + 2] = image.Data[i * 3 + 0]; // R
+                                data[i * 4 + 3] = 255;                   // A
+                            }
+                        }
+                        break;
+                    case ImageFormat.Rgb8:
+                        {
+                            for (int i = 0; i < pixels; i++)
+                            {
+                                var color = image.Data[i];
+                                data[i * 4 + 0] = color;
+                                data[i * 4 + 1] = color;
+                                data[i * 4 + 2] = color;
+                                data[i * 4 + 3] = 255;
+                            }
+                        }
+                        break;
+                    default:
+                        return null;
+                }
+            }
+
+            // Pin the array and pass the pointer to Bitmap
+            var handle = GCHandle.Alloc(data, GCHandleType.Pinned);
+            try
+            {
+                var ptr = Marshal.UnsafeAddrOfPinnedArrayElement(data, 0);
+                var bitmap = new Bitmap(
+                    Avalonia.Platform.PixelFormat.Bgra8888,
+                    Avalonia.Platform.AlphaFormat.Unpremul,
+                    ptr,
+                    new Avalonia.PixelSize(image.Width, image.Height),
+                    new Avalonia.Vector(96, 96),
+                    stride);
+                return bitmap;
+            }
+            finally
+            {
+                handle.Free();
+            }
+        }
     }
 }