CairoPlatformImage: replace dllimports and refactor Stream handling

src/Platform.Maui.Linux.Gtk4/Graphics/CairoGraphicsServices.cs

@@ -133,7 +133,7 @@ public IImage FromStream(Stream stream, ImageFormat format = ImageFormat.Png)
 	{
 		ArgumentNullException.ThrowIfNull(stream);
 
-		var image = CairoPlatformImage.FromStream(stream);
+		var image = CairoPlatformImage.FromStream(stream, format);
 		if (image == null)
 			throw new ArgumentException("Could not decode image from stream.");
 

src/Platform.Maui.Linux.Gtk4/Graphics/CairoPlatformImage.cs

@@ -17,8 +17,8 @@ public CairoPlatformImage(Cairo.ImageSurface surface)
 
 	internal Cairo.ImageSurface Surface { get; }
 
-	public float Width => cairo_image_surface_get_width(Surface.Handle.DangerousGetHandle());
-	public float Height => cairo_image_surface_get_height(Surface.Handle.DangerousGetHandle());
+	public float Width => Surface.Width;
+	public float Height => Surface.Height;
 
 	public IImage Downsize(float maxWidthOrHeight, bool disposeOriginal = false)
 	{
@@ -102,17 +102,8 @@ public IImage Resize(float width, float height, ResizeMode resizeMode = ResizeMo
 
 	public void Save(Stream stream, ImageFormat format = ImageFormat.Png, float quality = 1)
 	{
-		var tmpPath = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"maui_img_{Guid.NewGuid():N}.png");
-		try
-		{
-			cairo_surface_write_to_png(Surface.Handle.DangerousGetHandle(), tmpPath);
-			using var fs = File.OpenRead(tmpPath);
-			fs.CopyTo(stream);
-		}
-		finally
-		{
-			try { File.Delete(tmpPath); } catch { }
-		}
+		using var pixbuf = Surface.CreatePixbuf();
+		pixbuf.SaveToStream(stream, format);
 	}
 
 	public Task SaveAsync(Stream stream, ImageFormat format = ImageFormat.Png, float quality = 1)
@@ -122,37 +113,29 @@ public Task SaveAsync(Stream stream, ImageFormat format = ImageFormat.Png, float
 	}
 
 	/// <summary>
-	/// Creates a CairoPlatformImage from a PNG stream.
+	/// Creates a CairoPlatformImage from a stream.
 	/// </summary>
-	public static CairoPlatformImage? FromStream(Stream stream)
+	public static CairoPlatformImage? FromStream(Stream stream, ImageFormat imageFormat)
 	{
-		var tmpPath = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"maui_img_{Guid.NewGuid():N}.png");
 		try
 		{
-			using (var fs = File.Create(tmpPath))
-				stream.CopyTo(fs);
-
-			var surfaceHandle = cairo_image_surface_create_from_png(tmpPath);
-			if (surfaceHandle == nint.Zero)
+			using var pixbuf = PixbufExtensions.LoadFromStream(stream);
+			if (pixbuf is null)
 				return null;
 
-			// Wrap the unmanaged surface handle. We use an ImageSurface that manages its own lifetime.
-			var surface = new Cairo.ImageSurface(Cairo.Format.Argb32,
-				cairo_image_surface_get_width(surfaceHandle),
-				cairo_image_surface_get_height(surfaceHandle));
+			var surface = new Cairo.ImageSurface(Cairo.Format.Argb32, pixbuf.Width, pixbuf.Height);
 
-			// Copy the PNG data onto our managed surface
 			var cr = new Cairo.Context(surface);
-			cairo_set_source_surface(cr.Handle.DangerousGetHandle(), surfaceHandle, 0, 0);
-			Cairo.Internal.Context.Paint(cr.Handle);
+			cr.PaintPixbuf(pixbuf);
+
 			cr.Dispose();
-			cairo_surface_destroy(surfaceHandle);
 
 			return new CairoPlatformImage(surface);
 		}
 		finally
 		{
-			try { File.Delete(tmpPath); } catch { }
+			try { }
+			catch { }
 		}
 	}
 
@@ -161,21 +144,4 @@ public void Dispose()
 		Surface?.Dispose();
 	}
 
-	[DllImport("libcairo.so.2")]
-	private static extern int cairo_surface_write_to_png(nint surface, [MarshalAs(UnmanagedType.LPUTF8Str)] string filename);
-
-	[DllImport("libcairo.so.2")]
-	private static extern nint cairo_image_surface_create_from_png([MarshalAs(UnmanagedType.LPUTF8Str)] string filename);
-
-	[DllImport("libcairo.so.2")]
-	private static extern int cairo_image_surface_get_width(nint surface);
-
-	[DllImport("libcairo.so.2")]
-	private static extern int cairo_image_surface_get_height(nint surface);
-
-	[DllImport("libcairo.so.2")]
-	private static extern void cairo_set_source_surface(nint cr, nint surface, double x, double y);
-
-	[DllImport("libcairo.so.2")]
-	private static extern void cairo_surface_destroy(nint surface);
-}
+}

src/Platform.Maui.Linux.Gtk4/Graphics/PixbufExtensions.cs

@@ -0,0 +1,152 @@
+using Cairo;
+using GdkPixbuf;
+using Gio;
+using GLib;
+
+namespace Platform.Maui.Linux.Gtk4.Graphics;
+
+internal static class PixbufExtensions
+{
+	public static void PaintPixbuf(this Context context, Pixbuf pixbuf, double x = 0, double y = 0, double? width = default, double? height = default)
+	{
+		var translate = x != 0 || y != 0;
+		var scale = width.HasValue && height.HasValue && (width != pixbuf.Width || height != pixbuf.Height);
+		if (translate || scale)
+			context.Save();
+		if (translate)
+			context.Translate(x, y);
+		if (scale)
+			context.Scale(width.Value / pixbuf.Width, height.Value / pixbuf.Height);
+		Gdk.Functions.CairoSetSourcePixbuf(context, pixbuf, 0, 0);
+
+		using var p = context.GetSource();
+		if (p is SurfacePattern pattern)
+		{
+			// Fixes blur issue when rendering on an image surface
+			pattern.Filter =
+				width > pixbuf.Width || height > pixbuf.Height ? Filter.Fast : Filter.Good;
+		}
+
+		context.Paint();
+		if (translate || scale)
+			context.Restore();
+	}
+
+	public static Pixbuf? CreatePixbuf(this ImageSurface? surface)
+	{
+		if (surface == null)
+			return null;
+
+		var surfaceData = surface.GetData();
+		var nbytes = surface.Format == Format.Argb32 ? 4 : 3;
+		var pixData = new byte[surfaceData.Length / 4 * nbytes];
+
+		var i = 0;
+		var n = 0;
+		var stride = surface.Stride;
+		var ncols = surface.Width;
+
+		if (BitConverter.IsLittleEndian)
+		{
+			var row = surface.Height;
+
+			while (row-- > 0)
+			{
+				var prevPos = n;
+				var col = ncols;
+
+				while (col-- > 0)
+				{
+					var alphaFactor = nbytes == 4 ? 255d / surfaceData[n + 3] : 1;
+					pixData[i] = (byte)(surfaceData[n + 2] * alphaFactor + 0.5);
+					pixData[i + 1] = (byte)(surfaceData[n + 1] * alphaFactor + 0.5);
+					pixData[i + 2] = (byte)(surfaceData[n + 0] * alphaFactor + 0.5);
+
+					if (nbytes == 4)
+						pixData[i + 3] = surfaceData[n + 3];
+
+					n += 4;
+					i += nbytes;
+				}
+
+				n = prevPos + stride;
+			}
+		}
+		else
+		{
+			var row = surface.Height;
+
+			while (row-- > 0)
+			{
+				var prevPos = n;
+				var col = ncols;
+
+				while (col-- > 0)
+				{
+					var alphaFactor = nbytes == 4 ? 255d / surfaceData[n + 3] : 1;
+					pixData[i] = (byte)(surfaceData[n + 1] * alphaFactor + 0.5);
+					pixData[i + 1] = (byte)(surfaceData[n + 2] * alphaFactor + 0.5);
+					pixData[i + 2] = (byte)(surfaceData[n + 3] * alphaFactor + 0.5);
+
+					if (nbytes == 4)
+						pixData[i + 3] = surfaceData[n + 0];
+
+					n += 4;
+					i += nbytes;
+				}
+
+				n = prevPos + stride;
+			}
+		}
+
+		return Pixbuf.NewFromBytes(Bytes.New(pixData),
+			Colorspace.Rgb,
+			nbytes == 4,
+			8, surface.Width, surface.Height, surface.Width * nbytes);
+	}
+
+	public static string? ToImageExtension(this ImageFormat imageFormat) =>
+		imageFormat switch
+		{
+			ImageFormat.Bmp => "bmp",
+			ImageFormat.Png => "png",
+			ImageFormat.Jpeg => "jpeg",
+			ImageFormat.Gif => "gif",
+			ImageFormat.Tiff => "tiff",
+			_ => default
+		};
+
+	public static void SaveToStream(this Pixbuf? pixbuf, Stream stream, ImageFormat imageFormat = ImageFormat.Png)
+	{
+		if (pixbuf == null)
+			return;
+
+		using var outputStream = MemoryOutputStream.NewResizable();
+		var success = pixbuf.SaveToStreamv(outputStream, imageFormat.ToImageExtension(), default, default, default);
+
+		if (!success)
+			throw new Exception("Failed to save pixbuf to stream");
+
+		var bytes = outputStream.StealAsBytes();
+		stream.Write(bytes.GetRegionSpan<byte>(0, bytes.GetSize()));
+	}
+
+	public static Pixbuf? LoadFromStream(Stream stream)
+	{
+		var loader = PixbufLoader.New();
+		loader.LoadFromStream(stream);
+		return loader.GetPixbuf();
+	}
+
+	private static void LoadFromStream(this PixbufLoader loader, Stream input)
+	{
+		const int bufferSize = 8192;
+		var buffer = new byte[bufferSize];
+		int bytesRead;
+
+		while ((bytesRead = input.Read(buffer, 0, bufferSize)) != 0)
+		{
+			loader.Write(buffer.AsSpan(0, bytesRead));
+		}
+	}
+}

src/Platform.Maui.Linux.Gtk4/Platform.Maui.Linux.Gtk4.csproj

@@ -12,6 +12,7 @@
 
   <ItemGroup>
     <PackageReference Include="GirCore.Gtk-4.0" Version="0.7.0" />
+    <PackageReference Include="GirCore.GdkPixbuf-2.0" Version="0.7.0" />
     <PackageReference Include="GirCore.WebKit-6.0" Version="0.7.0" />
     <PackageReference Include="Microsoft.Maui.Controls" Version="$(MauiVersion)" />
   </ItemGroup>