Added members to decode a particular frame

- binding
 - tests

binding/Binding/Definitions.cs

@@ -925,6 +925,12 @@ namespace SkiaSharp
 			FrameIndex = 0;
 			HasPriorFrame = false;
 		}
+		public SKCodecOptions (int frameIndex, bool hasPriorFrame) {
+			ZeroInitialized = SKZeroInitialized.No;
+			Subset = null;
+			FrameIndex = frameIndex;
+			HasPriorFrame = hasPriorFrame;
+		}
 		public SKZeroInitialized ZeroInitialized { get; set; }
 		public SKRectI? Subset { get; set; }
 		public bool HasSubset => Subset != null;
@@ -932,6 +938,22 @@ namespace SkiaSharp
 		public bool HasPriorFrame { get; set; }
 	}
 
+	[StructLayout(LayoutKind.Sequential)]
+	public struct SKCodecFrameInfo {
+		private IntPtr requiredFrame;
+		private IntPtr duration;
+
+		public int RequiredFrame {
+			get { return (int)requiredFrame; }
+			set { requiredFrame = (IntPtr)value; }
+		}
+
+		public int Duration {
+			get { return (int)duration; }
+			set { duration = (IntPtr)value; }
+		}
+	}
+
 	[StructLayout(LayoutKind.Sequential)]
 	public struct SKPoint {
 		private float x, y;
@@ -2922,7 +2944,6 @@ typeMask = Mask.Scale | Mask.RectStaysRect
 					break;
 				default:
 					throw new ArgumentOutOfRangeException (nameof (color));
-					break;
 			}
 		}
 

binding/Binding/SKCodec.cs

@@ -80,6 +80,19 @@ namespace SkiaSharp
 			}
 		}
 
+		public int RepetitionCount => SkiaApi.sk_codec_get_repetition_count (Handle);
+
+		public int FrameCount => SkiaApi.sk_codec_get_frame_count (Handle);
+
+		public SKCodecFrameInfo[] FrameInfo {
+			get {
+				var length = SkiaApi.sk_codec_get_frame_count (Handle);
+				var info = new SKCodecFrameInfo [length];
+				SkiaApi.sk_codec_get_frame_info (Handle, info);
+				return info;
+			}
+		}
+
 		public SKCodecResult GetPixels (out byte[] pixels)
 		{
 			return GetPixels (Info, out pixels);
@@ -107,6 +120,12 @@ namespace SkiaSharp
 			}
 		}
 
+		public unsafe SKCodecResult GetPixels (SKImageInfo info, IntPtr pixels, int rowBytes, SKCodecOptions options)
+		{
+			var colorTableCount = 0;
+			return GetPixels (info, pixels, rowBytes, options, IntPtr.Zero, ref colorTableCount);
+		}
+
 		public unsafe SKCodecResult GetPixels (SKImageInfo info, IntPtr pixels, int rowBytes, SKCodecOptions options, IntPtr colorTable, ref int colorTableCount)
 		{
 			if (pixels == IntPtr.Zero)
@@ -125,6 +144,12 @@ namespace SkiaSharp
 			return SkiaApi.sk_codec_get_pixels (Handle, ref info, pixels, (IntPtr)rowBytes, ref nativeOptions, colorTable, ref colorTableCount);
 		}
 
+		public SKCodecResult GetPixels (SKImageInfo info, IntPtr pixels, SKCodecOptions options)
+		{
+			var colorTableCount = 0;
+			return GetPixels (info, pixels, options, IntPtr.Zero, ref colorTableCount);
+		}
+
 		public SKCodecResult GetPixels (SKImageInfo info, IntPtr pixels, SKCodecOptions options, IntPtr colorTable, ref int colorTableCount)
 		{
 			return GetPixels (info, pixels, info.RowBytes, options, colorTable, ref colorTableCount);

binding/Binding/SkiaApi.cs

@@ -1059,6 +1059,12 @@ namespace SkiaSharp
 		public extern static SKCodecResult sk_codec_start_incremental_decode(sk_codec_t codec, ref SKImageInfo info, IntPtr pixels, IntPtr rowBytes, IntPtr optionsZero, IntPtr ctableZero, IntPtr ctableCountZero);
 		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
 		public extern static SKCodecResult sk_codec_incremental_decode(sk_codec_t codec, out int rowsDecoded);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		public extern static int sk_codec_get_repetition_count(sk_codec_t codec);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		public extern static int sk_codec_get_frame_count(sk_codec_t codec);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		public extern static void sk_codec_get_frame_info(sk_codec_t codec, [Out] SKCodecFrameInfo[] frameInfo);
 
 		// Bitmap
 		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]

externals/skia

@@ -1 +1 @@
-Subproject commit 559dead6d57212457b989be1eae6c13ac8d43274
+Subproject commit 707ac58f0208b7bc8fb7cc008f4f8003be39b870

samples/SkiaSharpSample.Shared/SampleMedia.cs

@@ -24,6 +24,7 @@ namespace SkiaSharpSample
 			public static Stream NinePatch => Embedded.Load("nine-patch.png");
 			public static Stream BabyTux => Embedded.Load("baby_tux.webp");
 			public static Stream LogosSvg => Embedded.Load("logos.svg");
+			public static Stream AnimatedHeartGif => Embedded.Load("animated-heart.gif");
 		}
 
 		public static class Fonts

samples/SkiaSharpSample.Shared/SkiaSharpSample.Shared.projitems

@@ -59,15 +59,14 @@
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\adobe-dng.dng" />
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\baby_tux.webp" />
-  </ItemGroup>
-  <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\baboon.png" />
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\color-wheel.png" />
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\embedded-font.ttf" />
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\nine-patch.png" />
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\logos.svg" />
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\animated-heart.gif" />
   </ItemGroup>
   <ItemGroup>
     <None Include="$(MSBuildThisFileDirectory)Media\content-font.ttf" />
-    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Media\logos.svg" />
   </ItemGroup>
 </Project>

tests/SkiaSharp.Desktop.Tests/SkiaSharp.Desktop.Tests.csproj

@@ -175,6 +175,10 @@
       <Link>images\logos.svg</Link>
       <CopyToOutputDirectory>Always</CopyToOutputDirectory>
     </Content>
+    <Content Include="..\..\samples\SkiaSharpSample.Shared\Media\animated-heart.gif">
+      <Link>images\animated-heart.gif</Link>
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
     <None Include="packages.config" />
   </ItemGroup>
   <ItemGroup>

tests/Tests/SKCodecTest.cs

@@ -30,6 +30,47 @@ namespace SkiaSharp.Tests
 				}
 			}
 		}
+		
+		[Test]
+		public void GetGifFrames ()
+		{
+			const int FrameCount = 16;
+
+			var stream = new SKFileStream (Path.Combine (PathToImages, "animated-heart.gif"));
+			using (var codec = SKCodec.Create (stream)) {
+				Assert.AreEqual (-1, codec.RepetitionCount);
+
+				var frameInfos = codec.FrameInfo;
+				Assert.AreEqual (FrameCount, frameInfos.Length);
+
+				Assert.AreEqual (-1, frameInfos [0].RequiredFrame);
+
+				var cachedFrames = new SKBitmap [FrameCount];
+				var info = new SKImageInfo (codec.Info.Width, codec.Info.Height);
+
+				var decode = new Action<SKBitmap, bool, int> ((bm, cached, index) => {
+					if (cached) {
+						var requiredFrame = frameInfos [index].RequiredFrame;
+						if (requiredFrame != -1) {
+							Assert.IsTrue (cachedFrames [requiredFrame].CopyTo (bm));
+						}
+					}
+					var opts = new SKCodecOptions (index, cached);
+					var result = codec.GetPixels (info, bm.GetPixels (), opts);
+					Assert.AreEqual (SKCodecResult.Success, result);
+				});
+
+				for (var i = 0; i < FrameCount; i++) {
+					var cachedFrame = cachedFrames [i] = new SKBitmap (info);
+					decode (cachedFrame, true, i);
+
+					var uncachedFrame = new SKBitmap (info);
+					decode (uncachedFrame, false, i);
+
+					CollectionAssert.AreEqual (cachedFrame.Bytes, uncachedFrame.Bytes);
+				}
+			}
+		}
 
 		[Test]
 		public void GetEncodedInfo ()