Extremely BASIC iOS Gif support. (Have to start somewhere)

samples/ImageLoading.Forms.Sample/Shared/FFImageLoading.Forms.Sample.csproj

@@ -147,6 +147,10 @@
     <Compile Include="Pages\StreamListPageCell.xaml.cs">
       <DependentUpon>StreamListPageCell.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Pages\SimpleGifPageModel.cs" />
+    <Compile Include="Pages\SimpleGifPage.xaml.cs">
+      <DependentUpon>SimpleGifPage.xaml</DependentUpon>
+    </Compile>
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" />
   <Import Project="..\..\..\packages\Xamarin.Forms.2.0.1.6505\build\portable-win+net45+wp80+win81+wpa81+MonoAndroid10+MonoTouch10+Xamarin.iOS10\Xamarin.Forms.targets" Condition="Exists('..\..\..\packages\Xamarin.Forms.2.0.1.6505\build\portable-win+net45+wp80+win81+wpa81+MonoAndroid10+MonoTouch10+Xamarin.iOS10\Xamarin.Forms.targets')" />
@@ -278,6 +282,9 @@
     <EmbeddedResource Include="Pages\StreamListPageCell.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="Pages\SimpleGifPage.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <Folder Include="Pages\" />

samples/ImageLoading.Forms.Sample/Shared/Pages/MenuPageModel.cs

@@ -30,6 +30,15 @@ public MenuPageModel()
 					})
 				},
 
+                new MenuItem() {
+                    Section = "Basic",
+                    Title = "Simple Gif",
+                    Command = new BaseCommand(async (param) =>
+                    {
+                        await this.PushPageFromCacheAsync<SimpleGifPageModel>(pm => pm.Reload());
+                    })
+                },
+
 				new MenuItem() {
 					Section = "Basic",
 					Title = "Placeholders examples",

samples/ImageLoading.Forms.Sample/Shared/Pages/SimpleGifPage.xaml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" x:Class="FFImageLoading.Forms.Sample.SimpleGifPage"
+        xmlns:xamvvm="clr-namespace:Xamvvm;assembly=Xamvvm.Forms"
+        xmlns:ffimageloading="clr-namespace:FFImageLoading.Forms;assembly=FFImageLoading.Forms"
+        xmlns:fftransformations="clr-namespace:FFImageLoading.Transformations;assembly=FFImageLoading.Transformations"
+        Title="Simple Gif">
+    <ContentPage.Content>
+        <ffimageloading:CachedImage WidthRequest="300" HeightRequest="300"
+            DownsampleToViewSize="true" Source="{Binding ImageUrl}">
+        </ffimageloading:CachedImage>
+    </ContentPage.Content>
+</ContentPage>

samples/ImageLoading.Forms.Sample/Shared/Pages/SimpleGifPage.xaml.cs

@@ -0,0 +1,13 @@
+using Xamarin.Forms;
+using Xamvvm;
+
+namespace FFImageLoading.Forms.Sample
+{
+    public partial class SimpleGifPage : ContentPage, IBasePage<SimpleGifPageModel>
+    {
+        public SimpleGifPage()
+        {
+            InitializeComponent();
+        }
+    }
+}

samples/ImageLoading.Forms.Sample/Shared/Pages/SimpleGifPageModel.cs

@@ -0,0 +1,15 @@
+using Xamvvm;
+
+namespace FFImageLoading.Forms.Sample
+{
+    [PropertyChanged.ImplementPropertyChanged]
+    public class SimpleGifPageModel : BasePageModel
+    {
+        public void Reload()
+        {
+            ImageUrl = "https://media.giphy.com/media/l0Hlyi4ZMJI9MpFUQ/giphy.gif";
+        }
+
+        public string ImageUrl { get; set; }
+    }
+}

source/FFImageLoading.Touch/FFImageLoading.Touch.csproj

@@ -89,6 +89,7 @@
     <Compile Include="DataResolvers\FileDataResolver.cs" />
     <Compile Include="DataResolvers\UrlDataResolver.cs" />
     <Compile Include="DataResolvers\StreamDataResolver.cs" />
+    <Compile Include="Helpers\GifHelper.cs" />
   </ItemGroup>
   <Import Project="..\FFImageLoading.Cross\FFImageLoading.Cross.projitems" Label="Shared" Condition="Exists('..\FFImageLoading.Cross\FFImageLoading.Cross.projitems')" />
   <Import Project="..\FFImageLoading.Shared\FFImageLoading.Shared.projitems" Label="Shared" Condition="Exists('..\FFImageLoading.Shared\FFImageLoading.Shared.projitems')" />

source/FFImageLoading.Touch/Helpers/GifHelper.cs

@@ -0,0 +1,79 @@
+using System.Collections.Generic;
+using System.Linq;
+using Foundation;
+using ImageIO;
+using UIKit;
+
+namespace FFImageLoading.Helpers
+{
+    public static class GifHelper
+    {
+        public static UIImage AnimateGif(NSData data)
+        {
+            if (data?.Length == 0)
+                return null;
+
+            using (var source = CGImageSource.FromData(data))
+                return AnimateGifFromSource(source) ?? UIImage.LoadFromData(data);
+        }
+
+        private static UIImage AnimateGifFromSource(CGImageSource source)
+        {
+            var frameCount = source?.ImageCount;
+
+            // no need to animate
+            if (frameCount <= 1)
+                return null;
+
+            var frames = GetFrames(source);
+            var delays = GetDelays(source);
+            var totalDuration = delays.Sum();
+
+            // SUPER BASIC. Does not respect variable length frames. No memory optimizations.
+            return UIImage.CreateAnimatedImage(frames.ToArray(), totalDuration);
+        }
+
+        private static List<UIImage> GetFrames(CGImageSource source)
+        {
+            var retval = new List<UIImage>();
+
+            for (int i = 0; i < source?.ImageCount; i++)
+            {
+                using (var frameImage = source.CreateImage(i, null))
+                    retval.Add(UIImage.FromImage(frameImage));
+            }
+
+            return retval;
+        }
+
+        private static List<double> GetDelays(CGImageSource source)
+        {
+            var retval = new List<double>();
+
+            for (int i = 0; i < source?.ImageCount; i++)
+            {
+                var properties = source.GetProperties(i, null);
+                using (var gifProperties = properties.Dictionary["{GIF}"])
+                {
+                    using (var delayTime = gifProperties.ValueForKey(new NSString("DelayTime")))
+                    {
+                        var realDuration = double.Parse(delayTime.ToString());
+                        retval.Add(realDuration);
+                    }
+                }
+            }
+
+            return retval;
+        }
+
+        private static int GetLoopCount(CGImageSource source)
+        {
+            var var = source.GetProperties(null);
+            using (var gifProperties = var.Dictionary["{GIF}"])
+            {
+                var loopCount = gifProperties.ValueForKey(new NSString("LoopCount"));
+                return int.Parse(loopCount.ToString());
+            }
+        }
+    }
+}

source/FFImageLoading.Touch/Work/PlatformImageLoaderTask.cs

@@ -48,6 +48,12 @@ protected async override Task<UIImage> GenerateImageAsync(string path, ImageSour
                 {
                     imageIn = new WebP.Touch.WebPCodec().Decode(imageData);
                 }
+                // Special case to handle gif animations on iOS
+                else if (path.ToLowerInvariant().EndsWith(".gif", StringComparison.InvariantCulture))
+                {
+                    using (var nsdata = NSData.FromStream(imageData))
+                        imageIn = GifHelper.AnimateGif(nsdata);
+                }
                 else
                 {
                     var nsdata = NSData.FromStream(imageData);