feat(imageBrush): [iOS][macOS] Add support of WriteableBitmap

src/Uno.UI/UI/Xaml/Controls/Border/Border.iOSmacOS.cs

@@ -45,7 +45,10 @@ private void UpdateBorderLayer(_Image backgroundImage = null)
 		{
 			if (IsLoaded)
 			{
-				backgroundImage = backgroundImage ?? (Background as ImageBrush)?.ImageSource?.ImageData;
+				if (backgroundImage == null)
+				{
+					(Background as ImageBrush)?.ImageSource?.TryOpenSync(out backgroundImage);
+				}
 
 				BoundsPath = _borderRenderer.UpdateLayer(
 					this,

src/Uno.UI/UI/Xaml/Controls/Border/BorderLayerRenderer.iOSmacOS.cs

@@ -139,8 +139,8 @@ private static IDisposable InnerCreateLayer(UIElement owner, CALayer parent, Lay
 				}
 				else if (background is ImageBrush imgBackground)
 				{
-					var uiImage = imgBackground.ImageSource?.ImageData;
-					if (uiImage != null && uiImage.Size != CGSize.Empty)
+					var imgSrc = imgBackground.ImageSource;
+					if (imgSrc != null && imgSrc.TryOpenSync(out var uiImage) && uiImage.Size != CGSize.Empty)
 					{
 						var fillMask = new CAShapeLayer()
 						{
@@ -207,8 +207,8 @@ private static IDisposable InnerCreateLayer(UIElement owner, CALayer parent, Lay
 				}
 				else if (background is ImageBrush imgBackground)
 				{
-					var uiImage = imgBackground.ImageSource?.ImageData;
-					if (uiImage != null && uiImage.Size != CGSize.Empty)
+					var bgSrc = imgBackground.ImageSource;
+					if (bgSrc != null && bgSrc.TryOpenSync(out var uiImage) && uiImage.Size != CGSize.Empty)
 					{
 						var fullArea = new CGRect(
 								area.X + borderThickness.Left,
@@ -346,7 +346,7 @@ private static CGPath GetRoundedPath(CornerRadius cornerRadius, CGRect area)
 		/// <param name="fillMask">Optional mask layer (for when we use rounded corners)</param>
 		private static void CreateImageBrushLayers(CGRect fullArea, CGRect insideArea, CALayer layer, List<CALayer> sublayers, ref int insertionIndex, ImageBrush imageBrush, CAShapeLayer fillMask)
 		{
-			var uiImage = imageBrush.ImageSource.ImageData;
+			imageBrush.ImageSource.TryOpenSync(out var uiImage);
 
 			// This layer is the one we apply the mask on. It's the full size of the shape because the mask is as well.
 			var imageContainerLayer = new CALayer

src/Uno.UI/UI/Xaml/Controls/Image/Image.iOS.cs

@@ -94,19 +94,15 @@ private void TryOpenImage()
 			{
 				_openedImage = Source;
 
-				if (_openedImage is WriteableBitmap writeableBitmap)
-				{
-					SetImageFromWriteableBitmap(writeableBitmap);
-				}
-				else if (_openedImage == null || !_openedImage.HasSource())
+				if (_openedImage == null || !_openedImage.HasSource())
 				{
 					Image = null;
 					SetNeedsLayoutOrDisplay();
 					_imageFetchDisposable.Disposable = null;
 				}
-				else if (_openedImage.ImageData != null)
+				else if (_openedImage.TryOpenSync(out var img))
 				{
-					SetImage(_openedImage.ImageData);
+					SetImage(img);
 					_imageFetchDisposable.Disposable = null;
 				}
 				else
@@ -146,50 +142,6 @@ private void TryOpenImage()
 			}
 		}
 
-		private void SetImageFromWriteableBitmap(WriteableBitmap writeableBitmap)
-		{
-			if (writeableBitmap.PixelBuffer is InMemoryBuffer memoryBuffer)
-			{
-				// Convert RGB colorspace.
-				var bgraBuffer = memoryBuffer.Data;
-				var rgbaBuffer = new byte[memoryBuffer.Data.Length];
-
-				for (int i = 0; i < memoryBuffer.Data.Length; i += 4)
-				{
-					rgbaBuffer[i + 3] = bgraBuffer[i + 3]; // a
-					rgbaBuffer[i + 0] = bgraBuffer[i + 2]; // r
-					rgbaBuffer[i + 1] = bgraBuffer[i + 1]; // g
-					rgbaBuffer[i + 2] = bgraBuffer[i + 0]; // b
-				}
-
-				using (var dataProvider = new CGDataProvider(rgbaBuffer, 0, rgbaBuffer.Length))
-				{
-					using (var colorSpace = CGColorSpace.CreateDeviceRGB())
-					{
-						var bitsPerComponent = 8;
-						var bytesPerPixel = 4;
-
-						using (var cgImage = new CGImage(
-							writeableBitmap.PixelWidth,
-							writeableBitmap.PixelHeight,
-							bitsPerComponent,
-							bitsPerComponent * bytesPerPixel,
-							bytesPerPixel * writeableBitmap.PixelWidth,
-							colorSpace,
-							CGImageAlphaInfo.Last,
-							dataProvider,
-							null,
-							false,
-							CGColorRenderingIntent.Default
-						))
-						{
-							SetImage(UIImage.FromImage(cgImage));
-						}
-					}
-				}
-			}
-		}
-
 		private void SetImage(UIImage image)
 		{
 			using (

src/Uno.UI/UI/Xaml/Controls/Panel/Panel.iOS.cs

@@ -90,7 +90,10 @@ private void UpdateBackground(UIImage backgroundImage = null)
 			// Checking for Window avoids re-creating the layer until it is actually used.
 			if (IsLoaded)
 			{
-				backgroundImage = backgroundImage ?? (Background as ImageBrush)?.ImageSource?.ImageData;
+				if (backgroundImage == null)
+				{
+					(Background as ImageBrush)?.ImageSource?.TryOpenSync(out backgroundImage);
+				}
 
 				_borderRenderer.UpdateLayer(
 					this,

src/Uno.UI/UI/Xaml/Media/ImageBrush.iOSmacOS.cs

@@ -34,9 +34,9 @@ public partial class ImageBrush
 				oldValue?.Dispose();
 				_imageScheduler.Disposable = null;
 			}
-			else if (newValue.ImageData != null)
+			else if (newValue.TryOpenSync(out var image))
 			{
-				SetImage(newValue.ImageData);
+				SetImage(image);
 				oldValue?.Dispose();
 				_imageScheduler.Disposable = null;
 			}
@@ -52,11 +52,10 @@ private async void OpenImageAsync(ImageSource newValue)
 		{
 			CoreDispatcher.CheckThreadAccess();
 
-			var cd = new CancellationDisposable();
-
+			using var cd = new CancellationDisposable();
 			_imageScheduler.Disposable = cd;
 
-			var image = await Task.Run(() => newValue.Open(cd.Token));
+			var image = await Task.Run(() => newValue.Open(cd.Token), cd.Token);
 
 			if (cd.Token.IsCancellationRequested)
 			{

src/Uno.UI/UI/Xaml/Media/ImageSource.iOS.cs

@@ -50,10 +50,11 @@ protected ImageSource()
 		protected ImageSource(UIImage image)
 		{
 			_isOriginalSourceUIImage = true;
-			ImageData = image;
+			_imageData = image;
 		}
 
-		internal UIImage ImageData { get; private set; }
+		private UIImage _imageData;
+
 		internal string BundleName { get; private set; }
 		internal string BundlePath { get; private set; }
 
@@ -64,10 +65,11 @@ protected ImageSource(UIImage image)
 
 		public bool HasSource()
 		{
-			return Stream != null
+			return IsSourceReady
+				|| Stream != null
 				|| WebUri != null
 				|| FilePath.HasValueTrimmed()
-				|| ImageData != null
+				|| _imageData != null
 				|| HasBundle;
 		}
 
@@ -82,14 +84,14 @@ public bool HasSource()
 		/// </summary>
 		internal UIImage OpenBundle()
 		{
-			ImageData = OpenBundleFromString(BundleName) ?? OpenBundleFromString(BundlePath);
+			_imageData = OpenBundleFromString(BundleName) ?? OpenBundleFromString(BundlePath);
 
-			if (ImageData == null)
+			if (_imageData == null)
 			{
 				this.Log().ErrorFormat("Unable to locate bundle resource [{0}]", BundlePath ?? BundleName);
 			}
 
-			return ImageData;
+			return _imageData;
 		}
 
 		private static UIImage OpenBundleFromString(string bundle)
@@ -102,6 +104,48 @@ private static UIImage OpenBundleFromString(string bundle)
 			return null;
 		}
 
+		/// <summary>
+		/// Indicates that this ImageSource has enough information to be opened
+		/// </summary>
+		private protected virtual bool IsSourceReady => false;
+
+		private protected virtual bool TryOpenSourceSync(out UIImage image)
+		{
+			image = default;
+			return false;
+		}
+
+		private protected virtual bool TryOpenSourceAsync(out Task<UIImage> asyncImage)
+		{
+			asyncImage = default;
+			return false;
+		}
+
+		/// <summary>
+		/// Retrieves the already loaded image, or for supported source (eg. WriteableBitmap, cf remarks),
+		/// create a native image from the data in memory.
+		/// </summary>
+		/// <remarks>
+		/// This is only intended to convert **uncompressed data already in memory**,
+		/// and should not be used to decompress a JPEG for instance, even if the already in memory.
+		/// </remarks>
+		internal bool TryOpenSync(out UIImage image)
+		{
+			if (_imageData != null)
+			{
+				image = _imageData;
+				return true;
+			}
+
+			if (IsSourceReady && TryOpenSourceSync(out image))
+			{
+				return true;
+			}
+
+			image = default;
+			return false;
+		}
+
 		internal async Task<UIImage> Open(CancellationToken ct)
 		{
 			using (
@@ -117,38 +161,48 @@ internal async Task<UIImage> Open(CancellationToken ct)
 					return null;
 				}
 
+				if (IsSourceReady && TryOpenSourceSync(out var img))
+				{
+					return _imageData = img;
+				}
+
+				if (IsSourceReady && TryOpenSourceAsync(out var asyncImg))
+				{
+					return _imageData = await asyncImg;
+				}
+
 				if (Stream != null)
 				{
 					Stream.Position = 0;
 					using (var data = NSData.FromStream(Stream))
 					{
-						return ImageData = UIImage.LoadFromData(data);
+						return _imageData = UIImage.LoadFromData(data);
 					}
 				}
 
 				if (FilePath.HasValue())
 				{
 					var uri = new Uri(FilePath);
-					return ImageData = UIImage.FromFile(FilePath);
+					return _imageData = UIImage.FromFile(FilePath);
 				}
 
 				if (HasBundle)
 				{
 					if (SupportsAsyncFromBundle)
 					{
-						return ImageData = OpenBundle();
+						return _imageData = OpenBundle();
 					}
 					else
 					{
 						await CoreDispatcher.Main.RunAsync(
 							CoreDispatcherPriority.Normal,
 							async () =>
 							{
-								ImageData = OpenBundle();
+								_imageData = OpenBundle();
 							}
 						);
 
-						return ImageData;
+						return _imageData;
 					}
 				}
 
@@ -168,7 +222,7 @@ internal async Task<UIImage> Open(CancellationToken ct)
 					if (SupportsAsyncFromBundle)
 					{
 						// Since iOS9, UIImage.FromBundle is thread safe.
-						ImageData = UIImage.FromBundle(localFileUri.LocalPath);
+						_imageData = UIImage.FromBundle(localFileUri.LocalPath);
 					}
 					else
 					{
@@ -181,19 +235,19 @@ internal async Task<UIImage> Open(CancellationToken ct)
 									// FromBundle calls UIImage:fromName which caches the decoded image.
 									// This is done to avoid decoding images from the byte array returned 
 									// from the cache.
-									ImageData = UIImage.FromBundle(localFileUri.LocalPath);
+									_imageData = UIImage.FromBundle(localFileUri.LocalPath);
 								}
 								else
 								{
 									// On iOS 7, FromBundle doesn't work. We can use this method instead.
 									// Note that we must use OriginalString and not LocalPath.
-									ImageData = UIImage.LoadFromData(NSData.FromUrl(new NSUrl(localFileUri.OriginalString)));
+									_imageData = UIImage.LoadFromData(NSData.FromUrl(new NSUrl(localFileUri.OriginalString)));
 								}
 							}).AsTask(ct);
 					}
 				}
 
-				return ImageData;
+				return _imageData;
 			}
 		}
 
@@ -235,7 +289,7 @@ private async Task OpenUsingPlatformDownloader(CancellationToken ct)
 						}
 						else
 						{
-							ImageData = UIImage.LoadFromData(result.Data);
+							_imageData = UIImage.LoadFromData(result.Data);
 						}
 					}
 					catch (NSErrorException e)
@@ -301,16 +355,16 @@ internal void UnloadImageData()
 
 		private void DisposeUIImage()
 		{
-			if (ImageData != null)
+			if (_imageData != null)
 			{
-				ImageData.Dispose();
-				ImageData = null;
+				_imageData.Dispose();
+				_imageData = null;
 			}
 		}
 
 		public override string ToString()
 		{
-			var source = Stream ?? WebUri ?? FilePath ?? (object)ImageData ?? BundlePath ?? BundleName ?? "[No source]";
+			var source = Stream ?? WebUri ?? FilePath ?? (object)_imageData ?? BundlePath ?? BundleName ?? "[No source]";
 			return "ImageSource: {0}".InvariantCultureFormat(source);
 		}
 	}