Added Android implementation.

Xamarin.Forms.Platform.Android/Properties/AssemblyInfo.cs

@@ -56,6 +56,7 @@
 [assembly: ExportImageSourceHandler(typeof(StreamImageSource), typeof(StreamImagesourceHandler))]
 [assembly: ExportImageSourceHandler(typeof(UriImageSource), typeof(ImageLoaderSourceHandler))]
 [assembly: ExportImageSourceHandler(typeof(FontImageSource), typeof(FontImageSourceHandler))]
+[assembly: ExportImageSourceHandler(typeof(LayeredFontImageSource), typeof(FontImageSourceHandler))]
 [assembly: Xamarin.Forms.Dependency(typeof(Deserializer))]
 [assembly: Xamarin.Forms.Dependency(typeof(ResourcesProvider))]
 [assembly: Preserve]

Xamarin.Forms.Platform.Android/Renderers/FontImageSourceHandler.cs

@@ -1,4 +1,4 @@
-using System.Collections.Concurrent;
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 using Android.Content;
@@ -9,31 +9,93 @@ namespace Xamarin.Forms.Platform.Android
 {
 	public sealed class FontImageSourceHandler : IImageSourceHandler
 	{
+		private class LayerProperties
+		{
+			public Paint Paint { get; set; }
+			public int Baseline { get; set; }
+			public int Width { get; set; }
+			public int Height { get; set; }
+			public string Glyph { get; set; }
+		}
+
 		public Task<Bitmap> LoadImageAsync(
-			ImageSource imagesource,
+			ImageSource imageSource,
 			Context context,
 			CancellationToken cancelationToken = default(CancellationToken))
 		{
-			Bitmap image = null;
-			var fontsource = imagesource as FontImageSource;
-			if (fontsource != null)
+			var layerPropertiesList = new List<LayerProperties>();
+			var maxWidth = 0;
+			var maxHeight = 0;
+
+			if (imageSource is LayeredFontImageSource layeredFontImageSource)
+			{
+				var baseSize = TypedValue.ApplyDimension(ComplexUnitType.Dip, (float)layeredFontImageSource.Size, context.Resources.DisplayMetrics);
+				var baseColor = (layeredFontImageSource.Color != Color.Default ? layeredFontImageSource.Color : Color.White).ToAndroid();
+				var baseFont = layeredFontImageSource.FontFamily.ToTypeFace();
+
+				foreach (var layer in layeredFontImageSource.Layers)
+				{
+					var size = layer.IsSet(FontImageSource.SizeProperty) ?
+						TypedValue.ApplyDimension(ComplexUnitType.Dip, (float)layer.Size, context.Resources.DisplayMetrics) :
+						baseSize;
+					var color = layer.Color.IsDefault ? baseColor : layer.Color.ToAndroid();
+					var font = layer.FontFamily == null ? baseFont : layer.FontFamily.ToTypeFace();
+					var paint = new Paint
+					{
+						TextSize = size,
+						Color = (layer.Color != Color.Default ? layer.Color : Color.White).ToAndroid(),
+						TextAlign = Paint.Align.Left,
+						AntiAlias = true,
+					};
+
+					paint.SetTypeface(font);
+
+					var width = (int)(paint.MeasureText(layer.Glyph) + .5f);
+					var baseline = (int)(-paint.Ascent() + .5f);
+					var height = (int)(baseline + paint.Descent() + .5f);
+
+					if (width > maxWidth)
+					{
+						maxWidth = width;
+					}
+					if (height > maxHeight)
+					{
+						maxHeight = height;
+					}
+
+					layerPropertiesList.Add(new LayerProperties { Paint = paint, Baseline = (int)(-paint.Ascent() + .5f), Width = width, Height = height, Glyph = layer.Glyph });
+				}
+			}
+			else if (imageSource is FontImageSource fontSource)
 			{
 				var paint = new Paint
 				{
-					TextSize = TypedValue.ApplyDimension(ComplexUnitType.Dip, (float)fontsource.Size, context.Resources.DisplayMetrics),
-					Color = (fontsource.Color != Color.Default ? fontsource.Color : Color.White).ToAndroid(),
+					TextSize = TypedValue.ApplyDimension(ComplexUnitType.Dip, (float)fontSource.Size, context.Resources.DisplayMetrics),
+					Color = (fontSource.Color != Color.Default ? fontSource.Color : Color.White).ToAndroid(),
 					TextAlign = Paint.Align.Left,
 					AntiAlias = true,
 				};
 
-				paint.SetTypeface(fontsource.FontFamily.ToTypeFace());
+				paint.SetTypeface(fontSource.FontFamily.ToTypeFace());
 
-				var width = (int)(paint.MeasureText(fontsource.Glyph) + .5f);
+				var width = (int)(paint.MeasureText(fontSource.Glyph) + .5f);
 				var baseline = (int)(-paint.Ascent() + .5f);
 				var height = (int)(baseline + paint.Descent() + .5f);
-				image = Bitmap.CreateBitmap(width, height, Bitmap.Config.Argb8888);
-				var canvas = new Canvas(image);
-				canvas.DrawText(fontsource.Glyph, 0, baseline, paint);
+
+				maxWidth = width;
+				maxHeight = height;
+
+				layerPropertiesList.Add(new LayerProperties { Paint = paint, Baseline = (int)(-paint.Ascent() + .5f), Width = width, Height = height, Glyph = fontSource.Glyph });
+			}
+
+			var image = Bitmap.CreateBitmap(maxWidth, maxHeight, Bitmap.Config.Argb8888);
+			var canvas = new Canvas(image);
+
+			foreach (var layer in layerPropertiesList)
+			{
+				var x = (maxWidth - layer.Width) / 2;
+				var y = (maxHeight - layer.Height) / 2 + layer.Baseline;
+				canvas.DrawText(layer.Glyph, x, y, layer.Paint);
 			}
 
 			return Task.FromResult(image);

Xamarin.Forms.Platform.MacOS/ImageSourceHandlers.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using AppKit;