Added sample showing decoding info and drawing directly on the bitmap

samples/SkiaSharpSample.Shared/Samples/BitmapAnnotationSample.cs

@@ -0,0 +1,45 @@
+using System;
+
+using SkiaSharp;
+
+namespace SkiaSharpSample.Samples
+{
+	[Preserve(AllMembers = true)]
+	public class BitmapAnnotationSample : SampleBase
+	{
+		[Preserve]
+		public BitmapAnnotationSample()
+		{
+		}
+
+		public override string Title => "Bitmap Annotation";
+
+		public override SampleCategories Category => SampleCategories.BitmapDecoding;
+
+		protected override void OnDrawSample(SKCanvas canvas, int width, int height)
+		{
+			canvas.Clear(SKColors.White);
+
+			// decode the bitmap
+			var desiredInfo = new SKImageInfo(386, 395, SKImageInfo.PlatformColorType, SKAlphaType.Premul);
+			using (var stream = new SKManagedStream(SampleMedia.Images.BabyTux))
+			using (var bitmap = SKBitmap.Decode(stream, desiredInfo))
+			{
+				// draw directly on the bitmap
+				using (var annotationCanvas = new SKCanvas(bitmap))
+				using (var paint = new SKPaint())
+				{
+					paint.StrokeWidth = 3;
+					paint.Color = SampleMedia.Colors.XamarinLightBlue;
+					paint.Style = SKPaintStyle.Stroke;
+
+					var face = SKRectI.Create(100, 50, 190, 170);
+					annotationCanvas.DrawRect(face, paint);
+				}
+
+				// draw the modified bitmap to the screen
+				canvas.DrawBitmap(bitmap, 10, 10);
+			}
+		}
+	}
+}

samples/SkiaSharpSample.Shared/SkiaSharpSample.Shared.projitems

@@ -16,6 +16,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)SamplePlatforms.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SampleBase.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)SampleMedia.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Samples\BitmapAnnotationSample.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Samples\BitmapSubsetDecoderSample.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Samples\ManipulatedBitmapShaderSample.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Samples\PathMeasureSample.cs" />