Clean-up some documentation and info about min version to sample app

Author: michael-hawker

Microsoft.Toolkit.Uwp.SampleApp/SamplePages/samples.json

@@ -192,7 +192,9 @@
         "CodeUrl": "https://github.com/CommunityToolkit/WindowsCommunityToolkit/tree/main/Microsoft.Toolkit.Uwp.UI.Media/Shadows",
         "XamlCodeFile": "/SamplePages/Shadows/AttachedShadowWin2DXaml.bind",
         "Icon": "/SamplePages/Shadows/DropShadowPanel.png",
-        "DocumentationUrl": "https://raw.githubusercontent.com/MicrosoftDocs/WindowsCommunityToolkitDocs/master/docs/controls/DropShadowPanel.md"
+        "DocumentationUrl": "https://raw.githubusercontent.com/MicrosoftDocs/WindowsCommunityToolkitDocs/master/docs/controls/DropShadowPanel.md",
+        "BadgeUpdateVersionRequired": "May 2019 update required",
+        "ApiCheck": "Windows.UI.Composition.CompositionVisualSurface"
       },
       {
         "Name": "DropShadowPanel",

Microsoft.Toolkit.Uwp.UI.Media/Shadows/AttachedCardShadow.cs

@@ -17,7 +17,6 @@ public class AttachedCardShadow : AttachedShadowBase
         private const float MaxBlurRadius = 72;
         private static readonly TypedResourceKey<CompositionGeometricClip> ClipResourceKey = "Clip";
         private static readonly bool SupportsCompositionVisualSurface;
-        private static readonly bool SupportsCompositionGeometricClip;
 
         private static readonly TypedResourceKey<CompositionPathGeometry> PathGeometryResourceKey = "PathGeometry";
         private static readonly TypedResourceKey<CompositionRoundedRectangleGeometry> RoundedRectangleGeometryResourceKey = "RoundedGeometry";
@@ -34,12 +33,11 @@ public class AttachedCardShadow : AttachedShadowBase
                 nameof(CornerRadius),
                 typeof(double),
                 typeof(AttachedCardShadow),
-                new PropertyMetadata(8d, OnDependencyPropertyChanged));
+                new PropertyMetadata(4d, OnDependencyPropertyChanged)); // Default WinUI ControlCornerRadius is 4
 
         static AttachedCardShadow()
         {
-            SupportsCompositionGeometricClip = ApiInformation.IsTypePresent(typeof(CompositionGeometricClip).FullName);
-            SupportsCompositionVisualSurface = ApiInformation.IsTypePresent(typeof(CompositionVisualSurface).FullName); ;
+            SupportsCompositionVisualSurface = ApiInformation.IsTypePresent(typeof(CompositionVisualSurface).FullName); // Note: This is 1903 (18362) min
         }
 
         /// <summary>
@@ -51,15 +49,20 @@ public double CornerRadius
             set => SetValue(CornerRadiusProperty, value);
         }
 
+        /// <inheritdoc/>
         public override bool IsSupported => SupportsCompositionVisualSurface;
+
+        /// <inheritdoc/>
         protected override bool SupportsOnSizeChangedEvent => true;
 
+        /// <inheritdoc/>
         protected override void OnElementContextUninitialized(AttachedShadowElementContext context)
         {
             context.ClearAndDisposeResources();
             base.OnElementContextUninitialized(context);
         }
 
+        /// <inheritdoc/>
         protected override void OnPropertyChanged(AttachedShadowElementContext context, DependencyProperty property, object oldValue, object newValue)
         {
             if (property == CornerRadiusProperty)
@@ -78,6 +81,7 @@ protected override void OnPropertyChanged(AttachedShadowElementContext context,
             }
         }
 
+        /// <inheritdoc/>
         protected override CompositionBrush GetShadowMask(AttachedShadowElementContext context)
         {
             if (!SupportsCompositionVisualSurface)
@@ -115,6 +119,7 @@ protected override CompositionBrush GetShadowMask(AttachedShadowElementContext c
             return surfaceBrush;
         }
 
+        /// <inheritdoc/>
         protected override CompositionClip GetShadowClip(AttachedShadowElementContext context)
         {
             var pathGeom = context.GetResource(PathGeometryResourceKey) ??
@@ -141,6 +146,7 @@ protected override CompositionClip GetShadowClip(AttachedShadowElementContext co
             return clip;
         }
 
+        /// <inheritdoc/>
         protected override void OnSizeChanged(AttachedShadowElementContext context, Size newSize, Size previousSize)
         {
             var sizeAsVec2 = newSize.ToVector2();

Microsoft.Toolkit.Uwp.UI/Shadows/AttachedShadowBase.cs

@@ -46,7 +46,7 @@ public abstract class AttachedShadowBase : DependencyObject
             DependencyProperty.Register(nameof(Opacity), typeof(double), typeof(AttachedShadowBase), new PropertyMetadata(1d, OnDependencyPropertyChanged));
 
         /// <summary>
-        /// Returns whether or not this <see cref="AttachedShadowBase"/> implementation is supported on the current platform.
+        /// Gets a value indicating whether or not this <see cref="AttachedShadowBase"/> implementation is supported on the current platform.
         /// </summary>
         public abstract bool IsSupported { get; }
 
@@ -56,7 +56,7 @@ public abstract class AttachedShadowBase : DependencyObject
         private ConditionalWeakTable<FrameworkElement, AttachedShadowElementContext> ShadowElementContextTable { get; set; }
 
         /// <summary>
-        /// Gets or set the blur radius of the shadow.
+        /// Gets or sets the blur radius of the shadow.
         /// </summary>
         public double BlurRadius
         {
@@ -92,7 +92,7 @@ public Color Color
         }
 
         /// <summary>
-        /// Returns whether or not OnSizeChanged should be called when <see cref="FrameworkElement.SizeChanged"/> is fired.
+        /// Gets a value indicating whether or not OnSizeChanged should be called when <see cref="FrameworkElement.SizeChanged"/> is fired.
         /// </summary>
         protected internal abstract bool SupportsOnSizeChangedEvent { get; }
 
@@ -155,6 +155,7 @@ protected internal virtual void OnElementContextUninitialized(AttachedShadowElem
         /// <summary>
         /// Get the associated <see cref="AttachedShadowElementContext"/> for the specified <see cref="FrameworkElement"/>.
         /// </summary>
+        /// <returns>The <see cref="AttachedShadowElementContext"/> for the element.</returns>
         public AttachedShadowElementContext GetElementContext(FrameworkElement element)
         {
             if (ShadowElementContextTable != null && ShadowElementContextTable.TryGetValue(element, out var context))

Microsoft.Toolkit.Uwp.UI/Shadows/AttachedShadowElementContext.cs

@@ -279,6 +279,7 @@ public void ClearAndDisposeResources()
             {
                 (kvp.Value as IDisposable)?.Dispose();
             }
+
             _resources.Clear();
         }
     }