ShadowEffect

samples/XCT.Sample/Pages/Effects/ShadowEffectPage.xaml

@@ -0,0 +1,77 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<pages:BasePage xmlns="http://xamarin.com/schemas/2014/forms"
+                xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+                xmlns:xct="http://xamarin.com/schemas/2020/toolkit"
+                xmlns:pages="clr-namespace:Xamarin.CommunityToolkit.Sample.Pages"
+                x:Class="Xamarin.CommunityToolkit.Sample.Pages.Effects.ShadowEffectPage"
+                BackgroundColor="White"
+                x:Name="Page">
+
+    <pages:BasePage.Resources>
+        <Style x:Key="ShadowLabel" TargetType="Label">
+            <Setter Property="FontSize" Value="22" />
+            <Setter Property="FontAttributes" Value="Bold" />
+            <Setter Property="TextColor" Value="Black" />
+        </Style>
+    </pages:BasePage.Resources>
+
+    <ScrollView Padding="{StaticResource ContentPadding}">
+        <StackLayout Spacing="30"
+                     Padding="15, 0">
+
+            <StackLayout Spacing="10">
+                <Label Text="Labels:"/>
+
+                <Label Text="Label With Black Shadow"
+                       Style="{StaticResource ShadowLabel}"
+                       xct:ShadowEffect.Color="Black"/>
+
+                <Label Text="Label With Shifted Red Shadow"
+                       Style="{StaticResource ShadowLabel}"
+                       xct:ShadowEffect.Color="Red"
+                       xct:ShadowEffect.OffsetX="10"
+                       xct:ShadowEffect.OffsetY="10" />
+
+                <Label Text="Label With Gold Shadow"
+                       Style="{StaticResource ShadowLabel}"
+                       xct:ShadowEffect.Color="Gold"
+                       xct:ShadowEffect.Radius="20"/>
+            </StackLayout>
+
+            <StackLayout Spacing="10">
+                <Label Text="Stack Layout with Shadow" />
+                <StackLayout xct:ShadowEffect.Color="Black">
+                    <BoxView Color="White" />
+                    <BoxView Color="Red" />
+                    <BoxView Color="White" />
+                </StackLayout>
+            </StackLayout>
+
+            <StackLayout Spacing="10">
+                <Label Text="Box Views With Colored Shadows" />
+                <Grid RowDefinitions="*,*"
+                      ColumnDefinitions="*,*,*,*,*"
+                      RowSpacing="10"
+                      ColumnSpacing="10">
+
+                    <Grid.Behaviors>
+                        <xct:ImpliedOrderGridBehavior/>
+                    </Grid.Behaviors>
+
+                    <BoxView Color="White" xct:ShadowEffect.Color="Blue" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="Gold" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="Purple" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="HotPink" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="Orange" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="Brown" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="Lime" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="Yellow" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="DarkRed" />
+                    <BoxView Color="White" xct:ShadowEffect.Color="LightSalmon" />
+
+                </Grid>
+            </StackLayout>
+
+    </StackLayout>
+    </ScrollView>
+</pages:BasePage>

samples/XCT.Sample/Pages/Effects/ShadowEffectPage.xaml.cs

@@ -0,0 +1,11 @@
+
+namespace Xamarin.CommunityToolkit.Sample.Pages.Effects
+{
+	public partial class ShadowEffectPage
+	{
+		public ShadowEffectPage()
+		{
+			InitializeComponent();
+		}
+	}
+}

samples/XCT.Sample/ViewModels/Effects/EffectsGalleryViewModel.cs

@@ -33,6 +33,11 @@ public class EffectsGalleryViewModel : BaseGalleryViewModel
 				typeof(TouchEffectPage),
 				nameof(TouchEffect),
 				"The TouchEffect is an effect that allows changing the view's appearance depending on the touch state (normal, pressed, hovered). Also, it allows to handle long presses."),
+
+			new SectionModel(
+				typeof(ShadowEffectPage),
+				nameof(ShadowEffect),
+				"The ShadowEffect allows all views to display shadow."),
 		};
 	}
 }

src/CommunityToolkit/Xamarin.CommunityToolkit/Effects/EffectIds.shared.cs

@@ -40,5 +40,10 @@ sealed class EffectIds
 		/// Effect Id for <see cref="TouchEffect"/>
 		/// </summary>
 		public static string TouchEffect => $"{effectResolutionGroupName}.{nameof(TouchEffect)}";
+
+		/// <summary>
+		/// Effect Id for <see cref="ShadowEffect"/>
+		/// </summary>
+		public static string ShadowEffect => $"{effectResolutionGroupName}.{nameof(ShadowEffect)}";
 	}
 }

src/CommunityToolkit/Xamarin.CommunityToolkit/Effects/Shadow/PlatformShadowEffect.android.cs

@@ -0,0 +1,90 @@
+using Xamarin.Forms.Platform.Android;
+using Xamarin.Forms;
+using Android.Views;
+using AView = Android.Views.View;
+using Android.OS;
+using System.ComponentModel;
+using Xamarin.CommunityToolkit.Effects;
+using Xamarin.CommunityToolkit.Android.Effects;
+using Android.Widget;
+
+[assembly: ExportEffect(typeof(PlatformShadowEffect), nameof(ShadowEffect))]
+
+namespace Xamarin.CommunityToolkit.Android.Effects
+{
+	public class PlatformShadowEffect : PlatformEffect
+	{
+		const float defaultRadius = 10f;
+
+		const float defaultOpacity = 1f;
+
+		AView View => Control ?? Container;
+
+		protected override void OnAttached()
+			=> Update();
+
+		protected override void OnDetached()
+		{
+			if (View == null)
+				return;
+
+			View.Elevation = 0;
+		}
+
+		protected override void OnElementPropertyChanged(PropertyChangedEventArgs args)
+		{
+			base.OnElementPropertyChanged(args);
+
+			if (View == null)
+				return;
+
+			switch (args.PropertyName)
+			{
+				case nameof(ShadowEffect.ColorPropertyName):
+				case nameof(ShadowEffect.OpacityPropertyName):
+				case nameof(ShadowEffect.RadiusPropertyName):
+				case nameof(ShadowEffect.OffsetXPropertyName):
+				case nameof(ShadowEffect.OffsetYPropertyName):
+					View.Invalidate();
+					Update();
+					break;
+			}
+		}
+
+		void Update()
+		{
+			if (View == null || Build.VERSION.SdkInt < BuildVersionCodes.Lollipop)
+				return;
+
+			var radius = (float)ShadowEffect.GetRadius(Element);
+			if (radius < 0)
+				radius = defaultRadius;
+
+			var opacity = ShadowEffect.GetOpacity(Element);
+			if (opacity < 0)
+				opacity = defaultOpacity;
+
+			var androidColor = ShadowEffect.GetColor(Element).MultiplyAlpha(opacity).ToAndroid();
+
+			if (View is TextView textView)
+			{
+				var offsetX = (float)ShadowEffect.GetOffsetX(Element);
+				var offsetY = (float)ShadowEffect.GetOffsetY(Element);
+				textView.SetShadowLayer(radius, offsetX, offsetY, androidColor);
+				return;
+			}
+
+			View.OutlineProvider = (Element as VisualElement)?.BackgroundColor.A > 0
+				? ViewOutlineProvider.PaddedBounds
+				: ViewOutlineProvider.Bounds;
+
+			View.Elevation = View.Context.ToPixels(radius);
+
+			if (Build.VERSION.SdkInt < BuildVersionCodes.P)
+				return;
+
+			View.SetOutlineAmbientShadowColor(androidColor);
+			View.SetOutlineSpotShadowColor(androidColor);
+		}
+	}
+}

src/CommunityToolkit/Xamarin.CommunityToolkit/Effects/Shadow/PlatformShadowEffect.ios.macos.cs

@@ -0,0 +1,99 @@
+using System;
+using System.ComponentModel;
+using CoreGraphics;
+using Xamarin.CommunityToolkit.Effects;
+using Xamarin.Forms;
+
+#if __IOS__
+using NativeView = UIKit.UIView;
+using Xamarin.Forms.Platform.iOS;
+using Xamarin.CommunityToolkit.iOS.Effects;
+#elif __MACOS__
+using NativeView = AppKit.NSView;
+using Xamarin.Forms.Platform.MacOS;
+using Xamarin.CommunityToolkit.macOS.Effects;
+#endif
+
+[assembly: ExportEffect(typeof(PlatformShadowEffect), nameof(ShadowEffect))]
+
+#if __IOS__
+namespace Xamarin.CommunityToolkit.iOS.Effects
+#elif __MACOS__
+namespace Xamarin.CommunityToolkit.macOS.Effects
+#endif
+{
+	public class PlatformShadowEffect : PlatformEffect
+	{
+		const float defaultRadius = 10f;
+
+		const float defaultOpacity = .5f;
+
+		NativeView View => Control ?? Container;
+
+		protected override void OnAttached()
+		{
+			if (View == null)
+				return;
+
+			UpdateColor();
+			UpdateOpacity();
+			UpdateRadius();
+			UpdateOffset();
+		}
+
+		protected override void OnDetached()
+		{
+			if (View?.Layer == null)
+				return;
+
+			View.Layer.ShadowOpacity = 0;
+		}
+
+		protected override void OnElementPropertyChanged(PropertyChangedEventArgs args)
+		{
+			base.OnElementPropertyChanged(args);
+
+			if (View == null)
+				return;
+
+			switch (args.PropertyName)
+			{
+				case nameof(ShadowEffect.ColorPropertyName):
+					UpdateColor();
+					break;
+				case nameof(ShadowEffect.OpacityPropertyName):
+					UpdateOpacity();
+					break;
+				case nameof(ShadowEffect.RadiusPropertyName):
+					UpdateRadius();
+					break;
+				case nameof(ShadowEffect.OffsetXPropertyName):
+				case nameof(ShadowEffect.OffsetYPropertyName):
+					UpdateOffset();
+					break;
+			}
+		}
+
+		void UpdateColor()
+			=> View.Layer.ShadowColor = ShadowEffect.GetColor(Element).ToCGColor();
+
+		void UpdateOpacity()
+		{
+			var opacity = (float)ShadowEffect.GetOpacity(Element);
+			View.Layer.ShadowOpacity = opacity < 0
+				? defaultOpacity
+				: opacity;
+		}
+
+		void UpdateRadius()
+		{
+			var radius = (nfloat)ShadowEffect.GetRadius(Element);
+			View.Layer.ShadowRadius = radius < 0
+				? defaultRadius
+				: radius;
+		}
+
+		void UpdateOffset()
+			=> View.Layer.ShadowOffset = new CGSize((double)ShadowEffect.GetOffsetX(Element), (double)ShadowEffect.GetOffsetY(Element));
+	}
+}