From ce21a7e7542ca2261ac19cd47d238fe5e1b8f8f2 Mon Sep 17 00:00:00 2001
From: chasakisd <chasakisd@gmail.com>
Date: Tue, 21 Jan 2020 15:10:23 +0200
Subject: [PATCH] Shape Support Circle

---
 .../OutlineProviders/PathOutlineProvider.cs   |  2 +-
 .../PathProviders/BasePathProvider.cs         |  6 ++
 .../PathProviders/CirclePathProvider.cs       | 25 +++++++
 .../PathProviders/PathProvidersContainer.cs   |  1 +
 .../Renderers/MaterialShapeManager.cs         |  2 +
 .../XamarinBackgroundKit.Android.csproj       |  1 +
 .../PathProviders/CirclePathProvider.cs       | 59 +++++++++++++++++
 .../PathProviders/PathProvidersContainer.cs   |  1 +
 .../XamarinBackgroundKit.iOS.csproj           |  1 +
 src/XamarinBackgroundKit/Shapes/Circle.cs     |  4 ++
 .../ShapeExplorerPage.xaml                    | 65 +++++++++++++++----
 .../ShapeExplorerPage.xaml.cs                 |  3 +
 12 files changed, 155 insertions(+), 15 deletions(-)
 create mode 100644 src/XamarinBackgroundKit.Android/PathProviders/CirclePathProvider.cs
 create mode 100644 src/XamarinBackgroundKit.iOS/PathProviders/CirclePathProvider.cs
 create mode 100644 src/XamarinBackgroundKit/Shapes/Circle.cs

diff --git a/src/XamarinBackgroundKit.Android/OutlineProviders/PathOutlineProvider.cs b/src/XamarinBackgroundKit.Android/OutlineProviders/PathOutlineProvider.cs
index e181861..2ed0a49 100644
--- a/src/XamarinBackgroundKit.Android/OutlineProviders/PathOutlineProvider.cs
+++ b/src/XamarinBackgroundKit.Android/OutlineProviders/PathOutlineProvider.cs
@@ -35,7 +35,7 @@ public override void GetOutline(View view, Outline outline)
             }
 
             var clipPath = pathProvider.CreatePath(view.Width, view.Height);
-            if (!clipPath.IsConvex) return;
+            if (clipPath == null || !clipPath.IsConvex) return;
 
             outline.SetConvexPath(clipPath);
         }
diff --git a/src/XamarinBackgroundKit.Android/PathProviders/BasePathProvider.cs b/src/XamarinBackgroundKit.Android/PathProviders/BasePathProvider.cs
index 22e5ba6..d63fbd2 100644
--- a/src/XamarinBackgroundKit.Android/PathProviders/BasePathProvider.cs
+++ b/src/XamarinBackgroundKit.Android/PathProviders/BasePathProvider.cs
@@ -36,6 +36,8 @@ public void Invalidate()
 
         public Path CreatePath(int width, int height)
         {
+            if (_disposed) return null;
+
             /* If the path is not dirty return it */
             if (!IsPathDirty || !(_shape is TShape tShape)) return Path;
 
@@ -50,6 +52,8 @@ public Path CreatePath(int width, int height)
 
         public Path CreateBorderedPath(int width, int height)
         {
+            if (_disposed) return null;
+
             /* If the path provider, does not support border, use the default */
             if (!IsBorderSupported) return CreatePath(width, height);
 
@@ -72,6 +76,8 @@ public Path CreateBorderedPath(int width, int height)
 
         public virtual void SetShape(IBackgroundShape shape)
         {
+            if (_disposed) return;
+
             _shape = shape;
 
             Invalidate();
diff --git a/src/XamarinBackgroundKit.Android/PathProviders/CirclePathProvider.cs b/src/XamarinBackgroundKit.Android/PathProviders/CirclePathProvider.cs
new file mode 100644
index 0000000..6ebdda7
--- /dev/null
+++ b/src/XamarinBackgroundKit.Android/PathProviders/CirclePathProvider.cs
@@ -0,0 +1,25 @@
+using System;
+using Android.Graphics;
+using XamarinBackgroundKit.Shapes;
+
+namespace XamarinBackgroundKit.Android.PathProviders
+{
+    public class CirclePathProvider : BasePathProvider<Circle>
+    {
+        public override bool IsBorderSupported => true;
+
+        public override void CreatePath(Path path, Circle shape, int width, int height)
+        {
+            var radius = Math.Min(width, height) / 2f;
+
+            path.AddCircle(width / 2f, height / 2f, radius, Path.Direction.Ccw);
+        }
+
+        public override void CreateBorderedPath(Path path, Circle shape, int width, int height, int strokeWidth)
+        {
+            var radius = (Math.Min(width, height) - strokeWidth) / 2f;
+
+            path.AddCircle(width / 2f, height / 2f, radius, Path.Direction.Ccw);
+        }
+    }
+}
diff --git a/src/XamarinBackgroundKit.Android/PathProviders/PathProvidersContainer.cs b/src/XamarinBackgroundKit.Android/PathProviders/PathProvidersContainer.cs
index c382ca9..4799a33 100644
--- a/src/XamarinBackgroundKit.Android/PathProviders/PathProvidersContainer.cs
+++ b/src/XamarinBackgroundKit.Android/PathProviders/PathProvidersContainer.cs
@@ -15,6 +15,7 @@ public static void Init()
         {
             Register<Arc>(() => new ArcPathProvider());
             Register<Rect>(() => new RectPathProvider());
+            Register<Circle>(() => new CirclePathProvider());
             Register<Diagonal>(() => new DiagonalPathProvider());
             Register<Triangle>(() => new TrianglePathProvider());
             Register<RoundRect>(() => new RoundRectPathProvider());
diff --git a/src/XamarinBackgroundKit.Android/Renderers/MaterialShapeManager.cs b/src/XamarinBackgroundKit.Android/Renderers/MaterialShapeManager.cs
index 34bcf60..5d7fe02 100644
--- a/src/XamarinBackgroundKit.Android/Renderers/MaterialShapeManager.cs
+++ b/src/XamarinBackgroundKit.Android/Renderers/MaterialShapeManager.cs
@@ -19,6 +19,7 @@ public class MaterialShapeManager : IDisposable
         private Paint _maskPaint;
         private AView _nativeView;
         private IBackgroundShape _shape;
+
         public IPathProvider PathProvider { get; private set; }
 
         public MaterialShapeManager()
@@ -118,6 +119,7 @@ private void InitializeClipPath(int width, int height)
 
             /* Always prefer border path. If there is no need, the provider will return the default one */
             var clipPath = PathProvider.CreateBorderedPath(width, height);
+            if (clipPath == null) return;
 
             _clipPath.Reset();
             _clipPath.Set(clipPath);
diff --git a/src/XamarinBackgroundKit.Android/XamarinBackgroundKit.Android.csproj b/src/XamarinBackgroundKit.Android/XamarinBackgroundKit.Android.csproj
index ef46cdb..08a82f0 100644
--- a/src/XamarinBackgroundKit.Android/XamarinBackgroundKit.Android.csproj
+++ b/src/XamarinBackgroundKit.Android/XamarinBackgroundKit.Android.csproj
@@ -71,6 +71,7 @@
     <Compile Include="GradientProviders\BaseGradientProvider.cs" />
     <Compile Include="GradientProviders\LinearGradientProvider.cs" />
     <Compile Include="GradientProviders\GradientProvidersContainer.cs" />
+    <Compile Include="PathProviders\CirclePathProvider.cs" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Xamarin.Forms">
diff --git a/src/XamarinBackgroundKit.iOS/PathProviders/CirclePathProvider.cs b/src/XamarinBackgroundKit.iOS/PathProviders/CirclePathProvider.cs
new file mode 100644
index 0000000..f2e0ecf
--- /dev/null
+++ b/src/XamarinBackgroundKit.iOS/PathProviders/CirclePathProvider.cs
@@ -0,0 +1,59 @@
+using System;
+using CoreGraphics;
+using UIKit;
+using XamarinBackgroundKit.Shapes;
+
+namespace XamarinBackgroundKit.iOS.PathProviders
+{
+    public class CirclePathProvider : BasePathProvider<Circle>
+    {
+        public override bool IsBorderSupported => true;
+
+        public override void CreatePath(Circle shape, CGRect bounds)
+        {
+            using (var bezierPath = GetCirclePath(bounds))
+            {
+                Path = bezierPath.CGPath;
+            }
+        }
+
+        public override void CreateBorderedPath(Circle shape, CGRect bounds, double strokeWidth)
+        {
+            using (var bezierPath = GetCirclePath(bounds, (float)strokeWidth))
+            {
+                BorderPath = bezierPath.CGPath;
+            }
+        }
+
+        private static UIBezierPath GetCirclePath(CGRect bounds, float borderWidth = 0f)
+        {
+            var startX = bounds.Left;
+            var endX = bounds.Right;
+            var startY = bounds.Top;
+            var endY = bounds.Bottom;
+
+            var delta = (float)Math.Abs(bounds.Width - bounds.Height) / 2f;
+
+            if (bounds.Width > bounds.Height)
+            {
+                startX += delta;
+                endX -= 2 * delta;
+            }
+            else if (bounds.Width < bounds.Height)
+            {
+                startY += delta;
+                endY -= 2 * delta;
+            }
+
+            var croppedBounds = new CGRect(
+                startX, startY, endX, endY);
+
+            var strokedCroppedBounds = croppedBounds.Inset(
+                borderWidth, borderWidth);
+
+            var radius = ((float)Math.Min(bounds.Width, bounds.Height) - borderWidth) / 2;
+
+            return UIBezierPath.FromRoundedRect(strokedCroppedBounds, radius);
+        }
+    }
+}
diff --git a/src/XamarinBackgroundKit.iOS/PathProviders/PathProvidersContainer.cs b/src/XamarinBackgroundKit.iOS/PathProviders/PathProvidersContainer.cs
index 91795a0..a94cd36 100644
--- a/src/XamarinBackgroundKit.iOS/PathProviders/PathProvidersContainer.cs
+++ b/src/XamarinBackgroundKit.iOS/PathProviders/PathProvidersContainer.cs
@@ -15,6 +15,7 @@ public static void Init()
         {
             Register<Arc>(() => new ArcPathProvider());
             Register<Rect>(() => new RectPathProvider());
+            Register<Circle>(() => new CirclePathProvider());
             Register<Diagonal>(() => new DiagonalPathProvider());
             Register<Triangle>(() => new TrianglePathProvider());
             Register<RoundRect>(() => new RoundRectPathProvider());
diff --git a/src/XamarinBackgroundKit.iOS/XamarinBackgroundKit.iOS.csproj b/src/XamarinBackgroundKit.iOS/XamarinBackgroundKit.iOS.csproj
index c7c73f8..5be59fc 100644
--- a/src/XamarinBackgroundKit.iOS/XamarinBackgroundKit.iOS.csproj
+++ b/src/XamarinBackgroundKit.iOS/XamarinBackgroundKit.iOS.csproj
@@ -62,6 +62,7 @@
     <Compile Include="GradientProviders\BaseGradientProvider.cs" />
     <Compile Include="GradientProviders\LinearGradientProvider.cs" />
     <Compile Include="GradientProviders\GradientProvidersContainer.cs" />
+    <Compile Include="PathProviders\CirclePathProvider.cs" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Naxam.KVOController.iOS">
diff --git a/src/XamarinBackgroundKit/Shapes/Circle.cs b/src/XamarinBackgroundKit/Shapes/Circle.cs
new file mode 100644
index 0000000..69c5480
--- /dev/null
+++ b/src/XamarinBackgroundKit/Shapes/Circle.cs
@@ -0,0 +1,4 @@
+namespace XamarinBackgroundKit.Shapes
+{
+    public class Circle : BaseShape { }
+}
diff --git a/src/XamarinBackgroundKitSample/ShapeExplorerPage.xaml b/src/XamarinBackgroundKitSample/ShapeExplorerPage.xaml
index 0b22a2b..d79eae3 100644
--- a/src/XamarinBackgroundKitSample/ShapeExplorerPage.xaml
+++ b/src/XamarinBackgroundKitSample/ShapeExplorerPage.xaml
@@ -9,6 +9,7 @@
                     <x:Array Type="{x:Type x:String}">
                         <x:String>Arc</x:String>
                         <x:String>Rect</x:String>
+                        <x:String>Circle</x:String>
                         <x:String>RoundRect</x:String>
                         <x:String>Diagonal</x:String>
                         <x:String>Triangle</x:String>
@@ -120,21 +121,57 @@
                     <ColumnDefinition Width="*" />
                     <ColumnDefinition Width="*" />
                 </Grid.ColumnDefinitions>
-                    
-                <Label FontSize="24" Text="X" Grid.Row="0" Grid.Column="0" />
-                <Label FontSize="24" Text="Y" Grid.Row="0" Grid.Column="1" />
 
-                <Label FontSize="24" Text="Point A" Grid.Row="1" Grid.ColumnSpan="2" />
-                <Slider x:Name="PointAX" Grid.Row="2" Grid.Column="0" Maximum="1" Minimum="0" ValueChanged="OnTrianglePointsChanged" />
-                <Slider x:Name="PointAY" Grid.Row="2" Grid.Column="1" Maximum="1" Minimum="0" ValueChanged="OnTrianglePointsChanged" />
-
-                <Label FontSize="24" Text="Point B" Grid.Row="3" Grid.ColumnSpan="2" />
-                <Slider x:Name="PointBX" Grid.Row="4" Grid.Column="0" Maximum="1" Minimum="0" ValueChanged="OnTrianglePointsChanged" />
-                <Slider x:Name="PointBY" Grid.Row="4" Grid.Column="1" Maximum="1" Minimum="0" ValueChanged="OnTrianglePointsChanged" />
-
-                <Label FontSize="24" Text="Point C" Grid.Row="5" Grid.ColumnSpan="2" />
-                <Slider x:Name="PointCX" Grid.Row="6" Grid.Column="0" Maximum="1" Minimum="0" ValueChanged="OnTrianglePointsChanged" />
-                <Slider x:Name="PointCY" Grid.Row="6" Grid.Column="1" Maximum="1" Minimum="0" ValueChanged="OnTrianglePointsChanged" />
+                <Label Grid.Row="0" Grid.Column="0" FontSize="24" Text="X" />
+                <Label Grid.Row="0" Grid.Column="1" FontSize="24" Text="Y" />
+
+                <Label Grid.Row="1" Grid.ColumnSpan="2" FontSize="24" Text="Point A" />
+                <Slider
+                    x:Name="PointAX"
+                    Grid.Row="2"
+                    Grid.Column="0"
+                    Maximum="1"
+                    Minimum="0"
+                    ValueChanged="OnTrianglePointsChanged" />
+                <Slider
+                    x:Name="PointAY"
+                    Grid.Row="2"
+                    Grid.Column="1"
+                    Maximum="1"
+                    Minimum="0"
+                    ValueChanged="OnTrianglePointsChanged" />
+
+                <Label Grid.Row="3" Grid.ColumnSpan="2" FontSize="24" Text="Point B" />
+                <Slider
+                    x:Name="PointBX"
+                    Grid.Row="4"
+                    Grid.Column="0"
+                    Maximum="1"
+                    Minimum="0"
+                    ValueChanged="OnTrianglePointsChanged" />
+                <Slider
+                    x:Name="PointBY"
+                    Grid.Row="4"
+                    Grid.Column="1"
+                    Maximum="1"
+                    Minimum="0"
+                    ValueChanged="OnTrianglePointsChanged" />
+
+                <Label Grid.Row="5" Grid.ColumnSpan="2" FontSize="24" Text="Point C" />
+                <Slider
+                    x:Name="PointCX"
+                    Grid.Row="6"
+                    Grid.Column="0"
+                    Maximum="1"
+                    Minimum="0"
+                    ValueChanged="OnTrianglePointsChanged" />
+                <Slider
+                    x:Name="PointCY"
+                    Grid.Row="6"
+                    Grid.Column="1"
+                    Maximum="1"
+                    Minimum="0"
+                    ValueChanged="OnTrianglePointsChanged" />
             </Grid>
 
             <background:MaterialShapeView x:Name="ShapeView" HeightRequest="200" HorizontalOptions="FillAndExpand">
diff --git a/src/XamarinBackgroundKitSample/ShapeExplorerPage.xaml.cs b/src/XamarinBackgroundKitSample/ShapeExplorerPage.xaml.cs
index fed7bc8..3e015a4 100644
--- a/src/XamarinBackgroundKitSample/ShapeExplorerPage.xaml.cs
+++ b/src/XamarinBackgroundKitSample/ShapeExplorerPage.xaml.cs
@@ -30,6 +30,9 @@ private void UpdateShape()
                 case "Rect":
                     ShapeView.Shape = new Rect();
                     break;
+                case "Circle":
+                    ShapeView.Shape = new Circle();
+                    break;
                 case "RoundRect":
                     ShapeView.Shape = new RoundRect();
                     CornerRadiusConfigContainer.IsVisible = true;