Use Camera2 on Android. (#672)

Author: davidbritch

CustomRenderers/View/CustomRenderer/CameraPreview.cs

@@ -2,17 +2,18 @@
 
 namespace CustomRenderer
 {
-	public class CameraPreview : View
-	{
-		public static readonly BindableProperty CameraProperty = BindableProperty.Create (
-			propertyName: "Camera",
-			returnType: typeof(CameraOptions),
-			declaringType: typeof(CameraPreview),
-			defaultValue: CameraOptions.Rear);
+    public class CameraPreview : View
+    {
+        public static readonly BindableProperty CameraProperty = BindableProperty.Create(
+            propertyName: "Camera",
+            returnType: typeof(CameraOptions),
+            declaringType: typeof(CameraPreview),
+            defaultValue: CameraOptions.Rear);
 
-		public CameraOptions Camera {
-			get { return (CameraOptions)GetValue (CameraProperty); }
-			set { SetValue (CameraProperty, value); }
-		}
-	}
+        public CameraOptions Camera
+        {
+            get { return (CameraOptions)GetValue(CameraProperty); }
+            set { SetValue(CameraProperty, value); }
+        }
+    }
 }

CustomRenderers/View/CustomRenderer/CustomRenderer.csproj

@@ -18,4 +18,4 @@
     </EmbeddedResource>
   </ItemGroup>
 
-</Project>
+</Project>

CustomRenderers/View/CustomRenderer/MainPage.xaml

@@ -3,12 +3,11 @@
 			 xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
 			 xmlns:local="clr-namespace:CustomRenderer;assembly=CustomRenderer"
 			 x:Class="CustomRenderer.MainPage"
-			 Padding="0,20,0,0"
 			 Title="Main Page">
-	<ContentPage.Content>
-		<StackLayout>
-			<Label Text="Camera Preview:" />
-			<local:CameraPreview Camera="Rear" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" />
-		</StackLayout>
-	</ContentPage.Content>
+	<StackLayout Margin="20,35,20,20">
+		<Label Text="Camera Preview:" />
+		<local:CameraPreview Camera="Rear"
+							 HorizontalOptions="FillAndExpand"
+							 VerticalOptions="FillAndExpand" />
+	</StackLayout>
 </ContentPage>

CustomRenderers/View/Droid/AutoFitTextureView.cs

@@ -0,0 +1,84 @@
+using System;
+using Android.Content;
+using Android.Runtime;
+using Android.Util;
+using Android.Views;
+
+namespace CustomRenderer.Droid
+{
+    public class AutoFitTextureView : TextureView
+    {
+        int mRatioWidth = 0;
+        int mRatioHeight = 0;
+        readonly object locker = new object();
+
+        public AutoFitTextureView(Context context) : this(context, null)
+        {
+        }
+
+        public AutoFitTextureView(Context context, IAttributeSet attrs) : this(context, attrs, 0)
+        {
+        }
+
+        public AutoFitTextureView(Context context, IAttributeSet attrs, int defStyle) : base(context, attrs, defStyle)
+        {
+        }
+
+        protected AutoFitTextureView(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
+        {
+        }
+
+        public void SetAspectRatio(int width, int height)
+        {
+            if (width == 0 || height == 0)
+            {
+                throw new ArgumentException("Size can't be negative.");
+            }
+
+            mRatioWidth = width;
+            mRatioHeight = height;
+            RequestLayout();
+        }
+
+        protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
+        {
+            base.OnMeasure(widthMeasureSpec, heightMeasureSpec);
+
+            int width = MeasureSpec.GetSize(widthMeasureSpec);
+            int height = MeasureSpec.GetSize(heightMeasureSpec);
+
+            if (mRatioWidth == 0 || mRatioHeight == 0)
+            {
+                SetMeasuredDimension(width, height);
+            }
+            else
+            {
+                if (width < (float)height * mRatioWidth / mRatioHeight)
+                {
+                    SetMeasuredDimension(width, width * mRatioHeight / mRatioWidth);
+                }
+                else
+                {
+                    SetMeasuredDimension(height * mRatioWidth / mRatioHeight, height);
+                }
+            }
+        }
+
+        public void ClearCanvas(Android.Graphics.Color color)
+        {
+            using var canvas = LockCanvas(null);
+            lock (locker)
+            {
+                try
+                {
+                    canvas.DrawColor(color);
+                }
+                finally
+                {
+                    UnlockCanvasAndPost(canvas);
+                }
+                Invalidate();
+            }
+        }
+    }
+}

CustomRenderers/View/Droid/CameraCaptureStateListener.cs

@@ -0,0 +1,14 @@
+using System;
+using Android.Hardware.Camera2;
+
+namespace CustomRenderer.Droid
+{
+    class CameraCaptureStateListener : CameraCaptureSession.StateCallback
+    {
+		public Action<CameraCaptureSession> OnConfigureFailedAction;
+		public Action<CameraCaptureSession> OnConfiguredAction;
+
+		public override void OnConfigureFailed(CameraCaptureSession session) => OnConfigureFailedAction?.Invoke(session);
+		public override void OnConfigured(CameraCaptureSession session) => OnConfiguredAction?.Invoke(session);
+	}
+}