iOSCameraRenderer.cs

using System;
using AVFoundation;
using Foundation;
using OverlayCameraSample.Controls;
using OverlayCameraSample.iOS.Controls;
using OverlayCameraSample.iOS.Renderers;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
using OverlayCameraSample.iOS.Extensions;

[assembly: ExportRenderer(typeof(CameraPreview), typeof(CameraPreviewRenderer))]
namespace OverlayCameraSample.iOS.Renderers
{
	public class CameraPreviewRenderer : ViewRenderer<CameraPreview, UICameraPreview>
	{
		bool isBusy;
		UICameraPreview uiCameraPreview;

		protected override void OnElementChanged(ElementChangedEventArgs<CameraPreview> e)
		{
			base.OnElementChanged(e);

			if (Control == null)
			{
				uiCameraPreview = new UICameraPreview(e.NewElement.Camera, e.NewElement.CameraMode);
				SetNativeControl(uiCameraPreview);
			}
			if (e.OldElement != null)
			{
				// Unsubscribe
				uiCameraPreview.ImageCaptured -= OnImageCaptured;
			}
			if (e.NewElement != null)
			{
				// Subscribe
				uiCameraPreview.ShowFaceOverlay = Element.ShowCircleOverlayMask;
				uiCameraPreview.FaceOverlayColor = Element.CircleOverlayColor.ToUIColor();
				uiCameraPreview.FaceOverlayOpacity = Element.CircleOverlayOpacity;
				uiCameraPreview.StopOnCapture = Element.CameraStopOnImageCapture;
				uiCameraPreview.ImageCaptured += OnImageCaptured;
				Element.TakePictureCommand = new Command(async () =>
				{
					if (isBusy) return;

					isBusy = true;
					await uiCameraPreview.CaptureImage();
					isBusy = false;

				});
				Element.PrepareCameraCommand = new Command(() => uiCameraPreview.StartCamera(Element.Camera, Element.CameraMode));
				Element.StopCameraCommand = new Command(() => uiCameraPreview.StopCamera());
			}
		}

		protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
		{
			base.OnElementPropertyChanged(sender, e);

		       if (CameraPreview.FlashProperty.PropertyName == e.PropertyName)
		       {
				uiCameraPreview.FlashConfiguration(Element.Flash);
		       }
		       else if (CameraPreview.CameraProperty.PropertyName == e.PropertyName)
		        {
				Element.Flash = false;
				uiCameraPreview.Flip();
		        }
		       else if (CameraPreview.ShowCircleOverlayMaskProperty.PropertyName == e.PropertyName)
			{
				uiCameraPreview.ShowFaceOverlay = Element.ShowCircleOverlayMask;
			}
			else if (CameraPreview.CircleOverlayColorProperty.PropertyName == e.PropertyName)
			{
				uiCameraPreview.FaceOverlayColor = Element.CircleOverlayColor.ToUIColor();
			}
			else if (CameraPreview.CircleOverlayOpacityProperty.PropertyName == e.PropertyName)
			{
				uiCameraPreview.FaceOverlayOpacity = Element.CircleOverlayOpacity;
			}
			else if (CameraPreview.CameraStopOnImageCaptureProperty.PropertyName == e.PropertyName)
			{
				uiCameraPreview.StopOnCapture = Element.CameraStopOnImageCapture;
			}
		}

		void OnCameraPreviewTapped(object sender, EventArgs e)
		{
			if (uiCameraPreview.IsPreviewing)
			{
				uiCameraPreview.CaptureSession.StopRunning();
				uiCameraPreview.IsPreviewing = false;
			}
			else
			{
				uiCameraPreview.CaptureSession.StartRunning();
				uiCameraPreview.IsPreviewing = true;
			}
		}

		void OnImageCaptured(object sender, Tuple<string, bool, long> imageParams)
		{
			Element?.OnPictureTaken(this, imageParams);
		}

		protected override void Dispose(bool disposing)
		{
			if (disposing)
			{
				Control?.CaptureSession?.Dispose();
				Control?.Dispose();
			}
			base.Dispose(disposing);
		}
	}
}