Zoomable ScrollView Android Renderer

ZoomScrollViewRenderer.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Xamarin.Forms.Platform.Android;
using static Android.Views.ScaleGestureDetector;
using Android.Views.Animations;
using Xamarin.Forms;
using ZoomableApp.Droid.Renderers;

[assembly: ExportRenderer(typeof(Xamarin.Forms.ScrollView), typeof(ZoomScrollViewRenderer))]
namespace ZoomableApp.Droid.Renderers
{

  public class ZoomScrollViewRenderer : ScrollViewRenderer, IOnScaleGestureListener
  {
    private float mScale = 1f;
    private ScaleGestureDetector mScaleDetector;
    
    protected override void OnElementChanged(VisualElementChangedEventArgs e)
    {
    
        base.OnElementChanged(e);
        mScaleDetector = new ScaleGestureDetector(Context, this);

    }


    public override bool DispatchTouchEvent(MotionEvent e)
    {
        base.DispatchTouchEvent(e);
        return mScaleDetector.OnTouchEvent(e);
    }

    public bool OnScale(ScaleGestureDetector detector)
    {
        float scale = 1 - detector.ScaleFactor;

        float prevScale = mScale;
        mScale += scale;

        if (mScale < 0.5f) // Minimum scale condition:
        mScale = 0.5f;

        if (mScale > 1f) // Maximum scale condition:
        mScale = 1f;
        ScaleAnimation scaleAnimation = new ScaleAnimation(1f / prevScale, 1f / mScale, 1f / prevScale, 1f / mScale, detector.FocusX, detector.FocusY);
        scaleAnimation.Duration =0;
        scaleAnimation.FillAfter =true;
        StartAnimation(scaleAnimation);
        return true;
    }

    public bool OnScaleBegin(ScaleGestureDetector detector)
    {
        return true;
    }

    public void OnScaleEnd(ScaleGestureDetector detector)
    {

    }
  }
}