From e3ab9fcc3ff19d03a69f91acbe1fb8803c7f86cb Mon Sep 17 00:00:00 2001
From: Lucas Zimerman Fraulob <lucas-zimerman1@hotmail.com>
Date: Tue, 9 Mar 2021 23:36:52 -0300
Subject: [PATCH 1/2] WIP - Multi image picker performance page.

---
 .../Interfaces/IImageResizer.cs               |  9 +++
 .../Sample.Xamarin.Core.csproj                |  3 +
 .../ViewModels/ImageSelectorPageViewModel.cs  | 70 +++++++++++++++++++
 .../ViewModels/MainPageViewModel.cs           |  8 +++
 .../Views/ImageSelectorPage.xaml              | 34 +++++++++
 .../Views/ImageSelectorPage.xaml.cs           | 20 ++++++
 .../Sample.Xamarin.Core/Views/MainPage.xaml   | 15 ++++
 .../Sample.Xamarin.Droid.csproj               |  1 +
 .../Tools/ImageResizer.cs                     | 53 ++++++++++++++
 9 files changed, 213 insertions(+)
 create mode 100644 Samples/Sample.Xamarin.Core/Interfaces/IImageResizer.cs
 create mode 100644 Samples/Sample.Xamarin.Core/ViewModels/ImageSelectorPageViewModel.cs
 create mode 100644 Samples/Sample.Xamarin.Core/Views/ImageSelectorPage.xaml
 create mode 100644 Samples/Sample.Xamarin.Core/Views/ImageSelectorPage.xaml.cs
 create mode 100644 Samples/Sample.Xamarin.Droid/Tools/ImageResizer.cs

diff --git a/Samples/Sample.Xamarin.Core/Interfaces/IImageResizer.cs b/Samples/Sample.Xamarin.Core/Interfaces/IImageResizer.cs
new file mode 100644
index 0000000..ac674c1
--- /dev/null
+++ b/Samples/Sample.Xamarin.Core/Interfaces/IImageResizer.cs
@@ -0,0 +1,9 @@
+using System.Threading.Tasks;
+
+namespace Sample.Xamarin.Core.Interfaces
+{
+    public interface IImageResizer
+    {
+        Task<string> ResizeImage(string imagePath, int maxSize, string filename);
+    }
+}
diff --git a/Samples/Sample.Xamarin.Core/Sample.Xamarin.Core.csproj b/Samples/Sample.Xamarin.Core/Sample.Xamarin.Core.csproj
index dfce5ed..2db5391 100644
--- a/Samples/Sample.Xamarin.Core/Sample.Xamarin.Core.csproj
+++ b/Samples/Sample.Xamarin.Core/Sample.Xamarin.Core.csproj
@@ -65,6 +65,9 @@
     <EmbeddedResource Update="Resources\UnhandledSvg.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Update="Views\ImageSelectorPage.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
     <EmbeddedResource Update="Views\Popups\PaymentPopupPage.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
diff --git a/Samples/Sample.Xamarin.Core/ViewModels/ImageSelectorPageViewModel.cs b/Samples/Sample.Xamarin.Core/ViewModels/ImageSelectorPageViewModel.cs
new file mode 100644
index 0000000..da2e5b1
--- /dev/null
+++ b/Samples/Sample.Xamarin.Core/ViewModels/ImageSelectorPageViewModel.cs
@@ -0,0 +1,70 @@
+using Sample.Xamarin.Core.Interfaces;
+using Sentry;
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Xamarin.Forms;
+
+namespace Sample.Xamarin.Core.ViewModels
+{
+    public class ImageSelectorPageViewModel : NavigationService
+    {
+        public bool TaskCompleted { get; set; }
+        public int MaxThreads { get; set; }
+        public int MinThreads { get; set; }
+        private int _selectedMaxThreads;
+        public int SelectedMaxThreads 
+        {
+            get => _selectedMaxThreads;
+            set
+            {
+                _selectedMaxThreads = value;
+                OnPropertyChanged();
+            }
+        }
+        public ObservableCollection<ImageSource> Images { get; set; }
+
+        private List<string> _paths;
+
+        private readonly IImageResizer _imageResizer;
+
+        public ImageSelectorPageViewModel()
+        {
+            _imageResizer = DependencyService.Get<IImageResizer>();
+
+            MaxThreads = Environment.ProcessorCount;
+            SelectedMaxThreads = 1;
+            MinThreads = 1;
+            _paths = new List<string>();
+            _ = _paths;
+        }
+
+        public async Task LoadImagesFromPath(List<string> paths)
+        {
+            Images = new ObservableCollection<ImageSource>();
+            var throttler = new SemaphoreSlim(initialCount: MaxThreads);
+            var tasks = paths.Select(async item =>
+            {
+                try
+                {
+                    await throttler.WaitAsync();
+                    var resizedPath = await _imageResizer.ResizeImage(item, 1250, item + "_R");
+                    Images.Add(ImageSource.FromFile(resizedPath));
+                }
+                catch (Exception ex)
+                {
+                    SentrySdk.CaptureException(ex);
+                }
+                finally
+                {
+                    throttler.Release();
+                }
+            });
+            await Task.WhenAll(tasks);
+            TaskCompleted = true;
+        }
+    }
+}
diff --git a/Samples/Sample.Xamarin.Core/ViewModels/MainPageViewModel.cs b/Samples/Sample.Xamarin.Core/ViewModels/MainPageViewModel.cs
index 03525d2..8196d93 100644
--- a/Samples/Sample.Xamarin.Core/ViewModels/MainPageViewModel.cs
+++ b/Samples/Sample.Xamarin.Core/ViewModels/MainPageViewModel.cs
@@ -20,6 +20,7 @@ public class MainPageViewModel : NavigationService
         public Command PopupCmd { get; }
         public Command BrokenViewCmd { get; }
         public Command NativeCrashCmd { get; }
+        public Command ImageSelectorCmd { get; }
         public MainPageViewModel()
         {
             DiscoCmd = new Command(GotoDisco);
@@ -29,6 +30,8 @@ public MainPageViewModel()
             BrokenViewCmd = new Command(GotoBrokenView);
             FeedbackCmd = new Command(ShowFeedback);
             NativeCrashCmd = new Command(NativeCrash);
+            ImageSelectorCmd = new Command(ImageSelector);
+
             _nativeCrashService = DependencyService.Get<INativeCrash>();
         }
 
@@ -85,5 +88,10 @@ public MainPageViewModel()
             _nativeCrashService?.BrokenNativeCallback();
             DisplayAlert("Whoops", "A native crash sample wasn't implemented for this platform, mind opening a pull request? :)", "Yes");
         };
+
+        private Action ImageSelector => () =>
+        {
+            NavigateTo(new ImageSelectorPage());
+        };
     }
 }
diff --git a/Samples/Sample.Xamarin.Core/Views/ImageSelectorPage.xaml b/Samples/Sample.Xamarin.Core/Views/ImageSelectorPage.xaml
new file mode 100644
index 0000000..6c511c7
--- /dev/null
+++ b/Samples/Sample.Xamarin.Core/Views/ImageSelectorPage.xaml
@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             xmlns:viewmodels="clr-namespace:Sample.Xamarin.Core.ViewModels"
+             x:Class="Sample.Xamarin.Core.Views.ImageSelectorPage"
+             Title="Image Selector">
+    <ContentPage.BindingContext>
+        <viewmodels:ImageSelectorPageViewModel/>
+    </ContentPage.BindingContext>
+    <ContentPage.Content>
+        <StackLayout Margin="20">
+            <ActivityIndicator 
+                                HeightRequest="50"
+                                WidthRequest="50"
+                                IsVisible="True"
+                                IsRunning="True"/>
+
+            <Label Text="Welcome to Xamarin.Forms!"
+                VerticalOptions="CenterAndExpand" 
+                HorizontalOptions="CenterAndExpand" />
+            <Label>
+                <Label.FormattedText>
+                    <FormattedString>
+                        <Span Text="Parallel threads:"/>
+                        <Span Text="{Binding SelectedMaxThreads}"/>
+                    </FormattedString>
+                </Label.FormattedText>
+            </Label>
+            <Slider Maximum="{Binding MaxThreads}"
+                    Minimum="{Binding MinThreads}"
+                    Value="{Binding SelectedMaxThreads}"/>
+        </StackLayout>
+    </ContentPage.Content>
+</ContentPage>
\ No newline at end of file
diff --git a/Samples/Sample.Xamarin.Core/Views/ImageSelectorPage.xaml.cs b/Samples/Sample.Xamarin.Core/Views/ImageSelectorPage.xaml.cs
new file mode 100644
index 0000000..dcd6e1e
--- /dev/null
+++ b/Samples/Sample.Xamarin.Core/Views/ImageSelectorPage.xaml.cs
@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+using Xamarin.Forms;
+using Xamarin.Forms.Xaml;
+
+namespace Sample.Xamarin.Core.Views
+{
+    [XamlCompilation(XamlCompilationOptions.Compile)]
+    public partial class ImageSelectorPage : ContentPage
+    {
+        public ImageSelectorPage()
+        {
+            InitializeComponent();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Samples/Sample.Xamarin.Core/Views/MainPage.xaml b/Samples/Sample.Xamarin.Core/Views/MainPage.xaml
index 88f7d2a..2f718f4 100644
--- a/Samples/Sample.Xamarin.Core/Views/MainPage.xaml
+++ b/Samples/Sample.Xamarin.Core/Views/MainPage.xaml
@@ -138,6 +138,21 @@
                                HorizontalOptions="Center"/>
                     </StackLayout>
                 </Frame>
+                <Frame BorderColor="#A8A2A2" 
+                       Margin="5"
+                       CornerRadius="8" 
+                       HeightRequest="{OnIdiom Phone=150, Desktop=200, Tablet=200, Watch=100, TV=100, Default=150}"
+                       WidthRequest="{OnIdiom Phone=150, Desktop=200, Tablet=200, Watch=100, TV=100, Default=150}">
+                    <Frame.GestureRecognizers>
+                        <TapGestureRecognizer Command="{Binding ImageSelectorCmd}"/>
+                    </Frame.GestureRecognizers>
+                    <StackLayout HorizontalOptions="Center">
+                        <resources:UnhandledSvg HeightRequest="120" WidthRequest="120"/>
+                        <Label Text="Image Selector"
+                               FontSize="Medium"
+                               HorizontalOptions="Center"/>
+                    </StackLayout>
+                </Frame>
             </FlexLayout>
         </ScrollView>
     </StackLayout>
diff --git a/Samples/Sample.Xamarin.Droid/Sample.Xamarin.Droid.csproj b/Samples/Sample.Xamarin.Droid/Sample.Xamarin.Droid.csproj
index 9c6cdc0..3e2a2d6 100644
--- a/Samples/Sample.Xamarin.Droid/Sample.Xamarin.Droid.csproj
+++ b/Samples/Sample.Xamarin.Droid/Sample.Xamarin.Droid.csproj
@@ -75,6 +75,7 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Resources\Resource.designer.cs" />
     <Compile Include="SplashActivity.cs" />
+    <Compile Include="Tools\ImageResizer.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="Resources\AboutResources.txt" />
diff --git a/Samples/Sample.Xamarin.Droid/Tools/ImageResizer.cs b/Samples/Sample.Xamarin.Droid/Tools/ImageResizer.cs
new file mode 100644
index 0000000..14df54f
--- /dev/null
+++ b/Samples/Sample.Xamarin.Droid/Tools/ImageResizer.cs
@@ -0,0 +1,53 @@
+using Android.Graphics;
+using Sample.Xamarin.Core.Interfaces;
+using System.Threading.Tasks;
+using Xamarin.Essentials;
+
+namespace Sample.Xamarin.Droid.Tools
+{
+    internal class ImageResizer : IImageResizer
+    {
+        public async Task<string> ResizeImage(string imagePath, int maxSize, string filename)
+            => await Task.Run(() =>
+            {
+                var option = new BitmapFactory.Options()
+                {
+                    InSampleSize = 1
+                };
+
+                var originalImage = BitmapFactory.DecodeFile(imagePath, option);
+                var scaledSize = GetMeasure(originalImage.Width, originalImage.Height, maxSize);
+                var resizedImage = Bitmap.CreateScaledBitmap(originalImage, scaledSize.Item1, scaledSize.Item2, false);
+
+                var path = System.IO.Path.Combine(FileSystem.CacheDirectory, filename);
+                using (var f = System.IO.File.Create(path))
+                {
+                    resizedImage.Compress(Bitmap.CompressFormat.Jpeg, 35, f);
+                }
+                if (resizedImage != originalImage)
+                {
+                    originalImage.Recycle();
+                }
+                resizedImage.Recycle();
+                return path;
+            });
+
+        private (int, int) GetMeasure(int width, int height, int newMax)
+        {
+            double ratio;
+            if (width > newMax)
+            {
+                ratio = (double)newMax / width;
+                height = (int)(height * ratio);
+                width = (int)(width * ratio);
+            }
+            if (height > newMax)
+            {
+                ratio = (double)newMax / height;
+                width = (int)(width * ratio);
+                height = (int)(height * ratio);
+            }
+            return (width, height);
+        }
+    }
+}
\ No newline at end of file

From 25bddc44fa24c3484d21d8cef3b19a79140c1ab7 Mon Sep 17 00:00:00 2001
From: Lucas Zimerman Fraulob <lucas-zimerman1@hotmail.com>
Date: Tue, 16 Mar 2021 09:45:00 -0300
Subject: [PATCH 2/2] WIP

---
 .../CustomControls/CustomWebView.cs           | 13 ++++
 .../Renderer/CustomWebViewRenderer.cs         | 67 +++++++++++++++++++
 2 files changed, 80 insertions(+)
 create mode 100644 Samples/Sample.Xamarin.Core/CustomControls/CustomWebView.cs
 create mode 100644 Samples/Sample.Xamarin.Droid/Renderer/CustomWebViewRenderer.cs

diff --git a/Samples/Sample.Xamarin.Core/CustomControls/CustomWebView.cs b/Samples/Sample.Xamarin.Core/CustomControls/CustomWebView.cs
new file mode 100644
index 0000000..968464d
--- /dev/null
+++ b/Samples/Sample.Xamarin.Core/CustomControls/CustomWebView.cs
@@ -0,0 +1,13 @@
+using Xamarin.Forms;
+
+namespace Sample.Xamarin.Core.CustomControls
+{
+    /// <summary>
+    /// Sadly this extra class is required since you can't scale things properly 
+    /// with the default WebView.
+    /// Custom render, here we go :D
+    /// </summary>
+    public class CustomWebView : WebView
+    {
+    }
+}
diff --git a/Samples/Sample.Xamarin.Droid/Renderer/CustomWebViewRenderer.cs b/Samples/Sample.Xamarin.Droid/Renderer/CustomWebViewRenderer.cs
new file mode 100644
index 0000000..747b28e
--- /dev/null
+++ b/Samples/Sample.Xamarin.Droid/Renderer/CustomWebViewRenderer.cs
@@ -0,0 +1,67 @@
+using Android.App;
+using Android.Content;
+using Android.OS;
+using Android.Runtime;
+using Android.Views;
+using Android.Widget;
+using Sample.Xamarin.Core.CustomControls;
+using Sample.Xamarin.Droid.Renderer;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Threading.Tasks;
+using Xamarin.Forms;
+using Xamarin.Forms.Platform.Android;
+using static Android.Webkit.WebSettings;
+
+[assembly: ExportRenderer(typeof(CustomWebView), typeof(CustomWebViewRenderer))]
+namespace Sample.Xamarin.Droid.Renderer
+{
+    public class CustomWebViewRenderer : WebViewRenderer
+    {
+        public CustomWebViewRenderer(Context context) : base(context)
+        {
+
+        }
+
+        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            base.OnElementPropertyChanged(sender, e);
+
+            Control.SetWebViewClient(new ExtendedWebViewClient(Element as CustomWebView));
+
+        }
+
+        class ExtendedWebViewClient : Android.Webkit.WebViewClient
+        {
+            private CustomWebView _xwebView { get; set; }
+            public ExtendedWebViewClient(CustomWebView webView)
+            {
+                _xwebView = webView;
+            }
+
+            async public override void OnPageFinished(Android.Webkit.WebView view, string url)
+            {
+                if (_xwebView != null)
+                {
+                    _xwebView.HeightRequest = 0d;
+                    await Task.Delay(100);
+                    var result = await _xwebView.EvaluateJavaScriptAsync("(function(){return document.body.scrollHeight;})()");
+                    Console.WriteLine(result);
+                    var newResult = result;
+                    for (int i = 0; i < 1000 && result == newResult; i++)
+                    {
+                        await Task.Delay(100);
+                        newResult = await _xwebView.EvaluateJavaScriptAsync("(function(){return document.body.scrollHeight;})()");
+                        Console.WriteLine(newResult);
+                    }
+                    _xwebView.HeightRequest = Convert.ToDouble(newResult);
+                    view.SetInitialScale(40);
+
+                }
+
+                base.OnPageFinished(view, url);
+            }
+        }
+    }
+}