[FancyZones] Editor multi monitor support (#6562)

Co-authored-by: Enrico Giordani <enrico.giordani@gmail.com>
Co-authored-by: Enrico Giordani <enricogior@users.noreply.github.com>

src/modules/fancyzones/editor/FancyZonesEditor/ViewModels/MonitorViewModel.cs

@@ -0,0 +1,81 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Windows;
+using FancyZonesEditor.Utils;
+
+namespace FancyZonesEditor.ViewModels
+{
+    public class MonitorViewModel : INotifyPropertyChanged
+    {
+        private const int MaxPreviewDisplaySize = 160;
+        private const int MinPreviewDisplaySize = 98;
+
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        public delegate void MonitorChangedEventHandler(MonitorChangedEventArgs args);
+
+        public ObservableCollection<MonitorInfoModel> MonitorInfoForViewModel { get; set; }
+
+        public static double DesktopPreviewMultiplier { get; private set; }
+
+        public Visibility DesktopsPanelVisibility
+        {
+            get
+            {
+                return App.Overlay.MultiMonitorMode ? Visibility.Visible : Visibility.Collapsed;
+            }
+        }
+
+        public RelayCommand AddCommand { get; set; }
+
+        public RelayCommand DeleteCommand { get; set; }
+
+        public RelayCommand<MonitorInfoModel> SelectCommand { get; set; }
+
+        public MonitorViewModel()
+        {
+            SelectCommand = new RelayCommand<MonitorInfoModel>(SelectCommandExecute, SelectCommandCanExecute);
+
+            MonitorInfoForViewModel = new ObservableCollection<MonitorInfoModel>();
+            double maxDimension = 0, minDimension = double.MaxValue;
+
+            int i = 1;
+            foreach (var monitor in App.Overlay.Monitors)
+            {
+                Device device = monitor.Device;
+                var bounds = device.ScaledBounds;
+                maxDimension = System.Math.Max(System.Math.Max(maxDimension, bounds.Height), bounds.Width);
+                minDimension = System.Math.Min(System.Math.Min(minDimension, bounds.Height), bounds.Width);
+
+                MonitorInfoForViewModel.Add(new MonitorInfoModel(i, (int)bounds.Height, (int)bounds.Width, device.Dpi, App.Overlay.CurrentDesktop == i - 1));
+                i++;
+            }
+
+            double maxMultiplier = MaxPreviewDisplaySize / maxDimension;
+            double minMultiplier = MinPreviewDisplaySize / minDimension;
+            DesktopPreviewMultiplier = (minMultiplier + maxMultiplier) / 2;
+        }
+
+        private void RaisePropertyChanged(string propertyName)
+        {
+            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+
+        private bool SelectCommandCanExecute(MonitorInfoModel monitorInfo)
+        {
+            return true;
+        }
+
+        private void SelectCommandExecute(MonitorInfoModel monitorInfo)
+        {
+            MonitorInfoForViewModel[App.Overlay.CurrentDesktop].Selected = false;
+            MonitorInfoForViewModel[monitorInfo.Index - 1].Selected = true;
+
+            App.Overlay.CurrentDesktop = monitorInfo.Index - 1;
+        }
+    }
+}