Add preview background in welcome page 2

Author: Jack251970

Flow.Launcher/Resources/Pages/WelcomePage2.xaml.cs

@@ -2,11 +2,12 @@
 using Flow.Launcher.Infrastructure.Hotkey;
 using Flow.Launcher.Infrastructure.UserSettings;
 using System;
-using System.Windows;
-using System.Windows.Media;
 using System.Windows.Navigation;
 using CommunityToolkit.Mvvm.Input;
 using Flow.Launcher.ViewModel;
+using System.IO;
+using System.Windows.Media.Imaging;
+using System.Windows.Media;
 
 namespace Flow.Launcher.Resources.Pages
 {
@@ -29,5 +30,27 @@ private static void SetTogglingHotkey(HotkeyModel hotkey)
         {
             HotKeyMapper.SetHotkey(hotkey, HotKeyMapper.OnToggleHotkey);
         }
+
+        public Brush PreviewBackground
+        {
+            get
+            {
+                var wallpaper = WallpaperPathRetrieval.GetWallpaperPath();
+                if (wallpaper is not null && File.Exists(wallpaper))
+                {
+                    var memStream = new MemoryStream(File.ReadAllBytes(wallpaper));
+                    var bitmap = new BitmapImage();
+                    bitmap.BeginInit();
+                    bitmap.StreamSource = memStream;
+                    bitmap.DecodePixelWidth = 800;
+                    bitmap.DecodePixelHeight = 600;
+                    bitmap.EndInit();
+                    return new ImageBrush(bitmap) { Stretch = Stretch.UniformToFill };
+                }
+
+                var wallpaperColor = WallpaperPathRetrieval.GetWallpaperColor();
+                return new SolidColorBrush(wallpaperColor);
+            }
+        }
     }
 }