Added playing song info view and view model.

Harmonia.UI/Views/MainView.axaml

@@ -19,6 +19,7 @@
 			<RowDefinition Height="*"></RowDefinition>
 			<RowDefinition Height="Auto"></RowDefinition>
 		</Grid.RowDefinitions>
+		<views:PlayingSongInfo Grid.Row="0"></views:PlayingSongInfo>
 		<views:PlaybackBar Grid.Row="1"></views:PlaybackBar>
 	</Grid>
 

Harmonia.UI/Views/MainWindow.axaml.cs

@@ -1,11 +1,61 @@
 using Avalonia.Controls;
+using Harmonia.Core.Engine;
+using Harmonia.Core.Models;
+using Harmonia.Core.Player;
+using System.ComponentModel;
+using System.Linq;
 
 namespace Harmonia.UI.Views;
 
 public partial class MainWindow : Window
 {
-    public MainWindow()
+    private readonly IAudioPlayer _audioPlayer;
+
+    private const string ApplicationTitle = "Harmonia";
+
+    public MainWindow(IAudioPlayer audioPlayer)
     {
+        _audioPlayer = audioPlayer;
+        _audioPlayer.PropertyChanged += OnAudioPlayerPropertyChanged;
+
+        Title = ApplicationTitle;
+
         InitializeComponent();
     }
+
+    private void OnAudioPlayerPropertyChanged(object? sender, PropertyChangedEventArgs e)
+    {
+        switch (e.PropertyName)
+        {
+            case nameof(_audioPlayer.State):
+                Title = GetUpdatedAppTitle();
+                //PropertyChanged(nameof(Title));
+                break;
+        }
+    }
+
+    private string GetUpdatedAppTitle()
+    {
+        return _audioPlayer.State switch
+        {
+            AudioPlaybackState.Stopped => ApplicationTitle,
+            _ => $"{GetSongArtistsAndTitle()} - {ApplicationTitle}"
+        };
+    }
+
+    private string GetSongArtistsAndTitle()
+    {
+        if (_audioPlayer.PlayingSong == null)
+            return string.Empty;
+
+        Song song = _audioPlayer.PlayingSong.Song;
+
+        string[] values =
+        [
+            string.Join(" / ", song.Artists ?? song.AlbumArtists),
+            song.Title ?? song.ShortFileName
+        ];
+
+        return string.Join(" - ", values.Where(value => string.IsNullOrWhiteSpace(value) == false));
+    }
 }

Harmonia.UI/Views/PlaybackBar.axaml.cs

@@ -15,7 +15,7 @@ public partial class PlaybackBar : UserControl
         _viewModel = (PlaybackBarViewModel)DataContext!;
     }
 
-    private void Slider_Loaded(object? sender, Avalonia.Interactivity.RoutedEventArgs e)
+    private void Slider_Loaded(object? sender, RoutedEventArgs e)
     {
         if (sender is not Slider slider)
             return;

Harmonia.UI/Views/PlayingSongInfo.axaml

@@ -0,0 +1,27 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:vm="clr-namespace:Harmonia.UI.ViewModels"
+			 xmlns:converter="clr-namespace:Harmonia.UI.Converters"
+             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+			 DataContext="{x:Static vm:ViewModelLocator.PlayingSongInfoViewModel}"
+             x:Class="Harmonia.UI.Views.PlayingSongInfo"
+             x:DataType="vm:PlayingSongInfoViewModel">
+	<Grid>
+		<Image Source="{Binding SongImageSource, Mode=OneWay}" Stretch="UniformToFill" HorizontalAlignment="Center" VerticalAlignment="Center">
+			<Image.Effect>
+				<BlurEffect Radius="20" />
+			</Image.Effect>
+			<Image.RenderTransform>
+				<ScaleTransform ScaleX="1.05" ScaleY="1.05" />
+			</Image.RenderTransform>
+		</Image>
+		<Canvas Background="#99000000"></Canvas>
+		<Image Source="{Binding SongImageSource}" Stretch="Uniform" HorizontalAlignment="Center" VerticalAlignment="Center" Margin="20">
+			<Image.Effect>
+				<DropShadowEffect BlurRadius="10" Opacity=".4" OffsetX="3" OffsetY="3" />
+			</Image.Effect>
+		</Image>
+	</Grid>
+</UserControl>

Harmonia.UI/Views/PlayingSongInfo.axaml.cs

@@ -0,0 +1,17 @@
+using Avalonia.Controls;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Harmonia.UI.ViewModels;
+
+namespace Harmonia.UI.Views;
+
+public partial class PlayingSongInfo : UserControl
+{
+    private readonly PlayingSongInfoViewModel _viewModel;
+
+    public PlayingSongInfo()
+    {
+        InitializeComponent();
+        _viewModel = (PlayingSongInfoViewModel)DataContext!;
+    }
+}