UI fixes: combined play/pause button, tooltips.

ABStemPlayer/Converters/PlayPauseGeometryConverter .cs

@@ -0,0 +1,23 @@
+using System.Globalization;
+using Avalonia.Data.Converters;
+using Avalonia.Media;
+
+namespace ABStemPlayer.Converters;
+
+public class PlayPauseGeometryConverter : IValueConverter
+{
+    public object? Convert(object? value, Type targetType, object? parameter, CultureInfo culture)
+    {
+        bool isPlaying = value is bool b && b;
+
+        // Pause icon
+        if (isPlaying)
+            return Geometry.Parse("M 12 8 L 18 8 L 18 32 L 12 32 Z M 22 8 L 28 8 L 28 32 L 22 32 Z");
+
+        // Play icon
+        return Geometry.Parse("M 10 8 L 32 20 L 10 32 Z");
+    }
+    public object? ConvertBack(object? value, Type targetType, object? parameter, CultureInfo culture)
+        => throw new NotSupportedException();
+}
+

ABStemPlayer/ViewModels/PlaybackViewModel.cs

@@ -36,7 +36,6 @@ public sealed partial class PlaybackViewModel : ObservableObject
 
     public ICommand OpenFileCommand    { get; }
     public ICommand PlayCommand        { get; }
-    public ICommand PauseCommand       { get; }
     public ICommand StopCommand        { get; }
     public ICommand RewindCommand      { get; }
     public ICommand FastForwardCommand { get; }
@@ -48,6 +47,7 @@ public sealed partial class PlaybackViewModel : ObservableObject
     // Playback properties
     // -----------------------------
 
+    [ObservableProperty] private bool           _isPlaying;
     [ObservableProperty] private bool           _loopEnabled;
     [ObservableProperty] private float          _playbackSpeed = 1f;
     [ObservableProperty] private TimeSpan       _currentTime;
@@ -83,8 +83,7 @@ public sealed partial class PlaybackViewModel : ObservableObject
 
         OpenFileCommand         = new AsyncRelayCommand(OpenFileAsync);
         PlayCommand             = new AsyncRelayCommand(OnPlay);
-        PauseCommand            = new AsyncRelayCommand(() => _engine.PauseAsync());
+        StopCommand             = new AsyncRelayCommand(OnStop);
-        StopCommand             = new AsyncRelayCommand(async () => { await _engine.StopAsync(); await _engine.SeekAsync(TimeSpan.Zero); });
 
         RewindCommand           = new AsyncRelayCommand(() => _engine.SeekAsync(CurrentTime - TimeSpan.FromSeconds(5)));
         FastForwardCommand      = new AsyncRelayCommand(() => _engine.SeekAsync(CurrentTime + TimeSpan.FromSeconds(5)));
@@ -123,6 +122,13 @@ public sealed partial class PlaybackViewModel : ObservableObject
 
     private async Task OnPlay()
     {
+        if (IsPlaying)
+        {
+            await _engine.PauseAsync();
+            IsPlaying = false;
+            return;
+        }
+            
         if (_engine.CurrentSession == null)
             return;
 
@@ -135,6 +141,14 @@ public sealed partial class PlaybackViewModel : ObservableObject
         await _engine.UpdatePlaybackSpeedAsync(new PlaybackSpeedSettings { Speed = PlaybackSpeed });
 
         await _engine.PlayAsync();
+        IsPlaying = true;
+    }
+
+    private async Task OnStop()
+    {
+        await _engine.StopAsync();
+        IsPlaying   = false;
+        CurrentTime = TimeSpan.Zero;
     }
 
     partial void OnMixerChanged(MixerViewModel? oldValue, MixerViewModel newValue)

ABStemPlayer/Views/MainWindow.axaml

@@ -39,14 +39,12 @@
               Grid.Column="0"
               Margin="8">
 
-            <ScrollViewer Margin="8"
+            <ScrollViewer Margin="8" VerticalScrollBarVisibility="Auto">
-                          VerticalScrollBarVisibility="Auto">
-
                 <ItemsControl ItemsSource="{Binding Bands}"
                               Margin="0,2">
                     <ItemsControl.ItemsPanel>
                         <ItemsPanelTemplate>
-                            <StackPanel Orientation="Vertical"/>
+                            <VirtualizingStackPanel Orientation="Vertical"/>
                         </ItemsPanelTemplate>
                     </ItemsControl.ItemsPanel>
 
@@ -56,7 +54,6 @@
                         </DataTemplate>
                     </ItemsControl.ItemTemplate>
                 </ItemsControl>
-
             </ScrollViewer>
         </Grid>
 

ABStemPlayer/Views/PlaybackControls.axaml

@@ -3,10 +3,12 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:vm="using:ABStemPlayer.ViewModels"
              xmlns:conv="using:ABStemPlayer.Converters"
+             xmlns:av="clr-namespace:Avalonia;assembly=Avalonia.Base"
              x:DataType="vm:PlaybackViewModel"
              x:Class="ABStemPlayer.Views.PlaybackControls">
     <UserControl.Resources>
         <conv:BoolInvertConverter x:Key="BoolInvert" />
+        <conv:PlayPauseGeometryConverter x:Key="PlayPauseGeometry" />
     </UserControl.Resources>
 
     <Border Padding="8"
@@ -38,7 +40,8 @@
                             Width="40"
                             Height="40"
                             Grid.Column="0"
-                            Margin="0,0,6,0">
+                            Margin="0,0,6,0"
+                            ToolTip.Tip="Open File">
                         <Path Fill="#e0e0e0"
                               Stretch="None"
                               RenderTransformOrigin="0,0">
@@ -57,7 +60,8 @@
                             Width="40"
                             Height="40"
                             Grid.Column="1"
-                            Margin="0,0,6,0">
+                            Margin="0,0,6,0"
+                            ToolTip.Tip="Rewind">
                         <Path Fill="#e0e0e0"
                               Stretch="None"
                               RenderTransformOrigin="0,0">
@@ -72,41 +76,20 @@
                     </Button>
 
                     <!-- Play -->
-                    <Button Command="{Binding PlayCommand}"
+                    <Button Width="40"
-                            Width="40"
                             Height="40"
                             Grid.Column="2"
-                            Margin="0,0,6,0">
+                            Margin="0,0,6,0"
+                            ToolTip.Tip="Play/Pause"
+                            Command="{Binding PlayCommand}">
+    
                         <Path Fill="#e0e0e0"
                               Stretch="None"
-                              RenderTransformOrigin="0,0">
+                              RenderTransformOrigin="0,0"
+                              Data="{Binding IsPlaying, Converter={StaticResource PlayPauseGeometry}}">
                             <Path.RenderTransform>
                                 <TranslateTransform X="-8" Y="-8"/>
                             </Path.RenderTransform>
-
-                            <Path.Data>
-                                M 10 8 L 32 20 L 10 32 Z
-                            </Path.Data>
-                        </Path>
-                    </Button>
-
-                    <!-- Pause -->
-                    <Button Command="{Binding PauseCommand}"
-                            Width="40"
-                            Height="40"
-                            Grid.Column="3"
-                            Margin="0,0,6,0">
-                        <Path Fill="#e0e0e0"
-                              Stretch="None"
-                              RenderTransformOrigin="0,0">
-                            <Path.RenderTransform>
-                                <TranslateTransform X="-8" Y="-8"/>
-                            </Path.RenderTransform>
-
-                            <Path.Data>
-                                M 8 8 H 16 V 32 H 8 Z
-                                M 24 8 H 32 V 32 H 24 Z
-                            </Path.Data>
                         </Path>
                     </Button>
 
@@ -115,7 +98,8 @@
                             Width="40"
                             Height="40"
                             Grid.Column="4"
-                            Margin="0,0,6,0">
+                            Margin="0,0,6,0"
+                            ToolTip.Tip="Stop">
                         <Path Fill="#e0e0e0"
                               Stretch="None"
                               RenderTransformOrigin="0,0">
@@ -133,7 +117,8 @@
                     <Button Command="{Binding FastForwardCommand}"
                             Width="40"
                             Height="40"
-                            Grid.Column="5">
+                            Grid.Column="5"
+                            ToolTip.Tip="Fast Forward">
                         <Path Fill="#e0e0e0"
                               Stretch="None"
                               RenderTransformOrigin="0,0">
@@ -189,6 +174,8 @@
 
                     <ToggleSwitch IsChecked="{Binding LoopEnabled}"
                                   Content="Loop"
+                                  OnContent=""
+                                  OffContent=""
                                   VerticalAlignment="Center"
                                   Grid.Column="0"
                                   Margin="0,0,6,0"/>
@@ -197,7 +184,8 @@
                             Width="40"
                             Height="40"
                             Grid.Column="1"
-                            Margin="0,0,6,0">
+                            Margin="0,0,6,0"
+                            ToolTip.Tip="Set Loop Point A">
                         <Grid>
                             <Path Fill="#0080ff"
                                   Data="M 26 8 
@@ -212,7 +200,8 @@ L 26 8" />
                     <Button Command="{Binding SetPointBCommand}"
                             Width="40"
                             Height="40"
-                            Grid.Column="2">
+                            Grid.Column="2"
+                            ToolTip.Tip="Set Loop Point B">
                         <Grid>
                             <Path Fill="#0080ff"
                                   Data="M 14 8

AudioCore/Impl/StemPlaybackEngine.cs

@@ -454,7 +454,7 @@ public sealed class StemPlaybackEngine : IStemPlaybackEngine, IDisposable
         catch (OperationCanceledException) { }
         catch (Exception ex)
         {
-            Debug.WriteLine($"StemPlaybackEngine: Error in StretchLoopAsync: {ex.Message}");
+            Msg($"StemPlaybackEngine: Error in StretchLoopAsync: {ex.Message}");
             try { pipeline.Cts?.Cancel(); } catch { }
         }
     }