Merge pull request #53 from TruePadawan/add-undo-redo-buttons

Add undo redo buttons

Author: TruePadawan

Scribble/Assets/redo-disabled.png

@@ -29,12 +29,15 @@ public partial class MainViewModel : ViewModelBase
     public static int CanvasWidth => 10000;
     public static int CanvasHeight => 10000;
 
+    public event Action? RequestInvalidateSelection;
+    public event Action<int>? UndoStackChanged;
+    public event Action<int>? RedoStackChanged;
+
     [ObservableProperty] private Color _backgroundColor;
     public ScaleTransform ScaleTransform { get; }
     [ObservableProperty] private List<Stroke> _canvasStrokes = [];
     private readonly HashSet<Guid> _deletedActions = [];
     public Dictionary<Guid, List<Guid>> SelectionTargets { get; private set; } = [];
-    public event Action? RequestInvalidateSelection;
     public Queue<Event> CanvasEvents { get; private set; } = [];
 
     private readonly CollaborativeDrawingService _collaborativeDrawingService;
@@ -134,6 +137,9 @@ private void TrackAction(Guid actionId)
     {
         _undoStack.Push(actionId);
         _redoStack.Clear();
+
+        UndoStackChanged?.Invoke(_undoStack.Count);
+        RedoStackChanged?.Invoke(_redoStack.Count);
     }
 
     public void Undo()
@@ -148,8 +154,11 @@ public void Undo()
             }
         }
 
+        UndoStackChanged?.Invoke(_undoStack.Count);
+
         _redoStack.Push(actionId);
         ApplyEvent(new UndoEvent(Guid.NewGuid(), actionId), isLocalEvent: true);
+        RedoStackChanged?.Invoke(_redoStack.Count);
     }
 
     public void Redo()
@@ -164,8 +173,11 @@ public void Redo()
             }
         }
 
+        RedoStackChanged?.Invoke(_redoStack.Count);
+
         _undoStack.Push(actionId);
         ApplyEvent(new RedoEvent(Guid.NewGuid(), actionId), isLocalEvent: true);
+        UndoStackChanged?.Invoke(_undoStack.Count);
     }
 
     public void ApplyEvent(Event @event, bool isLocalEvent = true)

Scribble/Assets/redo.png

@@ -408,5 +408,20 @@
                 </StackPanel>
             </Border>
         </Panel>
+
+        <!-- Undo/Redo Buttons -->
+        <Border CornerRadius="16"
+                HorizontalAlignment="Left"
+                VerticalAlignment="Bottom"
+                Margin="8,0,0,12">
+            <StackPanel Orientation="Horizontal">
+                <Button ToolTip.Tip="Undo - Ctrl+Z" Name="UndoButton" Command="{Binding Undo}" IsEnabled="False">
+                    <Image Source="avares://Scribble/Assets/undo-disabled.png" Margin="4" Width="15" Height="15" />
+                </Button>
+                <Button ToolTip.Tip="Redo - Ctrl+Shift+Z" Name="RedoButton" Command="{Binding Redo}" IsEnabled="False">
+                    <Image Source="avares://Scribble/Assets/redo-disabled.png" Margin="4" Width="15" Height="15" />
+                </Button>
+            </StackPanel>
+        </Border>
     </Panel>
 </UserControl>

Scribble/Assets/undo-disabled.png

@@ -43,6 +43,10 @@ public partial class MainView : UserControl
     private MainViewModel? _viewModel;
     private readonly Selection _selection;
     private readonly ToolOptionsValues _toolOptionsValues;
+    private readonly Image _undoDisabledIcon;
+    private readonly Image _undoEnabledIcon;
+    private readonly Image _redoDisabledIcon;
+    private readonly Image _redoEnabledIcon;
 
     public MainView()
     {
@@ -56,13 +60,47 @@ public MainView()
             Bitmap.DecodeToWidth(AssetLoader.Open(new Uri("avares://Scribble/Assets/rotate.png")), 24);
         SelectionBorder.Cursor = new Cursor(moveIconBitmap, new PixelPoint(18, 18));
         SelectionRotationBtn.Cursor = new Cursor(rotateIconBitmap, new PixelPoint(12, 12));
+
+        _undoDisabledIcon = new Image
+        {
+            Source = new Bitmap(AssetLoader.Open(new Uri("avares://Scribble/Assets/undo-disabled.png"))),
+            Width = 15,
+            Height = 15,
+            Margin = new Thickness(4)
+        };
+
+        _undoEnabledIcon = new Image
+        {
+            Source = new Bitmap(AssetLoader.Open(new Uri("avares://Scribble/Assets/undo.png"))),
+            Width = 15,
+            Height = 15,
+            Margin = new Thickness(4)
+        };
+
+        _redoDisabledIcon = new Image
+        {
+            Source = new Bitmap(AssetLoader.Open(new Uri("avares://Scribble/Assets/redo-disabled.png"))),
+            Width = 15,
+            Height = 15,
+            Margin = new Thickness(4)
+        };
+
+        _redoEnabledIcon = new Image
+        {
+            Source = new Bitmap(AssetLoader.Open(new Uri("avares://Scribble/Assets/redo.png"))),
+            Width = 15,
+            Height = 15,
+            Margin = new Thickness(4)
+        };
     }
 
     protected override void OnDataContextChanged(EventArgs e)
     {
         if (_viewModel != null)
         {
             _viewModel.RequestInvalidateSelection -= VisualizeSelection;
+            _viewModel.UndoStackChanged -= UpdateUndoButton;
+            _viewModel.RedoStackChanged -= UpdateRedoButton;
         }
 
         base.OnDataContextChanged(e);
@@ -71,6 +109,8 @@ protected override void OnDataContextChanged(EventArgs e)
         {
             _viewModel = viewModel;
             _viewModel.RequestInvalidateSelection += VisualizeSelection;
+            _viewModel.UndoStackChanged += UpdateUndoButton;
+            _viewModel.RedoStackChanged += UpdateRedoButton;
 
             Toolbar.Children.Clear();
 
@@ -464,7 +504,8 @@ private void VisualizeSelection()
     {
         if (_viewModel == null) return;
 
-        var triggeringSelectionAction = _viewModel.CanvasEvents.Last() is EndSelectionEvent;
+        var hasEvents = _viewModel.CanvasEvents.Count > 0;
+        var triggeringSelectionAction = hasEvents && _viewModel.CanvasEvents.Last() is EndSelectionEvent;
         var allSelectedIds = _viewModel.SelectionTargets.Values.SelectMany(x => x).Distinct().ToList();
 
         if (allSelectedIds.Count > 0)
@@ -1041,4 +1082,16 @@ private void AboutOption_OnClick(object? sender, RoutedEventArgs e)
         AboutScribbleWindow.IsVisible = true;
         AboutScribbleWindowOverlay.IsVisible = true;
     }
+
+    private void UpdateUndoButton(int undoStackCount)
+    {
+        UndoButton.IsEnabled = undoStackCount > 0;
+        UndoButton.Content = undoStackCount > 0 ? _undoEnabledIcon : _undoDisabledIcon;
+    }
+
+    private void UpdateRedoButton(int redoStackCount)
+    {
+        RedoButton.IsEnabled = redoStackCount > 0;
+        RedoButton.Content = redoStackCount > 0 ? _redoEnabledIcon : _redoDisabledIcon;
+    }
 }