Added Invert Mask option to the Apply Filter Node

src/PixiEditor.ChangeableDocument/Changeables/Graph/Nodes/FilterNodes/ApplyFilterNode.cs

@@ -25,17 +25,19 @@ public class ApplyFilterNode : RenderNode, IRenderInput
     public RenderInputProperty Background { get; }
 
     public RenderInputProperty Mask { get; }
+    
+    public InputProperty<bool> InvertMask { get; }
 
     public ApplyFilterNode()
     {
         Background = CreateRenderInput("Input", "IMAGE");
         Filter = CreateInput<Filter>("Filter", "FILTER", null);
         Mask = CreateRenderInput("Mask", "MASK");
+        InvertMask = CreateInput("InvertMask", "INVERT_MASK", false);
         Output.FirstInChain = null;
         AllowHighDpiRendering = true;
     }
 
-
     protected override void Paint(RenderContext context, DrawingSurface surface)
     {
         AllowHighDpiRendering = (Background.Connection.Node as RenderNode)?.AllowHighDpiRendering ?? true;
@@ -105,6 +107,7 @@ public class ApplyFilterNode : RenderNode, IRenderInput
 
     private void ApplyWithMask(RenderContext context, DrawingSurface processedSurface, DrawingSurface finalSurface)
     {
+        _maskPaint.BlendMode = !InvertMask.Value ? BlendMode.DstIn : BlendMode.DstOut;
         var maskLayer = processedSurface.Canvas.SaveLayer(_maskPaint);
         Mask.Value?.Paint(context, processedSurface);
         processedSurface.Canvas.RestoreToCount(maskLayer);

src/PixiEditor/Data/Localization/Languages/en.json

@@ -1127,5 +1127,6 @@
   "ERROR_GPU_RESOURCES_CREATION": "Failed to create resources: Try updating your GPU drivers or try setting different rendering api in settings. \nError: '{0}'",
   "ERROR_SAVING_PREFERENCES_DESC": "Failed to save preferences with error: '{0}'. Please check if you have write permissions to the PixiEditor data folder.",
   "ERROR_SAVING_PREFERENCES": "Failed to save preferences",
-  "PREFERRED_RENDERER": "Preferred Render Api"
+  "PREFERRED_RENDERER": "Preferred Render Api",
+  "INVERT_MASK": "Invert mask"
 }

src/PixiEditor/Models/Handlers/INodePropertyHandler.cs

@@ -15,6 +15,7 @@ public interface INodePropertyHandler
     public ObservableCollection<INodePropertyHandler> ConnectedInputs { get; }
 
     public event NodePropertyValueChanged ValueChanged;
+    public event EventHandler ConnectedOutputChanged;
     public INodeHandler Node { get; set; }
     public Type PropertyType { get; }
     public void UpdateComputedValue();

src/PixiEditor/ViewModels/Document/Nodes/FilterNodes/ApplyFilterNodeViewModel.cs

@@ -1,3 +1,4 @@
+using System.Collections.Specialized;
 using PixiEditor.ChangeableDocument.Changeables.Graph.Nodes.FilterNodes;
 using PixiEditor.UI.Common.Fonts;
 using PixiEditor.ViewModels.Nodes;
@@ -5,4 +6,23 @@ using PixiEditor.ViewModels.Nodes;
 namespace PixiEditor.ViewModels.Document.Nodes.FilterNodes;
 
 [NodeViewModel("APPLY_FILTER_NODE", "FILTERS", PixiPerfectIcons.Magic)]
-internal class ApplyFilterNodeViewModel : NodeViewModel<ApplyFilterNode>;
+internal class ApplyFilterNodeViewModel : NodeViewModel<ApplyFilterNode>
+{
+    private NodePropertyViewModel MaskInput { get; set; }
+    
+    private NodePropertyViewModel MaskInvertInput { get; set; }
+
+    public override void OnInitialized()
+    {
+        MaskInput = FindInputProperty("Mask");
+        MaskInvertInput = FindInputProperty("InvertMask");
+        
+        UpdateInvertVisible();
+        MaskInput.ConnectedOutputChanged += (_, _) => UpdateInvertVisible();
+    }
+
+    private void UpdateInvertVisible()
+    {
+        MaskInvertInput.IsVisible = MaskInput.ConnectedOutput != null;
+    }
+}

src/PixiEditor/ViewModels/Nodes/NodePropertyViewModel.cs

@@ -27,6 +27,7 @@ internal abstract class NodePropertyViewModel : ViewModelBase, INodePropertyHand
     private INodePropertyHandler? connectedOutput;
 
     public event NodePropertyValueChanged? ValueChanged;
+    public event EventHandler? ConnectedOutputChanged;
 
     public string DisplayName
     {
@@ -115,6 +116,7 @@ internal abstract class NodePropertyViewModel : ViewModelBase, INodePropertyHand
             if (SetProperty(ref connectedOutput, value))
             {
                 OnPropertyChanged(nameof(ShowInputField));
+                ConnectedOutputChanged?.Invoke(this, EventArgs.Empty);
             }
         }
     }