Implemented the MathNode

src/PixiEditor.ChangeableDocument/Changeables/Graph/Nodes/MathNode.cs

@@ -0,0 +1,59 @@
+using PixiEditor.ChangeableDocument.Changeables.Animations;
+using PixiEditor.ChangeableDocument.Changeables.Graph.Interfaces;
+using PixiEditor.ChangeableDocument.Enums;
+using PixiEditor.DrawingApi.Core.Surface.ImageData;
+
+namespace PixiEditor.ChangeableDocument.Changeables.Graph.Nodes;
+
+public class MathNode : Node
+{
+    public FieldOutputProperty<double> Result { get; }
+
+    public InputProperty<MathNodeMode> Mode { get; }
+    
+    public InputProperty<bool> Clamp { get; }
+
+    public FieldInputProperty<double> X { get; }
+    
+    public FieldInputProperty<double> Y { get; }
+    
+    public MathNode()
+    {
+        Result = CreateFieldOutput(nameof(Result), "RESULT", Calculate);
+        Mode = CreateInput(nameof(Mode), "MATH_MODE", MathNodeMode.Add);
+        Clamp = CreateInput(nameof(Clamp), "CLAMP", false);
+        X = CreateFieldInput(nameof(X), "X", 0d);
+        Y = CreateFieldInput(nameof(Y), "Y", 0d);
+    }
+
+    private double Calculate(FieldContext context)
+    {
+        var (x, y) = GetValues(context);
+
+        var result = Mode.Value switch
+        {
+            MathNodeMode.Add => x + y,
+            MathNodeMode.Subtract => x - y,
+            MathNodeMode.Multiply => x * y,
+            MathNodeMode.Divide => x / y
+        };
+
+        if (Clamp.Value)
+        {
+            result = Math.Clamp(result, 0, 1);
+        }
+        
+        return result;
+    }
+
+    private (double x, double y) GetValues(FieldContext context) => (X.Value(context), Y.Value(context));
+    
+    protected override Image? OnExecute(KeyFrameTime frameTime)
+    {
+        return null;
+    }
+
+    public override bool Validate() => true;
+
+    public override Node CreateCopy() => new MathNode();
+}

src/PixiEditor.ChangeableDocument/Enums/MathNodeMode.cs

@@ -0,0 +1,9 @@
+namespace PixiEditor.ChangeableDocument.Enums;
+
+public enum MathNodeMode
+{
+    Add,
+    Subtract,
+    Multiply,
+    Divide
+}