Added RadialGradientBrush

Devices/Keyboard/Brushes/RadialGradientBrush.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Drawing;
+using CUE.NET.Devices.Keyboard.Brushes.Gradient;
+using CUE.NET.Helper;
+
+namespace CUE.NET.Devices.Keyboard.Brushes
+{
+    public class RadialGradientBrush : AbstractBrush
+    {
+        #region Properties & Fields
+
+        public PointF Center { get; set; } = new PointF(0.5f, 0.5f);
+        public IGradient Gradient { get; set; }
+
+        #endregion
+
+        #region Constructors
+
+        public RadialGradientBrush()
+        { }
+
+        public RadialGradientBrush(IGradient gradient)
+        {
+            this.Gradient = gradient;
+        }
+
+        public RadialGradientBrush(PointF center, IGradient gradient)
+        {
+            this.Center = center;
+            this.Gradient = gradient;
+        }
+
+        #endregion
+
+        #region Methods
+
+        public override Color GetColorAtPoint(RectangleF rectangle, PointF point)
+        {
+            PointF centerPoint = new PointF(rectangle.X + rectangle.Width * Center.X, rectangle.Y + rectangle.Height * Center.Y);
+
+            // Calculate the distance to the farthest point from the center as reference (this has to be a corner)
+            float refDistance = (float)Math.Max(Math.Max(Math.Max(GradientHelper.CalculateDistance(rectangle.Location, centerPoint),
+                GradientHelper.CalculateDistance(new PointF(rectangle.X + rectangle.Width, rectangle.Y), centerPoint)),
+                GradientHelper.CalculateDistance(new PointF(rectangle.X, rectangle.Y + rectangle.Height), centerPoint)),
+                GradientHelper.CalculateDistance(new PointF(rectangle.X + rectangle.Width, rectangle.Y + rectangle.Height), centerPoint));
+
+            float distance = GradientHelper.CalculateDistance(point, centerPoint);
+            float offset = distance / refDistance;
+            return FinalizeColor(Gradient.GetColor(offset));
+        }
+
+        #endregion
+    }
+}