Added some basic brushes

RGB.NET.Brushes/Helper/GradientHelper.cs

@@ -0,0 +1,80 @@
+// ReSharper disable MemberCanBePrivate.Global
+
+using System;
+using RGB.NET.Core;
+
+namespace RGB.NET.Brushes.Helper
+{
+    /// <summary>
+    /// Offers some extensions and helper-methods for gradient related things.
+    /// </summary>
+    public static class GradientHelper
+    {
+        // Based on https://web.archive.org/web/20170125201230/https://dotupdate.wordpress.com/2008/01/28/find-the-color-of-a-point-in-a-lineargradientbrush/
+        /// <summary>
+        /// Calculates the offset of an given <see cref="Point"/> on an gradient.
+        /// </summary>
+        /// <param name="startPoint">The start <see cref="Point"/> of the gradient.</param>
+        /// <param name="endPoint">The end <see cref="Point"/> of the gradient.</param>
+        /// <param name="point">The <see cref="Point"/> on the gradient to which the offset is calculated.</param>
+        /// <returns>The offset of the <see cref="Point"/> on the gradient.</returns>
+        public static double CalculateLinearGradientOffset(Point startPoint, Point endPoint, Point point)
+        {
+            Point intersectingPoint;
+            if (startPoint.Y.Equals(endPoint.Y)) // Horizontal case
+                intersectingPoint = new Point(point.X, startPoint.Y);
+
+            else if (startPoint.X.Equals(endPoint.X)) // Vertical case
+                intersectingPoint = new Point(startPoint.X, point.Y);
+
+            else // Diagonal case
+            {
+                double slope = (endPoint.Y - startPoint.Y) / (endPoint.X - startPoint.X);
+                double orthogonalSlope = -1 / slope;
+
+                double startYIntercept = startPoint.Y - (slope * startPoint.X);
+                double pointYIntercept = point.Y - (orthogonalSlope * point.X);
+
+                double intersectingPointX = (pointYIntercept - startYIntercept) / (slope - orthogonalSlope);
+                double intersectingPointY = (slope * intersectingPointX) + startYIntercept;
+                intersectingPoint = new Point(intersectingPointX, intersectingPointY);
+            }
+
+            // Calculate distances relative to the vector start
+            double intersectDistance = CalculateDistance(intersectingPoint, startPoint, endPoint);
+            double gradientLength = CalculateDistance(endPoint, startPoint, endPoint);
+
+            return intersectDistance / gradientLength;
+        }
+
+        // Based on https://web.archive.org/web/20170125201230/https://dotupdate.wordpress.com/2008/01/28/find-the-color-of-a-point-in-a-lineargradientbrush/
+        /// <summary>
+        /// Returns the signed magnitude of a <see cref="Point"/> on a vector.
+        /// </summary>
+        /// <param name="point">The <see cref="Point"/> on the vector of which the magnitude should be calculated.</param>
+        /// <param name="origin">The origin of the vector.</param>
+        /// <param name="direction">The direction of the vector.</param>
+        /// <returns>The signed magnitude of a <see cref="Point"/> on a vector.</returns>
+        public static double CalculateDistance(Point point, Point origin, Point direction)
+        {
+            double distance = CalculateDistance(point, origin);
+
+            return (((point.Y < origin.Y) && (direction.Y > origin.Y)) ||
+                ((point.Y > origin.Y) && (direction.Y < origin.Y)) ||
+                ((point.Y.Equals(origin.Y)) && (point.X < origin.X) && (direction.X > origin.X)) ||
+                ((point.Y.Equals(origin.Y)) && (point.X > origin.X) && (direction.X < origin.X)))
+                ? -distance : distance;
+        }
+
+        /// <summary>
+        /// Calculated the distance between two <see cref="Point"/>.
+        /// </summary>
+        /// <param name="point1">The first <see cref="Point"/>.</param>
+        /// <param name="point2">The second <see cref="Point"/>.</param>
+        /// <returns>The distance between the two <see cref="Point"/>.</returns>
+        public static double CalculateDistance(Point point1, Point point2)
+        {
+            return Math.Sqrt(((point1.Y - point2.Y) * (point1.Y - point2.Y)) + ((point1.X - point2.X) * (point1.X - point2.X)));
+        }
+    }
+}