添加项目文件。

JY.Control/Base/ColorMng.cs

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+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace JYControl
+{
+	/// <summary>
+	/// Manager for color
+	/// </summary>
+	public class LBColorManager : Object
+	{
+		public static double BlendColour(double fg, double bg, double alpha)
+		{
+			double result = bg + (alpha * (fg - bg));
+			if (result < 0.0)
+				result = 0.0;
+			if (result > 255)
+				result = 255;
+			return result;
+		}
+
+		public static Color StepColor(Color clr, int alpha)
+		{
+			if (alpha == 100)
+				return clr;
+
+			byte a = clr.A;
+			byte r = clr.R;
+			byte g = clr.G;
+			byte b = clr.B;
+			float bg = 0;
+
+			int _alpha = Math.Min(alpha, 200);
+			_alpha = Math.Max(alpha, 0);
+			double ialpha = ((double)(_alpha - 100.0)) / 100.0;
+
+			if (ialpha > 100)
+			{
+				// blend with white
+				bg = 255.0F;
+				ialpha = 1.0F - ialpha;  // 0 = transparent fg; 1 = opaque fg
+			}
+			else
+			{
+				// blend with black
+				bg = 0.0F;
+				ialpha = 1.0F + ialpha;  // 0 = transparent fg; 1 = opaque fg
+			}
+
+			r = (byte)(LBColorManager.BlendColour(r, bg, ialpha));
+			g = (byte)(LBColorManager.BlendColour(g, bg, ialpha));
+			b = (byte)(LBColorManager.BlendColour(b, bg, ialpha));
+
+			return Color.FromArgb(a, r, g, b);
+		}
+	};
+}