- TrendGraph에 trendline 추가

TrendLine.cs

@@ -0,0 +1,99 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace friction
+{
+	public class TrendLine
+	{
+		public struct POINT
+		{
+			public float X;
+			public float Y;
+		}
+
+
+		private readonly List<POINT> AxisValues;
+		private int count;
+		private float xAxisValuesSum;
+		private float xxSum;
+		private float xySum;
+		private float yAxisValuesSum;
+
+		//public TrendLine(IList<float> xAxisValues, IList<float> yAxisValues)
+		//{
+		//	this.xAxisValues = xAxisValues;
+		//	this.yAxisValues = yAxisValues;
+			
+
+		//	this.Initialize();
+		//}
+
+		public TrendLine(List<POINT> points)
+		{
+			AxisValues = points;
+			AxisValues.Sort((POINT a, POINT b) => (a.X == b.X) ? 0 : (a.X < b.X) ? -1 : 1);
+
+			this.Initialize();
+		}
+
+		public float Slope { get; private set; }
+		public float Intercept { get; private set; }
+		public float Start { get; private set; }
+		public float End { get; private set; }
+
+		private void Initialize()
+		{
+			this.count = this.AxisValues.Count;
+			this.yAxisValuesSum = this.AxisValues.Sum(e => e.Y);
+			this.xAxisValuesSum = this.AxisValues.Sum(e => e.X);
+			this.xxSum = 0;
+			this.xySum = 0;
+
+			for (int i = 0; i < this.count; i++)
+			{
+				this.xySum += (this.AxisValues[i].X * this.AxisValues[i].Y);
+				this.xxSum += (this.AxisValues[i].X * this.AxisValues[i].X);
+			}
+
+			this.Slope = this.CalculateSlope();
+			this.Intercept = this.CalculateIntercept();
+			this.Start = this.CalculateStart();
+			this.End = this.CalculateEnd();
+		}
+
+		private float CalculateSlope()
+		{
+			try
+			{
+				return ((this.count * this.xySum) - (this.xAxisValuesSum * this.yAxisValuesSum)) / ((this.count * this.xxSum) - (this.xAxisValuesSum * this.xAxisValuesSum));
+			}
+			catch (DivideByZeroException)
+			{
+				return 0;
+			}
+		}
+
+		private float CalculateIntercept()
+		{
+			return (this.yAxisValuesSum - (this.Slope * this.xAxisValuesSum)) / this.count;
+		}
+
+		private float CalculateStart()
+		{
+			return (this.Slope * this.AxisValues.First().X) + this.Intercept;
+		}
+
+		private float CalculateEnd()
+		{
+			return (this.Slope * this.AxisValues.Last().X) + this.Intercept;
+		}
+
+		public float GetY(float fX)
+		{
+			return (this.Slope * fX) + this.Intercept;
+		}
+	}
+}