feat: Implement Ehlers Ultimate Smoother Filter (USF) with documentation and tests

2026-08-18 02:28:05 +00:00 · 2025-12-20 15:57:38 -08:00
parent d21fea3c18
commit 54c309e5cf
10 changed files with 661 additions and 14 deletions
@@ -0,0 +1,65 @@
+using System.Drawing;
+using TradingPlatform.BusinessLayer;
+
+namespace QuanTAlib;
+
+public class UsfIndicator : Indicator, IWatchlistIndicator
+{
+    [InputParameter("Period", sortIndex: 1, 1, 2000, 1, 0)]
+    public int Period { get; set; } = 20;
+
+    [IndicatorExtensions.DataSourceInput]
+    public SourceType Source { get; set; } = SourceType.Close;
+
+    [InputParameter("Show cold values", sortIndex: 21)]
+    public bool ShowColdValues { get; set; } = true;
+
+    private Usf? ma;
+    protected LineSeries? Series;
+    protected string? SourceName;
+    private int _warmupBarIndex = -1;
+
+    public int MinHistoryDepths => Period;
+    int IWatchlistIndicator.MinHistoryDepths => MinHistoryDepths;
+
+    public override string ShortName => $"USF {Period}:{SourceName}";
+
+    public UsfIndicator()
+    {
+        OnBackGround = true;
+        SeparateWindow = false;
+        SourceName = Source.ToString();
+        Name = "USF - Ultimate Smoother Filter";
+        Description = "Ehlers Ultimate Smoother Filter";
+        Series = new(name: $"USF {Period}", color: IndicatorExtensions.Averages, width: 2, style: LineStyle.Solid);
+        AddLineSeries(Series);
+    }
+
+    protected override void OnInit()
+    {
+        ma = new Usf(Period);
+        SourceName = Source.ToString();
+        _warmupBarIndex = -1;
+        base.OnInit();
+    }
+
+    protected override void OnUpdate(UpdateArgs args)
+    {
+        TValue input = this.GetInputValue(args, Source);
+        bool isNew = args.Reason == UpdateReason.NewBar || args.Reason == UpdateReason.HistoricalBar;
+        
+        TValue result = ma!.Update(input, isNew);
+        Series!.SetValue(result.Value);
+        Series!.SetMarker(0, Color.Transparent);
+
+        if (_warmupBarIndex < 0 && ma!.IsHot)
+            _warmupBarIndex = Count;
+    }
+
+    public override void OnPaintChart(PaintChartEventArgs args)
+    {
+        base.OnPaintChart(args);
+        int warmupPeriod = _warmupBarIndex > 0 ? _warmupBarIndex : Count;
+        this.PaintSmoothCurve(args, Series!, warmupPeriod, showColdValues: ShowColdValues, tension: 0.2);
+    }
+}