Making SplineInterpolator generic

Pinta.Core/Classes/SplineInterpolator.cs

@@ -7,17 +7,18 @@
 
 using System.Collections.Generic;
 using System.Collections.Immutable;
+using System.Numerics;
 
 namespace Pinta.Core;
 
-public sealed class SplineInterpolator
+public sealed class SplineInterpolator<TNumber> where TNumber : IFloatingPoint<TNumber>
 {
-	private readonly SortedList<double, double> points = [];
-	private ImmutableArray<double> y2;
+	private readonly SortedList<TNumber, TNumber> points = [];
+	private ImmutableArray<TNumber> y2;
 
 	public int Count => points.Count;
 
-	public void Add (double x, double y)
+	public void Add (TNumber x, TNumber y)
 	{
 		points[x] = y;
 		y2 = default;
@@ -32,13 +33,13 @@ public void Clear ()
 	// NUMERICAL RECIPES IN C: THE ART OF SCIENTIFIC COMPUTING
 	// ISBN 0-521-43108-5, page 113, section 3.3.
 
-	public double Interpolate (double x)
+	public TNumber Interpolate (TNumber x)
 	{
 		if (y2.IsDefault)
 			y2 = PreCompute ();
 
-		IList<double> xa = points.Keys;
-		IList<double> ya = points.Values;
+		IList<TNumber> xa = points.Keys;
+		IList<TNumber> ya = points.Values;
 
 		int n = ya.Count;
 		int klo = 0;     // We will find the right place in the table by means of
@@ -55,45 +56,45 @@ public double Interpolate (double x)
 			}
 		}
 
-		double h = xa[khi] - xa[klo];
-		double a = (xa[khi] - x) / h;
-		double b = (x - xa[klo]) / h;
+		TNumber h = xa[khi] - xa[klo];
+		TNumber a = (xa[khi] - x) / h;
+		TNumber b = (x - xa[klo]) / h;
 
 		// Cubic spline polynomial is now evaluated.
 		return a * ya[klo] + b * ya[khi] +
-		    ((a * a * a - a) * y2[klo] + (b * b * b - b) * y2[khi]) * (h * h) / 6.0; // NRT - y2 is set above by PreCompute ()
+		    ((a * a * a - a) * y2[klo] + (b * b * b - b) * y2[khi]) * (h * h) / TNumber.CreateChecked (6); // NRT - y2 is set above by PreCompute ()
 	}
 
-	private ImmutableArray<double> PreCompute ()
+	private ImmutableArray<TNumber> PreCompute ()
 	{
 		int n = points.Count;
-		double[] u = new double[n];
-		IList<double> xa = points.Keys;
-		IList<double> ya = points.Values;
+		TNumber[] u = new TNumber[n];
+		IList<TNumber> xa = points.Keys;
+		IList<TNumber> ya = points.Values;
 
-		var resultingY2 = ImmutableArray.CreateBuilder<double> (n);
+		var resultingY2 = ImmutableArray.CreateBuilder<TNumber> (n);
 		resultingY2.Count = n;
 
-		u[0] = 0;
-		resultingY2[0] = 0;
+		u[0] = TNumber.Zero;
+		resultingY2[0] = TNumber.Zero;
 
 		for (int i = 1; i < n - 1; ++i) {
 			// This is the decomposition loop of the tridiagonal algorithm. 
 			// y2 and u are used for temporary storage of the decomposed factors.
-			double wx = xa[i + 1] - xa[i - 1];
-			double sig = (xa[i] - xa[i - 1]) / wx;
-			double p = sig * resultingY2[i - 1] + 2.0;
+			TNumber wx = xa[i + 1] - xa[i - 1];
+			TNumber sig = (xa[i] - xa[i - 1]) / wx;
+			TNumber p = sig * resultingY2[i - 1] + TNumber.CreateChecked (2);
 
-			resultingY2[i] = (sig - 1.0) / p;
+			resultingY2[i] = (sig - TNumber.One) / p;
 
-			double ddydx =
+			TNumber ddydx =
 			    (ya[i + 1] - ya[i]) / (xa[i + 1] - xa[i]) -
 			    (ya[i] - ya[i - 1]) / (xa[i] - xa[i - 1]);
 
-			u[i] = (6.0 * ddydx / wx - sig * u[i - 1]) / p;
+			u[i] = (TNumber.CreateChecked (6) * ddydx / wx - sig * u[i - 1]) / p;
 		}
 
-		resultingY2[n - 1] = 0;
+		resultingY2[n - 1] = TNumber.Zero;
 
 		// This is the backsubstitution loop of the tridiagonal algorithm
 		for (int i = n - 2; i >= 0; --i) {

Pinta.Effects/Adjustments/CurvesEffect.cs

@@ -95,10 +95,14 @@ private UnaryPixelOp MakeUop ()
 		int channels = transferCurves.Length;
 
 		for (int channel = 0; channel < channels; channel++) {
+
 			SortedList<int, int> channelControlPoints = Data.ControlPoints![channel]; // NRT - Code expects this to be not-null
+
 			IList<int> xa = channelControlPoints.Keys;
 			IList<int> ya = channelControlPoints.Values;
-			SplineInterpolator interpolator = new SplineInterpolator ();
+
+			SplineInterpolator<double> interpolator = new ();
+
 			int length = channelControlPoints.Count;
 
 			for (int i = 0; i < length; i++) {
@@ -117,20 +121,19 @@ private UnaryPixelOp MakeUop ()
 public sealed class CurvesData : EffectData
 {
 	public SortedList<int, int>[]? ControlPoints { get; set; }
-
 	public ColorTransferMode Mode { get; set; }
 
 	public override CurvesData Clone ()
 	{
-		//			Not sure if we have to copy contents of ControlPoints
-		//			var controlPoints = new SortedList<int, int> [ControlPoints.Length];
-		//			
-		//			for (int i = 0; i < ControlPoints.Length; i++)
-		//				controlPoints[i] = new SortedList<int, int> (ControlPoints[i]);
+		// Not sure if we have to copy contents of ControlPoints
+		// var controlPoints = new SortedList<int, int> [ControlPoints.Length];
+		// 
+		// for (int i = 0; i < ControlPoints.Length; i++)
+		//     controlPoints[i] = new SortedList<int, int> (ControlPoints[i]);
 
 		return new () {
 			Mode = Mode,
-			ControlPoints = ControlPoints
+			ControlPoints = ControlPoints,
 		};
 	}
 }

Pinta.Effects/Dialogs/Effects.CurvesDialog.cs

@@ -452,15 +452,15 @@ private IEnumerator<ControlPointDrawingInfo> GetDrawingInfos ()
 			yield break;
 		}
 
-		yield return new ControlPointDrawingInfo (
+		yield return new (
 			Color: new Color (0.9, 0, 0),
 			IsActive: check_red.Active);
 
-		yield return new ControlPointDrawingInfo (
+		yield return new (
 			Color: new Color (0, 0.9, 0),
 			IsActive: check_green.Active);
 
-		yield return new ControlPointDrawingInfo (
+		yield return new (
 			Color: new Color (0, 0, 0.9),
 			IsActive: check_blue.Active);
 	}
@@ -524,7 +524,7 @@ void DrawSpline (Context g)
 
 				int points = controlPoints.Count;
 
-				SplineInterpolator interpolator = new ();
+				SplineInterpolator<double> interpolator = new ();
 
 				IList<int> xa = controlPoints.Keys;
 				IList<int> ya = controlPoints.Values;