Plot2DHorizontalLinePainter.cs

using SkiaSharp;
using System;
 
namespace Waher.Script.Graphs.Functions.Plots
{
    public class Plot2DHorizontalLinePainter : SingleColorGraphPainter, IPainter2D
    {
        public void DrawGraph(SKCanvas Canvas, SKPoint[] Points, object[] Parameters, SKPoint[] PrevPoints, object[] PrevParameters,
            DrawingArea DrawingArea)
        {
            SKPaint Pen = null;
            SKPath Path = null;
            SKPoint Last = default;
            bool First = true;
            int Mode = Math.Sign(Expression.ToDouble(Parameters[0]));
 
            try
            {
                Pen = Graph.ToPen(Parameters[1], Parameters[2]);
                Path = new SKPath();
 
                foreach (SKPoint Point in Points)
                {
                    if (First)
                    {
                        First = false;
                        Path.MoveTo(Point);
                    }
                    else if (Point.Y == Last.Y || Point.X == Last.X)
                        Path.LineTo(Point);
                    else
                    {
                        switch (Mode)
                        {
                            case -1:
                                Path.LineTo(Last.X, Point.Y);
                                Path.LineTo(Point);
                                break;
 
                            case 0:
                                float xm = (Last.X + Point.X) / 2;
                                Path.LineTo(xm, Last.Y);
                                Path.LineTo(xm, Point.Y);
                                Path.LineTo(Point);
                                break;
 
                            case 1:
                                Path.LineTo(Point.X, Last.Y);
                                Path.LineTo(Point);
                                break;
                        }
 
                        Path.LineTo(Point);
                    }
 
                    Last = Point;
                }
 
                Canvas.DrawPath(Path, Pen);
            }
            finally
            {
                Pen?.Dispose();
                Path?.Dispose();
            }
        }
 
    }
}