How to draw A smooth line graph in SkiaSharp? - xamarin.forms

Question

Say, I have an array of float points (function xy). The first image is trying with SkiaSharp, the second is with System.Drawing of .NET Framework.
I understand that I should use a method like CubicTo, but I don't see how to combine it to achieve the expected result.
The example was created in WindowsForms (only uses 2 PictureBox) and SkiaSharp nuget. It is similar with Xamarin, the question is the same.
using System;
using System.Collections.Generic;
using System.IO;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Drawing2D;
using SkiaSharp;
namespace SKLab
{
public partial class BasicTestForm : Form
{
float startX = -4, stopX = 4;
float yi = -4, ye = 4;
float w = 200, h = 150;
float stepX = 1;
float x, px;
float y, py;
// pixel to cartesian
float pixelFromX(float cartX) => w * (cartX - startX) / (stopX - startX);
// cartesian to pixel
float pixelFromY(float cartY) => h * (cartY - yi) / (ye - yi);
public BasicTestForm()
{
InitializeComponent();
SkiaPlot(pictureBox1);
DrawingPlot(pictureBox2);
}
private void SkiaPlot(PictureBox p)
{
p.Size = new Size((int)w, (int)h);
using (var surface = SKSurface.Create(new SKImageInfo(p.Width, p.Height))) {
SKCanvas g = surface.Canvas;
g.Clear(SKColors.White);
using (var paint = new SKPaint()) {
paint.Style = SKPaintStyle.Stroke;
paint.IsAntialias = true;
paint.Color = SKColors.CornflowerBlue;
paint.StrokeWidth = 2;
var path = new SKPath();
for (x = startX; x <= stopX; x += stepX) {
px = pixelFromX(x);
py = pixelFromY((float)Math.Sin(x));
if (x == startX) {
path.MoveTo(px, py);
} else {
path.LineTo(px, py);
}
}
g.DrawPath(path, paint);
}
using (SKImage image = surface.Snapshot())
using (SKData data = image.Encode(SKEncodedImageFormat.Png, 100))
using (MemoryStream mStream = new MemoryStream(data.ToArray())) {
p.Image = new Bitmap(mStream, false);
}
}
}
void DrawingPlot(PictureBox p)
{
p.Size = new Size((int)w, (int)h); ;
// Make the Bitmap.
var canvas = new Bitmap(p.ClientSize.Width, p.ClientSize.Height);
using (var g = Graphics.FromImage(canvas)) {
// Clear.
g.Clear(Color.White);
// curve
var points = new List<PointF>();
for (x = startX; x <= stopX; x += stepX) {
points.Add(new PointF
{
X = pixelFromX(x),
Y = pixelFromY((float)Math.Sin(x))
});
}
g.SmoothingMode = SmoothingMode.AntiAlias;
using (var pen = new Pen(Color.CornflowerBlue, 2)) {
g.DrawCurve(pen, points.ToArray());
}
}
// Display the result.
p.Image = canvas;
}
}
}