HendecagramArrayPage.cs

using System;

using Xamarin.Forms;

using SkiaSharp;
using SkiaSharp.Views.Forms;

namespace SkiaSharpFormsDemos.Transforms
{
    public class HendecagramArrayPage : ContentPage
    {
        Random random = new Random();
        public static readonly SKPath HendecagramPath;

        static HendecagramArrayPage()
        {
            // Create 11-pointed star
            HendecagramPath = new SKPath();
            for (int i = 0; i < 11; i++)
            {
                double angle = 5 * i * 2 * Math.PI / 11;
                SKPoint pt = new SKPoint(100 * (float)Math.Sin(angle),
                                        -100 * (float)Math.Cos(angle));
                if (i == 0)
                {
                    HendecagramPath.MoveTo(pt);
                }
                else
                {
                    HendecagramPath.LineTo(pt);
                }
            }
            HendecagramPath.Close();
        }

        public HendecagramArrayPage()
        {
            Title = "Hendecagram";

            SKCanvasView canvasView = new SKCanvasView();
            canvasView.PaintSurface += OnCanvasViewPaintSurface;
            Content = canvasView;
        }

        void OnCanvasViewPaintSurface(object sender, SKPaintSurfaceEventArgs args)
        {
            SKImageInfo info = args.Info;
            SKSurface surface = args.Surface;
            SKCanvas canvas = surface.Canvas;

            canvas.Clear();

            using (SKPaint paint = new SKPaint())
            {
                for (int x = 100; x < info.Width + 100; x += 200)
                    for (int y = 100; y < info.Height + 100; y += 200)
                    {
                        // Set random color
                        byte[] bytes = new byte[3];
                        random.NextBytes(bytes);
                        paint.Color = new SKColor(bytes[0], bytes[1], bytes[2]);

                        // Display the hendecagram
                        canvas.Save();
                        canvas.Translate(x, y);
                        canvas.DrawPath(HendecagramPath, paint);
                        canvas.Restore();
                    }
            }
        }
    }
}