Black color in graphic cosmos

[keyvanplays]

please help me I have black color in my kernel

[koteProgrammist]

Enter Canvas.Display() at the end of graphics code part

[keyvanplays]

Is it true?
kernel.cs:
`using Cosmos.System.Graphics;
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Text;
using Sys = Cosmos.System;

namespace keyvanos
{
public class Kernel : Sys.Kernel
{
private Canvas canvas;
protected override void BeforeRun()
{
Console.Clear();
Console.WriteLine("welcome to keyvanos2");

    }

    protected override void Run()
    {
        Console.Write("Keyvanos2/$:");
        var input = Console.ReadLine();
        Console.WriteLine("your command:" + input);
        switch (input)
        {
            case "help":
                {
                    Console.WriteLine("barai khamosh shodan type konid khamosh" );
                    Console.WriteLine("barai restart lotfan type konid restart");
                    Console.WriteLine("barai run shodan mohitgraphic gui type konid");
                    break;
                }
            case "khamosh":
                {
                    Console.WriteLine("dar hal khamosh shodan");
                    Sys.Power.Shutdown();
                    break;
                }
            case "restart":
                {
                    Console.WriteLine("dar hal restart");
                    Sys.Power.Reboot();
                    break;  
                }
            case "clear":
                {
                    Console.Clear();
                    break;
                }
            case "gui":
                {
                    Console.Clear();
                    
                    
                    gui.update();

                    break;
                }
            default:
                {
                    Console.WriteLine("command eshtebah ast lotfan type konid help");
                    break;
                }
        }
    }
}

}
and gui.cs:using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;
using Cosmos.System.Graphics;

namespace keyvanos
{
class gui
{
private static int screenX = 800;
private static int screenY = 640;

    private static Color[] pixelBuffer = new Color[(screenX * screenY) + screenX];
    private static Color[] pixelBufferOld = new Color[(screenX * screenY) + screenX];


    private static Canvas canvas;

    public static void init()
    {
        canvas = FullScreenCanvas.GetFullScreenCanvas();
        canvas.Mode = new Mode(screenX, screenY, ColorDepth.ColorDepth32);
    }

    public static void setPixel(int x, int y, Color c)
    {
        if (x > screenX || y > screenY) return;
        pixelBuffer[(x * y) + x] = c;
    }

    public static void drawScreen()
    {
        Pen pen = new Pen(Color.Orange);
        for (int y = 0, h = screenY; y < h; y++)
        {
            for (int x = 0, w = screenX; x < w; x++)
            {
                if (!(pixelBuffer[(y * x) + x] == pixelBufferOld[(y * y) + x]))
                {
                    pen.Color = pixelBuffer[(y * screenX) + x];
                    canvas.DrawPoint(pen, x, y);
                }
            }
        }
        for (int i = 0, len = pixelBuffer.Length; i < len; i++)
        {
            pixelBuffer[i] = pixelBufferOld[i];
        }
    }


    public static void clearScreen(Color c)
    {
        for (int i = 0, len = pixelBuffer.Length; i < len; i++)
        {
            pixelBuffer[i] = c;
        }
    }

    public static void update()
    {
        clearScreen(Color.Blue);
        setPixel(1, 1, Color.Black);
        setPixel(1, 2, Color.Black);
        setPixel(2, 1, Color.Black);
        setPixel(2, 2, Color.Black);
        drawScreen();
        canvas.Display();
    }


}

}
`
but not work