Tela.cs

using System;
using System.Drawing;
using System.Windows.Forms;
using ScreenSaverMatrixStyle.Classes;

namespace ScreenSaverMatrixStyle
{
    public class Tela : Form
    {
        private System.Windows.Forms.Timer timer = null!;
        private MatrixColumn[] columns = null!;
        private int fontSize = 14;
        private int cols;
        private int rows;
        private Random random = new Random();
        private char[,] charGrid = null!;
        private long frameCount = 0;
        private Point? lastMousePosition = null;

        public Tela()
        {
            // Basic Form setup without Designer
            this.FormBorderStyle = FormBorderStyle.None;
            this.WindowState = FormWindowState.Maximized;
            this.BackColor = Color.Black;
            this.DoubleBuffered = true;
            Cursor.Hide(); // Hide cursor
            
            this.MouseMove += Tela_MouseMove;
            this.KeyDown += (s, e) => Application.Exit();
            this.MouseDown += (s, e) => Application.Exit();
        }

        public Tela(Rectangle bounds) : this()
        {
            this.Bounds = bounds;
            this.StartPosition = FormStartPosition.Manual;
        }

        private void Tela_MouseMove(object? sender, MouseEventArgs e)
        {
            if (lastMousePosition != null)
            {
                if (Math.Abs(lastMousePosition.Value.X - e.X) > 5 ||
                    Math.Abs(lastMousePosition.Value.Y - e.Y) > 5)
                {
                    Application.Exit();
                }
            }
            lastMousePosition = e.Location;
        }

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
            
            // Calculate grid dimensions
            cols = this.Width / fontSize;
            rows = this.Height / fontSize + 1; // +1 to cover bottom edge
            
            columns = new MatrixColumn[cols];
            charGrid = new char[cols, rows];
            
            for (int i = 0; i < cols; i++)
            {
                columns[i] = new MatrixColumn(i, rows);
                for (int j = 0; j < rows; j++)
                {
                    charGrid[i, j] = GetRandomChar();
                }
            }
            
            timer = new System.Windows.Forms.Timer();
            timer.Interval = 30;
            timer.Tick += Timer_Tick;
            timer.Start();
        }

        private char GetRandomChar()
        {
            string chars = "$%#@!*abcdefghijklmnopqrstuvwxyz1234567890?;:ABCDEFGHIJKLMNOPQRSTUVWXYZ^&";
            return chars[random.Next(chars.Length)];
        }

        private void Timer_Tick(object? sender, EventArgs e)
        {
            frameCount++;
            for (int i = 0; i < columns.Length; i++)
            {
                var column = columns[i];
                if (frameCount % column.Speed == 0)
                {
                    column.MoveDown();
                    if (column.ShouldReset())
                    {
                        column.Reset();
                    }
                }
            }
            this.Invalidate();
        }

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            Graphics g = e.Graphics;
            
            using (Font font = new Font("Consolas", fontSize))
            using (Brush whiteBrush = new SolidBrush(Color.White))
            using (Brush greenBrush = new SolidBrush(Color.FromArgb(0, 255, 0)))
            using (Brush darkGreenBrush = new SolidBrush(Color.FromArgb(0, 128, 0)))
            {
                for (int i = 0; i < cols; i++)
                {
                    var column = columns[i];
                    int x = i * fontSize;
                    
                    int headY = column.Y;
                    int tailY = column.GetTailY();
                    
                    // Optimization: only loop through visible part of the column
                    int startY = Math.Max(0, tailY);
                    int endY = Math.Min(rows - 1, headY);

                    for (int j = startY; j <= endY; j++)
                    {
                        char c = charGrid[i, j];
                        
                        // Randomly change character for "glitch" effect
                        if (random.Next(40) == 0) 
                        {
                            c = GetRandomChar();
                            charGrid[i, j] = c;
                        }

                        Brush brush = darkGreenBrush;
                        if (j == headY) brush = whiteBrush;
                        else if (j > headY - 2) brush = greenBrush;
                        
                        g.DrawString(c.ToString(), font, brush, x, j * fontSize);
                    }
                }
            }
        }
    }
}