Egérkezelés (Mouse handling)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace mousehandling
{
    public partial class Form1 : Form
    {
        Graphics g;
        List<PointF> points;

        public Form1()
        {
            InitializeComponent();
            g = CreateGraphics();
            points = new List<PointF>();
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
        }

        private void Form1_MouseClick(object sender, MouseEventArgs e)
        {
            points.Add(new PointF(e.X, e.Y));
            DrawPoints();
        }

        private void DrawPoints()
        {
            Invalidate();
            Update();
            foreach (var point in points)
            {
                g.DrawEllipse(Pens.Black, point.X, point.Y, 10, 10);
                g.FillEllipse(Brushes.Red, point.X, point.Y, 10, 10);
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                Kirajzolas();
            }
            catch
            {
                MessageBox.Show("Legalább két pontot tegyél!");
            }

        }

        private void Kirajzolas()
        {
            Invalidate();
            Update();
            if (points.Count < 2)
            {
                throw new Exception("Kevés pont!");
            }
            if (checkBox1.Checked) DrawPoints();
            g.DrawCurve(new Pen(Color.Blue, 3), points.ToArray());
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Invalidate();
            Update();
            points.Clear();
        }


    //Kiegészítés trackbarokkal

        private TrackBar trackBar1;
        private TrackBar trackBar2;

        private void trackBar1_Scroll(object sender, EventArgs e)
        {
            novekmeny = trackBar1.Value - elozoX;
            elozoX = trackBar1.Value;
            eltolX(novekmeny);
            DrawPoints();
            DrawCurve();
        }

        private void eltolX(int novekmeny)
        {
            for (int i = 0; i < points.Count; i++)
            {
                points[i] = new PointF(points[i].X + novekmeny, points[i].Y);
            }
        }

        private void trackBar2_Scroll(object sender, EventArgs e)
        {
            novekmeny = -trackBar2.Value - elozoY;
            elozoY = -trackBar2.Value;
            eltolY(novekmeny);
            DrawPoints();
            DrawCurve();
        }

        private void eltolY(int novekmeny)
        {
            for (int i = 0; i < points.Count; i++)
            {
                points[i] = new PointF(points[i].X, points[i].Y + novekmeny);
            }
        }

    // Forgatás (NE MÁSOLD, ÁTNEVEZTEM FÜGGVÉNYEKET ÉS VÁLTOZÓKAT, magyarról angolra)

    private TrackBar trackBar3;
        float prevAlpha;

        private void trackBar3_Scroll(object sender, EventArgs e)
        {
            float alpha = (float)((trackBar3.Value - prevAlpha) * Math.PI / 180.0); // és így lett radián!
            prevAlpha = trackBar3.Value;
            Rotate(alpha);
        }

        private void Rotate(float alpha)
        {
            float newX, newY;
            for (int i = 0; i < points.Count; i++)
            {
                int centerX = (int)points[points.Count / 2].X;
                int centerY = (int)points[points.Count / 2].Y;
                moveX(-centerX);
                moveY(-centerY);
                newX = (float)(points[i].X * Math.Cos(alpha) - points[i].Y * Math.Sin(alpha));
                newY = (float)(points[i].X * Math.Sin(alpha) + points[i].Y * Math.Cos(alpha));
                points[i] = new PointF(newX, newY);
                moveX(centerX);
                moveY(centerY);
                DrawPoints();
                DrawCurve();
            }
        }


    // Designer kód
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.checkBox1 = new System.Windows.Forms.CheckBox();
            this.SuspendLayout();
            //
            // button1
            //
            this.button1.Location = new System.Drawing.Point(12, 12);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 0;
            this.button1.Text = "Draw";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            //
            // button2
            //
            this.button2.Location = new System.Drawing.Point(12, 41);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(75, 23);
            this.button2.TabIndex = 1;
            this.button2.Text = "Reset";
            this.button2.UseVisualStyleBackColor = true;
            this.button2.Click += new System.EventHandler(this.button2_Click);
            //
            // checkBox1
            //
            this.checkBox1.AutoSize = true;
            this.checkBox1.Checked = true;
            this.checkBox1.CheckState = System.Windows.Forms.CheckState.Checked;
            this.checkBox1.Location = new System.Drawing.Point(12, 70);
            this.checkBox1.Name = "checkBox1";
            this.checkBox1.Size = new System.Drawing.Size(87, 17);
            this.checkBox1.TabIndex = 2;
            this.checkBox1.Text = "Visible points";
            this.checkBox1.UseVisualStyleBackColor = true;
            //
            // Form1
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(691, 366);
            this.Controls.Add(this.checkBox1);
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.MouseClick += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseClick);
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Button button2;
        private System.Windows.Forms.CheckBox checkBox1;
    }
}