OOP LV7 - Zadatak2

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

namespace LV7___Zadatak_2
{
    public partial class Form1 : Form
    {
        Graphics g;
        Pen p;

        public Form1()
        {
            InitializeComponent();
            g = pbDrawing.CreateGraphics();
        }

        private void pbDrawing_Click(object sender, EventArgs e)
        {

        }

        private void pbDrawing_MouseUp(object sender, MouseEventArgs e)
        {
            if (rbRed.Checked == true)
            {
                p = new Pen(Color.Red, sbThickness.Value);
            }
            else if (rbGreen.Checked == true)
            {
                p = new Pen(Color.Green, sbThickness.Value);
            }
            else if (rbBlue.Checked == true)
            {
                p = new Pen(Color.Blue, sbThickness.Value);
            }

            if (rbCircle.Checked == true)
            {
                Circle c = new Circle();
                c.draw(g, p, e.X, e.Y);
            }
            else if (rbSquare.Checked == true)
            {
                Square s = new Square();
                s.draw(g, p, e.X, e.Y);
            }
            else if (rbTriangle.Checked == true)
            {
                Triangle t = new Triangle();
                t.draw(g, p, e.X, e.Y);
            }
        }
    }

    class Circle
    {
        int r;
        public Circle()
        {
            r = 10;
        }
        public void draw(Graphics g, Pen p, int x, int y)
        {
            g.DrawEllipse(p, x, y, r, r);
        }
    }

    class Square
    {
        int a, b;
        public Square()
        {
            a = 10;
            b = 10;
        }
        public void draw(Graphics g, Pen p, int x, int y)
        {
            g.DrawRectangle(p, x, y, a, b);
        }
    }

    class Triangle
    {
        int a;
        public Triangle()
        {
        }
        public void draw(Graphics g, Pen p, int x, int y)
        {
            Point[] points = { new Point(x, y), new Point(x + 90, y), new Point(x + 40, y + 90) };
            g.DrawPolygon(p, points);
        }
    }
}