C# Tutorials

Drawing lines pixel by pixel using timer so user can see the animation.

Download source code (Microsoft Visual C# 2005 Express Edition)

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;

namespace WindowsApplication2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        List<PointF> PointList = new List<PointF>();
        int pointIndex = 0;

        private void Form1_Load(object sender, EventArgs e)
        {
            SetStyle(ControlStyles.UserPaint, true);
            SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            SetStyle(ControlStyles.DoubleBuffer, true);
            PointF[] pt = new PointF[] {
                new PointF(100, 100),
                new PointF(150, 150),
                new PointF(200, 100),
                new PointF(100, 100),

            };
            // Get Points From Line(s)
            float curDist = 0;
            float distance = 0;
            for (int i = 0; i < pt.Length - 1; i++)
            {
                PointF ptA = pt[i];
                PointF ptB = pt[i + 1];
                float deltaX = ptB.X - ptA.X;
                float deltaY = ptB.Y - ptA.Y;
                curDist = 0;
                distance = (float)Math.Sqrt(Math.Pow(deltaX, 2) + Math.Pow(deltaY, 2));
                while (curDist < distance)
                {
                    curDist++;
                    float offsetX = (float)((double)curDist / (double)distance * (double)deltaX);
                    float offsetY = (float)((double)curDist / (double)distance * (double)deltaY);
                    PointList.Add(new PointF(ptA.X + offsetX, ptA.Y + offsetY));
                }
            }
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
            for (int i = 0; i < pointIndex; i++)
            {
                e.Graphics.DrawLine(Pens.Black, PointList[i].X, PointList[i].Y, PointList[i + 1].X, PointList[i + 1].Y);
            }
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            if (pointIndex < PointList.Count - 1)
            {
                pointIndex++;
                this.Refresh();
            }
        }
    }
}

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