Csharp/C Sharp/2D Graphics/Curve

Bezier (Mouse Defines Control Points)

 
using System;
using System.Drawing;
using System.Windows.Forms;
   
class Bezier: Form
{
     protected Point[] apt = new Point[4];
   
     public static void Main()
     {
          Application.Run(new Bezier());
     }
     public Bezier()
     {
          ResizeRedraw = true;
   
          OnResize(EventArgs.Empty);
     }
     protected override void OnResize(EventArgs ea)
     {
          base.OnResize(ea);
   
          int cx = ClientSize.Width;
          int cy = ClientSize.Height;
   
          apt[0] = new Point(    cx / 4,     cy / 2);
          apt[1] = new Point(    cx / 2,     cy / 4);
          apt[2] = new Point(    cx / 2, 3 * cy / 4);
          apt[3] = new Point(3 * cx / 4,     cy / 2);
     }
     protected override void OnMouseDown(MouseEventArgs mea)
     {
          Point pt;
   
          if (mea.Button == MouseButtons.Left)
               pt = apt[1];
   
          else if (mea.Button == MouseButtons.Right)
               pt = apt[2];
   
          else
               return;
   
          Cursor.Position = PointToScreen(pt);
     }
     protected override void OnMouseMove(MouseEventArgs mea)
     {
          if (mea.Button == MouseButtons.Left)
          {
               apt[1] = new Point(mea.X, mea.Y);
               Invalidate();
          }
          else if (mea.Button == MouseButtons.Right)
          {
               apt[2] = new Point(mea.X, mea.Y);
               Invalidate();
          }
     }
     protected override void OnPaint(PaintEventArgs pea)
     {
          Graphics grfx = pea.Graphics;
   
          grfx.DrawBeziers(new Pen(ForeColor), apt);
   
          Pen pen = new Pen(Color.FromArgb(0x80, ForeColor));
   
          grfx.DrawLine(pen, apt[0], apt[1]);
          grfx.DrawLine(pen, apt[2], apt[3]);
     }
}

Click on the form to draw curve

using System;
using System.Drawing;
using System.Collections;
using System.ruponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Drawing2D;
public class Form1 : System.Windows.Forms.Form{
   private Point[] thePoints;
   private int counter;
   public Form1() {
      Console.WriteLine("click on the form to draw curve");
    
    
      InitializeComponent();
      thePoints = new Point[1000];
      for (int i=0;i<thePoints.Length; i++)
         thePoints[i] = new Point(0,0);
      counter =0;
   }
   protected override void OnPaint (PaintEventArgs e) {
      if (counter==0) 
         return;
      Pen redPen   = new Pen(Color.Red, 3);
      Pen greenPen = new Pen(Color.Red, 4);
      Point[] curvePoints = new Point[counter];
      
      for (int i=0; i<curvePoints.Length;i++)
      {
         curvePoints[i] = new Point(0,0);
         curvePoints[i].X = thePoints[i].X;
         curvePoints[i].Y = thePoints[i].Y;
      }
        
      e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
      e.Graphics.DrawCurve(greenPen, curvePoints);
   }
   private void InitializeComponent() {
      this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
      this.ClientSize = new System.Drawing.Size(292, 273);
      this.Name = "Form1";
      this.Text = "Form1";
      this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseDown);
   }
   static void Main() {
      Application.Run(new Form1());
   }
   private void Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e) {
      thePoints[counter].X = e.X;
      thePoints[counter].Y = e.Y;
      Label l = new Label();
      this.SuspendLayout();
      counter++;
      if (counter>4)
        this.Refresh();
  }
}

Draw closed curve

using System;
using System.Drawing;
using System.Collections;
using System.ruponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Drawing2D;
public class Form1 : System.Windows.Forms.Form{
   private Point[] thePoints;
   private int counter;
   public Form1() {
      Console.WriteLine("click on the form to draw closed curve.");
    
    
      InitializeComponent();
      thePoints = new Point[1000];
      for (int i=0;i<thePoints.Length; i++)
         thePoints[i] = new Point(0,0);
      counter =0;
   }
   protected override void OnPaint (PaintEventArgs e) {
      if (counter==0) 
         return;
      Pen redPen   = new Pen(Color.Red, 3);
      Pen greenPen = new Pen(Color.Red, 4);
      Point[] curvePoints = new Point[counter];
      
      for (int i=0; i<curvePoints.Length;i++)
      {
         curvePoints[i] = new Point(0,0);
         curvePoints[i].X = thePoints[i].X;
         curvePoints[i].Y = thePoints[i].Y;
      }
        
      e.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
      e.Graphics.DrawClosedCurve(greenPen, curvePoints);
   }
   private void InitializeComponent() {
      this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
      this.ClientSize = new System.Drawing.Size(292, 273);
      this.Name = "Form1";
      this.Text = "Form1";
      this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.Form1_MouseDown);
   }
   static void Main() {
      Application.Run(new Form1());
   }
   private void Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e) {
      thePoints[counter].X = e.X;
      thePoints[counter].Y = e.Y;
      Label l = new Label();
      this.SuspendLayout();
      counter++;
      if (counter>4)
        this.Refresh();
  }
}

Ellipse with DrawLines

 
using System;
using System.Drawing;
using System.Windows.Forms;
   
class PolyEllipse: Form
{
     public static void Main()
     {
          Application.Run(new PolyEllipse());
     }
     public PolyEllipse()
     {
          Text = "Ellipse with DrawLines";
          ResizeRedraw = true;
     }
     protected override void OnPaint(PaintEventArgs pea)
     {
          DoPage(pea.Graphics, ForeColor,ClientSize.Width, ClientSize.Height);
     }     
     protected void DoPage(Graphics grfx, Color clr, int cx, int cy)
     {
          int      iNum = 2 * (cx + cy);
          PointF[] aptf = new PointF[iNum];
   
          for (int i = 0; i < iNum; i++)
          {
               double dAng = i * 2 * Math.PI / (iNum - 1);
   
               aptf[i].X = (cx - 1) / 2f * (1 + (float)Math.Cos(dAng));
               aptf[i].Y = (cy - 1) / 2f * (1 + (float)Math.Sin(dAng));
          }
          grfx.DrawLines(new Pen(clr), aptf);
     }
}

Sine Curve

 

using System;
using System.Drawing;
using System.Windows.Forms;
   
class SineCurve: Form
{
     public static void Main()
     {
          Application.Run(new SineCurve());
     }
     public SineCurve()
     {
          Text = "Sine Curve";
          ResizeRedraw = true;
     }
     protected override void OnPaint(PaintEventArgs pea)
     {
          DoPage(pea.Graphics, ForeColor,ClientSize.Width, ClientSize.Height);
     }
     protected void DoPage(Graphics grfx, Color clr, int cx, int cy)
     {
          PointF[] aptf = new PointF[cx];
   
          for (int i = 0; i < cx; i++)
          {
               aptf[i].X = i;
               aptf[i].Y = cy / 2 * (1 -(float) 
                                   Math.Sin(i * 2 * Math.PI / (cx - 1)));
          }
          grfx.DrawLines(new Pen(clr), aptf);
     }
}

Spiral

 
using System;
using System.Drawing;
using System.Windows.Forms;
   
class Spiral: Form
{
     public static void Main()
     {
          Application.Run(new Spiral());
     }
     public Spiral()
     {
          ResizeRedraw = true;
     }
     protected override void OnPaint(PaintEventArgs pea)
     {
          DoPage(pea.Graphics, ForeColor,ClientSize.Width, ClientSize.Height);
     }
     protected void DoPage(Graphics grfx, Color clr, int cx, int cy)
     {
          const int iNumRevs   = 20;
          int       iNumPoints = iNumRevs * 2 * (cx + cy);
          PointF[]  aptf       = new PointF[iNumPoints];
          float     fAngle, fScale;
   
          for (int i = 0; i < iNumPoints; i++)
          {
               fAngle = (float)(i * 2 * Math.PI /(iNumPoints / iNumRevs));
               fScale = 1 - (float)i / iNumPoints;
   
               aptf[i].X = (float)(cx / 2 * (1 + fScale * Math.Cos(fAngle)));
               aptf[i].Y = (float)(cy / 2 * (1 + fScale * Math.Sin(fAngle)));
          }
          grfx.DrawLines(new Pen(clr), aptf);
     }
}