//------------------------------------------- 
 // ClockControl.cs © 2001 by Charles Petzold 
 //------------------------------------------- 
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace Petzold.ProgrammingWindowsWithCSharp
{
class ClockControl: UserControl
{
     DateTime dt;

     public ClockControl()
     {
          ResizeRedraw = true;
          Enabled = false;
     }
     public DateTime Time
     {
          get 
          { 
               return dt;  
          }
          set 
          { 
               Graphics grfx = CreateGraphics();
               InitializeCoordinates(grfx);

               Pen pen = new Pen(BackColor);

               if (dt.Hour != value.Hour)
               {
                    DrawHourHand(grfx, pen);
               }
               if (dt.Minute != value.Minute)
               {
                    DrawHourHand(grfx, pen);
                    DrawMinuteHand(grfx, pen);
               }
               if (dt.Second != value.Second)
               {
                    DrawMinuteHand(grfx, pen);
                    DrawSecondHand(grfx, pen);
               }
               if (dt.Millisecond != value.Millisecond)
               {
                    DrawSecondHand(grfx, pen);
               }          
               dt  = value;
               pen = new Pen(ForeColor);

               DrawHourHand(grfx, pen);
               DrawMinuteHand(grfx, pen);
               DrawSecondHand(grfx, pen);

               grfx.Dispose();
          }
     }
     protected override void OnPaint(PaintEventArgs pea)
     {
          Graphics grfx  = pea.Graphics;
          Pen      pen   = new Pen(ForeColor);
          Brush    brush = new SolidBrush(ForeColor);

          InitializeCoordinates(grfx);
          DrawDots(grfx, brush);
          DrawHourHand(grfx, pen);
          DrawMinuteHand(grfx, pen);
          DrawSecondHand(grfx, pen);
     }
     void InitializeCoordinates(Graphics grfx)
     {
          if (Width == 0 || Height == 0)
               return;

          grfx.TranslateTransform(Width / 2, Height / 2);

          float fInches = Math.Min(Width / grfx.DpiX, Height / grfx.DpiY);

          grfx.ScaleTransform(fInches * grfx.DpiX / 2000,
                              fInches * grfx.DpiY / 2000);
     }
     void DrawDots(Graphics grfx, Brush brush)
     {
          for (int i = 0; i < 60; i++)
          {
               int iSize = i % 5 == 0 ? 100 : 30;

               grfx.FillEllipse(brush, 0 - iSize / 2, -900 - iSize / 2, 
                                       iSize, iSize);
               grfx.RotateTransform(6);
          }          
     }
     protected virtual void DrawHourHand(Graphics grfx, Pen pen)
     {
          GraphicsState gs = grfx.Save();
          grfx.RotateTransform(360f * Time.Hour / 12 +
                                30f * Time.Minute / 60);

          grfx.DrawPolygon(pen, new Point[]
                              {
                                   new Point(0,  150), new Point( 100, 0),
                                   new Point(0, -600), new Point(-100, 0)
                              });
          grfx.Restore(gs);
     }
     protected virtual void DrawMinuteHand(Graphics grfx, Pen pen)
     {
          GraphicsState gs = grfx.Save();
          grfx.RotateTransform(360f * Time.Minute / 60 +
                                 6f * Time.Second / 60);

          grfx.DrawPolygon(pen, new Point[]
                              {
                                   new Point(0,  200), new Point( 50, 0),
                                   new Point(0, -800), new Point(-50, 0)
                              });
          grfx.Restore(gs);
     }
     protected virtual void DrawSecondHand(Graphics grfx, Pen pen)
     {
          GraphicsState gs = grfx.Save();
          grfx.RotateTransform(360f * Time.Second / 60 +
                                 6f * Time.Millisecond / 1000);

          grfx.DrawLine(pen, 0, 0, 0, -800);
          grfx.Restore(gs);          
     }
}
}