import java.awt.*;
import java.awt.image.*;

public class Graphics6
{

   static public void pause(int n) throws Exception
   {
      Thread.sleep( 100 * n );
   }

   static public void main(String[] args) throws Exception
   {
      final int YELLOW = 0xFFFF00;
      final int BLACK  = 0x000000;

      /* ------------------------------------------------
         Preparing to draw picture...
         ------------------------------------------------ */
      Canvas pic = new MyCanvas();          // Make a canvas (2 dim array)
      Frame f = new Frame( "My image" );    // Create a window

      f.add("Center", pic);                 // Put the canvas in the window
      f.setSize(400,300);                   // Set size of the window
      f.setVisible(true);                   // Make window visible 

      /* -----------------------------------------------------------
         Repeatedly draw a 10x10 box moving over a horizontal line
         ----------------------------------------------------------- */
      int x = 0, y = 100;

      while ( true )   // Repeat FOREVER !!!
      {
         /* ------------------------------------------------
            Paint the box at position (x,y)
            ------------------------------------------------ */
         for (int i = 0; i < 10; i++ ) 
            for (int j = 0; j < 10; j++ ) 
               MyCanvas.Image.setRGB(x+i, y+j, YELLOW); 

         pic.repaint();   // Repaint the picture

         pause(5);

         /* ------------------------------------------------
            ERASE the box (= paint it BLACK !)
            ------------------------------------------------ */
         for (int i = 0; i < 10; i++ )
            for (int j = 0; j < 10; j++ )
               MyCanvas.Image.setRGB(x+i, y+j, BLACK);

         pic.repaint();   // Repaint the picture

         
         /* ------------------------------------------------
            Move box 10 pixels to the right
            ------------------------------------------------ */
         x = x + 10;

         /* ----------------------------------------
            Check if the box has run off the canvas
            ---------------------------------------- */
         if ( (x + 10) > 400 )
            x = 0;               // If did, repeat from the left again
      }
   }
}