import java.awt.*;

class DrawGas extends java.awt.Canvas{

  private int     N,iborder,jborder,circle;
  private double  width;
  private Gas appletref;
  private GasSimulation gasSimRef;
  private int  xnow, ynow, oldx,oldy;


  DrawGas(Gas ref){              // constructor
    N=ref.N;
    circle=ref.diameter;
    iborder=ref.iborder;
    jborder=ref.jborder;
    setBackground(Color.white);
    appletref=ref;
  }
    
  public void paint(Graphics g){
    int i;
    int x;
    int y; 
    Graphics g2;

    g2=appletref.offscreenGraphics;

    g2.setColor(this.getBackground());
    g2.fillRect(0,0,500,500);
      
    for(i=1; i<=N; i++){
      g2.setColor(Color.red);
      switch(i){
        case 1:
          g2.setColor(Color.blue);
          break;
        case 2:
          g2.setColor(Color.green);
          break;
        case 3:
          g2.setColor(Color.yellow);
          break;
        case 4:
          g2.setColor(Color.orange);
          break;
        case 5:
          g2.setColor(Color.black);
          break;
      }
      x=(int)appletref.simulation.part[i].x;
      y=(int)appletref.simulation.part[i].y;
      g2.fillOval(x,y,circle,circle);
    }
    g.drawImage(appletref.offscreenImage,0,0,this);

  }

  public void update(Graphics g){
    paint(g);
  }


}