import java.awt.*;
import java.awt.event.*;

class FarveValgGUI {
  
  Scrollbar rød = new Scrollbar(Scrollbar.HORIZONTAL, 0, 1, 0, 255);
  Scrollbar grøn = new Scrollbar(Scrollbar.HORIZONTAL, 0, 1, 0, 255); 
  Scrollbar blå = new Scrollbar(Scrollbar.HORIZONTAL, 0, 1, 0, 255);
  Canvas farveCanvas = new FarveCanvas();
  
  int ri, gi, bi;

  class FarveCanvas extends Canvas {
    public void paint(Graphics gr) {
      gr.setColor(new Color(ri,gi,bi));
      gr.fillRect(0,0,200,200);
    }

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

    public Dimension getPreferredSize() { 
      return new Dimension(200,200); 
    }

    public Dimension getMinimumSize() { 
      return getPreferredSize(); 
    }
  }

  class SkyderLytterRød implements AdjustmentListener {
    public void adjustmentValueChanged(AdjustmentEvent e) {
      ri = e.getValue();
      farveCanvas.repaint();
    }
  }

  class SkyderLytterGrøn implements AdjustmentListener {
    public void adjustmentValueChanged(AdjustmentEvent e) {
      gi = e.getValue();
      farveCanvas.repaint();
    }
  }

  class SkyderLytterBlå implements AdjustmentListener {
    public void adjustmentValueChanged(AdjustmentEvent e) {
      bi = e.getValue();
      farveCanvas.repaint();
    }
  }

  Frame f  = new ClosableFrame("Farvevalg");

  FarveValgGUI() {
    f.setLayout(new BorderLayout());

    Panel skydere = new Panel();
    skydere.setLayout(new GridLayout(3,1));
    Panel canvas = new Panel();

    rød.addAdjustmentListener(new SkyderLytterRød());
    grøn.addAdjustmentListener(new SkyderLytterGrøn());
    blå.addAdjustmentListener(new SkyderLytterBlå());
    skydere.add(rød);
    skydere.add(grøn);
    skydere.add(blå);
    f.add(skydere, "North");
    canvas.add(farveCanvas);
    f.add(canvas, "South");
    
    f.pack();
    f.show();
  }

  public static void main(String[] args) {
    new FarveValgGUI();
  }
}