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

public class brush_bar3 extends Applet implements ActionListener, WindowListener {

Frame frame;
DistributionBar bar;
Button button;
double fractionOfMax;

public void init() 
{
	frame = new Frame("A frame");
	frame.setBackground(Color.blue);
	frame.setLayout(new GridBagLayout());
	frame.setBounds(100, 100, 600, 300);
	bar = new DistributionBar(32);
	bar.setToHeight(fractionOfMax = 0.1);
	constrain(frame, bar, 0, 0, 1, 1, GridBagConstraints.WEST, 0, 0, 0, 0, 
		GridBagConstraints.VERTICAL, 0, 1);
	button = new Button("Change bar");
	button.addActionListener(this);
	constrain(frame, button, 1, 0, 1, 1, GridBagConstraints.WEST, 0, 20, 0, 0, 
		GridBagConstraints.NONE, 0, 0);
	frame.validate();
	frame.show();
	frame.addWindowListener(this);
}

static final void constrain(Container container, Component component, int grid_x, int grid_y, 
		int grid_width, int grid_height, int anchor, int topPad, int leftPad, int bottomPad, 
		int rightPad, int fill, double weightx, double weighty)
{
	GridBagConstraints c = new GridBagConstraints();
	c.gridx = grid_x;
	c.gridy = grid_y;
	c.gridwidth = grid_width;
	c.gridheight = grid_height;
	c.anchor = anchor;
	c.insets.top   = topPad;
	c.insets.left  = leftPad;
	c.insets.bottom= bottomPad;
	c.insets.right = rightPad;
	c.fill = fill;
	c.weightx = weightx;
	c.weighty = weighty;
	((GridBagLayout)container.getLayout()).setConstraints(component, c);
	container.add(component);
}

public void windowOpened(WindowEvent we){}

public void windowClosed(WindowEvent we){}

public void windowIconified(WindowEvent we){}

public void windowDeiconified(WindowEvent we){}

public void windowActivated(WindowEvent we){}

public void windowDeactivated(WindowEvent we){}

public void windowClosing(WindowEvent we)
{
	if (we.getSource() == frame)
	{
		frame.setVisible(false);
		frame.dispose();
	}
}

public void paint(Graphics g)
{
	g.drawString("A frame should pop up", 10 , 20);
}

final double getProperHeight()
{
	fractionOfMax += 0.1;
	if (fractionOfMax >= 1.0) fractionOfMax = 0.1;
	return(fractionOfMax);
}

public void actionPerformed(ActionEvent ae)
{
	if (ae.getSource() == button)
	{
		bar.setToHeight(getProperHeight());
		bar.invalidate();
		invalidate();
		bar.validate();
		validate();
	}
}
}  // END OF Class brush_bar3



final class DistributionBar extends Canvas  { 

int width = 0;
int height = 0;
double fractionOfMax = 0.0;

DistributionBar(int width)
{
	this.width = width;
}

final void setToHeight(double fractionOfMax)
{
	this.fractionOfMax = fractionOfMax;
	repaint();
}

public void addNotify()
{
	super.addNotify();
	repaint();
}

public final void paint(Graphics g)
{
	height = getSize().height;
	int barHeight	= (int)(height * fractionOfMax);
	g.setColor(Color.black);
	g.fillRect(0, height-barHeight,	width, barHeight);			// bar 
}	

public final Dimension getMinimumSize()
{
	return(new Dimension(width, 10));
}

public final Dimension getPreferredSize()
{
	return(new Dimension(width, 140));
}
}  // END OF Class DistributionBar