// File $CISC370HOME/example-progs/threads/animation/ThermCanvas.java

import java.util.*;		// for Interface Observer
import java.awt.*;
import javax.swing.*;
 
public class ThermoCanvas extends JPanel implements Observer {
   Thermometer currT; 		// Variable for thermometer being observed

   public ThermoCanvas( Thermometer T )
   {
      currT = T;
      T.addObserver( this );	// Register ThermoCanvas as observer of T
   }

   public void update(Observable o, Object x)// From interface Observer
   {
    System.out.println("Entering ThermoCanvas.update(Observable,Object)");
    repaint();
   }

   public void paintComponent(Graphics g)
   {
    super.paintComponent( g );
    System.out.println("Entering ThermoCanvas method paint()");
    Dimension d = getSize();	   // Get size of canvas
    int thermometerH = 3*d.height/4; // Calculate thermometer display height
    int thermometerW = 10;	   // and display width
  
    int xOrigin = (d.width - thermometerW)/2;	// Center thermometer
    int yOrigin = (d.height - thermometerH)/2;	// on canvas

    // Draw empty tube
    g.drawRect(xOrigin, yOrigin, thermometerW, thermometerH);

    // Mark tube with temperature readings
    g.setFont(new Font("Helvetica", Font.PLAIN, 8));
    FontMetrics f = g.getFontMetrics();
    int fH = f.getHeight();
  
    int minTemp = currT.getMinTemp();
    int maxTemp = currT.getMaxTemp();
    int temp = currT.getTemp();

    g.drawLine(xOrigin + 14, yOrigin, xOrigin + 19, yOrigin);  // Max temp
    g.drawString(maxTemp + " F", xOrigin + 23, yOrigin + fH/2); 
    g.drawLine(xOrigin + 14, yOrigin + thermometerH/2,         // Mid temp
               xOrigin + 19, yOrigin + thermometerH/2);
    g.drawString(((maxTemp - minTemp)/2) + " F",
                 xOrigin + 23, yOrigin + (thermometerH + fH)/2); 
    g.drawLine(xOrigin + 14, yOrigin + thermometerH,           // Min temp
               xOrigin + 19, yOrigin + thermometerH);
    g.drawString(minTemp + " F", xOrigin + 23, yOrigin + thermometerH + fH/2); 

    // Calculate mercury height
    int mercuryH = thermometerH*(temp - minTemp)/(maxTemp - minTemp);

    // Fill tube w red mercury
    Color prevColor = g.getColor();	// Save current color
    g.setColor(Color.red);
    g.fillRect(xOrigin+1,
               yOrigin + thermometerH - mercuryH,
               thermometerW-1,
               mercuryH);

    // Draw bulb at bottom filled w red mercury
    g.fillOval(xOrigin - thermometerW/2+1, yOrigin + thermometerH+1,
               2*thermometerW-2, 2*thermometerW-2);
    g.setColor(prevColor);		// Restore previous color
    g.drawOval(xOrigin - thermometerW/2, yOrigin + thermometerH,
               2*thermometerW, 2*thermometerW);

    // Write title
    g.setFont(new Font("Helvetica", Font.BOLD, 10));
    f = g.getFontMetrics();
    String title = currT.getTitle();
    g.drawString(title, (d.width - f.stringWidth(title))/2, 
                 yOrigin + thermometerH + 2*(thermometerW + fH));
   }

 public Dimension getMinimumSize()
 {
  System.out.println("Entering ThermoCanvas method minimumSize()");
  return new Dimension(100,200);
 }

 public Dimension getPreferredSize()
 {
  System.out.println("Entering ThermoCanvas method preferredSize()");
  return new Dimension(200,400);
 }
}