748: Mainline

Now it is time to combine the definition for the Meter class provided in Segment 734 with the definition provided in Segment 746. The text is drawn on a baseline placed far enough under the lines to allow for the text and a reasonable separation from the lines:

import java.awt.*; 
import javax.swing.*; 
public class Meter extends JComponent implements MeterInterface { 
 String title = "Title to Be Supplied"; 
 int minValue, maxValue, value; 
 public Meter (int x, int y) { 
  minValue = x; maxValue = y; value = (y + x) / 2; 
 } 
 public void setValue(int v) {value = v; repaint();} 
 public void setTitle(String t) {title = t; repaint();} 
 public int getValueAtCoordinates (int x, int y) {               
  Dimension d = getSize();                                       
  int meterWidth = d.width * 3 / 4;                              
  int xOffset = (d.width - meterWidth) / 2;                      
  float fraction = (float)(x - xOffset) / meterWidth;            
  return (int)Math.round(fraction * (maxValue - minValue) + minValue); 
 }                                                               
 public void paint(Graphics g) { 
  // Obtain Dimension instance: 
  Dimension d = getSize();                               
  int meterWidth = d.width * 3 / 4;                              
  int meterHeight = meterWidth / 20;                             
  int pointerPosition                                            
   = meterWidth * (value - minValue) / (maxValue - minValue);    
  int lineXOffset = (d.width - meterWidth) / 2;                  
  int lineYOffset = d.height / 2;                                
  g.drawLine(lineXOffset, lineYOffset,  
             lineXOffset + meterWidth, lineYOffset);     
  g.drawLine(lineXOffset + pointerPosition, lineYOffset,                 
             lineXOffset + pointerPosition, lineYOffset - meterHeight);  
  // Prepare font 
  int fontSize = d.width / 30;                           
  g.setFont(new Font("Helvetica", Font.BOLD, fontSize)); 
  // Write title: 
  FontMetrics f = g.getFontMetrics();                    
  int stringWidth = f.stringWidth(title);                
  int textXOffset = (d.width - stringWidth) / 2;  
  int textYOffset = (d.height / 2) + (2 * f.getHeight());  
  g.drawString(title, textXOffset, textYOffset);  
 } 
 public Dimension getMinimumSize() {return new Dimension(150, 100);}  
 public Dimension getPreferredSize() {return new Dimension(150, 100);}  
}