Changing the size of a JComboBox
Greetings,
I am trying to build a mechanism to perform zooming on a JPanel with an arbitrary collection of components (including nested JPanels). I've tried a number of things with little success. The following is my most promising contraption. It can zoom labels, textfields, checkboxes, and buttons. However, for some reason, the combo box refuses to accept a changes to its size. I'm not sure why this is the case. Its font changes size appropriately.
Anyway, I'm running in JDK 1.4, and the following program lays out a palette of components. To change the size of the components, hit F1 to zoom in, and F2 to zoom out.
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.KeyEventPostProcessor;
import java.awt.KeyboardFocusManager;
import java.awt.event.KeyEvent;
import java.awt.geom.AffineTransform;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
publicclass Demoextends JPanel
{
publicclass Zoomer
{
privatedouble m_zoom = 1;
private JPanel m_panel;
public Zoomer(JPanel panel)
{
m_panel = panel;
}
private AffineTransform getTransform()
{
return AffineTransform.getScaleInstance(m_zoom, m_zoom);
}
private Font transform(Font font)
{
return font.deriveFont(getTransform());
}
private Dimension transform(Dimension dimension)
{
Dimension retval =new Dimension();
retval.setSize(dimension.getWidth() * m_zoom, dimension.getHeight() * m_zoom);
return retval;
}
privatevoid performZoom(Container container)
{
Component[] components = container.getComponents();
for(int i = 0; i < components.length; i++)
{
Component component = (Component)components[i];
component.setFont(transform(component.getFont()));
component.setSize(transform(component.getSize()));
}
for(int i = 0; i < components.length; i++)
{
Component component = components[i];
if(componentinstanceof Container)
{
performZoom((Container)component);
}
}
}
publicdouble getZoom()
{
return m_zoom;
}
publicvoid setZoom(double zoom)
{
if(zoom > 8.0 || zoom < 0.125)return;
m_zoom = zoom;
performZoom(m_panel);
}
publicvoid zoom(double factor)
{
setZoom(getZoom() * factor);
}
}
public Demo()
{
JPanel panel =new JPanel();
panel.add(buildPanel());
panel.add(buildPanel());
final Zoomer zoomer =new Zoomer(panel);
add(panel);
KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventPostProcessor(new KeyEventPostProcessor()
{
publicboolean postProcessKeyEvent(KeyEvent e)
{
if(e.getID() != KeyEvent.KEY_PRESSED)returnfalse;
if(e.getKeyCode() == KeyEvent.VK_F1)
{
zoomer.zoom(1.2);
}
if(e.getKeyCode() == KeyEvent.VK_F2)
{
zoomer.zoom(1/1.2);
}
returnfalse;
}
});
}
private JPanel buildPanel()
{
JPanel panel =new JPanel();
panel.add(new JLabel("label: "));
panel.add(new JTextField("Hello World"));
panel.add(new JCheckBox("checkbox"));
panel.add(new JComboBox(new String[]{"Bread","Milk","Butter"}));
panel.add(new JButton("Hit Me!"));
return panel;
}
/**
* Create the GUI and show it. For thread safety, this method should be
* invoked from the event-dispatching thread.
*/
privatestaticvoid createAndShowGUI()
{
// Create and set up the window.
JFrame frame =new JFrame("Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create and set up the content pane.
Demo newContentPane =new Demo();
newContentPane.setOpaque(true);// content panes must be opaque
frame.setContentPane(newContentPane);
// Display the window.
frame.pack();
frame.setVisible(true);
}
publicstaticvoid main(String[] args)
{
// Schedule a job for the event-dispatching thread:
// creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable()
{
publicvoid run()
{
createAndShowGUI();
}
});
}
}
