import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.beans.*;
import javax.swing.*;
import javax.swing.plaf.basic.*;
import javax.swing.event.*;
public class GradientPalletProgressBarDemo {
public JComponent makeUI() {
final JProgressBar progressBar = new JProgressBar();
progressBar.setOpaque(false);
progressBar.setUI(new GradientPalletProgressBarUI());
JPanel p = new JPanel();
p.add(progressBar);
p.add(new JButton(new AbstractAction("Start") {
@Override public void actionPerformed(ActionEvent e) {
SwingWorker<Void,Void> worker = new SwingWorker<Void,Void>() {
@Override public Void doInBackground() {
int current = 0, lengthOfTask = 100;
while(current<=lengthOfTask && !isCancelled()) {
try { // dummy task
Thread.sleep(50);
} catch(InterruptedException ie) {
return null;
}
setProgress(100 * current / lengthOfTask);
current++;
}
return null;
}
};
worker.addPropertyChangeListener(new ProgressListener(progressBar));
worker.execute();
}
}));
return p;
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override public void run() {
createAndShowGUI();
}
});
}
public static void createAndShowGUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.getContentPane().add(new GradientPalletProgressBarDemo().makeUI());
frame.setSize(320, 240);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
class ProgressListener implements PropertyChangeListener {
private final JProgressBar progressBar;
ProgressListener(JProgressBar progressBar) {
this.progressBar = progressBar;
this.progressBar.setValue(0);
}
@Override public void propertyChange(PropertyChangeEvent evt) {
String strPropertyName = evt.getPropertyName();
if("progress".equals(strPropertyName)) {
progressBar.setIndeterminate(false);
int progress = (Integer)evt.getNewValue();
progressBar.setValue(progress);
}
}
}
class GradientPalletProgressBarUI extends BasicProgressBarUI {
private final int[] pallet;
public GradientPalletProgressBarUI() {
super();
this.pallet = makeGradientPallet();
}
private static int[] makeGradientPallet() {
BufferedImage image = new BufferedImage(100, 1, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = image.createGraphics();
Point2D start = new Point2D.Float(0f, 0f);
Point2D end = new Point2D.Float(99f, 0f);
float[] dist = {0.0f, 0.5f, 1.0f};
Color[] colors = { Color.RED, Color.YELLOW, Color.GREEN };
g2.setPaint(new LinearGradientPaint(start, end, dist, colors));
g2.fillRect(0, 0, 100, 1);
g2.dispose();
int width = image.getWidth(null);
int[] pallet = new int[width];
PixelGrabber pg = new PixelGrabber(image, 0, 0, width, 1, pallet, 0, width);
try {
pg.grabPixels();
} catch(Exception e) {
e.printStackTrace();
}
return pallet;
}
private static Color getColorFromPallet(int[] pallet, float x) {
if(x < 0.0 || x > 1.0) {
throw new IllegalArgumentException("Parameter outside of expected range");
}
int i = (int)(pallet.length * x);
int max = pallet.length-1;
int index = i<0?0:i>max?max:i;
int pix = pallet[index] & 0x00ffffff | (0x64 << 24);
return new Color(pix, true);
}
@Override public void paintDeterminate(Graphics g, JComponent c) {
if (!(g instanceof Graphics2D)) {
return;
}
Insets b = progressBar.getInsets(); // area for border
int barRectWidth = progressBar.getWidth() - (b.right + b.left);
int barRectHeight = progressBar.getHeight() - (b.top + b.bottom);
if (barRectWidth <= 0 || barRectHeight <= 0) {
return;
}
int cellLength = getCellLength();
int cellSpacing = getCellSpacing();
// amount of progress to draw
int amountFull = getAmountFull(b, barRectWidth, barRectHeight);
if(progressBar.getOrientation() == JProgressBar.HORIZONTAL) {
// draw the cells
float x = amountFull / (float)barRectWidth;
g.setColor(getColorFromPallet(pallet, x));
g.fillRect(b.left, b.top, amountFull, barRectHeight);
} else { // VERTICAL
//...
}
// Deal with possible text painting
if(progressBar.isStringPainted()) {
paintString(g, b.left, b.top, barRectWidth, barRectHeight, amountFull, b);
}
}
}