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MainPanel.java
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/
MainPanel.java
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// -*- mode:java; encoding:utf-8 -*-
// vim:set fileencoding=utf-8:
// @homepage@
package example;
import java.awt.*;
import javax.swing.*;
public final class MainPanel extends JPanel {
private MainPanel() {
super(new BorderLayout());
JLabel label = new JLabel() {
@Override protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g.create();
int w = getWidth();
int h = getHeight();
g2.setPaint(new GradientPaint(0f, 0f, Color.ORANGE, w, h, Color.WHITE, true));
g2.fillRect(0, 0, w, h);
g2.dispose();
}
@Override public Dimension getPreferredSize() {
return new Dimension(640, 640);
}
};
label.setBorder(BorderFactory.createTitledBorder("Horizontal scroll: CTRL + Wheel"));
label.addMouseWheelListener(e -> {
Component c = e.getComponent();
Container s = SwingUtilities.getAncestorOfClass(JScrollPane.class, c);
if (s instanceof JScrollPane) {
JScrollPane scrollPane = (JScrollPane) s;
Component scrollBar = e.isControlDown()
? scrollPane.getHorizontalScrollBar()
: scrollPane.getVerticalScrollBar();
scrollBar.dispatchEvent(SwingUtilities.convertMouseEvent(c, e, scrollBar));
}
});
JScrollPane scroll = new JScrollPane(label);
scroll.getVerticalScrollBar().setUnitIncrement(10);
JScrollBar hsb = scroll.getHorizontalScrollBar();
hsb.setUnitIncrement(10);
hsb.addMouseWheelListener(e -> {
JScrollBar sb = (JScrollBar) e.getComponent();
Container c = SwingUtilities.getAncestorOfClass(JScrollPane.class, sb);
if (c instanceof JScrollPane) {
JViewport vport = ((JScrollPane) c).getViewport();
Point vp = vport.getViewPosition();
int d = hsb.getUnitIncrement() * e.getWheelRotation();
vp.translate(d, 0);
JComponent v = (JComponent) SwingUtilities.getUnwrappedView(vport);
v.scrollRectToVisible(new Rectangle(vp, vport.getSize()));
}
});
add(scroll);
setPreferredSize(new Dimension(320, 240));
}
public static void main(String[] args) {
EventQueue.invokeLater(MainPanel::createAndShowGui);
}
private static void createAndShowGui() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (UnsupportedLookAndFeelException ignored) {
Toolkit.getDefaultToolkit().beep();
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException ex) {
ex.printStackTrace();
return;
}
JFrame frame = new JFrame("@title@");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.getContentPane().add(new MainPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}