Code
public JComponent makeTranslucentScrollBar(JComponent c) {
JScrollPane scrollPane = new JScrollPane(c) {
@Override public boolean isOptimizedDrawingEnabled() {
return false; // JScrollBar is overlap
}
};
scrollPane.setVerticalScrollBarPolicy(
ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setHorizontalScrollBarPolicy(
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.setComponentZOrder(scrollPane.getVerticalScrollBar(), 0);
scrollPane.setComponentZOrder(scrollPane.getViewport(), 1);
scrollPane.getVerticalScrollBar().setOpaque(false);
scrollPane.setLayout(new ScrollPaneLayout() {
@Override public void layoutContainer(Container parent) {
JScrollPane scrollPane = (JScrollPane) parent;
Rectangle availR = scrollPane.getBounds();
availR.x = availR.y = 0;
Insets insets = parent.getInsets();
availR.x = insets.left;
availR.y = insets.top;
availR.width -= insets.left + insets.right;
availR.height -= insets.top + insets.bottom;
Rectangle vsbR = new Rectangle();
vsbR.width = 12;
vsbR.height = availR.height;
vsbR.x = availR.x + availR.width - vsbR.width;
vsbR.y = availR.y;
if (viewport != null) {
viewport.setBounds(availR);
}
if (vsb != null) {
vsb.setVisible(true);
vsb.setBounds(vsbR);
}
}
});
scrollPane.getVerticalScrollBar().setUI(new BasicScrollBarUI() {
private final Color defaultColor = new Color(220, 100, 100, 100);
private final Color draggingColor = new Color(200, 100, 100, 100);
private final Color rolloverColor = new Color(255, 120, 100, 100);
private final Dimension d = new Dimension();
@Override protected JButton createDecreaseButton(int orientation) {
return new JButton() {
@Override public Dimension getPreferredSize() {
return d;
}
};
}
@Override protected JButton createIncreaseButton(int orientation) {
return new JButton() {
@Override public Dimension getPreferredSize() {
return d;
}
};
}
@Override protected void paintTrack(Graphics g, JComponent c, Rectangle r) {}
@Override protected void paintThumb(Graphics g, JComponent c, Rectangle r) {
Color color;
JScrollBar sb = (JScrollBar) c;
if (!sb.isEnabled() || r.width > r.height) {
return;
} else if (isDragging) {
color = draggingColor;
} else if (isThumbRollover()) {
color = rolloverColor;
} else {
color = defaultColor;
}
Graphics2D g2 = (Graphics2D) g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g2.setPaint(color);
g2.fillRect(r.x, r.y, r.width - 1, r.height - 1);
g2.setPaint(Color.WHITE);
g2.drawRect(r.x, r.y, r.width - 1, r.height - 1);
g2.dispose();
}
@Override protected void setThumbBounds(int x, int y, int width, int height) {
super.setThumbBounds(x, y, width, height);
//scrollbar.repaint(x, 0, width, scrollbar.getHeight());
scrollbar.repaint();
}
});
return scrollPane;
}
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