Code
class TitledSeparator extends JLabel {
private final String title;
private final Color target;
private final int height;
private final int titlePosition;
public TitledSeparator(String title, int height, int titlePosition) {
this(title, null, height, titlePosition);
}
public TitledSeparator(
String title, Color target, int height, int titlePosition) {
super();
this.title = title;
this.target = target;
this.height = height;
this.titlePosition = titlePosition;
updateBorder();
}
private void updateBorder() {
Icon icon = new TitledSeparatorIcon();
setBorder(BorderFactory.createTitledBorder(
BorderFactory.createMatteBorder(height, 0, 0, 0, icon), title,
TitledBorder.DEFAULT_JUSTIFICATION, titlePosition));
}
@Override public Dimension getMaximumSize() {
Dimension d = super.getPreferredSize();
d.width = Short.MAX_VALUE;
return d;
}
@Override public void updateUI() {
super.updateUI();
EventQueue.invokeLater(this::updateBorder);
}
private class TitledSeparatorIcon implements Icon {
private int width = -1;
private Paint painter1;
private Paint painter2;
@Override public void paintIcon(Component c, Graphics g, int x, int y) {
int w = c.getWidth();
if (w != width || painter1 == null || painter2 == null) {
width = w;
Point2D start = new Point2D.Float();
Point2D end = new Point2D.Float(width, 0);
float[] dist = {0f, 1f};
Color ec = Optional.ofNullable(getBackground())
.orElse(UIManager.getColor("Panel.background"));
Color sc = Optional.ofNullable(target).orElse(ec);
painter1 = new LinearGradientPaint(
start, end, dist, new Color[] {sc.darker(), ec});
painter2 = new LinearGradientPaint(
start, end, dist, new Color[] {sc.brighter(), ec});
}
int h = getIconHeight() / 2;
Graphics2D g2 = (Graphics2D) g.create();
g2.setPaint(painter1);
g2.fillRect(x, y, width, getIconHeight());
g2.setPaint(painter2);
g2.fillRect(x, y + h, width, getIconHeight() - h);
g2.dispose();
}
@Override public int getIconWidth() {
return 200; // sample width
}
@Override public int getIconHeight() {
return height;
}
}
}
References
