JScrollBar search highlighter

• download example.jar
• download src.zip
• repository

Code

Override WindowsScrollBarUI#paintTrack(...)

scrollbar.setUI(new WindowsScrollBarUI() {
  @Override protected void paintTrack(
      Graphics g, JComponent c, Rectangle trackBounds) {
    super.paintTrack(g, c, trackBounds);

    Rectangle rect = textArea.getBounds();
    double sy = trackBounds.getHeight() / rect.getHeight();
    AffineTransform at = AffineTransform.getScaleInstance(1.0, sy);
    Highlighter highlighter = textArea.getHighlighter();
    g.setColor(Color.YELLOW);
    try{
      for(Highlighter.Highlight hh: highlighter.getHighlights()) {
        Rectangle r = textArea.modelToView(hh.getStartOffset());
        Rectangle s = at.createTransformedShape(r).getBounds();
        int h = 2; //Math.max(2, s.height-2);
        g.fillRect(trackBounds.x, trackBounds.y+s.y, trackBounds.width, h);
      }
    }catch(BadLocationException e) {
      e.printStackTrace();
    }
  }
});

JLabel + Icon + RowHeader

final JScrollPane scroll = new JScrollPane(textArea);
JLabel label = new JLabel(new Icon() {
  private final Color THUMB_COLOR = new Color(0,0,255,50);
  private final Rectangle thumbRect = new Rectangle();
  private final JTextComponent textArea;
  private final JScrollBar scrollbar;
  public HighlightIcon(JTextComponent textArea, JScrollBar scrollbar) {
    this.textArea  = textArea;
    this.scrollbar = scrollbar;
  }
  @Override public void paintIcon(Component c, Graphics g, int x, int y) {
    //Rectangle rect   = textArea.getBounds();
    //Dimension sbSize = scrollbar.getSize();
    //Insets sbInsets  = scrollbar.getInsets();
    //double sy = (sbSize.height-sbInsets.top-sbInsets.bottom)/rect.getHeight();
    int itop = scrollbar.getInsets().top;
    BoundedRangeModel range = scrollbar.getModel();
    double sy = range.getExtent()/(double)(range.getMaximum()-range.getMinimum());
    AffineTransform at = AffineTransform.getScaleInstance(1.0, sy);
    Highlighter highlighter = textArea.getHighlighter();

    //paint Highlight
    g.setColor(Color.RED);
    try{
      for(Highlighter.Highlight hh: highlighter.getHighlights()) {
        Rectangle r = textArea.modelToView(hh.getStartOffset());
        Rectangle s = at.createTransformedShape(r).getBounds();
        int h = 2; //Math.max(2, s.height-2);
        g.fillRect(x, y+itop+s.y, getIconWidth(), h);
      }
    }catch(BadLocationException e) {
      e.printStackTrace();
    }

    //paint Thumb
    if(scrollbar.isVisible()) {
      //JViewport vport = Objects.requireNonNull(
      //  (JViewport)SwingUtilities.getAncestorOfClass(JViewport.class, textArea));
      //Rectangle thumbRect = vport.getBounds();
      thumbRect.height = range.getExtent();
      thumbRect.y = range.getValue(); //vport.getViewPosition().y;
      g.setColor(THUMB_COLOR);
      Rectangle s = at.createTransformedShape(thumbRect).getBounds();
      g.fillRect(x, y+itop+s.y, getIconWidth(), s.height);
    }
  }
  @Override public int getIconWidth() {
    return 8;
  }
  @Override public int getIconHeight() {
    JViewport vport = Objects.requireNonNull(
        (JViewport)SwingUtilities.getAncestorOfClass(JViewport.class, textArea));
    return vport.getHeight();
  }
});

scroll.setVerticalScrollBar(scrollbar);
/*
// Fixed Versions: 7 (b134)
scroll.setRowHeaderView(label);
/*/
// [JDK-6826074] JScrollPane does not revalidate the component hierarchy after scrolling - Java Bug System
// https://bugs.openjdk.java.net/browse/JDK-6826074
// Affected Versions: 6u12,6u16,7
JViewport vp = new JViewport() {
  @Override public void setViewPosition(Point p) {
    super.setViewPosition(p);
    revalidate();
  }
};
vp.setView(label);
scroll.setRowHeader(vp);

MatteBorder + Icon + RowHeader

JScrollBar scrollBar = new JScrollBar(JScrollBar.VERTICAL) {
  @Override public Dimension getPreferredSize() {
    Dimension d = super.getPreferredSize();
    d.width += getInsets().left;
    return d;
  }
  @Override public void updateUI() {
    super.updateUI();
    setBorder(BorderFactory.createMatteBorder(0, 4, 0, 0, new Icon() {
      @Override public void paintIcon(Component c, Graphics g, int x, int y) {
        //...
      }
      @Override public int getIconWidth() {
        return getInsets().left;
      }
      @Override public int getIconHeight() {
        return getHeight();
      }
    }));
  }
};
scroll.setVerticalScrollBar(scrollBar);

References

• JScrollBar search highlighter(Japanese)