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Stretching background colour across whole JTextPane for one line of text

843806 Member Posts: 49,998
edited Mar 17, 2008 9:13AM in Swing
Hey guys,

There's something I'd like to do with my JTextPane, but I don't know if it's possible without too much fooling around.

When a line of text is entered into the JTextPane the foreground and the background of the entered message are coloured. All of that works fine, but if possible I would like to also fill the remaining white space of the line the same colour as the existing background, just to make everything look nicer. I would also want the background colour to stretch if the window is stretched, as the JTextPane stretches

This is how I'm going about it.
SimpleAttributeSet attrs = new SimpleAttributeSet();

SimpleAttributeSet attrs2 = new SimpleAttributeSet();
StyleConstants.setForeground(attrs2, Color.gray);

Document doc = conversion.getDocument();

FileCredential credential = ((ClientService)pixecurFile).getCredential();

conversion.getDocument().insertString(doc.getLength(), credential.userData(FileCredential.USER_NAME) + " Says:  ", attrs);
conversion.getDocument().insertString(doc.getLength(), now("yyyy-MM-dd HH:mm:ss aa")+"\n", attrs2);
conversion.getDocument().insertString(doc.getLength(), "   " + chatMessage.getText()+"\n", attrs);
I'm willing to bet that there is no clean way to go about what I'm looking to do, but I hope I'm wrong.

Also, I don't think this matters, but the JTextPane in question is inside of a JScrollPane.

Thanks in advance,


  • darrylburke
    darrylburke Member Posts: 18,007
    Probably not very efficient, but seems to work ... fairly clean imho :-)
    import java.awt.BorderLayout;
    import java.awt.Color;
    import java.awt.Dimension;
    import java.awt.Graphics;
    import java.awt.Rectangle;
    import javax.swing.JFrame;
    import javax.swing.JScrollPane;
    import javax.swing.JTextPane;
    import javax.swing.SwingUtilities;
    import javax.swing.event.CaretEvent;
    import javax.swing.event.CaretListener;
    import javax.swing.plaf.basic.BasicTextPaneUI;
    import javax.swing.text.BadLocationException;
    public class LineHighlightTextPane {
       public LineHighlightTextPane () {
       void makeUI () {
          JTextPane textPane = new JTextPane ();
          textPane.setUI (new LineHighlightTextPaneUI (textPane));
          JScrollPane scrollPane = new JScrollPane (textPane);
          JFrame frame = new JFrame ("Line Highlight Text Pane");
          frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
          frame.setSize (300, 300);
          frame.add (scrollPane, BorderLayout.CENTER);
          frame.setVisible (true);
       public static void main (String[] args) {
          SwingUtilities.invokeLater (new Runnable () {
             public void run () {
                new LineHighlightTextPane ().makeUI ();
    class LineHighlightTextPaneUI extends BasicTextPaneUI {
       JTextPane tc;
       LineHighlightTextPaneUI (JTextPane t) {
          tc = t;
          tc.addCaretListener (new CaretListener () {
             public void caretUpdate (CaretEvent e) {
                tc.repaint ();
       public void paintBackground (Graphics g) {
          super.paintBackground (g);
          try {
             Rectangle rect = modelToView(tc, tc.getCaretPosition ());
             int y = rect.y;
             int h = rect.height;
             g.setColor (Color.YELLOW);
             g.fillRect (0, y, tc.getWidth (), h);
          } catch (BadLocationException ex) {
    Is that what you wanted or have I misread the requirement?

  • camickr
    camickr Member Posts: 24,931
    Or some code that should work on any JTextComponent:
  • 843806
    843806 Member Posts: 49,998
    Thanks a lot for the help guys! I was able to do exactly what I needed.
This discussion has been closed.