How to highlight entire line

Question

I am currently implementing an IDE. I try to highlight entire line(not only text but also following blank field) when users set a breakpoint on that line.
Using Highlighter.addhighlight(start, end, HighlightPainter) only allow me to highlight the text part in the line. I haven't figure out how to do that.
Any helps are appreciated.

Answer 1

one way to highlight a full line or draw a breakpoint
symbol on a particular is to create a custom highlight
painter and override the paint method. If you want to
highlight the full line then use the width from the
JTextArea and only the y coordinate and height from
the view coordinates.
If you would like a breakpoint symbol and a particular
line then just put a drawImage call in the paint method
which draws an icon on that line
I've included some code for custom painter for both
highlighting a full line and rendering a breakpoint
icon.
     private class     SingleLineHighlighterPainter      extends DefaultHighlighter.DefaultHighlightPainter {
               public     SingleLineHighlighterPainter( Color color )
               {     super( color );          }
     * Paints a highlight over a single line.
               * just uses the first point a work around only
     * @param g the graphics context
     * @param offs0 the starting model offset >= 0
     * @param offs1 the ending model offset >= offs1
     * @param bounds the bounding box for the highlight
     * @param c the editor
          public void paint(Graphics g, int offs0, int offs1, Shape bounds, JTextComponent c) {
                    Rectangle alloc = bounds.getBounds();
                         Rectangle area = c.getBounds();
                         try {
                    // --- determine locations ---
                                   TextUI mapper = c.getUI();
                                   Rectangle p0 = mapper.modelToView(c, offs0);
                    // --- render ---
                                   Color color = getColor();
                                   if (color == null) {
                                   g.setColor(c.getSelectionColor());
                                   else {
                                   g.setColor(color);
                    // render using just the y coordinates and height from the initial point
                                   g.fillRect(0, p0.y, alloc.width, p0.height);
                         catch (BadLocationException e) {
                    // can't render
     private class     BreakpointPainter      extends DefaultHighlighter.DefaultHighlightPainter {
                    public     BreakpointPainter()
                    {     super( Color.green );          }
          * Paints a breakpoint image
                    * just uses the first point a work around only
          * @param g the graphics context
          * @param offs0 the starting model offset >= 0
          * @param offs1 the ending model offset >= offs1
          * @param bounds the bounding box for the highlight
          * @param c the editor
               public void paint(Graphics g, int offs0, int offs1, Shape bounds, JTextComponent c) {
                         Rectangle alloc = bounds.getBounds();
                              Rectangle area = c.getBounds();
                              try {
                         // --- determine locations ---
                                        TextUI mapper = c.getUI();
                                        Rectangle p0 = mapper.modelToView(c, offs0);
                                        Image im = ( (ImageIcon) Icons.stopSignIcon ).getImage();
                         // render using just the y coordinates and height from the initial point
                                        g.drawImage( im,0,p0.y+2,null );          
                              catch (BadLocationException e) {
                         // can't render
to use these do the following
     DefaultHighlighter dh = new DefaultHighlighter();
          dh.setDrawsLayeredHighlights( false );
          SingleLineHighlighterPainter     dhp = new SingleLineHighlighterPainter(Color.green);
          BreakpointPainter                    bpp = new BreakpointPainter();
          buff.setHighlighter(dh);
          try {
               dh.addHighlight(25, 30, dhp);     // single line highlighter here
               dh.addHighlight(60, 60, bpp);     // add breakpoint highlighter here
               dh.addHighlight(120,120,bpp);     // add breakpoint highlighter here
          catch (javax.swing.text.BadLocationException jst) { };
          buff.setMargin( new Insets( 0,20,0,0 ) );
where numbers used with the addHighlight method are
the location within the model. In this case the
addHighlight( 25,30, dhp ) will highlight the line with
a view location corresponding to position 25 in
the model. So just need to specify any model location
on the line you want to highlight.
Setting breakpoints is the same just need one model
position on the line where you want the image to be
drawn.
Hope that's clear.
Also helps to look at the source code for
DefaultHighlighter.java.
eric
[email protected]