TableCellRenderer with JTextPane and HTML

Question

I'm writing a TableCellRenderer that will be rendering HTML content using a custom extension to the JTextPane class. Where I'm having trouble is in calculating the necessary height to set the table row based on the content of the cell (in this case HTML text in my JTextPane component). I know the width of the table cell and I can figure out the width of the content (taking into account the formatting because of the HTML content). This all works perfectly until the column width shrinks enough to cause the underlying view to word wrap.
Here is the code snippet from my JTextPane to count the number of lines of text and calculate the width of the content
  public int getWidthOfContent() {
    getLineCount();
    return m_iWidthOfContent;
  public int getWidthOfContent(int p_iWidthOfArea) {
    getLineCount(p_iWidthOfArea);
    return m_iWidthOfContent;
  public int getLineCount(int iComponentWidth) {
    int iWidth = 0;
    int iBreakCount = 0;
    int iHardBreakCount = 0;
    int iTotalWidth = 0;
    int iTotalContentWidth = 0;
    int iMaxHeight = 0;
    Document doc = getDocument();
    ElementIterator it = new ElementIterator(doc.getDefaultRootElement());
    StyleSheet styleSheet = null;
    if(doc instanceof HTMLDocument) {
      styleSheet = ((HTMLDocument)doc).getStyleSheet();
    if(iComponentWidth == -1) {
      iWidth = getWidth();
    else {
      iWidth = iComponentWidth;
    Element e;
    while ((e=it.next()) != null) {
      AttributeSet attributes = e.getAttributes();
      Enumeration enumeration = attributes.getAttributeNames();
      boolean bBreakDetected = false;
      while(enumeration.hasMoreElements()) {
        Object objName = enumeration.nextElement();
        Object objAttr = attributes.getAttribute(objName);
        if(objAttr instanceof HTML.Tag) {
          HTML.Tag tag = (HTML.Tag)objAttr;
//          if(tag == HTML.Tag.BODY) {
//            UCSParagraphView pv = new UCSParagraphView(e);
//            if(pv.willWidthBreakView(iWidth)) {
//              iHardBreakCount++;
          FontMetrics fontMetrics = null;
          if(styleSheet != null && styleSheet.getFont(attributes) != null) {
            fontMetrics = getFontMetrics(styleSheet.getFont(attributes));
          if(fontMetrics != null && fontMetrics.getHeight() > iMaxHeight) {
            iMaxHeight = fontMetrics.getHeight();
          if(tag.breaksFlow()) {
            //This must be a breaking tag....this will add another line to the count
            bBreakDetected = true;
            if(tag.equals(HTML.Tag.BR) || tag.isBlock() && (!tag.equals(HTML.Tag.HEAD) && !tag.equals(HTML.Tag.BODY))) {
              if(iTotalContentWidth == 0) {
                iTotalContentWidth = iTotalWidth;
                iTotalWidth = 0;
              else if(iTotalWidth > iTotalContentWidth) {
                iTotalContentWidth = iTotalWidth;
                iTotalWidth = 0;
              else {
                iTotalWidth = 0;
              if(tag.equals(HTML.Tag.H1) || tag.equals(HTML.Tag.H2) || tag.equals(HTML.Tag.H3) || tag.equals(HTML.Tag.H4)) {
                iHardBreakCount += 3; //These count as three lines (Blank - Content - Blank)
              else {
                iHardBreakCount++;
            iBreakCount++;
      if(!bBreakDetected) {
        Font font;
        FontMetrics fontMetrics;
        if(e.getDocument() instanceof HTMLDocument) {
          font = ((HTMLDocument)e.getDocument()).getStyleSheet().getFont(e.getAttributes());
          fontMetrics = getFontMetrics(font);
        else {
          font = getFont();
          fontMetrics = getFontMetrics(font);
        int iRangeStart = e.getStartOffset();
        int iRangeEnd = e.getEndOffset();
        if(fontMetrics.getHeight() > iMaxHeight) {
          iMaxHeight = fontMetrics.getHeight();
        if(e.isLeaf()) {
          String strText;
          try {
            strText = this.getText(iRangeStart, iRangeEnd - iRangeStart);
            if(strText.equals("\n")) {
              //iBreakCount++;
            iTotalWidth += SwingUtilities.computeStringWidth(fontMetrics, strText);
          catch (BadLocationException ex) {
            //Something happened.....don't care....just eat the exception
    m_iMaxFontHeight = iMaxHeight;
    m_iWidthOfContent = iTotalWidth;
    m_iHardBreakCount = iHardBreakCount;
    if(iWidth > 0) {
      int iLineCount = (iTotalWidth / iWidth) + iBreakCount;
      return iLineCount;
    return 1;
  }And here is the code from my TableCellRenderer that uses the above information
   public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected,
                                                  boolean hasFocus, int row, int column) {
     if(ValidationHelper.hasText(value) && value.toString().indexOf("<html>") != -1) {
       UCSHTMLTextPane pane = new UCSHTMLTextPane();
       pane.setText(ValidationHelper.getTrimmedText(value.toString()));
       BigDecimal lWidthCell = new BigDecimal(table.getCellRect(row, column, false).getWidth() - 15);
       BigDecimal lWidthContent = new BigDecimal(pane.getWidthOfContent(lWidthCell.intValue()));
       int iHardBreakCount = pane.getHardBreakCount();
       BigDecimal lLineCount = lWidthContent.divide(lWidthCell, BigDecimal.ROUND_CEILING);
       int iLineCount = lLineCount.intValue();
       double dWidthCell = lWidthCell.doubleValue();
       double dWidthContent = lWidthContent.doubleValue();
       double dWidthContentPlusFivePercent = dWidthContent + (dWidthContent * .01);
       double dWidthContentMinumFivePercent = dWidthContent - (dWidthContent * .01);
       if(dWidthCell >= dWidthContentMinumFivePercent && dWidthCell <= dWidthContentPlusFivePercent) {
         iLineCount++;
       iLineCount += iHardBreakCount;
       int iMaxFontHeight = pane.getMaxFontHeight();
       int iHeight = (iMaxFontHeight * iLineCount) + 5;
       if ( (iLineCount > 0) && (table.getRowHeight(row) != iHeight)) {
         pane.setPreferredSize(new Dimension(0, iHeight));
         if(m_bAutoAdjustHeight) {
           table.setRowHeight(row, iHeight);
       if(iLineCount == 1) {
         if(iHeight != table.getRowHeight()) {
           if(m_bAutoAdjustHeight) {
             table.setRowHeight(iHeight);
       setComponentUI(pane, table, row, column, isSelected, hasFocus);
       return pane;
}Any suggestions?

Answer 1

Hello,
You must initialize correctly your JTextPane like this:
javax.swing.text.html.HTMLEditorKit htmlEditorKit = new javax.swing.text.html.HTMLEditorKit();
javax.swing.text.html.HTMLDocument htmlDoc = (javax.swing.text.html.HTMLDocument)htmlEditorKit.createDefaultDocument();
setEditorKit(htmlEditorKit);
setDocument(htmlDoc);
setEditable(true);
setContentType("text/html");