void redrawFrom(int lno) {
   if (lno < 0 || lno >= text.getLineCount()) return;
   int y = text.getLocationAtOffset(text.getOffsetAtLine(lno)).y;
   int height = text.getClientArea().height - y;
   int width = text.getClientArea().width + text.getHorizontalPixel();
   text.redraw(0, y, width, height, false);
 }
 void drawLine(int lno) {
   if (lno < 0 || lno >= text.getLineCount()) return;
   int y = text.getLocationAtOffset(text.getOffsetAtLine(lno)).y;
   int height = 0;
   if (text.getLineCount() > lno + 1)
     height = text.getLocationAtOffset(text.getOffsetAtLine(lno + 1)).y - y;
   else height = text.getLocationAtOffset(text.getCharCount()).y + text.getLineHeight();
   int width = text.getClientArea().width + text.getHorizontalPixel();
   text.redraw(0, y, width, height, false);
 }