IVerticalRuler ruler = testIface.getVerticalRuler();
testIface.setTopIndex(lineNo-1);
int y1 = 0, y2;
while (ruler.toDocumentLineNumber(y1) < lineNo-1) y1++;
y2 = y1;
while (ruler.toDocumentLineNumber(y2) < lineNo) y2++;
return ruler.getControl().toDisplay(ruler.getWidth()/3, y1+(y2-y1)/2);
}