Returns the font metrics for the specified line index.
@param lineIndex the line index
@return the font metrics
@exception IllegalArgumentException <ul>
<li>ERROR_INVALID_ARGUMENT - if the line index is out of range</li>
</ul>
@exception SWTException <ul>
<li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li>
</ul>
Returns the font metrics for the specified line index.
@param lineIndex the line index @return the font metrics
@exception IllegalArgumentException <ul> <li>ERROR_INVALID_ARGUMENT - if the line index is out of range</li> </ul> @exception SWTException <ul> <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li> </ul>