Sets the top index. Do nothing if there is no text set.
<p>
The top index is the index of the line that is currently at the top
of the widget. The top index changes when the widget is scrolled.
Indexing starts from zero.
Note: The top index is reset to 0 when new text is set in the widget.
</p>
@param topIndex new top index. Must be between 0 and
getLineCount() - fully visible lines per page. If no lines are fully
visible the maximum value is getLineCount() - 1. An out of range
index will be adjusted accordingly.
@exception SWTException <ul>
<li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
<li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
</ul>
Sets the top index. Do nothing if there is no text set. <p> The top index is the index of the line that is currently at the top of the widget. The top index changes when the widget is scrolled. Indexing starts from zero. Note: The top index is reset to 0 when new text is set in the widget. </p>
@param topIndex new top index. Must be between 0 and getLineCount() - fully visible lines per page. If no lines are fully visible the maximum value is getLineCount() - 1. An out of range index will be adjusted accordingly. @exception SWTException <ul> <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> </ul>