Gets the top pixel.
<p>
The top pixel is the pixel position of the line that is
currently at the top of the widget. The text widget can be scrolled by pixels
by dragging the scroll thumb so that a partial line may be displayed at the top
the widget. The top pixel changes when the widget is scrolled. The top pixel
does not include the widget trimming.
</p>
@return pixel position of the top line
@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>
Gets the top pixel. <p> The top pixel is the pixel position of the line that is currently at the top of the widget. The text widget can be scrolled by pixels by dragging the scroll thumb so that a partial line may be displayed at the top the widget. The top pixel changes when the widget is scrolled. The top pixel does not include the widget trimming. </p>
@return pixel position of the top line @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>