GEF中区分mouse move和mouse drag

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查看DomainEventDispatcher的源代码
/**
* @see EventDispatcher#dispatchMouseMoved(org.eclipse.swt.events.MouseEvent)
*/
public void dispatchMouseMoved(org.eclipse.swt.events.MouseEvent me) {
if (!editorCaptured) {
  super.dispatchMouseMoved(me);
  if (draw2dBusy())
   return;
}
//在GEF中，区分mouse move和mouse drag，在mouse move的同时，假如按下了鼠标键，就会当作是mouse drag去处理了
if (okToDispatch()) {
  if ((me.stateMask & InputEvent.ANY_BUTTON) != 0)
   domain.mouseDrag(me, viewer);
  else
   domain.mouseMove(me, viewer);
}
}

我们还可以查看Tool源代码中的说明：

/**
* Called when a Viewer receives a mouse drag. SWT does not distinguish(区分) between mouse
* drags and mouse moves, but GEF Viewers will make this distinction when dispatching
* events. A drag occurs if any mouse button is down.
* @param mouseEvent the SWT mouse event
* @param viewer the Viewer which received a drag
* SWT并不区分mouse drag和mouse move，在gef中，在mouse move的过程中，按下任意的鼠标键的同时，就代表mouse drag事件
*/
void mouseDrag(MouseEvent mouseEvent, EditPartViewer viewer);