Defines the DataLabelTool class.
A tool for dragging a data label.
Attach this tool to a DataLabel object by setting the tool’s component to the DataLabel.
Use the root of the label’s arrow (if any) as the closest corner of the label?
The mouse button that initiates the drag.
Called when a mouse event causes the drag operation to end.
Called when the drag operation starts.
This method is called for every mouse_move event that the tool receives while the user is dragging the mouse.
Implements DragTool. Moves and redraws the label.
Returns whether the (x,y) position is in a region that is OK to drag.