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:mod:`!tkinter.dnd` --- Drag and drop support
=============================================
.. module:: tkinter.dnd
:platform: Tk
:synopsis: Tkinter drag-and-drop interface
**Source code:** :source:`Lib/tkinter/dnd.py`
--------------
.. note:: This is experimental and due to be deprecated when it is replaced
with the Tk DND.
The :mod:`tkinter.dnd` module provides drag-and-drop support for objects within
a single application, within the same window or between windows. To enable an
object to be dragged, you must create an event binding for it that starts the
drag-and-drop process. Typically, you bind a ButtonPress event to a callback
function that you write (see :ref:`Bindings-and-Events`). The function should
call :func:`dnd_start`, where 'source' is the object to be dragged, and 'event'
is the event that invoked the call (the argument to your callback function).
Selection of a target object occurs as follows:
#. Top-down search of area under mouse for target widget
* Target widget should have a callable *dnd_accept* attribute
* If *dnd_accept* is not present or returns ``None``, search moves to parent widget
* If no target widget is found, then the target object is ``None``
2. Call to *<old_target>.dnd_leave(source, event)*
#. Call to *<new_target>.dnd_enter(source, event)*
#. Call to *<target>.dnd_commit(source, event)* to notify of drop
#. Call to *<source>.dnd_end(target, event)* to signal end of drag-and-drop
.. class:: DndHandler(source, event)
The *DndHandler* class handles drag-and-drop events tracking Motion and
ButtonRelease events on the root of the event widget.
.. method:: cancel(event=None)
Cancel the drag-and-drop process.
.. method:: finish(event, commit=0)
Execute end of drag-and-drop functions.
.. method:: on_motion(event)
Inspect area below mouse for target objects while drag is performed.
.. method:: on_release(event)
Signal end of drag when the release pattern is triggered.
.. function:: dnd_start(source, event)
Factory function for drag-and-drop process.
.. seealso::
:ref:`Bindings-and-Events`
|
