Event handling and picking

matplotlib works with a number of user interface toolkits (wxpython,

Matplotlib works with a number of user interface toolkits (wxpython,

tkinter, qt4, gtk, and macosx) and in order to support features like

interactive panning and zooming of figures, it is helpful to the

developers to have an API for interacting with the figure via key

..note::

The canvas retains only weak references to the callbacks. Therefore

if a callback is a method of a class instance, you need to retain

a reference to that instance. Otherwise the instance will be

garbage-collected and the callback will vanish.

The canvas retains only weak references to instance methods used as

callbacks. Therefore, you need to retain a reference to instances owning

such methods. Otherwise the instance will be garbage-collected and the

callback will vanish.

This does not affect free functions used as callbacks.

Here are the events that you can connect to, the class instances that

are sent back to you when the event occurs, and the event descriptions

are sent back to you when the event occurs, and the event descriptions:

.. _event_handling_examples:

EventHandling

Eventhandling

==============

Matplotlib supports event handling with a GUI neutral event model, so

you can connect to Matplotlib events without knowledge of what user

interface Matplotlib will ultimately be plugged in to. This has two

advantages: the code you write will be more portable, and Matplotlib

events are aware of things like data coordinate space and which axes

the event occurs in so you don't have to mess with low level

transformation details to go from canvas space to data space. Object

picking examples are also included.

Matplotlib supports :doc:`event handling</users/event_handling>` with a GUI

neutral event model, so you can connect to Matplotlib events without knowledge

of what user interface Matplotlib will ultimately be plugged in to. This has

two advantages: the code you write will be more portable, and Matplotlib events

are aware of things like data coordinate space and which axes the event occurs

in so you don't have to mess with low level transformation details to go from

canvas space to data space. Object picking examples are also included.