Class KeyEvent

lib/matplotlib/backend_bases.py:1497–1547

A key event (key press, key release). A KeyEvent has a number of special attributes in addition to those defined by the parent `Event` and `LocationEvent` classes. Attributes ---------- key : None or str The key(s) pressed. Could be *None*, a single case sensitive

class KeyEvent(LocationEvent):
    """
    A key event (key press, key release).

    A KeyEvent has a number of special attributes in addition to those defined
    by the parent `Event` and `LocationEvent` classes.

    Attributes
    ----------
    key : None or str
        The key(s) pressed. Could be *None*, a single case sensitive Unicode
        character ("g", "G", "#", etc.), a special key ("control", "shift",
        "f1", "up", etc.) or a combination of the above (e.g., "ctrl+alt+g",
        "ctrl+alt+G").

    Notes
    -----
    Modifier keys will be prefixed to the pressed key and will be in the order
    "ctrl", "alt", "super". The exception to this rule is when the pressed key
    is itself a modifier key, therefore "ctrl+alt" and "alt+control" can both
    be valid key values.

    Examples
    --------
    ::

        def on_key(event):
            print('you pressed', event.key, event.xdata, event.ydata)

        cid = fig.canvas.mpl_connect('key_press_event', on_key)
    """

    def __init__(self, name, canvas, key, x=0, y=0, guiEvent=None):
        super().__init__(name, canvas, x, y, guiEvent=guiEvent)
        self.key = key

    @classmethod
    def _from_ax_coords(cls, name, ax, xy, key, *args, **kwargs):
        """
        Generate a synthetic event at a given axes coordinate.

        This method is intended for creating events during testing.  The event
        can be emitted by calling its ``_process()`` method.
        """
        # Separate from MouseEvent._from_ax_coords instead of being defined in the base
        # class, due to different parameter order in the constructor signature.
        x, y = ax.transData.transform(xy)
        event = cls(name, ax.figure.canvas, key, x, y, *args, **kwargs)
        event.inaxes = ax
        event.xdata, event.ydata = xy  # Force exact xy to avoid fp roundtrip issues.
        return event


# Default callback for key events.