'''
Button
======

.. image:: images/button.jpg
    :align: right

The :class:`Button` is a :class:`~kivy.uix.label.Label` with associated actions
that are triggered when the button is pressed (or released after a
click/touch). To configure the button, the same properties (padding,
font_size, etc) and
:ref:`sizing system <kivy-uix-label-sizing-and-text-content>`
are used as for the :class:`~kivy.uix.label.Label` class::

    button = Button(text='Hello world', font_size=14)

To attach a callback when the button is pressed (clicked/touched), use
:class:`~kivy.uix.widget.Widget.bind`::

    def callback(instance):
        print('The button <%s> is being pressed' % instance.text)

    btn1 = Button(text='Hello world 1')
    btn1.bind(on_press=callback)
    btn2 = Button(text='Hello world 2')
    btn2.bind(on_press=callback)

If you want to be notified every time the button state changes, you can bind
to the :attr:`Button.state` property::

    def callback(instance, value):
        print('My button <%s> state is <%s>' % (instance, value))
    btn1 = Button(text='Hello world 1')
    btn1.bind(state=callback)

Kv Example::

    Button:
        text: 'press me'
        on_press: print("ouch! More gently please")
        on_release: print("ahhh")
        on_state:
            print("my current state is {}".format(self.state))

'''

__all__ = ('Button', )

from kivy.uix.label import Label
from kivy.properties import StringProperty, ListProperty, ColorProperty
from kivy.uix.behaviors import ButtonBehavior


class Button(ButtonBehavior, Label):
    '''Button class, see module documentation for more information.

    .. versionchanged:: 1.8.0
        The behavior / logic of the button has been moved to
        :class:`~kivy.uix.behaviors.ButtonBehaviors`.

    '''

    background_color = ColorProperty([1, 1, 1, 1])
    '''Background color, in the format (r, g, b, a).

    This acts as a *multiplier* to the texture colour. The default
    texture is grey, so just setting the background color will give
    a darker result. To set a plain color, set the
    :attr:`background_normal` to ``''``.

    .. versionadded:: 1.0.8

    The :attr:`background_color` is a
    :class:`~kivy.properties.ColorProperty` and defaults to [1, 1, 1, 1].

    .. versionchanged:: 2.0.0
        Changed from :class:`~kivy.properties.ListProperty` to
        :class:`~kivy.properties.ColorProperty`.
    '''

    background_normal = StringProperty(
        'atlas://data/images/defaulttheme/button')
    '''Background image of the button used for the default graphical
    representation when the button is not pressed.

    .. versionadded:: 1.0.4

    :attr:`background_normal` is a :class:`~kivy.properties.StringProperty`
    and defaults to 'atlas://data/images/defaulttheme/button'.
    '''

    background_down = StringProperty(
        'atlas://data/images/defaulttheme/button_pressed')
    '''Background image of the button used for the default graphical
    representation when the button is pressed.

    .. versionadded:: 1.0.4

    :attr:`background_down` is a :class:`~kivy.properties.StringProperty` and
    defaults to 'atlas://data/images/defaulttheme/button_pressed'.
    '''

    background_disabled_normal = StringProperty(
        'atlas://data/images/defaulttheme/button_disabled')
    '''Background image of the button used for the default graphical
    representation when the button is disabled and not pressed.

    .. versionadded:: 1.8.0

    :attr:`background_disabled_normal` is a
    :class:`~kivy.properties.StringProperty` and defaults to
    'atlas://data/images/defaulttheme/button_disabled'.
    '''

    background_disabled_down = StringProperty(
        'atlas://data/images/defaulttheme/button_disabled_pressed')
    '''Background image of the button used for the default graphical
    representation when the button is disabled and pressed.

    .. versionadded:: 1.8.0

    :attr:`background_disabled_down` is a
    :class:`~kivy.properties.StringProperty` and defaults to
    'atlas://data/images/defaulttheme/button_disabled_pressed'.
    '''

    border = ListProperty([16, 16, 16, 16])
    '''Border used for :class:`~kivy.graphics.vertex_instructions.BorderImage`
    graphics instruction. Used with :attr:`background_normal` and
    :attr:`background_down`. Can be used for custom backgrounds.

    It must be a list of four values: (bottom, right, top, left). Read the
    BorderImage instruction for more information about how to use it.

    :attr:`border` is a :class:`~kivy.properties.ListProperty` and defaults to
    (16, 16, 16, 16)
    '''
