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Source code for kivy.uix.anchorlayout

'''
Anchor Layout
=============

.. only:: html

    .. image:: images/anchorlayout.gif
        :align: right

.. only:: latex

    .. image:: images/anchorlayout.png
        :align: right

The :class:`AnchorLayout` aligns its children to a border (top, bottom,
left, right) or center.


To draw a button in the lower-right corner::

    layout = AnchorLayout(
        anchor_x='right', anchor_y='bottom')
    btn = Button(text='Hello World')
    layout.add_widget(btn)

'''

__all__ = ('AnchorLayout', )

from kivy.uix.layout import Layout
from kivy.properties import OptionProperty, VariableListProperty


[docs]class AnchorLayout(Layout): '''Anchor layout class. See the module documentation for more information. ''' padding = VariableListProperty([0, 0, 0, 0]) '''Padding between the widget box and its children, in pixels: [padding_left, padding_top, padding_right, padding_bottom]. padding also accepts a two argument form [padding_horizontal, padding_vertical] and a one argument form [padding]. :attr:`padding` is a :class:`~kivy.properties.VariableListProperty` and defaults to [0, 0, 0, 0]. ''' anchor_x = OptionProperty('center', options=( 'left', 'center', 'right')) '''Horizontal anchor. :attr:`anchor_x` is an :class:`~kivy.properties.OptionProperty` and defaults to 'center'. It accepts values of 'left', 'center' or 'right'. ''' anchor_y = OptionProperty('center', options=( 'top', 'center', 'bottom')) '''Vertical anchor. :attr:`anchor_y` is an :class:`~kivy.properties.OptionProperty` and defaults to 'center'. It accepts values of 'top', 'center' or 'bottom'. ''' def __init__(self, **kwargs): super(AnchorLayout, self).__init__(**kwargs) fbind = self.fbind update = self._trigger_layout fbind('children', update) fbind('parent', update) fbind('padding', update) fbind('anchor_x', update) fbind('anchor_y', update) fbind('size', update) fbind('pos', update) def do_layout(self, *largs): _x, _y = self.pos width = self.width height = self.height anchor_x = self.anchor_x anchor_y = self.anchor_y padding = self.padding for c in self.children: x, y = _x, _y w, h = c.size if c.size_hint[0] is not None: w = c.size_hint[0] * width - (padding[0] + padding[2]) if c.size_hint[1] is not None: h = c.size_hint[1] * height - (padding[1] + padding[3]) if anchor_x == 'left': x = x + padding[0] if anchor_x == 'right': x = x + width - (w + padding[2]) if self.anchor_x == 'center': x = x + (width / 2) - (w / 2) if anchor_y == 'bottom': y = y + padding[1] if anchor_y == 'top': y = y + height - (h + padding[3]) if anchor_y == 'center': y = y + (height / 2) - (h / 2) c.x = x c.y = y c.width = w c.height = h