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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)
[docs] 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 pad_left, pad_top, pad_right, pad_bottom = self.padding for c in self.children: x, y = _x, _y cw, ch = c.size shw, shh = c.size_hint shw_min, shh_min = c.size_hint_min shw_max, shh_max = c.size_hint_max if shw is not None: cw = shw * (width - pad_left - pad_right) if shw_min is not None and cw < shw_min: cw = shw_min elif shw_max is not None and cw > shw_max: cw = shw_max if shh is not None: ch = shh * (height - pad_top - pad_bottom) if shh_min is not None and ch < shh_min: ch = shh_min elif shh_max is not None and ch > shh_max: ch = shh_max if anchor_x == 'left': x = x + pad_left elif anchor_x == 'right': x = x + width - (cw + pad_right) else: x = x + (width - pad_right + pad_left - cw) / 2 if anchor_y == 'bottom': y = y + pad_bottom elif anchor_y == 'top': y = y + height - (ch + pad_top) else: y = y + (height - pad_top + pad_bottom - ch) / 2 c.pos = x, y c.size = cw, ch