#------------------------------------------------------------------------------
# Copyright (c) 2012, Enthought, Inc.
# All rights reserved.
#------------------------------------------------------------------------------
from traits.api import Enum, Range, Property, cached_property
from enaml.core.trait_types import CoercingInstance
from enaml.layout.geometry import Size
from .container import Container
from .widget import Widget
[docs]class FlowItem(Widget):
""" A widget which can be used as an item in a FlowArea.
A FlowItem is a widget which can be used as a child of a FlowArea
widget. It can have at most a single child widget which is an
instance of Container.
"""
#: The preferred size of this flow item. This size will be used as
#: the size of the item in the layout, bounded to the computed min
#: and max size. A size of (-1, -1) indicates to use the widget's
#: size hint as the preferred size.
preferred_size = CoercingInstance(Size, (-1, -1))
#: The alignment of this item in the direction orthogonal to the
#: layout flow.
align = Enum('leading', 'trailing', 'center')
#: The stretch factor for this item in the flow direction, relative
#: to other items in the same line. The default is zero which means
#: that the item will not expand in the direction orthogonal to the
#: layout flow.
stretch = Range(low=0, value=0)
#: The stretch factor for this item in the orthogonal direction
#: relative to other items in the layout. The default is zero
#: which means that the item will not expand in the direction
#: orthogonal to the layout flow.
ortho_stretch = Range(low=0, value=0)
#: A read only property which returns the items's flow widget.
flow_widget = Property(depends_on='children')
#--------------------------------------------------------------------------
# Initialization
#--------------------------------------------------------------------------
[docs] def snapshot(self):
""" Returns the snapshot dict for the FlowItem.
"""
snap = super(FlowItem, self).snapshot()
snap['preferred_size'] = self.preferred_size
snap['align'] = self.align
snap['stretch'] = self.stretch
snap['ortho_stretch'] = self.ortho_stretch
return snap
[docs] def bind(self):
""" Bind the change handler for the FlowItem.
"""
super(FlowItem, self).bind()
attrs = ('preferred_size', 'align', 'stretch', 'ortho_stretch')
self.publish_attributes(*attrs)
#--------------------------------------------------------------------------
# Private API
#--------------------------------------------------------------------------
@cached_property
def _get_flow_widget(self):
""" The getter for the 'flow_widget' property.
Returns
-------
result : Container or None
The flow widget for the FlowItem, or None if not provided.
"""
widget = None
for child in self.children:
if isinstance(child, Container):
widget = child
return widget