#------------------------------------------------------------------------------
# Copyright (c) 2013, Nucleic Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file LICENSE, distributed with this software.
#------------------------------------------------------------------------------
from atom.api import Atom, Enum, Int, Range, Typed, ForwardTyped, set_default
from enaml.core.declarative import d_, observe
from .constraints_widget import ConstraintsWidget, ProxyConstraintsWidget
from .stack_item import StackItem
[docs]
class Transition(Atom):
""" An object representing an animated transition.
Once a transition is created, it should be considered read-only.
"""
#: The type of transition effect to use.
type = Enum('slide', 'wipe', 'iris', 'fade', 'crossfade')
#: The direction of the transition effect. Some transition types
#: will ignore the direction if it doesn't apply to the effect.
direction = Enum(
'left_to_right', 'right_to_left', 'top_to_bottom', 'bottom_to_top'
)
#: The duration of the transition, in milliseconds.
duration = Range(low=0, value=250)
class ProxyStack(ProxyConstraintsWidget):
""" The abstract definition of a proxy Stack object.
"""
#: A reference to the Stack declaration.
declaration = ForwardTyped(lambda: Stack)
def set_index(self, index):
raise NotImplementedError
def set_transition(self, transition):
raise NotImplementedError
def set_size_hint_mode(self, mode):
raise NotImplementedError
[docs]
class Stack(ConstraintsWidget):
""" A component which displays its children as a stack of widgets,
only one of which is visible at a time.
"""
#: The index of the visible widget in the stack. The widget itself
#: does not provide a means to changing this index. That control
#: must be supplied externally. If the given index falls outside of
#: the range of stack items, no widget will be visible.
index = d_(Int(0))
#: The item transition to use when changing between stack items.
transition = d_(Typed(Transition))
#: The size hint mode for the stack. The default is 'union' and
#: means that the size hint of the stack is the union of all the
#: stack item size hints. 'current' means the size hint of the
#: stack will be the size hint of the current stack item.
size_hint_mode = d_(Enum('union', 'current'))
#: A Stack expands freely in height and width by default
hug_width = set_default('ignore')
hug_height = set_default('ignore')
#: A reference to the ProxyStack widget.
proxy = Typed(ProxyStack)
[docs]
def stack_items(self):
""" Get the stack items defined on the stack
"""
return [c for c in self.children if isinstance(c, StackItem)]
#--------------------------------------------------------------------------
# Observers
#--------------------------------------------------------------------------
@observe('index', 'transition', 'size_hint_mode')
def _update_proxy(self, change):
""" An observer which sends state change to the proxy.
"""
# The superclass handler implementation is sufficient.
super(Stack, self)._update_proxy(change)