#------------------------------------------------------------------------------
# Copyright (c) 2013, Nucleic Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file COPYING.txt, distributed with this software.
#------------------------------------------------------------------------------
from atom.api import (
Bool, IntEnum, Unicode, Coerced, Typed, ForwardTyped, observe
)
from enaml.colors import ColorMember
from enaml.core.declarative import d_, d_func
from enaml.fonts import FontMember
from enaml.layout.geometry import Size
from enaml.styling import Stylable
from .toolkit_object import ToolkitObject, ProxyToolkitObject
class ProxyWidget(ProxyToolkitObject):
""" The abstract definition of a proxy Widget object.
"""
#: A reference to the Widget declaration.
declaration = ForwardTyped(lambda: Widget)
def set_enabled(self, enabled):
raise NotImplementedError
def set_visible(self, visible):
raise NotImplementedError
def set_background(self, background):
raise NotImplementedError
def set_foreground(self, foreground):
raise NotImplementedError
def set_font(self, font):
raise NotImplementedError
def set_minimum_size(self, minimum_size):
raise NotImplementedError
def set_maximum_size(self, maximum_size):
raise NotImplementedError
def set_tool_tip(self, tool_tip):
raise NotImplementedError
def set_status_tip(self, status_tip):
raise NotImplementedError
def ensure_visible(self):
raise NotImplementedError
def ensure_hidden(self):
raise NotImplementedError
def restyle(self):
raise NotImplementedError
def set_focus(self):
raise NotImplementedError
def clear_focus(self):
raise NotImplementedError
def has_focus(self):
raise NotImplementedError
def focus_next_child(self):
raise NotImplementedError
def focus_previous_child(self):
raise NotImplementedError
class Feature(IntEnum):
""" An IntEnum defining the advanced widget features.
"""
#: Enables support for custom focus traversal functions.
FocusTraversal = 0x1
#: Enables support for focus events.
FocusEvents = 0x2
#: Enables support for drag operations.
DragEnabled = 0x4
#: Enables support for drop operations.
DropEnabled = 0x8
class Widget(ToolkitObject, Stylable):
""" The base class of visible widgets in Enaml.
"""
#: Whether or not the widget is enabled.
enabled = d_(Bool(True))
#: Whether or not the widget is visible.
visible = d_(Bool(True))
#: The background color of the widget.
background = d_(ColorMember())
#: The foreground color of the widget.
foreground = d_(ColorMember())
#: The font used for the widget.
font = d_(FontMember())
#: The minimum size for the widget. The default means that the
#: client should determine an intelligent minimum size.
minimum_size = d_(Coerced(Size, (-1, -1)))
#: The maximum size for the widget. The default means that the
#: client should determine an intelligent maximum size.
maximum_size = d_(Coerced(Size, (-1, -1)))
#: The tool tip to show when the user hovers over the widget.
tool_tip = d_(Unicode())
#: The status tip to show when the user hovers over the widget.
status_tip = d_(Unicode())
#: Set the extra features to enable for this widget. This value must
#: be provided when the widget is instantiated. Runtime changes to
#: this value are ignored.
features = d_(Coerced(Feature.Flags))
#: A reference to the ProxyWidget object.
proxy = Typed(ProxyWidget)
#--------------------------------------------------------------------------
# Observers
#--------------------------------------------------------------------------
@observe('enabled', 'visible', 'background', 'foreground', 'font',
'minimum_size', 'maximum_size', 'tool_tip', 'status_tip')
def _update_proxy(self, change):
""" Update the proxy widget when the Widget data changes.
This method only updates the proxy when an attribute is updated;
not when it is created or deleted.
"""
# The superclass implementation is sufficient.
super(Widget, self)._update_proxy(change)
#--------------------------------------------------------------------------
# Reimplementations
#--------------------------------------------------------------------------
def restyle(self):
""" Restyle the toolkit widget.
This method is invoked by the Stylable class when the style
dependencies have changed for the widget. This will trigger a
proxy restyle if necessary. This method should not typically be
called directly by user code.
"""
if self.proxy_is_active:
self.proxy.restyle()
#--------------------------------------------------------------------------
# Public API
#--------------------------------------------------------------------------
def show(self):
""" Ensure the widget is shown.
Calling this method will also set the widget visibility to True.
"""
self.visible = True
if self.proxy_is_active:
self.proxy.ensure_visible()
def hide(self):
""" Ensure the widget is hidden.
Calling this method will also set the widget visibility to False.
"""
self.visible = False
if self.proxy_is_active:
self.proxy.ensure_hidden()
def set_focus(self):
""" Set the keyboard input focus to this widget.
FOR ADVANCED USE CASES ONLY: DO NOT ABUSE THIS!
"""
if self.proxy_is_active:
self.proxy.set_focus()
def clear_focus(self):
""" Clear the keyboard input focus from this widget.
FOR ADVANCED USE CASES ONLY: DO NOT ABUSE THIS!
"""
if self.proxy_is_active:
self.proxy.clear_focus()
def has_focus(self):
""" Test whether this widget has input focus.
FOR ADVANCED USE CASES ONLY: DO NOT ABUSE THIS!
Returns
-------
result : bool
True if this widget has input focus, False otherwise.
"""
if self.proxy_is_active:
return self.proxy.has_focus()
return False
def focus_next_child(self):
""" Give focus to the next widget in the focus chain.
FOR ADVANCED USE CASES ONLY: DO NOT ABUSE THIS!
"""
if self.proxy_is_active:
self.proxy.focus_next_child()
def focus_previous_child(self):
""" Give focus to the previous widget in the focus chain.
FOR ADVANCED USE CASES ONLY: DO NOT ABUSE THIS!
"""
if self.proxy_is_active:
self.proxy.focus_previous_child()
@d_func
def next_focus_child(self, current):
""" Compute the next widget which should gain focus.
When the FocusTraversal feature of the widget is enabled, this
method will be invoked as a result of a Tab key press or from
a call to the 'focus_next_child' method on a decendant of the
owner widget. It should be reimplemented in order to provide
custom logic for computing the next focus widget.
** The FocusTraversal feature must be enabled for the widget in
order for this method to be called. **
Parameters
----------
current : Widget or None
The current widget with input focus, or None if no widget
has focus or if the toolkit widget with focus does not
correspond to an Enaml widget.
Returns
-------
result : Widget or None
The next widget which should gain focus, or None to follow
the default toolkit behavior.
"""
return None
@d_func
def previous_focus_child(self, current):
""" Compute the previous widget which should gain focus.
When the FocusTraversal feature of the widget is enabled, this
method will be invoked as a result of a Shift+Tab key press or
from a call to the 'focus_prev_child' method on a decendant of
the owner widget. It should be reimplemented in order to provide
custom logic for computing the previous focus widget.
** The FocusTraversal feature must be enabled for the widget in
order for this method to be called. **
Parameters
----------
current : Widget or None
The current widget with input focus, or None if no widget
has focus or if the toolkit widget with focus does not
correspond to an Enaml widget.
Returns
-------
result : Widget or None
The previous widget which should gain focus, or None to
follow the default toolkit behavior.
"""
return None
@d_func
def focus_gained(self):
""" A method invoked when the widget gains input focus.
** The FocusEvents feature must be enabled for the widget in
order for this method to be called. **
"""
pass
@d_func
def focus_lost(self):
""" A method invoked when the widget loses input focus.
** The FocusEvents feature must be enabled for the widget in
order for this method to be called. **
"""
pass
@d_func
def drag_start(self):
""" A method called at the start of a drag-drop operation.
This method is called when the user starts a drag operation
by dragging the widget with the left mouse button. It returns
the drag data for the drag operation.
** The DragEnabled feature must be enabled for the widget in
order for this method to be called. **
Returns
-------
result : DragData
An Enaml DragData object which holds the drag data. If
this is not provided, no drag operation will occur.
"""
return None
@d_func
def drag_end(self, drag_data, result):
""" A method called at the end of a drag-drop operation.
This method is called after the user has completed the drop
operation by releasing the left mouse button. It is passed
the original drag data object along with the resulting drop
action of the operation.
** The DragEnabled feature must be enabled for the widget in
order for this method to be called. **
Parameters
----------
data : DragData
The drag data created by the `drag_start` method.
result : DropAction
The requested drop action when the drop completed.
"""
pass
@d_func
def drag_enter(self, event):
""" A method invoked when a drag operation enters the widget.
The widget should inspect the mime data of the event and
accept the event if it can handle the drop action. The event
must be accepted in order to receive further drag-drop events.
** The DropEnabled feature must be enabled for the widget in
order for this method to be called. **
Parameters
----------
event : DropEvent
The event representing the drag-drop operation.
"""
pass
@d_func
def drag_move(self, event):
""" A method invoked when a drag operation moves in the widget.
This method will not normally be implemented, but it can be
useful for supporting advanced drag-drop interactions.
** The DropEnabled feature must be enabled for the widget in
order for this method to be called. **
Parameters
----------
event : DropEvent
The event representing the drag-drop operation.
"""
pass
@d_func
def drag_leave(self):
""" A method invoked when a drag operation leaves the widget.
** The DropEnabled feature must be enabled for the widget in
order for this method to be called. **
"""
pass
@d_func
def drop(self, event):
""" A method invoked when the user drops the data on the widget.
The widget should either accept the proposed action, or set
the drop action to an appropriate action before accepting the
event, or set the drop action to DropAction.Ignore and then
ignore the event.
** The DropEnabled feature must be enabled for the widget in
order for this method to be called. **
Parameters
----------
event : DropEvent
The event representing the drag-drop operation.
"""
pass