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#------------------------------------------------------------------------------
# Copyright (c) 2005, Enthought, Inc.
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in enthought/LICENSE.txt and may be redistributed only
# under the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
# Thanks for using Enthought open source!
#
# Author: Enthought, Inc.
# Description: <Enthought pyface package component>
#------------------------------------------------------------------------------
""" The interface of a pyface GUI. """
# Standard library imports.
import logging
import os
# Enthought library imports.
from traits.etsconfig.api import ETSConfig
from traits.api import Bool, Interface, Unicode
# Logging.
logger = logging.getLogger(__name__)
class IGUI(Interface):
""" The interface of a pyface GUI. """
#### 'GUI' interface ######################################################
#: Is the GUI busy (i.e. should the busy cursor, often an hourglass, be
#: displayed)?
busy = Bool(False)
#: Has the GUI's event loop been started?
started = Bool(False)
#: A directory on the local file system that we can read and write to at
#: will. This is used to persist layout information etc. Note that
#: individual toolkits will have their own directory.
state_location = Unicode
###########################################################################
# 'object' interface.
###########################################################################
def __init__(self, splash_screen=None):
""" Initialise a new GUI.
Parameters
----------
splash_screen : ISplashScreen instance or None
An optional splash screen that will be displayed until the event
loop is started.
"""
###########################################################################
# 'GUI' class interface.
###########################################################################
@staticmethod
def allow_interrupt():
""" Override SIGINT to prevent swallowing KeyboardInterrupt
Override the SIGINT handler to ensure the process can be
interrupted. This prevents GUI toolkits from swallowing
KeyboardInterrupt exceptions.
Warning: do not call this method if you intend your application to be
run interactively.
"""
@classmethod
def invoke_after(cls, millisecs, callable, *args, **kw):
""" Call a callable after a specific delay in the main GUI thread.
Parameters
----------
millisecs : float
Delay in milliseconds
callable : callable
Callable to be called after the delay
args, kwargs :
Arguments and keyword arguments to be used when calling.
"""
@classmethod
def invoke_later(cls, callable, *args, **kw):
""" Call a callable in the main GUI thread.
Parameters
----------
callable : callable
Callable to be called after the delay
args, kwargs :
Arguments and keyword arguments to be used when calling.
"""
@classmethod
def set_trait_after(cls, millisecs, obj, trait_name, new):
""" Sets a trait after a specific delay in the main GUI thread.
Parameters
----------
millisecs : float
Delay in milliseconds
obj : HasTraits instance
Object on which the trait is to be set
trait_name : str
The name of the trait to set
new : any
The value to set.
"""
@classmethod
def set_trait_later(cls, obj, trait_name, new):
""" Sets a trait in the main GUI thread.
Parameters
----------
obj : HasTraits instance
Object on which the trait is to be set
trait_name : str
The name of the trait to set
new : any
The value to set.
"""
@staticmethod
def process_events(allow_user_events=True):
""" Process any pending GUI events.
Parameters
----------
allow_user_events : bool
If allow_user_events is ``False`` then user generated events are not
processed.
"""
@staticmethod
def set_busy(busy=True):
"""Specify if the GUI is busy.
Parameters
----------
busy : bool
If ``True`` is passed, the cursor is set to a 'busy' cursor.
Passing ``False`` will reset the cursor to the default.
"""
###########################################################################
# 'GUI' interface.
###########################################################################
def start_event_loop(self):
""" Start the GUI event loop. """
def stop_event_loop(self):
""" Stop the GUI event loop. """
class MGUI(object):
""" The mixin class that contains common code for toolkit specific
implementations of the IGUI interface.
Implements: _default_state_location()
"""
@staticmethod
def allow_interrupt():
""" Override SIGINT to prevent swallowing KeyboardInterrupt
Override the SIGINT handler to ensure the process can be
interrupted. This prevents GUI toolkits from swallowing
KeyboardInterrupt exceptions.
Warning: do not call this method if you intend your application to be
run interactively.
"""
import signal
signal.signal(signal.SIGINT, signal.SIG_DFL)
def _default_state_location(self):
""" Return the default state location. """
state_location = os.path.join(ETSConfig.application_home, 'pyface', ETSConfig.toolkit)
if not os.path.exists(state_location):
os.makedirs(state_location)
logger.debug('GUI state location is <%s>', state_location)
return state_location