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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 GUI for a Pyface application. """
# Standard library imports.
import sys
import logging
# Major package imports.
import wx
# Enthought library imports.
from enthought.traits.api import HasTraits, Bool
# Local imports.
from system_metrics import SystemMetrics
# Create a logger for this module.
logger = logging.getLogger(__name__)
# fixme: Shouldn't this use delegation instead of inheriting from a wx class?
class GUI(wx.PySimpleApp, HasTraits):
""" The GUI for a Pyface application. """
#### '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)
###########################################################################
# 'GUI' CLASS interface.
###########################################################################
def invoke_after(cls, millisecs, callable, *args, **kw):
""" Invokes a callable after a specific delay in the main GUI thread.
Returns the instance using which one can obtain the return value of the
callable.
fixme: This returns a wx-specific object!
"""
return wx.FutureCall(millisecs, callable, *args, **kw)
invoke_after = classmethod(invoke_after)
def invoke_later(cls, callable, *args, **kw):
""" Invokes a callable in the main GUI thread. """
wx.CallAfter(callable, *args, **kw)
return
invoke_later = classmethod(invoke_later)
def set_trait_after(cls, millisecs, obj, trait_name, new):
""" Sets a trait after a specific delay in the main GUI thread.
fixme: This returns a wx-specific object!
"""
return wx.FutureCall(millisecs, setattr, obj, trait_name, new)
set_trait_after = classmethod(set_trait_after)
def set_trait_later(cls, obj, trait_name, new):
""" Sets a trait in the main GUI thread. """
wx.CallAfter(setattr, obj, trait_name, new)
return
set_trait_later = classmethod(set_trait_later)
def process_events(allow_user_events=True):
""" Process any pending GUI events. If allow_user_events is False then
user generated events are not processed.
"""
if allow_user_events:
wx.Yield()
else:
wx.SafeYield()
process_events = staticmethod(process_events)
def set_busy(busy=True):
"""Specify if the GUI is busy. If `True` is passed, the
cursor is set to a 'busy' cursor. Passing `False` will reset
the cursor to the default.
"""
if busy:
GUI._cursor = wx.BusyCursor()
else:
GUI._cursor = None
set_busy = staticmethod(set_busy)
###########################################################################
# 'object' interface.
###########################################################################
def __init__(self, splash_screen=None, redirect=False, filename=None):
""" Creates a new GUI. """
# The (optional) splash screen.
#
# fixme: For now, we have disabled splash screens on non-Windows
# platforms as on Linux they cause the application to hang when they
# are supposed to close (allegedly, this is for applications that use
# the workbench plugin).
if sys.platform == 'win32':
self._splash_screen = splash_screen
else:
logger.warn('splash screen disabled on non-Windows platforms')
self._splash_screen = None
# The system metrics.
self.system_metrics = SystemMetrics()
# Base-class constructor.
wx.PySimpleApp.__init__(self, redirect=redirect, filename=filename)
return
###########################################################################
# 'Wx.App' interface.
###########################################################################
def OnInit(self):
""" wx application initialization. """
logger.debug("---------- starting GUI ---------- ")
# Before we can load any images we have to initialize wxPython's image
# handlers.
wx.InitAllImageHandlers()
# Show the (optional) splash screen.
if self._splash_screen is not None:
self._splash_screen.open()
return True
def OnExit(self):
""" Called when the user wants to exit the application.
OnExit() is called after destroying all application windows and
controls, but before wxWindows cleanup.
"""
logger.debug("---------- exiting GUI ---------- ")
return
###########################################################################
# 'GUI' interface.
###########################################################################
def start_event_loop(self):
""" Start the GUI event loop. """
if self._splash_screen is not None:
self._splash_screen.close()
logger.debug("---------- starting GUI event loop ---------- ")
# Make sure that we only set the 'started' trait after the main loop
# has really started.
self.invoke_after(10, setattr, self, "started", True)
# A hack to force menus to appear for applications run on Mac
# OS X.
if sys.platform == 'darwin':
def _mac_os_x_hack():
f = wx.Frame(None, -1)
f.Show(True)
f.Close()
self.invoke_later(_mac_os_x_hack)
self.MainLoop()
self.started = False
return
def stop_event_loop(self):
""" Stop the GUI event loop. """
self.ExitMainLoop()
return
#### Deprecated ###########################################################
def event_loop(self):
""" Start the GUI event loop. """
logger.debug('DEPRECATED: Use GUI.start_event_loop')
self.start_event_loop()
return
###########################################################################
# Private 'GUI' interface.
###########################################################################
#### Trait change handlers ################################################
def _busy_changed(self):
""" Static trait change handler. """
if self.busy:
self._cursor = wx.BusyCursor()
else:
del self._cursor
return
#### EOF ######################################################################
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