# pylint: disable=W0611
'''
Kivy Base
=========
This module contains the Kivy core functionality and is not intended for end
users. Feel free to look through it, but bare in mind that calling any of
these methods directly may result in an unpredictable behavior as the calls
access directly the event loop of an application.
'''
__all__ = (
'EventLoop',
'EventLoopBase',
'ExceptionHandler',
'ExceptionManagerBase',
'ExceptionManager',
'runTouchApp',
'async_runTouchApp',
'stopTouchApp',
)
import sys
import os
from kivy.config import Config
from kivy.logger import Logger
from kivy.utils import platform
from kivy.clock import Clock
from kivy.event import EventDispatcher
from kivy.lang import Builder
from kivy.context import register_context
# private vars
EventLoop = None
[docs]class ExceptionHandler(object):
'''Base handler that catches exceptions in :func:`runTouchApp`.
You can subclass and extend it as follows::
class E(ExceptionHandler):
def handle_exception(self, inst):
Logger.exception('Exception caught by ExceptionHandler')
return ExceptionManager.PASS
ExceptionManager.add_handler(E())
Then, all exceptions will be set to PASS, and logged to the console!
'''
[docs] def handle_exception(self, exception):
'''Called by :class:`ExceptionManagerBase` to handle a exception.
Defaults to returning :attr:`ExceptionManager.RAISE` that re-raises the
exception. Return :attr:`ExceptionManager.PASS` to indicate that the
exception was handled and should be ignored.
This may be called multiple times with the same exception, if
:attr:`ExceptionManager.RAISE` is returned as the exception bubbles
through multiple kivy exception handling levels.
'''
return ExceptionManager.RAISE
[docs]class ExceptionManagerBase:
'''ExceptionManager manages exceptions handlers.'''
RAISE = 0
"""The exception should be re-raised.
"""
PASS = 1
"""The exception should be ignored as it was handled by the handler.
"""
def __init__(self):
self.handlers = []
self.policy = ExceptionManagerBase.RAISE
[docs] def add_handler(self, cls):
'''Add a new exception handler to the stack.'''
if cls not in self.handlers:
self.handlers.append(cls)
[docs] def remove_handler(self, cls):
'''Remove the exception handler from the stack.'''
if cls in self.handlers:
self.handlers.remove(cls)
[docs] def handle_exception(self, inst):
'''Called when an exception occurred in the :func:`runTouchApp`
main loop.'''
ret = self.policy
for handler in self.handlers:
r = handler.handle_exception(inst)
if r == ExceptionManagerBase.PASS:
ret = r
return ret
#: Instance of a :class:`ExceptionManagerBase` implementation.
ExceptionManager: ExceptionManagerBase = register_context(
'ExceptionManager', ExceptionManagerBase)
"""The :class:`ExceptionManagerBase` instance that handles kivy exceptions.
"""
[docs]class EventLoopBase(EventDispatcher):
'''Main event loop. This loop handles the updating of input and
dispatching events.
'''
__events__ = ('on_start', 'on_pause', 'on_stop')
def __init__(self):
super(EventLoopBase, self).__init__()
self.quit = False
self.input_events = []
self.postproc_modules = []
self.status = 'idle'
self.stopping = False
self.input_providers = []
self.input_providers_autoremove = []
self.event_listeners = []
self.window = None
self.me_list = []
@property
def touches(self):
'''Return the list of all touches currently in down or move states.
'''
return self.me_list
[docs] def ensure_window(self):
'''Ensure that we have a window.
'''
import kivy.core.window # NOQA
if not self.window:
Logger.critical('App: Unable to get a Window, abort.')
sys.exit(1)
[docs] def set_window(self, window):
'''Set the window used for the event loop.
'''
self.window = window
[docs] def add_event_listener(self, listener):
'''Add a new event listener for getting touch events.
'''
if listener not in self.event_listeners:
self.event_listeners.append(listener)
[docs] def remove_event_listener(self, listener):
'''Remove an event listener from the list.
'''
if listener in self.event_listeners:
self.event_listeners.remove(listener)
[docs] def start(self):
'''Must be called before :meth:`EventLoopBase.run()`. This starts all
configured input providers.
.. versionchanged:: 2.1.0
Method can be called multiple times, but event loop will start only
once.
'''
if self.status == 'started':
return
self.status = 'started'
self.quit = False
Clock.start_clock()
for provider in self.input_providers:
provider.start()
self.dispatch('on_start')
[docs] def close(self):
'''Exit from the main loop and stop all configured
input providers.'''
self.quit = True
self.stop()
self.status = 'closed'
[docs] def stop(self):
'''Stop all input providers and call callbacks registered using
`EventLoop.add_stop_callback()`.
.. versionchanged:: 2.1.0
Method can be called multiple times, but event loop will stop only
once.
'''
if self.status != 'started':
return
# XXX stop in reverse order that we started them!! (like push
# pop), very important because e.g. wm_touch and WM_PEN both
# store old window proc and the restore, if order is messed big
# problem happens, crashing badly without error
for provider in reversed(self.input_providers[:]):
provider.stop()
self.remove_input_provider(provider)
# ensure any restart will not break anything later.
self.input_events = []
Clock.stop_clock()
self.stopping = False
self.status = 'stopped'
self.dispatch('on_stop')
[docs] def add_postproc_module(self, mod):
'''Add a postproc input module (DoubleTap, TripleTap, DeJitter
RetainTouch are defaults).'''
if mod not in self.postproc_modules:
self.postproc_modules.append(mod)
[docs] def remove_postproc_module(self, mod):
'''Remove a postproc module.'''
if mod in self.postproc_modules:
self.postproc_modules.remove(mod)
[docs] def remove_android_splash(self, *args):
'''Remove android presplash in SDL2 bootstrap.'''
try:
from android import remove_presplash
remove_presplash()
except ImportError:
Logger.warning(
'Base: Failed to import "android" module. '
'Could not remove android presplash.')
return
[docs] def post_dispatch_input(self, etype, me):
'''This function is called by :meth:`EventLoopBase.dispatch_input()`
when we want to dispatch an input event. The event is dispatched to
all listeners and if grabbed, it's dispatched to grabbed widgets.
'''
# update available list
if etype == 'begin':
self.me_list.append(me)
elif etype == 'end':
if me in self.me_list:
self.me_list.remove(me)
# dispatch to listeners
if not me.grab_exclusive_class:
for listener in self.event_listeners:
listener.dispatch('on_motion', etype, me)
# dispatch grabbed touch
if not me.is_touch:
# Non-touch event must be handled by the event manager
return
me.grab_state = True
for weak_widget in me.grab_list[:]:
# weak_widget is a weak reference to widget
wid = weak_widget()
if wid is None:
# object is gone, stop.
me.grab_list.remove(weak_widget)
continue
root_window = wid.get_root_window()
if wid != root_window and root_window is not None:
me.push()
try:
root_window.transform_motion_event_2d(me, wid)
except AttributeError:
me.pop()
continue
me.grab_current = wid
wid._context.push()
if etype == 'begin':
# don't dispatch again touch in on_touch_down
# a down event are nearly uniq here.
# wid.dispatch('on_touch_down', touch)
pass
elif etype == 'update':
if wid._context.sandbox:
with wid._context.sandbox:
wid.dispatch('on_touch_move', me)
else:
wid.dispatch('on_touch_move', me)
elif etype == 'end':
if wid._context.sandbox:
with wid._context.sandbox:
wid.dispatch('on_touch_up', me)
else:
wid.dispatch('on_touch_up', me)
wid._context.pop()
me.grab_current = None
if wid != root_window and root_window is not None:
me.pop()
me.grab_state = False
me.dispatch_done()
def _dispatch_input(self, *ev):
# remove the save event for the touch if exist
if ev in self.input_events:
self.input_events.remove(ev)
self.input_events.append(ev)
def mainloop(self):
while not self.quit and self.status == 'started':
try:
self.idle()
if self.window:
self.window.mainloop()
except BaseException as inst:
# use exception manager first
r = ExceptionManager.handle_exception(inst)
if r == ExceptionManager.RAISE:
stopTouchApp()
raise
else:
pass
async def async_mainloop(self):
while not self.quit and self.status == 'started':
try:
await self.async_idle()
if self.window:
self.window.mainloop()
except BaseException as inst:
# use exception manager first
r = ExceptionManager.handle_exception(inst)
if r == ExceptionManager.RAISE:
stopTouchApp()
raise
else:
pass
Logger.info("Window: exiting mainloop and closing.")
self.close()
[docs] def idle(self):
'''This function is called after every frame. By default:
* it "ticks" the clock to the next frame.
* it reads all input and dispatches events.
* it dispatches `on_update`, `on_draw` and `on_flip` events to the
window.
'''
# update dt
Clock.tick()
# read and dispatch input from providers
if not self.quit:
self.dispatch_input()
# flush all the canvas operation
if not self.quit:
Builder.sync()
# tick before draw
if not self.quit:
Clock.tick_draw()
# flush all the canvas operation
if not self.quit:
Builder.sync()
if not self.quit:
window = self.window
if window and window.canvas.needs_redraw:
window.dispatch('on_draw')
window.dispatch('on_flip')
# don't loop if we don't have listeners !
if len(self.event_listeners) == 0:
Logger.error('Base: No event listeners have been created')
Logger.error('Base: Application will leave')
self.exit()
return False
return self.quit
[docs] async def async_idle(self):
'''Identical to :meth:`idle`, but instead used when running
within an async event loop.
'''
# update dt
await Clock.async_tick()
# read and dispatch input from providers
if not self.quit:
self.dispatch_input()
# flush all the canvas operation
if not self.quit:
Builder.sync()
# tick before draw
if not self.quit:
Clock.tick_draw()
# flush all the canvas operation
if not self.quit:
Builder.sync()
if not self.quit:
window = self.window
if window and window.canvas.needs_redraw:
window.dispatch('on_draw')
window.dispatch('on_flip')
# don't loop if we don't have listeners !
if len(self.event_listeners) == 0:
Logger.error('Base: No event listeners have been created')
Logger.error('Base: Application will leave')
self.exit()
return False
return self.quit
[docs] def run(self):
'''Main loop'''
while not self.quit:
self.idle()
self.exit()
[docs] def exit(self):
'''Close the main loop and close the window.'''
self.close()
if self.window:
self.window.close()
[docs] def on_stop(self):
'''Event handler for `on_stop` events which will be fired right
after all input providers have been stopped.'''
pass
[docs] def on_pause(self):
'''Event handler for `on_pause` which will be fired when
the event loop is paused.'''
pass
[docs] def on_start(self):
'''Event handler for `on_start` which will be fired right
after all input providers have been started.'''
pass
#: EventLoop instance
EventLoop = EventLoopBase()
def _runTouchApp_prepare(widget=None):
from kivy.input import MotionEventFactory, kivy_postproc_modules
# Ok, we got one widget, and we are not in embedded mode
# so, user don't create the window, let's create it for him !
if widget:
EventLoop.ensure_window()
# Instance all configured input
for key, value in Config.items('input'):
Logger.debug('Base: Create provider from %s' % (str(value)))
# split value
args = str(value).split(',', 1)
if len(args) == 1:
args.append('')
provider_id, args = args
provider = MotionEventFactory.get(provider_id)
if provider is None:
Logger.warning('Base: Unknown <%s> provider' % str(provider_id))
continue
# create provider
p = provider(key, args)
if p:
EventLoop.add_input_provider(p, True)
# add postproc modules
for mod in list(kivy_postproc_modules.values()):
EventLoop.add_postproc_module(mod)
# add main widget
if widget and EventLoop.window:
if widget not in EventLoop.window.children:
EventLoop.window.add_widget(widget)
# start event loop
Logger.info('Base: Start application main loop')
EventLoop.start()
# remove presplash on the next frame
if platform == 'android':
Clock.schedule_once(EventLoop.remove_android_splash)
# in non-embedded mode, there are 2 issues
#
# 1. if user created a window, call the mainloop from window.
# This is due to glut, it need to be called with
# glutMainLoop(). Only FreeGLUT got a gluMainLoopEvent().
# So, we are executing the dispatching function inside
# a redisplay event.
#
# 2. if no window is created, we are dispatching event loop
# ourself (previous behavior.)
#
[docs]def runTouchApp(widget=None, embedded=False):
'''Static main function that starts the application loop.
You can access some magic via the following arguments:
See :mod:`kivy.app` for example usage.
:Parameters:
`<empty>`
To make dispatching work, you need at least one
input listener. If not, application will leave.
(MTWindow act as an input listener)
`widget`
If you pass only a widget, a MTWindow will be created
and your widget will be added to the window as the root
widget.
`embedded`
No event dispatching is done. This will be your job.
`widget + embedded`
No event dispatching is done. This will be your job but
we try to get the window (must be created by you beforehand)
and add the widget to it. Very useful for embedding Kivy
in another toolkit. (like Qt, check kivy-designed)
'''
_runTouchApp_prepare(widget=widget)
# we are in embedded mode, don't do dispatching.
if embedded:
return
try:
EventLoop.mainloop()
finally:
stopTouchApp()
[docs]async def async_runTouchApp(widget=None, embedded=False, async_lib=None):
'''Identical to :func:`runTouchApp` but instead it is a coroutine
that can be run in an existing async event loop.
``async_lib`` is the async library to use. See :mod:`kivy.app` for details
and example usage.
.. versionadded:: 2.0.0
'''
if async_lib is not None:
Clock.init_async_lib(async_lib)
_runTouchApp_prepare(widget=widget)
# we are in embedded mode, don't do dispatching.
if embedded:
return
try:
await EventLoop.async_mainloop()
finally:
stopTouchApp()
[docs]def stopTouchApp():
'''Stop the current application by leaving the main loop.
See :mod:`kivy.app` for example usage.
'''
if EventLoop is None:
return
if EventLoop.status in ('stopped', 'closed'):
return
if EventLoop.status != 'started':
if not EventLoop.stopping:
EventLoop.stopping = True
Clock.schedule_once(lambda dt: stopTouchApp(), 0)
return
Logger.info('Base: Leaving application in progress...')
EventLoop.close()
