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Source code for kivy.base

# 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_input_provider(self, provider, auto_remove=False): '''Add a new input provider to listen for touch events. ''' if provider not in self.input_providers: self.input_providers.append(provider) if auto_remove: self.input_providers_autoremove.append(provider)
[docs] def remove_input_provider(self, provider): '''Remove an input provider. .. versionchanged:: 2.1.0 Provider will be also removed if it exist in auto-remove list. ''' if provider in self.input_providers: self.input_providers.remove(provider) if provider in self.input_providers_autoremove: self.input_providers_autoremove.remove(provider)
[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)
[docs] def dispatch_input(self): '''Called by :meth:`EventLoopBase.idle()` to read events from input providers, pass events to postproc, and dispatch final events. ''' # first, acquire input events for provider in self.input_providers: provider.update(dispatch_fn=self._dispatch_input) # execute post-processing modules for mod in self.postproc_modules: self.input_events = mod.process(events=self.input_events) # real dispatch input input_events = self.input_events pop = input_events.pop post_dispatch_input = self.post_dispatch_input while input_events: post_dispatch_input(*pop(0))
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()