#----------------------------------------------------------------------------- # Copyright (c) 2012 - 2019, Anaconda, Inc., and Bokeh Contributors. # All rights reserved. # # The full license is in the file LICENSE.txt, distributed with this software. #----------------------------------------------------------------------------- ''' Represent granular events that can be used to trigger callbacks. Bokeh documents and applications are capable of supporting various kinds of interactions. These are often associated with events, such as mouse or touch events, interactive downsampling mode activation, widget or tool events, and others. The classes in this module represent these different events, so that callbacks can be attached and executed when they occur. It is possible to respond to events with ``CustomJS`` callbacks, which will function with or without a Bokeh server. This can be accomplished by passing and event class, and a ``CustomJS`` model to the :func:`~bokeh.model.Model.js_on_event` method. When the ``CustomJS`` is executed in the browser, its ``cb_obj`` argument will contain the concrete event object that triggered the callback. .. code-block:: python from bokeh.events import ButtonClick from bokeh.models import Button, CustomJS button = Button() button.js_on_event(ButtonClick, CustomJS(code='console.log("JS:Click")')) Alternatively it is possible to trigger Python code to run when events happen, in the context of a Bokeh application running on a Bokeh server. This can accomplished by passing an event class, and a callback function to the the :func:`~bokeh.model.Model.on_event` method. The callback should accept a single argument ``event``, which will be passed the concrete event object that triggered the callback. .. code-block:: python from bokeh.events import ButtonClick from bokeh.models import Button button = Button() def callback(event): print('Python:Click') button.on_event(ButtonClick, callback) .. note :: There is no throttling of events. Some events such as ``MouseMove`` may trigger at a very high rate. ''' #----------------------------------------------------------------------------- # Boilerplate #----------------------------------------------------------------------------- from __future__ import absolute_import, division, print_function, unicode_literals import logging log = logging.getLogger(__name__) #----------------------------------------------------------------------------- # Imports #----------------------------------------------------------------------------- # Standard library imports # External imports # Bokeh imports from .util.future import with_metaclass #----------------------------------------------------------------------------- # Globals and constants #----------------------------------------------------------------------------- __all__ = ( 'ButtonClick', 'DoubleTap', 'Event', 'LODStart', 'LODEnd', 'MenuItemClick', 'MouseEnter', 'MouseLeave', 'MouseMove', 'MouseWheel', 'Pan', 'PanEnd', 'PanStart', 'Pinch', 'PinchEnd', 'PinchStart', 'Rotate', 'RotateEnd', 'RotateStart', 'PlotEvent', 'PointEvent', 'Press', 'PressUp', 'Reset', 'SelectionGeometry', 'Tap', ) #----------------------------------------------------------------------------- # Private API #----------------------------------------------------------------------------- _CONCRETE_EVENT_CLASSES = dict() class _MetaEvent(type): ''' Metaclass used to keep track of all classes subclassed from Event. All Concrete Event classes (i.e. not "abstract" event base classes with no ``event_name``) will be added to the _CONCRETE_EVENT_CLASSES set which is used to decode event instances from JSON. ''' def __new__(cls, clsname, bases, attrs): newclass = super(_MetaEvent, cls).__new__(cls, clsname, bases, attrs) if newclass.event_name is not None: _CONCRETE_EVENT_CLASSES[newclass.event_name] = newclass return newclass #----------------------------------------------------------------------------- # General API #----------------------------------------------------------------------------- [docs]class Event(with_metaclass(_MetaEvent, object)): ''' Base class for all Bokeh events. This base class is not typically useful to instantiate on its own. ''' _event_classes = [] event_name = None [docs] def __init__(self, model): ''' Create a new base event. Args: model (Model) : a Bokeh model to register event callbacks on ''' self._model_id = None if model is not None: self._model_id = model.id [docs] @classmethod def decode_json(cls, dct): ''' Custom JSON decoder for Events. Can be used as the ``object_hook`` argument of ``json.load`` or ``json.loads``. Args: dct (dict) : a JSON dictionary to decode The dictionary should have keys ``event_name`` and ``event_values`` Raises: ValueError, if the event_name is unknown Examples: .. code-block:: python >>> import json >>> from bokeh.events import Event >>> data = '{"event_name": "pan", "event_values" : {"model_id": 1, "x": 10, "y": 20, "sx": 200, "sy": 37}}' >>> json.loads(data, object_hook=Event.decode_json) <bokeh.events.Pan object at 0x1040f84a8> ''' if not ('event_name' in dct and 'event_values' in dct): return dct event_name = dct['event_name'] if event_name not in _CONCRETE_EVENT_CLASSES: raise ValueError("Could not find appropriate Event class for event_name: %r" % event_name) event_values = dct['event_values'] model_id = event_values.pop('model_id') event = _CONCRETE_EVENT_CLASSES[event_name](model=None, **event_values) event._model_id = model_id return event [docs]class ButtonClick(Event): ''' Announce a button click event on a Bokeh button widget. ''' event_name = 'button_click' def __init__(self, model): from .models.widgets import AbstractButton if model is not None and not isinstance(model, AbstractButton): msg ='{clsname} event only applies to button models' raise ValueError(msg.format(clsname=self.__class__.__name__)) super(ButtonClick, self).__init__(model=model) [docs]class MenuItemClick(Event): ''' Announce a button click event on a Bokeh menu item. ''' event_name = 'menu_item_click' def __init__(self, model, item=None): self.item = item super(MenuItemClick, self).__init__(model=model) [docs]class PlotEvent(Event): ''' The base class for all events applicable to Plot models. ''' def __init__(self, model): from .models import Plot if model is not None and not isinstance(model, Plot): msg ='{clsname} event only applies to Plot models' raise ValueError(msg.format(clsname=self.__class__.__name__)) super(PlotEvent, self).__init__(model=model) [docs]class LODStart(PlotEvent): ''' Announce the start of "interactive level-of-detail" mode on a plot. During interactive actions such as panning or zooming, Bokeh can optionally, temporarily draw a reduced set of the data, in order to maintain high interactive rates. This is referred to as interactive Level-of-Detail (LOD) mode. This event fires whenever a LOD mode has just begun. ''' event_name = 'lodstart' [docs]class LODEnd(PlotEvent): ''' Announce the end of "interactive level-of-detail" mode on a plot. During interactive actions such as panning or zooming, Bokeh can optionally, temporarily draw a reduced set of the data, in order to maintain high interactive rates. This is referred to as interactive Level-of-Detail (LOD) mode. This event fires whenever a LOD mode has just ended. ''' event_name = 'lodend' [docs]class SelectionGeometry(PlotEvent): ''' Announce the coordinates of a selection event on a plot. Attributes: geometry (dict) : a dictionary containing the coordinates of the selection event. final (bool) : whether the selection event is the last selection event in the case of selections on every mousemove. ''' event_name = "selectiongeometry" def __init__(self, model, geometry=None, final=True): self.geometry = geometry self.final = final super(SelectionGeometry, self).__init__(model=model) [docs]class Reset(PlotEvent): ''' Announce a button click event on a plot ``ResetTool``. ''' event_name = "reset" def __init__(self, model): super(Reset, self).__init__(model=model) [docs]class PointEvent(PlotEvent): ''' Base class for UI events associated with a specific (x,y) point. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space Note that data space coordinates are relative to the default range, not any extra ranges, and the the screen space origin is at the top left of the HTML canvas. ''' event_name = None def __init__(self, model, sx=None, sy=None, x=None, y=None): self.sx = sx self.sy = sy self.x = x self.y = y super(PointEvent, self).__init__(model=model) [docs]class Tap(PointEvent): ''' Announce a tap or click event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space ''' event_name = 'tap' [docs]class DoubleTap(PointEvent): ''' Announce a double-tap or double-click event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space ''' event_name = 'doubletap' [docs]class Press(PointEvent): ''' Announce a press event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space ''' event_name = 'press' [docs]class PressUp(PointEvent): ''' Announce a pressup event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space ''' event_name = 'pressup' [docs]class MouseEnter(PointEvent): ''' Announce a mouse enter event onto a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: The enter event is generated when the mouse leaves the entire Plot canvas, including any border padding and space for axes or legends. ''' event_name = 'mouseenter' [docs]class MouseLeave(PointEvent): ''' Announce a mouse leave event from a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: The leave event is generated when the mouse leaves the entire Plot canvas, including any border padding and space for axes or legends. ''' event_name = 'mouseleave' [docs]class MouseMove(PointEvent): ''' Announce a mouse movement event over a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: This event can fire at a very high rate, potentially increasing network traffic or CPU load. ''' event_name = 'mousemove' [docs]class MouseWheel(PointEvent): ''' Announce a mouse wheel event on a Bokeh plot. Attributes: delta (float) : the (signed) scroll speed sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: By default, Bokeh plots do not prevent default scroll events unless a ``WheelZoomTool`` or ``WheelPanTool`` is active. This may change in future releases. ''' event_name = 'wheel' def __init__(self, model, delta=None, **kwargs): self.delta = delta super(MouseWheel, self).__init__(model, **kwargs) [docs]class Pan(PointEvent): ''' Announce a pan event on a Bokeh plot. Attributes: delta_x (float) : the amount of scroll in the x direction delta_y (float) : the amount of scroll in the y direction direction (float) : the direction of scroll (1 or -1) sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space ''' event_name = 'pan' def __init__(self, model, delta_x=None, delta_y=None, direction=None, **kwargs): self.delta_x = delta_x self.delta_y = delta_y self.direction = direction super(Pan, self).__init__(model, **kwargs) [docs]class PanEnd(PointEvent): ''' Announce the end of a pan event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space ''' event_name = 'panend' [docs]class PanStart(PointEvent): ''' Announce the start of a pan event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space ''' event_name = 'panstart' [docs]class Pinch(PointEvent): ''' Announce a pinch event on a Bokeh plot. Attributes: scale (float) : the (signed) amount of scaling sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: This event is only applicable for touch-enabled devices. ''' event_name = 'pinch' def __init__(self, model, scale=None, **kwargs): self.scale = scale super(Pinch, self).__init__(model, **kwargs) [docs]class PinchEnd(PointEvent): ''' Announce the end of a pinch event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: This event is only applicable for touch-enabled devices. ''' event_name = 'pinchend' [docs]class PinchStart(PointEvent): ''' Announce the start of a pinch event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: This event is only applicable for touch-enabled devices. ''' event_name = 'pinchstart' [docs]class Rotate(PointEvent): ''' Announce a rotate event on a Bokeh plot. Attributes: rotation (float) : the rotation that has been done (in deg) sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: This event is only applicable for touch-enabled devices. ''' event_name = 'rotate' def __init__(self, model, rotation=None, **kwargs): self.rotation = rotation super(Rotate, self).__init__(model, **kwargs) [docs]class RotateEnd(PointEvent): ''' Announce the end of a rotate event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: This event is only applicable for touch-enabled devices. ''' event_name = 'rotateend' [docs]class RotateStart(PointEvent): ''' Announce the start of a rotate event on a Bokeh plot. Attributes: sx (float) : x-coordinate of the event in *screen* space sy (float) : y-coordinate of the event in *screen* space x (float) : x-coordinate of the event in *data* space y (float) : y-coordinate of the event in *data* space .. note:: This event is only applicable for touch-enabled devices. ''' event_name = 'rotatestart' #----------------------------------------------------------------------------- # Dev API #----------------------------------------------------------------------------- #----------------------------------------------------------------------------- # Code #-----------------------------------------------------------------------------