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 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.
CustomJS
js_on_event()
cb_obj
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 on_event() method. The callback should accept a single argument event, which will be passed the concrete event object that triggered the callback.
on_event()
event
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.
MouseMove
ButtonClick
Announce a button click event on a Bokeh button widget.
DocumentEvent
Base class for all Bokeh Document events.
This base class is not typically useful to instantiate on its own.
DocumentReady
Announce when a Document is fully idle.
DoubleTap
Announce a double-tap or double-click event on a Bokeh plot.
sx
x-coordinate of the event in screen space
float
sy
y-coordinate of the event in screen space
x
x-coordinate of the event in data space
y
y-coordinate of the event in data space
Event
Base class for all Bokeh events.
decode_json
Custom JSON decoder for Events.
Can be used as the object_hook argument of json.load or json.loads.
object_hook
json.load
json.loads
dct (dict) – a JSON dictionary to decode The dictionary should have keys event_name and event_values
event_name
event_values
ValueError, if the event_name is unknown –
Examples
>>> 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>
LODEnd
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.
LODStart
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.
MenuItemClick
Announce a button click event on a Bokeh menu item.
ModelEvent
Base class for all Bokeh Model events.
__init__
Create a new base event.
model (Model) – a Bokeh model to register event callbacks on
MouseEnter
Announce a mouse enter event onto a Bokeh plot.
The enter event is generated when the mouse leaves the entire Plot canvas, including any border padding and space for axes or legends.
MouseLeave
Announce a mouse leave event from a Bokeh plot.
The leave event is generated when the mouse leaves the entire Plot canvas, including any border padding and space for axes or legends.
Announce a mouse movement event over a Bokeh plot.
This event can fire at a very high rate, potentially increasing network traffic or CPU load.
MouseWheel
Announce a mouse wheel event on a Bokeh plot.
delta
the (signed) scroll speed
By default, Bokeh plots do not prevent default scroll events unless a WheelZoomTool or WheelPanTool is active. This may change in future releases.
WheelZoomTool
WheelPanTool
Pan
Announce a pan event on a Bokeh plot.
delta_x
the amount of scroll in the x direction
delta_y
the amount of scroll in the y direction
direction
the direction of scroll (1 or -1)
PanEnd
Announce the end of a pan event on a Bokeh plot.
PanStart
Announce the start of a pan event on a Bokeh plot.
Pinch
Announce a pinch event on a Bokeh plot.
scale
the (signed) amount of scaling
This event is only applicable for touch-enabled devices.
PinchEnd
Announce the end of a pinch event on a Bokeh plot.
PinchStart
Announce the start of a pinch event on a Bokeh plot.
PlotEvent
The base class for all events applicable to Plot models.
PointEvent
Base class for UI events associated with a specific (x,y) point.
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.
Press
Announce a press event on a Bokeh plot.
PressUp
Announce a pressup event on a Bokeh plot.
Reset
Announce a button click event on a plot ResetTool.
ResetTool
Rotate
Announce a rotate event on a Bokeh plot.
rotation
the rotation that has been done (in deg)
RotateEnd
Announce the end of a rotate event on a Bokeh plot.
RotateStart
Announce the start of a rotate event on a Bokeh plot.
SelectionGeometry
Announce the coordinates of a selection event on a plot.
geometry
a dictionary containing the coordinates of the selection event.
dict
final
whether the selection event is the last selection event in the case of selections on every mousemove.
bool
Tap
Announce a tap or click event on a Bokeh plot.