Bezier

class Bezier(*args: Any, id: ID | None = None, **kwargs: Any)

Bases: LineGlyph

Render Bezier curves.

For more information consult the Wikipedia article for Bezier curve.

Example

import numpy as np

from bokeh.io import curdoc, show
from bokeh.models import Bezier, ColumnDataSource, Grid, LinearAxis, Plot

N = 9
x = np.linspace(-2, 2, N)
y = x**2

source = ColumnDataSource(dict(
        x=x,
        y=y,
        xp02=x+0.4,
        xp01=x+0.1,
        xm01=x-0.1,
        yp01=y+0.2,
        ym01=y-0.2,
    ),
)

plot = Plot(
    title=None, width=300, height=300,
    min_border=0, toolbar_location=None)

glyph = Bezier(x0="x", y0="y", x1="xp02", y1="y", cx0="xp01", cy0="yp01", cx1="xm01", cy1="ym01", line_color="#d95f02", line_width=2)
plot.add_glyph(source, glyph)

xaxis = LinearAxis()
plot.add_layout(xaxis, 'below')

yaxis = LinearAxis()
plot.add_layout(yaxis, 'left')

plot.add_layout(Grid(dimension=0, ticker=xaxis.ticker))
plot.add_layout(Grid(dimension=1, ticker=yaxis.ticker))

curdoc().add_root(plot)

show(plot)

JSON Prototype

{
  "cx0": {
    "field": "cx0", 
    "type": "field"
  }, 
  "cx1": {
    "field": "cx1", 
    "type": "field"
  }, 
  "cy0": {
    "field": "cy0", 
    "type": "field"
  }, 
  "cy1": {
    "field": "cy1", 
    "type": "field"
  }, 
  "decorations": [], 
  "id": "p57688", 
  "js_event_callbacks": {
    "type": "map"
  }, 
  "js_property_callbacks": {
    "type": "map"
  }, 
  "line_alpha": {
    "type": "value", 
    "value": 1.0
  }, 
  "line_cap": {
    "type": "value", 
    "value": "butt"
  }, 
  "line_color": {
    "type": "value", 
    "value": "black"
  }, 
  "line_dash": {
    "type": "value", 
    "value": []
  }, 
  "line_dash_offset": {
    "type": "value", 
    "value": 0
  }, 
  "line_join": {
    "type": "value", 
    "value": "bevel"
  }, 
  "line_width": {
    "type": "value", 
    "value": 1
  }, 
  "name": null, 
  "subscribed_events": {
    "type": "set"
  }, 
  "syncable": true, 
  "tags": [], 
  "x0": {
    "field": "x0", 
    "type": "field"
  }, 
  "x1": {
    "field": "x1", 
    "type": "field"
  }, 
  "y0": {
    "field": "y0", 
    "type": "field"
  }, 
  "y1": {
    "field": "y1", 
    "type": "field"
  }
}

cx0 = Field(field='cx0', transform=Unspecified, units=Unspecified)

Type:

NumberSpec

The x-coordinates of first control points.

cx1 = Field(field='cx1', transform=Unspecified, units=Unspecified)

Type:

NumberSpec

The x-coordinates of second control points.

cy0 = Field(field='cy0', transform=Unspecified, units=Unspecified)

Type:

NumberSpec

The y-coordinates of first control points.

cy1 = Field(field='cy1', transform=Unspecified, units=Unspecified)

Type:

NumberSpec

The y-coordinates of second control points.

decorations = []

Type:

List

A collection of glyph decorations, e.g. arrow heads.

Use GlyphRenderer.add_decoration() for easy setup for all glyphs of a glyph renderer. Use this property when finer control is needed.

Note

Decorations are only for aiding visual appearance of a glyph, but they don’t participate in hit testing, etc.

line_alpha = 1.0

Type:

AlphaSpec

The line alpha values for the Bezier curves.

line_cap = 'butt'

Type:

LineCapSpec

The line cap values for the Bezier curves.

line_color = 'black'

Type:

ColorSpec

The line color values for the Bezier curves.

line_dash = []

Type:

DashPatternSpec

The line dash values for the Bezier curves.

line_dash_offset = 0

Type:

IntSpec

The line dash offset values for the Bezier curves.

line_join = 'bevel'

Type:

LineJoinSpec

The line join values for the Bezier curves.

line_width = 1

Type:

NumberSpec

The line width values for the Bezier curves.

name = None

Type:

Nullable(String)

An arbitrary, user-supplied name for this model.

This name can be useful when querying the document to retrieve specific Bokeh models.

>>> plot.circle([1,2,3], [4,5,6], name="temp")
>>> plot.select(name="temp")
[GlyphRenderer(id='399d53f5-73e9-44d9-9527-544b761c7705', ...)]

Note

No uniqueness guarantees or other conditions are enforced on any names that are provided, nor is the name used directly by Bokeh for any reason.

syncable = True

Type:

Bool

Indicates whether this model should be synchronized back to a Bokeh server when updated in a web browser. Setting to False may be useful to reduce network traffic when dealing with frequently updated objects whose updated values we don’t need.

Note

Setting this property to False will prevent any on_change() callbacks on this object from triggering. However, any JS-side callbacks will still work.

tags = []

Type:

List

An optional list of arbitrary, user-supplied values to attach to this model.

This data can be useful when querying the document to retrieve specific Bokeh models:

>>> r = plot.circle([1,2,3], [4,5,6])
>>> r.tags = ["foo", 10]
>>> plot.select(tags=['foo', 10])
[GlyphRenderer(id='1de4c3df-a83d-480a-899b-fb263d3d5dd9', ...)]

Or simply a convenient way to attach any necessary metadata to a model that can be accessed by CustomJS callbacks, etc.

Note

No uniqueness guarantees or other conditions are enforced on any tags that are provided, nor are the tags used directly by Bokeh for any reason.

x0 = Field(field='x0', transform=Unspecified, units=Unspecified)

Type:

NumberSpec

The x-coordinates of the starting points.

x1 = Field(field='x1', transform=Unspecified, units=Unspecified)

Type:

NumberSpec

The x-coordinates of the ending points.

y0 = Field(field='y0', transform=Unspecified, units=Unspecified)

Type:

NumberSpec

The y-coordinates of the starting points.

y1 = Field(field='y1', transform=Unspecified, units=Unspecified)

Type:

NumberSpec

The y-coordinates of the ending points.

apply_theme(property_values: dict[str, Any]) → None

Apply a set of theme values which will be used rather than defaults, but will not override application-set values.

The passed-in dictionary may be kept around as-is and shared with other instances to save memory (so neither the caller nor the HasProps instance should modify it).

Parameters:

property_values (dict) – theme values to use in place of defaults

Returns:

None

classmethod clear_extensions() → None

Clear any currently defined custom extensions.

Serialization calls will result in any currently defined custom extensions being included with the generated Document, whether or not there are utlized. This method can be used to clear out all existing custom extension definitions.

clone(**overrides: Any) → Self

Duplicate a HasProps object.

This creates a shallow clone of the original model, i.e. any mutable containers or child models will not be duplicated. Allows to override particular properties while cloning.

classmethod dataspecs() → dict[str, DataSpec]

Collect the names of all DataSpec properties on this class.

This method always traverses the class hierarchy and includes properties defined on any parent classes.

Returns:

names of DataSpec properties

Return type:

set[str]

classmethod descriptors() → list[PropertyDescriptor[Any]]

List of property descriptors in the order of definition.

destroy() → None

Clean up references to the document and property

equals(other: HasProps) → bool

Structural equality of models.

Parameters:

other (HasProps) – the other instance to compare to

Returns:

True, if properties are structurally equal, otherwise False

js_link(attr: str, other: Model, other_attr: str, attr_selector: int | str | None = None) → None

Link two Bokeh model properties using JavaScript.

This is a convenience method that simplifies adding a CustomJS callback to update one Bokeh model property whenever another changes value.

Parameters:

• attr (str) – The name of a Bokeh property on this model

• other (Model) – A Bokeh model to link to self.attr

• other_attr (str) – The property on other to link together

• attr_selector (int | str) – The index to link an item in a subscriptable attr

Added in version 1.1

Raises:

ValueError –

Examples

This code with js_link:

select.js_link('value', plot, 'sizing_mode')

is equivalent to the following:

from bokeh.models import CustomJS
select.js_on_change('value',
    CustomJS(args=dict(other=plot),
             code="other.sizing_mode = this.value"
    )
)

Additionally, to use attr_selector to attach the left side of a range slider to a plot’s x_range:

range_slider.js_link('value', plot.x_range, 'start', attr_selector=0)

which is equivalent to:

from bokeh.models import CustomJS
range_slider.js_on_change('value',
    CustomJS(args=dict(other=plot.x_range),
             code="other.start = this.value[0]"
    )
)

js_on_change(event: str, *callbacks: JSChangeCallback) → None

Attach a CustomJS callback to an arbitrary BokehJS model event.

On the BokehJS side, change events for model properties have the form "change:property_name". As a convenience, if the event name passed to this method is also the name of a property on the model, then it will be prefixed with "change:" automatically:

# these two are equivalent
source.js_on_change('data', callback)
source.js_on_change('change:data', callback)

However, there are other kinds of events that can be useful to respond to, in addition to property change events. For example to run a callback whenever data is streamed to a ColumnDataSource, use the "stream" event on the source:

source.js_on_change('streaming', callback)

classmethod lookup(name: str, *, raises: bool = True) → PropertyDescriptor[Any] | None

Find the PropertyDescriptor for a Bokeh property on a class, given the property name.

Parameters:

• name (str) – name of the property to search for

• raises (bool) – whether to raise or return None if missing

Returns:

descriptor for property named name

Return type:

PropertyDescriptor

on_change(attr: str, *callbacks: PropertyCallback) → None

Add a callback on this object to trigger when attr changes.

Parameters:

• attr (str) – an attribute name on this object

• *callbacks (callable) – callback functions to register

Returns:

None

Examples

widget.on_change('value', callback1, callback2, ..., callback_n)

on_event(event: str | type[Event], *callbacks: Callable[[Event], None] | Callable[[], None]) → None

Run callbacks when the specified event occurs on this Model

Not all Events are supported for all Models. See specific Events in bokeh.events for more information on which Models are able to trigger them.

classmethod parameters() → list[Parameter]

Generate Python Parameter values suitable for functions that are derived from the glyph.

Returns:

list(Parameter)

classmethod properties(*, _with_props: bool = False) → set[str] | dict[str, Property[Any]]

Collect the names of properties on this class.

Warning

In a future version of Bokeh, this method will return a dictionary mapping property names to property objects. To future-proof this current usage of this method, wrap the return value in list.

Returns:

property names

classmethod properties_with_refs() → dict[str, Property[Any]]

Collect the names of all properties on this class that also have references.

This method always traverses the class hierarchy and includes properties defined on any parent classes.

Returns:

names of properties that have references

Return type:

set[str]

properties_with_values(*, include_defaults: bool = True, include_undefined: bool = False) → dict[str, Any]

Collect a dict mapping property names to their values.

This method always traverses the class hierarchy and includes properties defined on any parent classes.

Non-serializable properties are skipped and property values are in “serialized” format which may be slightly different from the values you would normally read from the properties; the intent of this method is to return the information needed to losslessly reconstitute the object instance.

Parameters:

include_defaults (bool, optional) – Whether to include properties that haven’t been explicitly set since the object was created. (default: True)

Returns:

mapping from property names to their values

Return type:

dict

query_properties_with_values(query: Callable[[PropertyDescriptor[Any]], bool], *, include_defaults: bool = True, include_undefined: bool = False) → dict[str, Any]

Query the properties values of HasProps instances with a predicate.

Parameters:

• query (callable) – A callable that accepts property descriptors and returns True or False

• include_defaults (bool, optional) – Whether to include properties that have not been explicitly set by a user (default: True)

Returns:

mapping of property names and values for matching properties

Return type:

dict

references() → set[Model]

Returns all Models that this object has references to.

remove_on_change(attr: str, *callbacks: Callable[[str, Any, Any], None]) → None

Remove a callback from this object

select(selector: SelectorType) → Iterable[Model]

Query this object and all of its references for objects that match the given selector.

Parameters:

selector (JSON-like)

Returns:

seq[Model]

select_one(selector: SelectorType) → Model | None

Query this object and all of its references for objects that match the given selector. Raises an error if more than one object is found. Returns single matching object, or None if nothing is found :param selector: :type selector: JSON-like

Returns:

Model

set_from_json(name: str, value: Any, *, setter: Setter | None = None) → None

Set a property value on this object from JSON.

Parameters:

• name (str) – name of the attribute to set

• value (JSON-value) – value to set to the attribute to

• setter (ClientSession or ServerSession or None, optional) –

  This is used to prevent “boomerang” updates to Bokeh apps.

  In the context of a Bokeh server application, incoming updates to properties will be annotated with the session that is doing the updating. This value is propagated through any subsequent change notifications that the update triggers. The session can compare the event setter to itself, and suppress any updates that originate from itself.

Returns:

None

set_select(selector: type[Model] | SelectorType, updates: dict[str, Any]) → None

Update objects that match a given selector with the specified attribute/value updates.

Parameters:

• selector (JSON-like)

• updates (dict)

Returns:

None

themed_values() → dict[str, Any] | None

Get any theme-provided overrides.

Results are returned as a dict from property name to value, or None if no theme overrides any values for this instance.

Returns:

dict or None

to_serializable(serializer: Serializer) → ObjectRefRep

Converts this object to a serializable representation.

trigger(attr: str, old: Any, new: Any, hint: DocumentPatchedEvent | None = None, setter: Setter | None = None) → None

unapply_theme() → None

Remove any themed values and restore defaults.

Returns:

None

update(**kwargs: Any) → None

Updates the object’s properties from the given keyword arguments.

Returns:

None

Examples

The following are equivalent:

from bokeh.models import Range1d

r = Range1d

# set properties individually:
r.start = 10
r.end = 20

# update properties together:
r.update(start=10, end=20)

property document: Document | None

The Document this model is attached to (can be None)