Image¶

class Image(*args, **kwargs)[source]¶

Bases: bokeh.models.glyph.XYGlyph

Render images given as scalar data together with a color mapper.

In addition to the defined model properties, Image also can accept a keyword argument palette in place of an explicit color_mapper. The value should be a list of colors, or the name of one of the built-in palettes in bokeh.palettes. This palette will be used to automatically construct a ColorMapper model for the color_mapper property.

If both palette and color_mapper are passed, a ValueError exception will be raised. If neither is passed, then the Greys9 palette will be used as a default.

JSON Prototype

{
  "color_mapper": {
    "id": "16131"
  },
  "dh": {
    "field": "dh"
  },
  "dilate": false,
  "dw": {
    "field": "dw"
  },
  "global_alpha": {
    "value": 1.0
  },
  "id": "16130",
  "image": {
    "field": "image"
  },
  "js_event_callbacks": {},
  "js_property_callbacks": {},
  "name": null,
  "subscribed_events": [],
  "syncable": true,
  "tags": [],
  "x": {
    "field": "x"
  },
  "y": {
    "field": "y"
  }
}

Public Data Attributes:

`image`	The arrays of scalar data for the images to be colormapped.
`x`	The x-coordinates to locate the image anchors.
`y`	The y-coordinates to locate the image anchors.
`dw_units`	Units to use for the associated property: screen or data
`dw`	The widths of the plot regions that the images will occupy.
`dh_units`	Units to use for the associated property: screen or data
`dh`	The height of the plot region that the image will occupy.
`global_alpha`	An overall opacity that each image is rendered with (in addition to any alpha values applied explicitly in a color mapper).
`dilate`	Whether to always round fractional pixel locations in such a way as to make the images bigger.
`color_mapper`	A `ColorMapper` to use to map the scalar data from `image` into RGBA values for display.

Inherited from Model

`model_class_reverse_map`
`id`
`ref`
`struct`	A Bokeh protocol "structure" of this model, i.e. a dict of the form:.
`name`	An arbitrary, user-supplied name for this model.
`tags`	An optional list of arbitrary, user-supplied values to attach to this model.
`js_event_callbacks`	A mapping of event names to lists of `CustomJS` callbacks.
`subscribed_events`	List of events that are subscribed to by Python callbacks.
`js_property_callbacks`	A mapping of attribute names to lists of `CustomJS` callbacks, to be set up on BokehJS side when the document is created.
`syncable`	Indicates whether this model should be synchronized back to a Bokeh server when updated in a web browser.

Inherited from HasDocumentRef

document

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

Public Methods:

__init__(**kwargs)

Inherited from Glyph

parameters()

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

Inherited from Model

`__init_subclass__`()
`__new__`(cls, args, *kwargs)
`__init__`(**kwargs)
`__str__`()	Return str(self).
`__repr__`()	Return repr(self).
`destroy`()	Clean up references to the document and property
`js_on_event`(event, *callbacks)
`js_link`(attr, other, other_attr[, attr_selector])	Link two Bokeh model properties using JavaScript.
`js_on_change`(event, *callbacks)	Attach a `CustomJS` callback to an arbitrary BokehJS model event.
`on_change`(attr, *callbacks)	Add a callback on this object to trigger when `attr` changes.
`references`()	Returns all `Models` that this object has references to.
`select`(selector)	Query this object and all of its references for objects that match the given selector.
`select_one`(selector)	Query this object and all of its references for objects that match the given selector.
`set_select`(selector, updates)	Update objects that match a given selector with the specified attribute/value updates.
`to_json`(include_defaults)	Returns a dictionary of the attributes of this object, containing only "JSON types" (string, number, boolean, none, dict, list).
`to_json_string`(include_defaults)	Returns a JSON string encoding the attributes of this object.
`trigger`(attr, old, new[, hint, setter])

Inherited from HasProps

`__init__`(**kwargs)
`__setattr__`(name, value)	Intercept attribute setting on HasProps in order to special case a few situations:
`__getattr__`(name)	Intercept attribute setting on HasProps in order to special case a few situations:
`__str__`()	Return str(self).
`__repr__`()	Return repr(self).
`equals`(other)	Structural equality of models.
`static_to_serializable`(serializer)
`to_serializable`(serializer)
`set_from_json`(name, json, *[, models, setter])	Set a property value on this object from JSON.
`update`(**kwargs)	Updates the object's properties from the given keyword arguments.
`update_from_json`(json_attributes, *[, ...])	Updates the object's properties from a JSON attributes dictionary.
`lookup`(name, *[, raises])	Find the `PropertyDescriptor` for a Bokeh property on a class, given the property name.
`properties`(*[, _with_props])	Collect the names of properties on this class.
`properties_with_refs`()	Collect the names of all properties on this class that also have references.
`dataspecs`()	Collect the names of all `DataSpec` properties on this class.
`properties_with_values`(*[, ...])	Collect a dict mapping property names to their values.
`query_properties_with_values`(query, *[, ...])	Query the properties values of `HasProps` instances with a predicate.
`themed_values`()	Get any theme-provided overrides.
`apply_theme`(property_values)	Apply a set of theme values which will be used rather than defaults, but will not override application-set values.
`unapply_theme`()	Remove any themed values and restore defaults.

Inherited from HasDocumentRef

__init__(**kwargs)

Inherited from PropertyCallbackManager

`__init__`(**kwargs)
`on_change`(attr, *callbacks)	Add a callback on this object to trigger when `attr` changes.
`remove_on_change`(attr, *callbacks)	Remove a callback from this object
`trigger`(attr, old, new[, hint, setter])

Inherited from EventCallbackManager

`__init__`(**kwargs)
`on_event`(event, *callbacks)	Run callbacks when the specified event occurs on this Model

color_mapper = LinearColorMapper(id='16136', ...)¶

Type: Instance(ColorMapper)

A ColorMapper to use to map the scalar data from image into RGBA values for display.

Note

The color mapping step happens on the client.

dh = {'field': 'dh'}¶

Type: DistanceSpec

The height of the plot region that the image will occupy.

Note

This is not the number of pixels that an image is tall. That number is fixed by the image itself.

dh_units = 'data'¶

Type: Enum(SpatialUnits)

Units to use for the associated property: screen or data

dilate = False¶

Type: Bool

Whether to always round fractional pixel locations in such a way as to make the images bigger.

This setting may be useful if pixel rounding errors are causing images to have a gap between them, when they should appear flush.

dw = {'field': 'dw'}¶

Type: DistanceSpec

The widths of the plot regions that the images will occupy.

Note

This is not the number of pixels that an image is wide. That number is fixed by the image itself.

dw_units = 'data'¶

Type: Enum(SpatialUnits)

Units to use for the associated property: screen or data

global_alpha = 1.0¶

Type: NumberSpec

An overall opacity that each image is rendered with (in addition to any alpha values applied explicitly in a color mapper).

image = {'field': 'image'}¶

Type: NumberSpec

The arrays of scalar data for the images to be colormapped.

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.

x = {'field': 'x'}¶

Type: NumberSpec

The x-coordinates to locate the image anchors.

y = {'field': 'y'}¶

Type: NumberSpec

The y-coordinates to locate the image anchors.

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 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]

destroy() → None¶: Clean up references to the document and property

equals(other: bokeh.core.has_props.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 (Union[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: JSEventCallback) → 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

Example:

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

on_event(event: str | Type[Event], *callbacks: EventCallback) → 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()¶

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

Returns: list(Parameter)

classmethod properties(*, _with_props: bool = False) → Union[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[[bokeh.core.property.descriptors.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[bokeh.model.model.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, json: JSON, *, models: Dict[ID, HasProps] | None = None, setter: Setter | None = None) → None¶

Set a property value on this object from JSON.

Parameters

name – (str) : name of the attribute to set
json – (JSON-value) : value to set to the attribute to
models (dict or None, optional) –
Mapping of model ids to models (default: None)

This is needed in cases where the attributes to update also have values that have references.
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, Unknown]) → 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, Unknown] | 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_json(include_defaults: bool) → JSON¶

Returns a dictionary of the attributes of this object, containing only “JSON types” (string, number, boolean, none, dict, list).

References to other objects are serialized as “refs” (just the object ID and type info), so the deserializer will need to separately have the full attributes of those other objects.

There’s no corresponding from_json() because to deserialize an object is normally done in the context of a Document (since the Document can resolve references).

For most purposes it’s best to serialize and deserialize entire documents.

Parameters: include_defaults (bool) – whether to include attributes that haven’t been changed from the default

to_json_string(include_defaults: bool) → str¶

Returns a JSON string encoding the attributes of this object.

References to other objects are serialized as references (just the object ID and type info), so the deserializer will need to separately have the full attributes of those other objects.

There’s no corresponding from_json_string() because to deserialize an object is normally done in the context of a Document (since the Document can resolve references).

For most purposes it’s best to serialize and deserialize entire documents.

Parameters: include_defaults (bool) – whether to include attributes that haven’t been changed from the default

trigger(attr: str, old: Unknown, new: Unknown, 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)

update_from_json(json_attributes: Dict[str, JSON], *, models: Mapping[ID, HasProps] | None = None, setter: Setter | None = None) → None¶

Updates the object’s properties from a JSON attributes dictionary.

Parameters

json_attributes – (JSON-dict) : attributes and values to update
models (dict or None, optional) –
Mapping of model ids to models (default: None)

This is needed in cases where the attributes to update also have values that have references.
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

property document: Document | None¶: The Document this model is attached to (can be None)

property struct: bokeh.core.types.ReferenceJson¶

A Bokeh protocol “structure” of this model, i.e. a dict of the form:

{
    'type' : << view model name >>
    'id'   : << unique model id >>
}

Additionally there may be a subtype field if this model is a subtype.

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