bokeh.models.HoverTool#

class HoverTool(*args: Any, id: ID | None = None, **kwargs: Any)[source]#

Bases: InspectTool

toolbar icon:

The hover tool is a passive inspector tool. It is generally on at all times, but can be configured in the inspector’s menu associated with the toolbar icon shown above.

By default, the hover tool displays informational tooltips whenever the cursor is directly over a glyph. The data to show comes from the glyph’s data source, and what to display is configurable with the tooltips property that maps display names to columns in the data source, or to special known variables.

Here is an example of how to configure and use the hover tool:

# Add tooltip (name, field) pairs to the tool. See below for a
# description of possible field values.
hover.tooltips = [
    ("index", "$index"),
    ("(x,y)", "($x, $y)"),
    ("radius", "@radius"),
    ("fill color", "$color[hex, swatch]:fill_color"),
    ("fill color", "$color[hex]:fill_color"),
    ("fill color", "$color:fill_color"),
    ("fill color", "$swatch:fill_color"),
    ("foo", "@foo"),
    ("bar", "@bar"),
    ("baz", "@baz{safe}"),
    ("total", "@total{$0,0.00}"),
]

You can also supply a Callback to the HoverTool, to build custom interactions on hover. In this case you may want to turn the tooltips off by setting tooltips=None.

Warning

When supplying a callback or custom template, the explicit intent of this Bokeh Model is to embed raw HTML and JavaScript code for a browser to execute. If any part of the code is derived from untrusted user inputs, then you must take appropriate care to sanitize the user input prior to passing to Bokeh.

Hover tool does not currently work with the following glyphs:

annulus
arc
bezier
image_url

oval
patch
quadratic

ray
step
text

Property index#
`anchor`	`attachment`
`callback`	`description`
`filters`	`formatters`
`group`	`icon`
`limit`	`line_policy`
`mode`	`muted_policy`
`name`	`point_policy`
`renderers`	`show_arrow`
`sort_by`	`syncable`
`tags`	`toggleable`
`tooltips`	`visible`
`document`

Properties#

anchor = 'center'#

Type:: Enum(Anchor)

If point policy is set to “snap_to_data”, anchor defines the attachment point of a tooltip. The default is to attach to the center of a glyph.

attachment = 'horizontal'#

Type:: Enum(TooltipAttachment)

Whether the tooltip should be displayed to the left or right of the cursor position or above or below it, or if it should be automatically placed in the horizontal or vertical dimension.

callback = None#

Type:: Nullable(Instance(Callback))

A callback to run in the browser whenever the input’s value changes. The cb_data parameter that is available to the Callback code will contain two HoverTool specific fields:

Index:: object containing the indices of the hovered points in the data source
Geometry:: object containing the coordinates of the hover cursor

description = None#

Type:: Nullable(String)

A string describing the purpose of this tool. If not defined, an auto-generated description will be used. This description will be typically presented in the user interface as a tooltip.

filters = {}#

Type:: Dict(String, Either(Instance(CustomJS), List))

Allows filtering hover results using a CustomJS callback.

An example of a simple filter function: .. code:

filter = '''
    export default (args, tool, {value: x, row, index, field, data_source, vars}) => {
        return x >= 0
    }
'''
HoverTool(filters={"@x": CustomJS(args={}, code=filter)})

formatters = {}#

Type:: Dict(

String,

Either(

Enum(TooltipFieldFormatter),

Instance(CustomJSHover)

)

)

Specify the formatting scheme for data source columns, e.g.

tool.formatters = {"@date": "datetime"}

will cause format specifications for the “date” column to be interpreted according to the “datetime” formatting scheme. The following schemes are available:

“numeral”:: Provides a wide variety of formats for numbers, currency, bytes, times, and percentages. The full set of formats can be found in the NumeralTickFormatter reference documentation.
“datetime”:: Provides formats for date and time values. The full set of formats is listed in the DatetimeTickFormatter reference documentation.
“printf”:: Provides formats similar to C-style “printf” type specifiers. See the PrintfTickFormatter reference documentation for complete details.

If no formatter is specified for a column name, the default "numeral" formatter is assumed.

group = True#

Type:: Either(String, Bool)

The name of the group this tool belongs to.

By default set to True, indicating the default group. If set to False, it will prevent the tool from being grouped altogether (regardless of Toolbar.group setting).

icon = None#

Type:: Nullable(

Either(

Image,

Enum(ToolIcon),

Regex,

Regex,

Regex

)

)

An icon to display in the toolbar.

The icon can provided as well known tool icon name, a CSS class selector, a data URI with an image/* MIME, a path to an image, a PIL Image object, or an RGB(A) NumPy array. If None, then the intrinsic icon will be used (may depend on tool’s configuration).

limit = None#

Type:: Nullable(Positive)

Limit the number the number of data points for which tooltips will be showed.

By default HoverTool will show tooltips for all hit data points.

line_policy = 'nearest'#

Type:: Enum(

Enumeration(

prev,

next,

nearest,

interp,

none

)

)

Specifies where the tooltip will be positioned when hovering over line glyphs:

“prev”:: between the nearest two adjacent line points, positions the tooltip at the point with the lower (“previous”) index
“next”:: between the nearest two adjacent line points, positions the tooltip at the point with the higher (“next”) index
“nearest”:: between the nearest two adjacent line points, positions the tooltip on the point that is nearest to the mouse cursor location
“interp”:: positions the tooltip at an interpolated point on the segment joining the two nearest adjacent line points.
“none”:: positions the tooltip directly under the mouse cursor location

mode = 'mouse'#

Type:: Enum(Enumeration(mouse, hline, vline))

Whether to consider hover pointer as a point (x/y values), or a span on h or v directions.

muted_policy = 'show'#

Type:: Enum(Enumeration(show, ignore))

Whether to avoid showing tooltips on muted glyphs.

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.scatter([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.

point_policy = 'snap_to_data'#

Type:: Enum(

Enumeration(

snap_to_data,

follow_mouse,

none

)

)

Whether the tooltip position should snap to the “center” (or other anchor) position of the associated glyph, or always follow the current mouse cursor position.

renderers = 'auto'#

Type:: Either(Auto, List)

A list of renderers to hit test against. If unset, defaults to all renderers on a plot.

show_arrow = True#

Type:: Bool

Whether tooltip’s arrow should be shown.

sort_by = None#

Type:: Nullable(Either(String, List))

Allows sorting hover results by a field or a sequence of fields.

Additionally sort direction can be provided when using the sequence form, even if providing a single field. The default sort order is based on data index and/or proximity to the hit point.

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.scatter([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.

toggleable = True#

Type:: Bool

This is a backwards compatibility alias for the ‘visible’ property.

Note

Property ‘toggleable’ was deprecated in Bokeh 3.4.0 and will be removed in the future. Update your code to use ‘visible’ instead.

tooltips = [('index', '$index'), ('data (x, y)', '($x, $y)'), ('screen (x, y)', '($sx, $sy)')]#

Type:: Either(Null, Instance(DOMElement), String, List)

The (name, field) pairs describing what the hover tool should display when there is a hit.

Field names starting with “@” are interpreted as columns on the data source. For instance, “@temp” would look up values to display from the “temp” column of the data source.

Field names starting with “$” are special, known fields:

$index:: index of hovered point in the data source
$name:: value of the name property of the hovered glyph renderer
$x:: x-coordinate under the cursor in data space
$y:: y-coordinate under the cursor in data space
$sx:: x-coordinate under the cursor in screen (canvas) space
$sy:: y-coordinate under the cursor in screen (canvas) space
$color:: color data from data source, with the syntax: $color[options]:field_name. The available options are: hex (to display the color as a hex value), swatch (color data from data source displayed as a small color box)
$swatch:: color data from data source displayed as a small color box

Field names that begin with @ are associated with columns in a ColumnDataSource. For instance the field name "@price" will display values from the "price" column whenever a hover is triggered. If the hover is for the 17th glyph, then the hover tooltip will correspondingly display the 17th price value.

Note that if a column name contains spaces, the it must be supplied by surrounding it in curly braces, e.g. @{adjusted close} will display values from a column named "adjusted close".

Sometimes (especially with stacked charts) it is desirable to allow the name of the column be specified indirectly. The field name @$name is distinguished in that it will look up the name field on the hovered glyph renderer, and use that value as the column name. For instance, if a user hovers with the name "US East", then @$name is equivalent to @{US East}.

By default, values for fields (e.g. @foo) are displayed in a basic numeric format. However it is possible to control the formatting of values more precisely. Fields can be modified by appending a format specified to the end in curly braces. Some examples are below.

"@foo{0,0.000}"    # formats 10000.1234 as: 10,000.123

"@foo{(.00)}"      # formats -10000.1234 as: (10000.123)

"@foo{($ 0.00 a)}" # formats 1230974 as: $ 1.23 m

Specifying a format {safe} after a field name will override automatic escaping of the tooltip data source. Any HTML tags in the data tags will be rendered as HTML in the resulting HoverTool output. See Custom tooltip for a more detailed example.

None is also a valid value for tooltips. This turns off the rendering of tooltips. This is mostly useful when supplying other actions on hover via the callback property.

Note

The tooltips attribute can also be configured with a mapping type, e.g. dict or OrderedDict.

visible = True#

Type:: Bool

Whether a tool button associated with this tool should appear in the toolbar.

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

Methods#

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 utilized. 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

classmethod from_string(name: str) → Tool#: Takes a string and returns a corresponding Tool instance.

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: 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() → 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: PropertyCallback) → 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.

Parameters:: 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)