bokeh.models.ScaleBar

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

Bases: Annotation

Represents a scale bar annotation.

Property index

anchor	background_fill_alpha
background_fill_color	background_hatch_alpha
background_hatch_color	background_hatch_extra
background_hatch_pattern	background_hatch_scale
background_hatch_weight	bar_length
bar_length_units	bar_line_alpha
bar_line_cap	bar_line_color
bar_line_dash	bar_line_dash_offset
bar_line_join	bar_line_width
border_line_alpha	border_line_cap
border_line_color	border_line_dash
border_line_dash_offset	border_line_join
border_line_width	context_menu
coordinates	css_classes
css_variables	dimensional
elements	group
html_attributes	html_id
label	label_align
label_location	label_standoff
label_text_align	label_text_alpha
label_text_baseline	label_text_color
label_text_font	label_text_font_size
label_text_font_style	label_text_line_height
label_text_outline_color	label_text_outline_width
length_sizing	level
location	margin
name	orientation
padding	propagate_hover
range	renderers
styles	stylesheets
syncable	tags
ticker	title
title_align	title_location
title_standoff	title_text_align
title_text_alpha	title_text_baseline
title_text_color	title_text_font
title_text_font_size	title_text_font_style
title_text_line_height	title_text_outline_color
title_text_outline_width	unit
visible	x_range_name
x_units	y_range_name
y_units	document

Properties

anchor = 'auto'

Type:

Either(

Auto,

Enum(Anchor),

Tuple(

Either(

Auto,

Either(

Enum(Align),

Enum(HAlign),

Percent

)

),

Either(

Auto,

Either(

Enum(Align),

Enum(VAlign),

Percent

)

)

)

)

The origin for scale bar positioning.

If "auto" in any or both dimensions, then the anchor in these dimensions will be determined based on the position, so that the scale bar looks good.

background_fill_alpha = 0.95

Type:

Alpha

The fill alpha for the scale bar background fill style.

background_fill_color = '#ffffff'

Type:

Nullable(Color)

The fill color for the scale bar background fill style.

background_hatch_alpha = 1.0

Type:

Alpha

The hatch alpha for the scale bar background hatch style.

background_hatch_color = 'black'

Type:

Nullable(Color)

The hatch color for the scale bar background hatch style.

background_hatch_extra = {}

Type:

Dict(String, Instance(Texture))

The hatch extra for the scale bar background hatch style.

background_hatch_pattern = None

Type:

Nullable(String)

The hatch pattern for the scale bar background hatch style.

background_hatch_scale = 12.0

Type:

Size

The hatch scale for the scale bar background hatch style.

background_hatch_weight = 1.0

Type:

Size

The hatch weight for the scale bar background hatch style.

bar_length = 0.2

Type:

NonNegative

The length of the bar.

This is either a fraction of the frame, a number of pixels or distance in the data space, depending on the configuration of bar_length_units.

bar_length_units = 'screen'

Type:

Enum(Enumeration(screen, data, percent))

Defines how to interpret bar_length.

Supported values are:

• "screen" - the length is provided in pixels or as a percentage of the parent container (e.g. the frame) if the value provided is in [0, 1] range

• "data" - the length is provided in data space units

• "percent" - the length is a percentage of the parent container (e.g. the frame)

Note

"data" units assume a linear scale or a linear like scale (e.g. categorical scale) is used. Otherwise the length of the bar would be position dependent.

bar_line_alpha = 1.0

Type:

Alpha

The line alpha values for the bar line style.

bar_line_cap = 'butt'

Type:

Enum(LineCap)

The line cap values for the bar line style.

bar_line_color = 'black'

Type:

Nullable(Color)

The line color values for the bar line style.

bar_line_dash = []

Type:

DashPattern

The line dash values for the bar line style.

bar_line_dash_offset = 0

Type:

Int

The line dash offset values for the bar line style.

bar_line_join = 'bevel'

Type:

Enum(LineJoin)

The line join values for the bar line style.

bar_line_width = 2

Type:

Float

The line width values for the bar line style.

border_line_alpha = 0.5

Type:

Alpha

The line alpha for the scale bar border line style.

border_line_cap = 'butt'

Type:

Enum(LineCap)

The line cap for the scale bar border line style.

border_line_color = '#e5e5e5'

Type:

Nullable(Color)

The line color for the scale bar border line style.

border_line_dash = []

Type:

DashPattern

The line dash for the scale bar border line style.

border_line_dash_offset = 0

Type:

Int

The line dash offset for the scale bar border line style.

border_line_join = 'bevel'

Type:

Enum(LineJoin)

The line join for the scale bar border line style.

border_line_width = 1

Type:

Float

The line width for the scale bar border line style.

context_menu = None

Type:

Nullable(Instance(Menu))

A menu to display when user right clicks on the component.

Note

Use shift key when right clicking to display the native context menu.

coordinates = None

Type:

Nullable(Instance(CoordinateMapping))

css_classes = []

Type:

List

A list of additional CSS classes to add to the underlying DOM element.

css_variables = {}

Type:

Dict(String, Either(String, Instance(Node)))

Allows to define dynamically computed CSS variables.

This can be used, for example, to coordinate positioning and styling between canvas’ renderers and/or visuals and HTML-based UI elements.

Variables defined here are equivalent to setting the same variables under :host { ... } in a CSS stylesheet.

Note

This property is experimental and may change at any point.

dimensional = MetricLength(id='p56720', ...)

Type:

Instance(Dimensional)

Defines the units of measurement.

elements = []

Type:

List

A collection of DOM-based UI elements attached to this renderer.

This can include floating elements like tooltips, allowing to establish a parent-child relationship between this renderer and its UI elements.

Note

This property is an equivalent of Pane.elements in DOM-based UIs.

group = None

Type:

Nullable(Instance(RendererGroup))

Note

This property is experimental and may change at any point.

html_attributes = {}

Type:

Dict(String, String)

Allows to configure HTML attributes on the underlying HTML element.

html_id = None

Type:

Nullable(String)

Sets the id attribute of the underlying HTML element.

This is a shorthand for the common HTML id attribute. Alternatively the id can be set in the html_attributes dictionary. html_id takes precedence.

label = '@{value} @{unit}'

Type:

String

The label template.

This can use special variables:

• @{value} The current value. Optionally can provide a number formatter with e.g. @{value}{%.2f}.

• @{unit} The unit of measurement.

label_align = 'center'

Type:

Enum(Align)

Specifies where to align scale bar’s label along the bar.

This property effective when placing the label above or below a horizontal scale bar, or left or right of a vertical one.

label_location = 'below'

Type:

Enum(Location)

Specifies on which side of the scale bar the label will be located.

label_standoff = 5

Type:

Int

The distance (in pixels) to separate the label from the scale bar.

label_text_align = 'left'

Type:

Enum(TextAlign)

The text align values for the label text style.

label_text_alpha = 1.0

Type:

Alpha

The text alpha values for the label text style.

label_text_baseline = 'middle'

Type:

Enum(TextBaseline)

The text baseline values for the label text style.

label_text_color = '#444444'

Type:

Nullable(Color)

The text color values for the label text style.

label_text_font = 'helvetica'

Type:

String

The text font values for the label text style.

label_text_font_size = '13px'

Type:

FontSize

The text font size values for the label text style.

label_text_font_style = 'normal'

Type:

Enum(FontStyle)

The text font style values for the label text style.

label_text_line_height = 1.2

Type:

Float

The text line height values for the label text style.

label_text_outline_color = None

Type:

Nullable(Color)

The text outline color values for the label text style.

label_text_outline_width = 1

Type:

Float

The text outline width values for the label text style.

length_sizing = 'adaptive'

Type:

Enum(Enumeration(adaptive, exact))

Defines how the length of the bar is interpreted.

This can either be:

• "adaptive" - the computed length is fit into a set of ticks provided be the dimensional model. If no ticks are provided, then the behavior is the same as if "exact" sizing was used

• "exact" - the computed length is used as-is

level = 'annotation'

Type:

Enum(RenderLevel)

Specifies the level in which to paint this renderer.

location = 'top_right'

Type:

Either(

Enum(Anchor),

Tuple(

Either(

Enum(HAlign),

Float,

Either(

Float,

Datetime,

Factor

)

),

Either(

Enum(VAlign),

Float,

Either(

Float,

Datetime,

Factor

)

)

)

)

Position of the scale bar within the parent container (usually cartesian frame).

margin = 10

Type:

Int

Amount of margin (in pixels) around the outside of the scale bar.

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.

orientation = 'horizontal'

Type:

Enum(Orientation)

Whether the scale bar should be oriented horizontally or vertically.

padding = 10

Type:

Int

Amount of padding (in pixels) between the contents of the scale bar and its border.

propagate_hover = False

Type:

Bool

Allows to propagate hover events to the parent renderer, frame or canvas.

Note

This property is experimental and may change at any point.

range = 'auto'

Type:

Either(Instance(Range), Auto)

The range for which to display the scale.

This can be either a range reference or "auto", in which case the scale bar will pick the default x or y range of the frame, depending on the orientation of the scale bar.

renderers = []

Type:

List

A collection of renderers attached to this renderer.

Note

This property is experimental and may change at any point.

styles = {}

Type:

Either(

Dict(

String,

Nullable(String)

),

Instance(Styles)

)

Inline CSS styles applied to the underlying DOM element.

stylesheets = []

Type:

List

Additional style-sheets to use for the underlying DOM element.

Note that all bokeh’s components use shadow DOM, thus any included style sheets must reflect that, e.g. use :host CSS pseudo selector to access the root DOM element.

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.

ticker = FixedTicker(id='p56721', ...)

Type:

Instance(Ticker)

A ticker to use for computing locations of axis components.

Note that if using the default fixed ticker with no predefined ticks, then the appearance of the scale bar will be just a solid bar with no additional markings.

title = ''

Type:

String

The title text to render.

title_align = 'center'

Type:

Enum(Align)

Specifies where to align scale bar’s title along the bar.

This property effective when placing the title above or below a horizontal scale bar, or left or right of a vertical one.

title_location = 'above'

Type:

Enum(Location)

Specifies on which side of the legend the title will be located.

title_standoff = 5

Type:

Int

The distance (in pixels) to separate the title from the scale bar.

title_text_align = 'left'

Type:

Enum(TextAlign)

The text align values for the title text style.

title_text_alpha = 1.0

Type:

Alpha

The text alpha values for the title text style.

title_text_baseline = 'bottom'

Type:

Enum(TextBaseline)

The text baseline values for the title text style.

title_text_color = '#444444'

Type:

Nullable(Color)

The text color values for the title text style.

title_text_font = 'helvetica'

Type:

String

The text font values for the title text style.

title_text_font_size = '13px'

Type:

FontSize

The text font size values for the title text style.

title_text_font_style = 'italic'

Type:

Enum(FontStyle)

The text font style values for the title text style.

title_text_line_height = 1.2

Type:

Float

The text line height values for the title text style.

title_text_outline_color = None

Type:

Nullable(Color)

The text outline color values for the title text style.

title_text_outline_width = 1

Type:

Float

The text outline width values for the title text style.

unit = 'm'

Type:

String

The unit of the range property.

visible = True

Type:

Bool

Is the renderer visible.

x_range_name = 'default'

Type:

String

A particular (named) x-range to use for computing screen locations when rendering glyphs on the plot. If unset, use the default x-range.

x_units = 'data'

Type:

Enum(Enumeration(data, screen, view, percent))

The interpretation of x coordinate values provided in position property.

y_range_name = 'default'

Type:

String

A particular (named) y-range to use for computing screen locations when rendering glyphs on the plot. If unset, use the default y-range.

y_units = 'data'

Type:

Enum(Enumeration(data, screen, view, percent))

The interpretation of y coordinate values provided in position property.

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

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)

JSON Prototype

{
  "anchor": "auto", 
  "background_fill_alpha": 0.95, 
  "background_fill_color": "#ffffff", 
  "background_hatch_alpha": 1.0, 
  "background_hatch_color": "black", 
  "background_hatch_extra": {
    "type": "map"
  }, 
  "background_hatch_pattern": null, 
  "background_hatch_scale": 12.0, 
  "background_hatch_weight": 1.0, 
  "bar_length": 0.2, 
  "bar_length_units": "screen", 
  "bar_line_alpha": 1.0, 
  "bar_line_cap": "butt", 
  "bar_line_color": "black", 
  "bar_line_dash": [], 
  "bar_line_dash_offset": 0, 
  "bar_line_join": "bevel", 
  "bar_line_width": 2, 
  "border_line_alpha": 0.5, 
  "border_line_cap": "butt", 
  "border_line_color": "#e5e5e5", 
  "border_line_dash": [], 
  "border_line_dash_offset": 0, 
  "border_line_join": "bevel", 
  "border_line_width": 1, 
  "context_menu": null, 
  "coordinates": null, 
  "css_classes": [], 
  "css_variables": {
    "type": "map"
  }, 
  "dimensional": {
    "attributes": {
      "include": null
    }, 
    "id": "p56718", 
    "name": "MetricLength", 
    "type": "object"
  }, 
  "elements": [], 
  "group": null, 
  "html_attributes": {
    "type": "map"
  }, 
  "html_id": null, 
  "id": "p56717", 
  "js_event_callbacks": {
    "type": "map"
  }, 
  "js_property_callbacks": {
    "type": "map"
  }, 
  "label": "@{value} @{unit}", 
  "label_align": "center", 
  "label_location": "below", 
  "label_standoff": 5, 
  "label_text_align": "left", 
  "label_text_alpha": 1.0, 
  "label_text_baseline": "middle", 
  "label_text_color": "#444444", 
  "label_text_font": "helvetica", 
  "label_text_font_size": "13px", 
  "label_text_font_style": "normal", 
  "label_text_line_height": 1.2, 
  "label_text_outline_color": null, 
  "label_text_outline_width": 1, 
  "length_sizing": "adaptive", 
  "level": "annotation", 
  "location": "top_right", 
  "margin": 10, 
  "name": null, 
  "orientation": "horizontal", 
  "padding": 10, 
  "propagate_hover": false, 
  "range": "auto", 
  "renderers": [], 
  "styles": {
    "type": "map"
  }, 
  "stylesheets": [], 
  "subscribed_events": {
    "type": "set"
  }, 
  "syncable": true, 
  "tags": [], 
  "ticker": {
    "attributes": {
      "minor_ticks": [], 
      "ticks": []
    }, 
    "id": "p56719", 
    "name": "FixedTicker", 
    "type": "object"
  }, 
  "title": "", 
  "title_align": "center", 
  "title_location": "above", 
  "title_standoff": 5, 
  "title_text_align": "left", 
  "title_text_alpha": 1.0, 
  "title_text_baseline": "bottom", 
  "title_text_color": "#444444", 
  "title_text_font": "helvetica", 
  "title_text_font_size": "13px", 
  "title_text_font_style": "italic", 
  "title_text_line_height": 1.2, 
  "title_text_outline_color": null, 
  "title_text_outline_width": 1, 
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