altair.Header

class altair.Header(format=Undefined, formatType=Undefined, labelAlign=Undefined, labelAnchor=Undefined, labelAngle=Undefined, labelBaseline=Undefined, labelColor=Undefined, labelExpr=Undefined, labelFont=Undefined, labelFontSize=Undefined, labelFontStyle=Undefined, labelFontWeight=Undefined, labelLimit=Undefined, labelLineHeight=Undefined, labelOrient=Undefined, labelPadding=Undefined, labels=Undefined, orient=Undefined, title=Undefined, titleAlign=Undefined, titleAnchor=Undefined, titleAngle=Undefined, titleBaseline=Undefined, titleColor=Undefined, titleFont=Undefined, titleFontSize=Undefined, titleFontStyle=Undefined, titleFontWeight=Undefined, titleLimit=Undefined, titleLineHeight=Undefined, titleOrient=Undefined, titlePadding=Undefined, **kwds)

Header schema wrapper

Mapping(required=[]) Headers of row / column channels for faceted plots.

Attributes:
format : anyOf(string, Mapping(required=[]))

When used with the default "number" and "time" format type, the text formatting pattern for labels of guides (axes, legends, headers) and text marks.

See the format documentation for more examples.

When used with a custom “formatType” that takes datum.value and format parameter as input), this property represents the format parameter.

Default value: Derived from numberFormat config for number format and from timeFormat config for time format.

formatType : string

The format type for labels ( "number" or "time" or a registered custom format type ).

Default value:

  • "time" for temporal fields and ordinal and nomimal fields with timeUnit.
  • "number" for quantitative fields as well as ordinal and nomimal fields without timeUnit.
labelAlign : Align

Horizontal text alignment of header labels. One of "left", "center", or "right".

labelAnchor : TitleAnchor

The anchor position for placing the labels. One of "start", "middle", or "end". For example, with a label orientation of top these anchor positions map to a left-, center-, or right-aligned label.

labelAngle : float

The rotation angle of the header labels.

Default value: 0 for column header, -90 for row header.

labelBaseline : TextBaseline

The vertical text baseline for the header labels. One of "alphabetic" (default), "top", "middle", "bottom", "line-top", or "line-bottom". The "line-top" and "line-bottom" values operate similarly to "top" and "bottom", but are calculated relative to the titleLineHeight rather than titleFontSize alone.

labelColor : Color

The color of the header label, can be in hex color code or regular color name.

labelExpr : string

Vega expression for customizing labels.

Note: The label text and value can be assessed via the label and value properties of the header’s backing datum object.

labelFont : string

The font of the header label.

labelFontSize : float

The font size of the header label, in pixels.

labelFontStyle : FontStyle

The font style of the header label.

labelFontWeight : FontWeight

The font weight of the header label.

labelLimit : float

The maximum length of the header label in pixels. The text value will be automatically truncated if the rendered size exceeds the limit.

Default value: 0, indicating no limit

labelLineHeight : float

Line height in pixels for multi-line header labels or title text with "line-top" or "line-bottom" baseline.

labelOrient : Orient

The orientation of the header label. One of "top", "bottom", "left" or "right".

labelPadding : float

The padding, in pixel, between facet header’s label and the plot.

Default value: 10

labels : boolean

A boolean flag indicating if labels should be included as part of the header.

Default value: true.

orient : Orient

Shortcut for setting both labelOrient and titleOrient.

title : anyOf(Text, None)

A title for the field. If null, the title will be removed.

Default value: derived from the field’s name and transformation function ( aggregate, bin and timeUnit ). If the field has an aggregate function, the function is displayed as part of the title (e.g., "Sum of Profit" ). If the field is binned or has a time unit applied, the applied function is shown in parentheses (e.g., "Profit (binned)", "Transaction Date (year-month)" ). Otherwise, the title is simply the field name.

Notes :

1) You can customize the default field title format by providing the fieldTitle property in the config or fieldTitle function via the compile function’s options.

2) If both field definition’s title and axis, header, or legend title are defined, axis/header/legend title will be used.

titleAlign : Align

Horizontal text alignment (to the anchor) of header titles.

titleAnchor : TitleAnchor

The anchor position for placing the title. One of "start", "middle", or "end". For example, with an orientation of top these anchor positions map to a left-, center-, or right-aligned title.

titleAngle : float

The rotation angle of the header title.

Default value: 0.

titleBaseline : TextBaseline

The vertical text baseline for the header title. One of "alphabetic" (default), "top", "middle", "bottom", "line-top", or "line-bottom". The "line-top" and "line-bottom" values operate similarly to "top" and "bottom", but are calculated relative to the titleLineHeight rather than titleFontSize alone.

Default value: "middle"

titleColor : Color

Color of the header title, can be in hex color code or regular color name.

titleFont : string

Font of the header title. (e.g., "Helvetica Neue" ).

titleFontSize : float

Font size of the header title.

titleFontStyle : FontStyle

The font style of the header title.

titleFontWeight : FontWeight

Font weight of the header title. This can be either a string (e.g "bold", "normal" ) or a number ( 100, 200, 300, …, 900 where "normal" = 400 and "bold" = 700 ).

titleLimit : float

The maximum length of the header title in pixels. The text value will be automatically truncated if the rendered size exceeds the limit.

Default value: 0, indicating no limit

titleLineHeight : float

Line height in pixels for multi-line header title text or title text with "line-top" or "line-bottom" baseline.

titleOrient : Orient

The orientation of the header title. One of "top", "bottom", "left" or "right".

titlePadding : float

The padding, in pixel, between facet header’s title and the label.

Default value: 10

__init__(format=Undefined, formatType=Undefined, labelAlign=Undefined, labelAnchor=Undefined, labelAngle=Undefined, labelBaseline=Undefined, labelColor=Undefined, labelExpr=Undefined, labelFont=Undefined, labelFontSize=Undefined, labelFontStyle=Undefined, labelFontWeight=Undefined, labelLimit=Undefined, labelLineHeight=Undefined, labelOrient=Undefined, labelPadding=Undefined, labels=Undefined, orient=Undefined, title=Undefined, titleAlign=Undefined, titleAnchor=Undefined, titleAngle=Undefined, titleBaseline=Undefined, titleColor=Undefined, titleFont=Undefined, titleFontSize=Undefined, titleFontStyle=Undefined, titleFontWeight=Undefined, titleLimit=Undefined, titleLineHeight=Undefined, titleOrient=Undefined, titlePadding=Undefined, **kwds)

Methods

__init__([format, formatType, labelAlign, …])
copy([deep, ignore]) Return a copy of the object
from_dict(dct[, validate, _wrapper_classes]) Construct class from a dictionary representation
from_json(json_string[, validate]) Instantiate the object from a valid JSON string
resolve_references([schema]) Resolve references in the context of this object’s schema or root schema.
to_dict([validate, ignore, context]) Return a dictionary representation of the object
to_json([validate, ignore, context, indent, …]) Emit the JSON representation for this object as a string.
validate(instance[, schema]) Validate the instance against the class schema in the context of the rootschema.
validate_property(name, value[, schema]) Validate a property against property schema in the context of the
copy(deep=True, ignore=())

Return a copy of the object

Parameters:
deep : boolean or list, optional

If True (default) then return a deep copy of all dict, list, and SchemaBase objects within the object structure. If False, then only copy the top object. If a list or iterable, then only copy the listed attributes.

ignore : list, optional

A list of keys for which the contents should not be copied, but only stored by reference.

from_dict(dct, validate=True, _wrapper_classes=None)

Construct class from a dictionary representation

Parameters:
dct : dictionary

The dict from which to construct the class

validate : boolean

If True (default), then validate the input against the schema.

_wrapper_classes : list (optional)

The set of SchemaBase classes to use when constructing wrappers of the dict inputs. If not specified, the result of cls._default_wrapper_classes will be used.

Returns:
obj : Schema object

The wrapped schema

Raises:
jsonschema.ValidationError :

if validate=True and dct does not conform to the schema

from_json(json_string, validate=True, **kwargs)

Instantiate the object from a valid JSON string

Parameters:
json_string : string

The string containing a valid JSON chart specification.

validate : boolean

If True (default), then validate the input against the schema.

**kwargs :

Additional keyword arguments are passed to json.loads

Returns:
chart : Chart object

The altair Chart object built from the specification.

resolve_references(schema=None)

Resolve references in the context of this object’s schema or root schema.

to_dict(validate=True, ignore=None, context=None)

Return a dictionary representation of the object

Parameters:
validate : boolean or string

If True (default), then validate the output dictionary against the schema. If “deep” then recursively validate all objects in the spec. This takes much more time, but it results in friendlier tracebacks for large objects.

ignore : list

A list of keys to ignore. This will not passed to child to_dict function calls.

context : dict (optional)

A context dictionary that will be passed to all child to_dict function calls

Returns:
dct : dictionary

The dictionary representation of this object

Raises:
jsonschema.ValidationError :

if validate=True and the dict does not conform to the schema

to_json(validate=True, ignore=[], context={}, indent=2, sort_keys=True, **kwargs)

Emit the JSON representation for this object as a string.

Parameters:
validate : boolean or string

If True (default), then validate the output dictionary against the schema. If “deep” then recursively validate all objects in the spec. This takes much more time, but it results in friendlier tracebacks for large objects.

ignore : list

A list of keys to ignore. This will not passed to child to_dict function calls.

context : dict (optional)

A context dictionary that will be passed to all child to_dict function calls

indent : integer, default 2

the number of spaces of indentation to use

sort_keys : boolean, default True

if True, sort keys in the output

**kwargs

Additional keyword arguments are passed to json.dumps()

Returns:
spec : string

The JSON specification of the chart object.

validate(instance, schema=None)

Validate the instance against the class schema in the context of the rootschema.

validate_property(name, value, schema=None)

Validate a property against property schema in the context of the rootschema