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

formatanyOf(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.

• If the format type is "number" (e.g., for quantitative fields), this is D3’s number format pattern.

• If the format type is "time" (e.g., for temporal fields), this is D3’s time format pattern.

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.

formatTypestring

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.

labelAlignAlign

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

labelAnchorTitleAnchor

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.

labelAnglefloat

The rotation angle of the header labels.

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

labelBaselineTextBaseline

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.

labelColorColor

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

labelExprstring

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.

labelFontstring

The font of the header label.

labelFontSizefloat

The font size of the header label, in pixels.

labelFontStyleFontStyle

The font style of the header label.

labelFontWeightFontWeight

The font weight of the header label.

labelLimitfloat

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

labelLineHeightfloat

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

labelOrientOrient

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

labelPaddingfloat

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

Default value: 10

labelsboolean

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

Default value: true.

orientOrient

Shortcut for setting both labelOrient and titleOrient.

titleanyOf(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.

titleAlignAlign

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

titleAnchorTitleAnchor

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.

titleAnglefloat

The rotation angle of the header title.

Default value: 0.

titleBaselineTextBaseline

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"

titleColorColor

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

titleFontstring

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

titleFontSizefloat

Font size of the header title.

titleFontStyleFontStyle

The font style of the header title.

titleFontWeightFontWeight

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 ).

titleLimitfloat

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

titleLineHeightfloat

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

titleOrientOrient

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

titlePaddingfloat

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

Default value: 10

__init__(self, 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)

Initialize self. See help(type(self)) for accurate signature.

Methods

__init__(self[, format, formatType, …])	Initialize self.
copy(self[, 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(self[, validate, ignore, context])	Return a dictionary representation of the object
to_json(self[, validate, ignore, context, …])	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 rootschema

copy(self, deep=True, ignore=())

Return a copy of the object

Parameters

deepboolean 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.

ignorelist, optional

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

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

Construct class from a dictionary representation

Parameters

dctdictionary

The dict from which to construct the class

validateboolean

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

_wrapper_classeslist (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

objSchema object

The wrapped schema

Raises

jsonschema.ValidationError :

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

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

Instantiate the object from a valid JSON string

Parameters

json_stringstring

The string containing a valid JSON chart specification.

validateboolean

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

**kwargs :

Additional keyword arguments are passed to json.loads

Returns

chartChart object

The altair Chart object built from the specification.

classmethod resolve_references(schema=None)

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

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

Return a dictionary representation of the object

Parameters

validateboolean 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.

ignorelist

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

contextdict (optional)

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

Returns

dctdictionary

The dictionary representation of this object

Raises

jsonschema.ValidationError :

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

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

Emit the JSON representation for this object as a string.

Parameters

validateboolean 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.

ignorelist

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

contextdict (optional)

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

indentinteger, default 2

the number of spaces of indentation to use

sort_keysboolean, default True

if True, sort keys in the output

**kwargs

Additional keyword arguments are passed to json.dumps()

Returns

specstring

The JSON specification of the chart object.

classmethod validate(instance, schema=None)

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

classmethod validate_property(name, value, schema=None)

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