AttrList

class AttrList(**kwargs)

A PangoAttrList represents a list of attributes that apply to a section of text.

The attributes in a PangoAttrList are, in general, allowed to overlap in an arbitrary fashion. However, if the attributes are manipulated only through change, the overlap between properties will meet stricter criteria.

Since the PangoAttrList structure is stored as a linear list, it is not suitable for storing attributes for large amounts of text. In general, you should not use a single PangoAttrList for more than one paragraph of text.

Constructors

class AttrList
classmethod new() → AttrList

Create a new empty attribute list with a reference count of one.

Methods

class AttrList
change(attr: Attribute) → None

Insert the given attribute into the PangoAttrList.

It will replace any attributes of the same type on that segment and be merged with any adjoining attributes that are identical.

This function is slower than insert for creating an attribute list in order (potentially much slower for large lists). However, insert is not suitable for continually changing a set of attributes since it never removes or combines existing attributes.

Parameters:

attr – the attribute to insert

equal(other_list: AttrList) → bool

Checks whether list and other_list contain the same attributes and whether those attributes apply to the same ranges.

Beware that this will return wrong values if any list contains duplicates.

Added in version 1.46.

Parameters:

other_list – the other PangoAttrList

filter(func: Callable[[...], bool], *data: Any) → AttrList | None

Given a PangoAttrList and callback function, removes any elements of list for which func returns True and inserts them into a new list.

Added in version 1.2.

Parameters:

  • func – callback function; returns True if an attribute should be filtered out

  • data – Data to be passed to func

from_string(text: str) → AttrList | None

Deserializes a PangoAttrList from a string.

This is the counterpart to to_string. See that functions for details about the format.

Added in version 1.50.

Parameters:

text – a string

get_attributes() → list[Attribute]

Gets a list of all attributes in list.

Added in version 1.44.

get_iterator() → AttrIterator

Create a iterator initialized to the beginning of the list.

list must not be modified until this iterator is freed.

insert(attr: Attribute) → None

Insert the given attribute into the PangoAttrList.

It will be inserted after all other attributes with a matching start_index.

Parameters:

attr – the attribute to insert

insert_before(attr: Attribute) → None

Insert the given attribute into the PangoAttrList.

It will be inserted before all other attributes with a matching start_index.

Parameters:

attr – the attribute to insert

splice(other: AttrList, pos: int, len: int) → None

This function opens up a hole in list, fills it in with attributes from the left, and then merges other on top of the hole.

This operation is equivalent to stretching every attribute that applies at position pos in list by an amount len, and then calling change with a copy of each attribute in other in sequence (offset in position by pos, and limited in length to len).

This operation proves useful for, for instance, inserting a pre-edit string in the middle of an edit buffer.

For backwards compatibility, the function behaves differently when len is 0. In this case, the attributes from other are not imited to len, and are just overlayed on top of list.

This mode is useful for merging two lists of attributes together.

Parameters:

  • other – another PangoAttrList

  • pos – the position in list at which to insert other

  • len – the length of the spliced segment. (Note that this must be specified since the attributes in other may only be present at some subsection of this range)

to_string() → str

Serializes a PangoAttrList to a string.

In the resulting string, serialized attributes are separated by newlines or commas. Individual attributes are serialized to a string of the form

START END TYPE VALUE

Where START and END are the indices (with -1 being accepted in place of MAXUINT), TYPE is the nickname of the attribute value type, e.g. weight or stretch, and the value is serialized according to its type:

  • enum values as nick or numeric value

  • boolean values as true or false

  • integers and floats as numbers

  • strings as string, optionally quoted

  • font features as quoted string

  • PangoLanguage as string

  • PangoFontDescription as serialized by to_string, quoted

  • PangoColor as serialized by to_string

Examples:

0 10 foreground red, 5 15 weight bold, 0 200 font-desc "Sans 10"

0 -1 weight 700
0 100 family Times

To parse the returned value, use from_string.

Note that shape attributes can not be serialized.

Added in version 1.50.

update(pos: int, remove: int, add: int) → None

Update indices of attributes in list for a change in the text they refer to.

The change that this function applies is removing remove bytes at position pos and inserting add bytes instead.

Attributes that fall entirely in the (pos, pos + remove) range are removed.

Attributes that start or end inside the (pos, pos + remove) range are shortened to reflect the removal.

Attributes start and end positions are updated if they are behind pos + remove.

Added in version 1.44.

Parameters:

  • pos – the position of the change

  • remove – the number of removed bytes

  • add – the number of added bytes