r"""
`kitty text sizing protocol`_ (OSC 66) parsing and measurement.
The kitty text sizing protocol allows terminal apps to explicitly tell
terminals how many cells text occupies, using the escape sequence::
ESC ] 66 ; metadata ; text BEL/ST
Metadata is colon-separated ``key=value`` pairs:
- ``s``: scale
- ``w``: width in cells
- ``n``: fractional numerator
- ``d``: fractional denominator
- ``v``: vertical alignment
- ``h``: horizontal alignment
Parsing is pretty straight-forward:
- When ``w > 0``, return ``s * w``.
- Otherwise ``w == 0``, ``s * wcswidth(inner_text_width)`` cells.
Numerator, denominator, and alignment codes and values are parsed but otherwise ignored
and have no effect on measurements made in this library.
.. _`kitty text sizing protocol`: https://sw.kovidgoyal.net/kitty/text-sizing-protocol/
.. versionadded:: 0.7.0
"""
from __future__ import annotations
# std imports
import re
import typing
# local
from ._wcswidth import wcswidth
class _FieldMeta(typing.NamedTuple):
name: str
low: int
high: int
default: int
TEXT_FIELD_MAPPING: dict[str, _FieldMeta] = {
's': _FieldMeta(name='scale', low=1, high=7, default=1),
'w': _FieldMeta(name='width', low=0, high=7, default=0),
'n': _FieldMeta(name='numerator', low=0, high=15, default=0),
'd': _FieldMeta(name='denominator', low=0, high=15, default=0),
'v': _FieldMeta(name='vertical_align', low=0, high=2, default=0),
'h': _FieldMeta(name='horizontal_align', low=0, high=2, default=0)}
[docs]
class TextSizingParams(typing.NamedTuple):
"""
Parsed parameters from a text sizing escape sequence (OSC 66).
:param scale: Scale factor (1-7). Text occupies ``scale`` rows tall and ``scale * width``
columns wide.
:param width: Width in cells (0-7). When 0, width is auto-calculated from the inner text.
:param numerator: Fractional scaling numerator (0-15).
:param denominator: Fractional scaling denominator (0-15).
:param vertical_align: Vertical alignment (0=top, 1=bottom, 2=center).
:param horizontal_align: Horizontal alignment (0=left, 1=right, 2=center).
"""
scale: int = 1
width: int = 0
numerator: int = 0
denominator: int = 0
vertical_align: int = 0
horizontal_align: int = 0
def __repr__(self) -> str:
"""
Return a compact representation including only non-default fields.
This avoids verbose output when most fields are defaults.
"""
# modified to show values only when non-default
repr_fmt = ', '.join(f'{field.name}={getattr(self, field.name)}'
for field in TEXT_FIELD_MAPPING.values()
if getattr(self, field.name) != field.default)
return f'{self.__class__.__name__}({repr_fmt})'
def make_sequence(self) -> str:
"""Build and return sub-part of an OSC 66 sequence."""
parts = []
# build string for all known parameters of non-default values
for field_key, field in TEXT_FIELD_MAPPING.items():
if (val := getattr(self, field.name)) != field.default:
parts.append(f'{field_key}={val}')
return ':'.join(parts)
@classmethod
def from_params(cls, raw: str, control_codes: str = 'parse') -> TextSizingParams:
"""
Parse colon-separated ``key=value`` metadata string.
:param raw: Metadata string, e.g. ``'s=2:w=3'``.
:param control_codes: 'parse' or 'strict'.
:raises ValueError: If ``control_codes='strict'`` unrecognized text sizing parameters raise
ValueError.
:returns: Parsed parameters with values clamped to valid ranges.
Unknown keys are ignored. Non-integer values use defaults.
Example::
>>> TextSizingParams.from_params('s=2:w=3')
TextSizingParams(scale=2, width=3, numerator=0, denominator=0, \
vertical_align=0, horizontal_align=0)
"""
kwargs: typing.Dict[str, int] = {}
if not raw:
return cls()
for part in raw.split(':'):
if '=' not in part:
if control_codes == 'strict':
raise ValueError(f"Expected '=' in text sizing parameter (key=val), "
f"got {part!r} in OSC 66 sequence, {raw!r}")
continue
key, _eq, val = part.partition('=')
field = TEXT_FIELD_MAPPING.get(key)
if field is None:
if control_codes == 'strict':
raise ValueError(f"Unknown text sizing field '{key}' "
f"in OSC 66 sequence, {raw!r}")
# ignore unknown fields unless 'strict'
continue
try:
value = int(val)
except ValueError as exc:
if control_codes == 'strict':
raise ValueError(f"Illegal text sizing value '{val}' "
f"in OSC 66 sequence, {raw!r}: {exc}") from exc
# ignore value, uses default value without warning unless 'strict'
continue
if control_codes == 'strict' and (value > field.high or value < field.low):
raise ValueError(f"Out of bounds text sizing value '{val}' "
f"in OSC 66 sequence, {raw!r}: "
f"allowed range for '{key}' ({field.name}) "
f"is {field.low} to {field.high}")
kwargs[field.name] = max(field.low, min(field.high, value))
return cls(**kwargs)
[docs]
class TextSizing(typing.NamedTuple):
"""Basic horizontal width measurement for kitty text sizing protocol."""
params: TextSizingParams
text: str
terminator: str
@classmethod
def from_match(cls, match: re.Match[str], control_codes: str = 'parse') -> TextSizing:
r"""
Parse using matching OSC 66 Sequence.
:param match: match object from :attr:`wcwidth.escape_sequences.TEXT_SIZING_PATTERN`.
:param control_codes: 'parse' or 'strict', same meaning as delegated by
:func:`wcwidth.width`.
:raises ValueError: When ``control_codes='strict'`` for unrecognized, invalid, or out of
bounds text sizing parameters.
:returns: TextSizing object from parsed sequence
Example::
from wcwidth.escape_sequences import TEXT_SIZING_PATTERN
>>> TextSizing.from_match(TEXT_SIZING_PATTERN.match('\x1b]66;w=2;XY\x07'))
TextSizing(params=TextSizingParams(scale=1, width=2, numerator=0, denominator=0, \
vertical_align=0, horizontal_align=0), text='XY', terminator='\x07')
"""
return cls(params=TextSizingParams.from_params(match.group(1), control_codes=control_codes),
text=match.group(2),
terminator=match.group(3))
def display_width(self, ambiguous_width: int = 1) -> int:
"""
Calculate the display width of a text sizing sequence.
:param ambiguous_width: Width for East Asian Ambiguous characters.
:returns: Display width in terminal cells. When ``width > 0``, returns
``params.scale * params.width``. When ``width == 0``, returns
``params.scale * measured_inner_width``.
.. note: Fractional scaling (numerator/denominator) does not affect the
cell count, it adjusts only the font size within the cells allocated by 'w'.
"""
if self.params.width > 0:
return self.params.scale * self.params.width
w = wcswidth(self.text, ambiguous_width=ambiguous_width)
if w < 0:
w = 0
return self.params.scale * w
def make_sequence(self) -> str:
"""Build and return complete OSC 66 Terminal Sequence."""
return f'\x1b]66;{self.params.make_sequence()};{self.text}{self.terminator}'