contour.py

from __future__ import annotations

import warnings
from collections.abc import MutableSequence
from typing import TYPE_CHECKING, Iterable, Iterator, List, Optional, overload

from attrs import define, field
from fontTools.pens.basePen import AbstractPen
from fontTools.pens.pointPen import AbstractPointPen, PointToSegmentPen

from ufoLib2.objects.misc import BoundingBox, getBounds, getControlBounds
from ufoLib2.objects.point import Point
from ufoLib2.serde import serde
from ufoLib2.typing import GlyphSet

# For Python 3.7 compatibility.
if TYPE_CHECKING:
    ContourMapping = MutableSequence[Point]
else:
    ContourMapping = MutableSequence


@serde
@define
class Contour(ContourMapping):
    """Represents a contour as a list of points.

    Behavior:
        The Contour object has list-like behavior. This behavior allows you to interact
        with point data directly. For example, to get a particular point::

            point = contour[0]

        To iterate over all points::

            for point in contour:
                ...

        To get the number of points::

            pointCount = len(contour)

        To delete a particular point::

            del contour[0]

        To set a particular point to another Point object::

            contour[0] = anotherPoint
    """

    points: List[Point] = field(factory=list)
    """The list of points in the contour."""

    identifier: Optional[str] = field(default=None, repr=False)
    """The globally unique identifier of the contour."""

    # collections.abc.MutableSequence interface

    def __delitem__(self, index: int | slice) -> None:
        del self.points[index]

    @overload
    def __getitem__(self, index: int) -> Point:
        ...

    @overload
    def __getitem__(self, index: slice) -> list[Point]:  # noqa: F811
        ...

    def __getitem__(self, index: int | slice) -> Point | list[Point]:  # noqa: F811
        return self.points[index]

    def __setitem__(  # noqa: F811
        self, index: int | slice, point: Point | Iterable[Point]
    ) -> None:
        if isinstance(index, int) and isinstance(point, Point):
            self.points[index] = point
        elif (
            isinstance(index, slice)
            and isinstance(point, Iterable)
            and all(isinstance(p, Point) for p in point)
        ):
            self.points[index] = point
        else:
            raise TypeError(
                f"Expected Point or Iterable[Point], found {type(point).__name__}."
            )

    def __iter__(self) -> Iterator[Point]:
        return iter(self.points)

    def __len__(self) -> int:
        return len(self.points)

    def insert(self, index: int, value: Point) -> None:
        """Insert Point object ``value`` into the contour at ``index``."""
        if not isinstance(value, Point):
            raise TypeError(f"Expected Point, found {type(value).__name__}.")
        self.points.insert(index, value)

    # TODO: rotate method?

    @property
    def open(self) -> bool:
        """Returns whether the contour is open or closed."""
        if not self.points:
            return True
        return self.points[0].type == "move"

    def move(self, delta: tuple[float, float]) -> None:
        """Moves contour by (x, y) font units."""
        for point in self.points:
            point.move(delta)

    def getBounds(self, layer: GlyphSet | None = None) -> BoundingBox | None:
        """Returns the (xMin, yMin, xMax, yMax) bounding box of the glyph,
        taking the actual contours into account.

        Args:
            layer: Not applicable to contours, here for API symmetry.
        """
        return getBounds(self, layer)

    @property
    def bounds(self) -> BoundingBox | None:
        """Returns the (xMin, yMin, xMax, yMax) bounding box of the glyph,
        taking the actual contours into account.

        |defcon_compat|
        """
        return self.getBounds()

    def getControlBounds(self, layer: GlyphSet | None = None) -> BoundingBox | None:
        """Returns the (xMin, yMin, xMax, yMax) bounding box of the glyph,
        taking only the control points into account.

        Args:
            layer: Not applicable to contours, here for API symmetry.
        """
        return getControlBounds(self, layer)

    @property
    def controlPointBounds(self) -> BoundingBox | None:
        """Returns the (xMin, yMin, xMax, yMax) bounding box of the glyph,
        taking only the control points into account.

        |defcon_compat|
        """
        return self.getControlBounds()

    # -----------
    # Pen methods
    # -----------

    def draw(self, pen: AbstractPen) -> None:
        """Draws contour into given pen."""
        pointPen = PointToSegmentPen(pen)
        self.drawPoints(pointPen)

    def drawPoints(self, pointPen: AbstractPointPen) -> None:
        """Draws points of contour into given point pen."""
        try:
            pointPen.beginPath(identifier=self.identifier)
            for p in self.points:
                pointPen.addPoint(
                    (p.x, p.y),
                    segmentType=p.type,
                    smooth=p.smooth,
                    name=p.name,
                    identifier=p.identifier,
                )
        except TypeError:
            pointPen.beginPath()
            for p in self.points:
                pointPen.addPoint(
                    (p.x, p.y), segmentType=p.type, smooth=p.smooth, name=p.name
                )
            warnings.warn(
                "The pointPen needs an identifier kwarg. "
                "Identifiers have been discarded.",
                UserWarning,
            )
        pointPen.endPath()