rich/measure.py

from operator import itemgetter
from typing import Callable, Iterable, NamedTuple, Optional, TYPE_CHECKING

from . import errors
from .protocol import is_renderable

if TYPE_CHECKING:
    from .console import Console, ConsoleOptions, RenderableType


class Measurement(NamedTuple):
    """Stores the minimum and maximum widths (in characters) required to render an object."""

    minimum: int
    """Minimum number of cells required to render."""
    maximum: int
    """Maximum number of cells required to render."""

    @property
    def span(self) -> int:
        """Get difference between maximum and minimum."""
        return self.maximum - self.minimum

    def normalize(self) -> "Measurement":
        """Get measurement that ensures that minimum <= maximum and minimum >= 0

        Returns:
            Measurement: A normalized measurement.
        """
        minimum, maximum = self
        minimum = min(max(0, minimum), maximum)
        return Measurement(max(0, minimum), max(0, max(minimum, maximum)))

    def with_maximum(self, width: int) -> "Measurement":
        """Get a RenderableWith where the widths are <= width.

        Args:
            width (int): Maximum desired width.

        Returns:
            Measurement: New Measurement object.
        """
        minimum, maximum = self
        return Measurement(min(minimum, width), min(maximum, width))

    def with_minimum(self, width: int) -> "Measurement":
        """Get a RenderableWith where the widths are >= width.

        Args:
            width (int): Minimum desired width.

        Returns:
            Measurement: New Measurement object.
        """
        minimum, maximum = self
        width = max(0, width)
        return Measurement(max(minimum, width), max(maximum, width))

    def clamp(
        self, min_width: Optional[int] = None, max_width: Optional[int] = None
    ) -> "Measurement":
        """Clamp a measurement within the specified range.

        Args:
            min_width (int): Minimum desired width, or ``None`` for no minimum. Defaults to None.
            max_width (int): Maximum desired width, or ``None`` for no maximum. Defaults to None.

        Returns:
            Measurement: New Measurement object.
        """
        measurement = self
        if min_width is not None:
            measurement = measurement.with_minimum(min_width)
        if max_width is not None:
            measurement = measurement.with_maximum(max_width)
        return measurement

    @classmethod
    def get(
        cls, console: "Console", options: "ConsoleOptions", renderable: "RenderableType"
    ) -> "Measurement":
        """Get a measurement for a renderable.

        Args:
            console (~rich.console.Console): Console instance.
            options (~rich.console.ConsoleOptions): Console options.
            renderable (RenderableType): An object that may be rendered with Rich.

        Raises:
            errors.NotRenderableError: If the object is not renderable.

        Returns:
            Measurement: Measurement object containing range of character widths required to render the object.
        """
        _max_width = options.max_width
        if _max_width < 1:
            return Measurement(0, 0)
        if isinstance(renderable, str):
            renderable = console.render_str(renderable, markup=options.markup)
        if hasattr(renderable, "__rich__"):
            renderable = renderable.__rich__()  # type: ignore
        if is_renderable(renderable):
            get_console_width: Callable[
                ["Console", "ConsoleOptions"], "Measurement"
            ] = getattr(renderable, "__rich_measure__", None)
            if get_console_width is not None:
                render_width = (
                    get_console_width(console, options)
                    .normalize()
                    .with_maximum(_max_width)
                )
                if render_width.maximum < 1:
                    return Measurement(0, 0)
                return render_width.normalize()
            else:
                return Measurement(0, _max_width)
        else:
            raise errors.NotRenderableError(
                f"Unable to get render width for {renderable!r}; "
                "a str, Segment, or object with __rich_console__ method is required"
            )


def measure_renderables(
    console: "Console",
    options: "ConsoleOptions",
    renderables: Iterable["RenderableType"],
) -> "Measurement":
    """Get a measurement that would fit a number of renderables.

    Args:
        console (~rich.console.Console): Console instance.
        renderables (Iterable[RenderableType]): One or more renderable objects.
        max_width (int): The maximum width available.

    Returns:
        Measurement: Measurement object containing range of character widths required to
        contain all given renderables.
    """
    if not renderables:
        return Measurement(0, 0)
    get_measurement = Measurement.get
    measurements = [
        get_measurement(console, options, renderable) for renderable in renderables
    ]
    measured_width = Measurement(
        max(measurements, key=itemgetter(0)).minimum,
        max(measurements, key=itemgetter(1)).maximum,
    )
    return measured_width