malevich 0.7.0

//! The range mark: vertical intervals, with optional body and marker channels.

use crate::data::{IntoSeries, Series};
use crate::render::Color;

/// Vertical intervals at positions: error bars, box plots, candles, event ticks —
/// one mark, optional channels.
///
/// The base channels draw a thin whisker from `low` to `high` with end caps. An
/// optional [`Range::body`] fills a thick sub-interval (the box of a box plot, the
/// body of a candle), and an optional [`Range::marker`] draws a highlighted
/// crossbar (the median). Gaps (`NaN`) in any channel skip that interval.
#[derive(Clone)]
pub struct Range<'a> {
    pub(crate) placement: RangePlacement<'a>,
    pub(crate) low: Series<'a>,
    pub(crate) high: Series<'a>,
    pub(crate) body: Option<(Series<'a>, Series<'a>)>,
    pub(crate) marker: Option<Series<'a>>,
    pub(crate) color: Option<Color>,
    pub(crate) label: Option<String>,
}

/// Where ranges sit on the x axis.
#[derive(Clone)]
pub(crate) enum RangePlacement<'a> {
    /// At numeric x positions (`None` means indices `0, 1, 2, …`).
    Numeric(Option<Series<'a>>),
    /// One range per named band, like bars.
    Bands(Vec<String>),
}

impl<'a> Range<'a> {
    /// Intervals from `low` to `high` at positions `x`.
    ///
    /// # Panics
    ///
    /// Panics if the series have different lengths.
    pub fn xy(
        x: impl IntoSeries<'a>,
        low: impl IntoSeries<'a>,
        high: impl IntoSeries<'a>,
    ) -> Range<'a> {
        let x = x.into_series();
        let low = low.into_series();
        let high = high.into_series();
        assert!(
            x.len() == low.len() && low.len() == high.len(),
            "Range::xy requires series of equal length"
        );
        Range {
            placement: RangePlacement::Numeric(Some(x)),
            low,
            high,
            body: None,
            marker: None,
            color: None,
            label: None,
        }
    }

    /// Intervals from `low` to `high` against their indices.
    ///
    /// # Panics
    ///
    /// Panics if the series have different lengths.
    pub fn y(low: impl IntoSeries<'a>, high: impl IntoSeries<'a>) -> Range<'a> {
        let low = low.into_series();
        let high = high.into_series();
        assert_eq!(
            low.len(),
            high.len(),
            "Range::y requires series of equal length"
        );
        Range {
            placement: RangePlacement::Numeric(None),
            low,
            high,
            body: None,
            marker: None,
            color: None,
            label: None,
        }
    }

    /// One interval per named band — the box-plot arrangement. Bands share the
    /// categorical x axis with any bars in the plot.
    ///
    /// # Panics
    ///
    /// Panics if the series lengths differ from the category count.
    pub fn over(
        categories: impl IntoIterator<Item = impl Into<String>>,
        low: impl IntoSeries<'a>,
        high: impl IntoSeries<'a>,
    ) -> Range<'a> {
        let categories: Vec<String> = categories.into_iter().map(Into::into).collect();
        let low = low.into_series();
        let high = high.into_series();
        assert!(
            categories.len() == low.len() && low.len() == high.len(),
            "Range::over requires one category per interval"
        );
        Range {
            placement: RangePlacement::Bands(categories),
            low,
            high,
            body: None,
            marker: None,
            color: None,
            label: None,
        }
    }

    /// Adds a thick filled sub-interval — the box of a box plot.
    ///
    /// # Panics
    ///
    /// Panics if the body series lengths differ from the range's.
    #[must_use]
    pub fn body(mut self, low: impl IntoSeries<'a>, high: impl IntoSeries<'a>) -> Range<'a> {
        let low = low.into_series();
        let high = high.into_series();
        assert!(
            low.len() == self.low.len() && high.len() == self.low.len(),
            "Range::body requires series matching the range length"
        );
        self.body = Some((low, high));
        self
    }

    /// Adds a highlighted crossbar at each value — the median of a box plot.
    ///
    /// # Panics
    ///
    /// Panics if the marker series length differs from the range's.
    #[must_use]
    pub fn marker(mut self, values: impl IntoSeries<'a>) -> Range<'a> {
        let values = values.into_series();
        assert_eq!(
            values.len(),
            self.low.len(),
            "Range::marker requires a series matching the range length"
        );
        self.marker = Some(values);
        self
    }

    /// Sets an explicit color; without one, layers take colors from the palette.
    #[must_use]
    pub fn color(mut self, color: Color) -> Range<'a> {
        self.color = Some(color);
        self
    }

    /// Names this layer in the legend.
    #[must_use]
    pub fn label(mut self, label: impl Into<String>) -> Range<'a> {
        self.label = Some(label.into());
        self
    }

    /// Detaches from any borrowed storage, making the mark `'static`.
    pub fn into_owned(self) -> Range<'static> {
        Range {
            placement: match self.placement {
                RangePlacement::Numeric(x) => RangePlacement::Numeric(x.map(Series::into_owned)),
                RangePlacement::Bands(categories) => RangePlacement::Bands(categories),
            },
            low: self.low.into_owned(),
            high: self.high.into_owned(),
            body: self
                .body
                .map(|(low, high)| (low.into_owned(), high.into_owned())),
            marker: self.marker.map(Series::into_owned),
            color: self.color,
            label: self.label,
        }
    }
}

impl std::fmt::Debug for Range<'_> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("Range")
            .field("intervals", &self.low.len())
            .field("boxed", &self.body.is_some())
            .field("color", &self.color)
            .finish()
    }
}

#[cfg(test)]
#[path = "tests/range_tests.rs"]
mod tests;