four-bar 7.0.5

//! Plot utitlities.
//!
//! Please see [`crate::plot::fb::Figure`] and [`crate::plot::sfb::Figure`] for
//! more information.
//!
//! # Single Plot Example
//!
//! ```
//! use four_bar::plot::*;
//!
//! let fig = fb::Figure::new().add_line("", vec![[0.; 2], [1.; 2]], Style::Line, BLACK);
//! let mut buf = String::new();
//! let svg = SVGBackend::with_string(&mut buf, (1600, 1600));
//! fig.plot(svg).unwrap();
//! ```
//!
//! # Sub-plots Example
//!
//! ```
//! use four_bar::plot::*;
//!
//! let fig = fb::Figure::new().add_line("", vec![[0.; 2], [1.; 2]], Style::Line, BLACK);
//! let mut buf = String::new();
//! let svg = SVGBackend::with_string(&mut buf, (1600, 800));
//! let (root_l, root_r) = svg.into_drawing_area().split_horizontally(800);
//! fig.plot(root_l).unwrap();
//! fig.plot(root_r).unwrap();
//! ```
use self::{ball::*, dashed_line::*, dotted_line::*};
use crate::*;
use efd::na;
use fmtastic::Subscript;
#[doc(no_inline)]
pub use plotters::{prelude::*, *};
use std::{borrow::Cow, iter::zip};

mod ball;
mod dashed_line;
mod dotted_line;
pub mod fb;
pub mod mfb;
pub mod sfb;

pub(crate) type PResult<T, B> = Result<T, DrawingAreaErrorKind<<B as DrawingBackend>::ErrorType>>;
pub(crate) type Canvas<B> = DrawingArea<B, coord::Shift>;

macro_rules! inner_opt {
    ($($(#[$meta:meta])+ fn $name:ident($ty:ty))+) => {$(
        $(#[$meta])+
        pub fn $name(mut self, $name: $ty) -> Self {
            self.$name = $name;
            self
        }
    )+};
}

#[inline]
pub(crate) fn to_i((x, y): (f32, f32)) -> (i32, i32) {
    (x.round() as i32, y.round() as i32)
}

#[inline]
pub(crate) fn to_f((x, y): (i32, i32)) -> (f32, f32) {
    (x as f32, y as f32)
}

// Rounding float numbers without trailing zeros
pub(crate) fn formatter(v: &f64) -> String {
    let mut s = format!("{v:.04}");
    let sub = s.trim_end_matches('0');
    s.truncate(sub.strip_suffix('.').unwrap_or(sub).len());
    if s == "-0" {
        s.remove(0);
    }
    s
}

/// The extreme values of the data.
///
/// ```
/// use four_bar::plot::ExtBound;
///
/// let data = vec![[1.], [2.], [3.]];
/// let ext = ExtBound::from_pts(&data);
/// assert_eq!(ext.min, [1.]);
/// assert_eq!(ext.max, [3.]);
/// ```
pub struct ExtBound<const D: usize> {
    /// Minimum values.
    pub min: [f64; D],
    /// Maximum values.
    pub max: [f64; D],
}

impl<T, const D: usize> FromIterator<T> for ExtBound<D>
where
    T: std::borrow::Borrow<[f64; D]>,
{
    /// Allow `Iter<Item = [f64; D]>` and `&[f64; D]` to be converted to
    /// `ExtBound<D>`.
    fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
        iter.into_iter().fold(Self::INFINITY, |mut bound, p| {
            for ((max, min), p) in zip(zip(&mut bound.max, &mut bound.min), p.borrow()) {
                *min = min.min(*p);
                *max = max.max(*p);
            }
            bound
        })
    }
}

impl<const D: usize> FromIterator<ExtBound<D>> for ExtBound<D> {
    fn from_iter<T: IntoIterator<Item = ExtBound<D>>>(iter: T) -> Self {
        iter.into_iter().fold(Self::INFINITY, |mut bound, ext| {
            let ext = zip(&ext.max, &ext.min);
            for ((max, min), (ext_max, ext_min)) in zip(zip(&mut bound.max, &mut bound.min), ext) {
                *min = min.min(*ext_min);
                *max = max.max(*ext_max);
            }
            bound
        })
    }
}

impl<const D: usize> ExtBound<D> {
    /// Create a new boundary with infinity.
    pub const INFINITY: Self = Self::new([f64::INFINITY; D], [f64::NEG_INFINITY; D]);

    /// Create a new boundary.
    pub const fn new(min: [f64; D], max: [f64; D]) -> Self {
        Self { min, max }
    }

    /// Map the extreme values to another type.
    pub fn map_to<F, R>(self, f: F) -> [R; D]
    where
        F: Fn(f64, f64) -> R,
    {
        std::array::from_fn(|i| f(self.min[i], self.max[i]))
    }

    /// Get the center of the boundary.
    pub fn center(&self) -> [f64; D] {
        std::array::from_fn(|i| (self.min[i] + self.max[i]) * 0.5)
    }

    /// Change to square boundary by the maximum range.
    ///
    /// ```
    /// use four_bar::plot::ExtBound;
    ///
    /// let ext = ExtBound::new([0., 0.], [1., 2.]).to_square(0.);
    /// assert_eq!(ext.min, [-0.5, 0.]);
    /// assert_eq!(ext.max, [1.5, 2.]);
    /// ```
    pub fn to_square(mut self, margin: f64) -> Self {
        let center = self.center();
        let width = zip(&self.min, &self.max)
            .map(|(min, max)| (max - min).abs())
            .fold(0., f64::max)
            * 0.5
            * (1. + margin);
        // Extand to same range
        for ((min, max), center) in zip(zip(&mut self.min, &mut self.max), &center) {
            *min = center - width;
            *max = center + width;
        }
        self
    }
}

/// Line style.
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[derive(Clone, Copy, PartialEq, Eq, Default)]
#[non_exhaustive]
pub enum Style {
    /// Continuous Line
    #[default]
    Line,
    /// Dashed Line
    DashedLine,
    /// Dotted Line
    DottedLine,
    /// Dash-dotted Line
    DashDottedLine,
    /// Circle Marker
    Circle,
    /// Triangle Marker
    Triangle,
    /// Cross Marker
    Cross,
    /// Square Marker
    Square,
}

impl Style {
    /// Style list.
    pub const LIST: [Self; 8] = [
        Self::Line,
        Self::DashedLine,
        Self::DottedLine,
        Self::DashDottedLine,
        Self::Circle,
        Self::Triangle,
        Self::Cross,
        Self::Square,
    ];

    /// Get the style names.
    pub const fn name(&self) -> &'static str {
        match self {
            Self::Line => "Continuous Line",
            Self::DashedLine => "Dashed Line",
            Self::DottedLine => "Dotted Line",
            Self::DashDottedLine => "Dash-dotted Line",
            Self::Circle => "Circle Marker",
            Self::Triangle => "Triangle Marker",
            Self::Cross => "Cross Marker",
            Self::Square => "Square Marker",
        }
    }

    /// Check if the style is a line or marker.
    pub const fn is_line(&self) -> bool {
        matches!(
            self,
            Self::Line | Self::DashedLine | Self::DottedLine | Self::DashDottedLine
        )
    }

    pub(crate) fn draw<'a, DB, CT, I>(
        &self,
        chart: &mut ChartContext<'a, DB, CT>,
        line: I,
        &color: &ShapeStyle,
        label: &str,
        font: f64,
    ) -> PResult<(), DB>
    where
        DB: DrawingBackend + 'a,
        CT: CoordTranslate,
        CT::From: Clone + 'static,
        I: IntoIterator<Item = CT::From>,
        I::IntoIter: Clone,
    {
        let font = (font * 0.9) as i32;
        let gap = color.stroke_width as i32;
        let has_label = !label.is_empty();
        macro_rules! impl_marker {
            ($mk:expr) => {{
                let dot_size = color.stroke_width * 2;
                let color = color.stroke_width(color.stroke_width / 2);
                let mk_f = $mk; // Generic function 1
                let line = line.into_iter().map(|c| mk_f(c, dot_size, color));
                let anno = chart.draw_series(line)?;
                if has_label {
                    let mk_f = $mk; // Generic function 2
                    anno.label(label)
                        .legend(move |(x, y)| mk_f((x + font / 2, y), dot_size, color));
                }
            }};
        }
        match self {
            Self::Line => {
                let line = LineSeries::new(line, color);
                let anno = chart.draw_series(line)?;
                if has_label {
                    anno.label(label);
                    anno.legend(move |c| {
                        EmptyElement::at(c) + PathElement::new([(gap, 0), (font - gap, 0)], color)
                    });
                }
            }
            Self::DashedLine => {
                let series = DashedPath::new(line, 30, 15, color).series();
                let anno = chart.draw_series(series)?;
                if has_label {
                    anno.label(label);
                    anno.legend(move |c| {
                        EmptyElement::at(c)
                            + DashedPath::new([(gap, 0), (font - gap, 0)], 30, 15, color)
                    });
                }
            }
            Self::DottedLine => {
                let dot_size = color.stroke_width;
                let mk_color = color.stroke_width(color.stroke_width / 2);
                let mk_f = move |c| Circle::new(c, dot_size, mk_color);
                let series = DottedPath::new(line, 0, 20, mk_f).series();
                let anno = chart.draw_series(series)?;
                if has_label {
                    anno.label(label);
                    anno.legend(move |c| {
                        EmptyElement::at(c)
                            + DottedPath::new([(gap, 0), (font - gap, 0)], 0, 20, mk_f)
                    });
                }
            }
            Self::DashDottedLine => {
                let line = line.into_iter();
                let series = DashedPath::new(line.clone(), 30, 16, color).series();
                chart.draw_series(series)?;
                let dot_size = color.stroke_width / 2;
                let mk_f = move |c| Circle::new(c, dot_size, color.filled());
                let series = DottedPath::new(line, 30 + 8, 30 + 16, mk_f).series();
                let anno = chart.draw_series(series)?;
                if has_label {
                    anno.label(label);
                    let points = [(gap, 0), (font - gap, 0)];
                    anno.legend(move |c| {
                        EmptyElement::at(c)
                            + DashedPath::new(points, 30, 16, color)
                            + DottedPath::new(points, 30 + 8, 30 + 16, mk_f)
                    });
                }
            }
            Self::Circle => impl_marker!(Circle::new),
            Self::Triangle => impl_marker!(TriangleMarker::new),
            Self::Cross => impl_marker!(Cross::new),
            Self::Square => impl_marker!(|pos, dot_size, color| {
                let r = dot_size as i32 / 2;
                EmptyElement::at(pos) + Rectangle::new([(r, r), (-r, -r)], color)
            }),
        }
        Ok(())
    }
}

/// Legend position option.
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "clap", derive(clap::ValueEnum))]
#[derive(Clone, Copy, PartialEq, Eq, Default, Debug)]
pub enum LegendPos {
    /// Hide Legend
    Hide,
    /// Upper Left
    UL,
    /// Middle Left
    ML,
    /// Lower Left
    LL,
    /// Upper Middle
    UM,
    /// Middle Middle
    MM,
    /// Lower Middle
    LM,
    /// Upper Right
    #[default]
    UR,
    /// Middle Right
    MR,
    /// Lower Right
    LR,
}

impl LegendPos {
    /// Position list.
    pub const LIST: [Self; 10] = [
        Self::Hide,
        Self::UL,
        Self::ML,
        Self::LL,
        Self::UM,
        Self::MM,
        Self::LM,
        Self::UR,
        Self::MR,
        Self::LR,
    ];

    /// Get the option names.
    pub const fn name(&self) -> &'static str {
        match self {
            Self::Hide => "Hide",
            Self::UL => "Upper Left",
            Self::ML => "Middle Left",
            Self::LL => "Lower Left",
            Self::UM => "Upper Middle",
            Self::MM => "Middle Middle",
            Self::LM => "Lower Middle",
            Self::UR => "Upper Right",
            Self::MR => "Middle Right",
            Self::LR => "Lower Right",
        }
    }

    /// Transform to plotters option.
    pub fn to_plotter_pos(&self) -> Option<SeriesLabelPosition> {
        use SeriesLabelPosition::*;
        Some(match self {
            Self::Hide => None?,
            Self::UL => UpperLeft,
            Self::ML => MiddleLeft,
            Self::LL => LowerLeft,
            Self::UM => UpperMiddle,
            Self::MM => MiddleMiddle,
            Self::LM => LowerMiddle,
            Self::UR => UpperRight,
            Self::MR => MiddleRight,
            Self::LR => LowerRight,
        })
    }
}

/// Line type of the [`LineData`].
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[derive(Clone)]
pub enum LineType<'a, C: Clone> {
    /// Simple Line
    Line(Cow<'a, [C]>),
    /// Motion Line
    Pose {
        /// Curve data
        curve_p: Cow<'a, [C]>,
        /// Pose data (`curve` + `uvec`)
        curve_q: Cow<'a, [C]>,
        /// Use frame style
        is_frame: bool,
    },
}

impl<'a, C: Clone> LineType<'a, C> {
    /// Create a new empty line.
    pub const fn new_empty() -> Self {
        Self::Line(Cow::Borrowed(&[]))
    }
}

impl<'a, const D: usize> LineType<'a, [f64; D]> {
    /// Get the boundary of the line.
    pub fn boundary(&self) -> ExtBound<D> {
        match self {
            Self::Line(line) => line.iter().collect(),
            Self::Pose { curve_p: curve, curve_q: pose, is_frame: _ } => {
                curve.iter().chain(pose.iter()).collect()
            }
        }
    }
}

impl<C: Clone> Default for LineType<'_, C> {
    fn default() -> Self {
        Self::new_empty()
    }
}

/// Drawing options of a line series.
#[cfg_attr(
    feature = "serde",
    derive(serde::Deserialize, serde::Serialize),
    serde(default)
)]
#[derive(Clone)]
pub struct LineData<'a, C: Clone> {
    /// Label of the line
    pub label: Cow<'a, str>,
    /// Line data
    pub line: LineType<'a, C>,
    /// Line style
    pub style: Style,
    /// Line color
    #[cfg_attr(feature = "serde", serde(with = "ShapeStyleSerde"))]
    pub color: ShapeStyle,
}

impl<const D: usize> LineData<'_, [f64; D]> {
    fn draw<'a, DB, CT>(
        &self,
        chart: &mut ChartContext<'a, DB, CT>,
        stroke: u32,
        font: f64,
    ) -> PResult<(), DB>
    where
        DB: DrawingBackend + 'a,
        CT: CoordTranslate,
        CT::From: From<[f64; D]> + Clone + 'static,
    {
        let LineData { label, line, style, color } = self;
        let color = color.stroke_width(stroke);
        match line {
            LineType::Line(line) => {
                let line = line.iter().map(|&c| c.into());
                style.draw(chart, line, &color, label, font)
            }
            LineType::Pose { curve_p: curve, curve_q: pose, is_frame } => {
                let curve = curve.iter().map(|&c| c.into());
                let pose = pose.iter().map(|&c| c.into());
                if *is_frame {
                    let iter = zip(curve.clone(), pose.clone());
                    let last = iter.len();
                    for (i, (p, v)) in iter.enumerate() {
                        if i == 0 || i == last - 1 {
                            style.draw(chart, [p, v], &color, "", font)?;
                        }
                    }
                } else {
                    for (p, v) in zip(curve.clone(), pose.clone()) {
                        style.draw(chart, [p, v], &color, "", font)?;
                    }
                }
                style.draw(chart, curve, &color, label, font)?;
                let guid_style = if *is_frame { style } else { &Style::Circle };
                guid_style.draw(chart, pose, &color, "", font)
            }
        }
    }
}

#[cfg(feature = "serde")]
#[derive(serde::Serialize, serde::Deserialize)]
#[serde(remote = "RGBAColor")]
struct RGBAColorSerde(u8, u8, u8, f64);

#[cfg(feature = "serde")]
#[derive(serde::Serialize, serde::Deserialize)]
#[serde(remote = "ShapeStyle")]
struct ShapeStyleSerde {
    #[serde(with = "RGBAColorSerde")]
    color: RGBAColor,
    filled: bool,
    stroke_width: u32,
}

impl<'a, C: Clone> Default for LineData<'a, C> {
    fn default() -> Self {
        Self {
            label: Cow::Borrowed(""),
            line: LineType::default(),
            style: Style::default(),
            color: RED.into(),
        }
    }
}

/// Drawing implementation.
pub trait Plot {
    /// Plot the figure with the backend and an optional time parameter.
    fn plot_by<B>(&self, root: &Canvas<B>, t: Option<f64>) -> PResult<(), B>
    where
        B: DrawingBackend;

    /// Plot the figure with the backend.
    fn plot<B, R>(&self, root: R) -> PResult<(), B>
    where
        B: DrawingBackend,
        Canvas<B>: From<R>,
    {
        self.plot_by(&Canvas::from(root), None)
    }
}

/// Option type base.
#[cfg_attr(
    feature = "serde",
    derive(serde::Deserialize, serde::Serialize),
    serde(default)
)]
#[derive(Clone)]
pub struct FigureBase<'a, 'b, M: Clone, C: Clone> {
    /// Linkage
    pub fb: Option<Cow<'b, M>>,
    /// Line data
    pub lines: Vec<LineData<'a, C>>,
    /// Drawing options
    pub opt: Opt<'a>,
}

impl<M: Clone, C: Clone> Default for FigureBase<'_, '_, M, C> {
    fn default() -> Self {
        Self::new()
    }
}

impl<'a, 'b, M: Clone, C: Clone> FigureBase<'a, 'b, M, C> {
    /// Create a new figure without linkage.
    pub const fn new() -> Self {
        Self { fb: None, lines: Vec::new(), opt: Opt::new() }
    }

    /// Create from an optional linkage.
    pub const fn new_fb(fb: M) -> Self {
        Self {
            fb: Some(Cow::Owned(fb)),
            lines: Vec::new(),
            opt: Opt::new(),
        }
    }

    /// Create from an optional linkage reference.
    pub const fn new_ref(fb: &'b M) -> Self {
        Self {
            fb: Some(Cow::Borrowed(fb)),
            lines: Vec::new(),
            opt: Opt::new(),
        }
    }

    /// Set the linkage.
    pub fn set_fb(&mut self, fb: M) {
        self.fb = Some(Cow::Owned(fb));
    }

    /// Set the linkage.
    pub fn set_fb_ref(&mut self, fb: &'b M) {
        self.fb = Some(Cow::Borrowed(fb));
    }

    /// Remove linkage.
    pub fn remove_fb(&mut self) {
        self.fb = None;
    }

    /// Set the font family.
    pub fn font_family(mut self, family: impl Into<Cow<'a, str>>) -> Self {
        self.font_family = Some(family.into());
        self
    }

    inner_opt! {
        /// Set the line stroke of the linkage.
        fn stroke(u32)
        /// Set font size.
        fn font(f64)
        /// Use grid in the plot.
        fn grid(bool)
        /// Show the axis.
        fn axis(bool)
        /// Set legend position.
        fn legend(LegendPos)
    }

    /// Set the inner options.
    pub fn with_opt(self, opt: Opt<'a>) -> Self {
        Self { opt, ..self }
    }

    /// Add a line.
    pub fn add_line<S, L>(mut self, label: S, line: L, style: Style, color: RGBColor) -> Self
    where
        S: Into<Cow<'a, str>>,
        L: Into<Cow<'a, [C]>>,
    {
        self.push_line(label, line, style, color);
        self
    }

    /// Add a line with default settings.
    pub fn add_line_default<S, L>(mut self, label: S, line: L) -> Self
    where
        S: Into<Cow<'a, str>>,
        L: Into<Cow<'a, [C]>>,
    {
        self.push_line_default(label, line);
        self
    }

    /// Add a line from a [`LineData`] instance.
    pub fn add_line_data(mut self, data: LineData<'a, C>) -> Self {
        self.push_line_data(data);
        self
    }

    /// Add a line in-placed.
    pub fn push_line<S, L, Color>(&mut self, label: S, line: L, style: Style, color: Color)
    where
        S: Into<Cow<'a, str>>,
        L: Into<Cow<'a, [C]>>,
        Color: Into<ShapeStyle>,
    {
        self.push_line_data(LineData {
            label: label.into(),
            line: LineType::Line(line.into()),
            style,
            color: color.into(),
        });
    }

    /// Add a line with default settings in-placed.
    pub fn push_line_default<S, L>(&mut self, label: S, line: L)
    where
        S: Into<Cow<'a, str>>,
        L: Into<Cow<'a, [C]>>,
    {
        self.push_line(label, line, Style::default(), RED);
    }

    /// Add a line from a [`LineData`] instance in-placed.
    pub fn push_line_data(&mut self, data: LineData<'a, C>) {
        self.lines.push(data);
    }

    /// Iterate over lines.
    pub fn lines(&self) -> impl Iterator<Item = &LineData<'a, C>> {
        self.lines.iter()
    }

    /// Get a mutable reference to the lines.
    pub fn lines_mut(&mut self) -> impl Iterator<Item = &mut LineData<'a, C>> {
        self.lines.iter_mut()
    }

    /// Retain lines with a predicate.
    pub fn retain_lines(&mut self, mut f: impl FnMut(usize, &mut LineData<'a, C>) -> bool) {
        let mut i = 0;
        self.lines.retain_mut(|line| {
            i += 1;
            f(i, line)
        });
    }

    /// Swap two lines with their indices.
    pub fn swap_lines(&mut self, i: usize, j: usize) {
        self.lines.swap(i, j);
    }

    pub(crate) fn has_legend(&self) -> bool {
        self.lines.iter().any(|data| !data.label.is_empty())
    }

    #[inline]
    pub(crate) fn check_empty<B: DrawingBackend>(&self) -> PResult<(), B> {
        (!self.lines.is_empty() || self.fb.is_some())
            .then_some(())
            .ok_or(DrawingAreaErrorKind::LayoutError)
    }

    pub(crate) fn as_fb(&self) -> Option<&M> {
        self.fb.as_deref()
    }

    fn get_t<const D: usize>(&self, curr: usize, total: usize) -> f64
    where
        M: crate::mech::CurveGen<D>,
    {
        use std::f64::consts::TAU;
        let Some([start, end]) = self.as_fb().and_then(|fb| fb.angle_bound().to_value()) else {
            return 0.;
        };
        let end = if end > start { end } else { end + TAU };
        let step = (end - start) / total as f64;
        start + curr as f64 * step
    }

    pub(crate) fn get_joints<const D: usize>(&self, t: f64) -> Option<[[f64; D]; 5]>
    where
        M: crate::mech::CurveGen<D>,
    {
        self.as_fb().and_then(|fb| fb.pos(t))
    }

    pub(crate) fn get_joints_auto<F, const D: usize>(&self, coord_map: F) -> Option<[[f64; D]; 5]>
    where
        M: crate::mech::CurveGen<D>,
        F: Fn([f64; D]) -> na::Point2<f64>,
    {
        use std::f64::consts::TAU;
        const RES: usize = 90;
        fn angle(a: na::Point2<f64>, b: na::Point2<f64>, c: na::Point2<f64>) -> f64 {
            let ab = a - b;
            let cb = c - b;
            (ab.dot(&cb) / (ab.norm() * cb.norm())).acos()
        }
        let fb = self.as_fb()?;
        let [start, end] = fb.angle_bound().to_value()?;
        let end = if end > start { end } else { end + TAU };
        let step = (end - start) / RES as f64;
        let (t, _) = (0..=RES)
            .map(|t| start + t as f64 * step)
            .filter_map(|t| Some((t, fb.pos(t)?)))
            .map(|(t, p)| {
                let [p1, p2, p3, p4, p5] = p.map(&coord_map);
                let min_angle = angle(p1, p3, p4)
                    .min(angle(p1, p3, p5))
                    .min(angle(p2, p4, p3))
                    .min(angle(p2, p4, p5));
                (t, min_angle)
            })
            .max_by(|(_, a1), (_, a2)| a1.partial_cmp(a2).unwrap())?;
        fb.pos(t)
    }

    // (stroke, dot_size)
    pub(crate) fn get_dot_size(&self) -> (u32, u32) {
        (self.stroke, (self.stroke as f32 * 1.5) as u32)
    }

    #[inline]
    fn get_family(&self) -> &str {
        const DEFAULT_FONT: &str = "Times New Roman";
        self.font_family.as_deref().unwrap_or(DEFAULT_FONT)
    }

    pub(crate) fn get_font(&self) -> FontDesc<'_> {
        (self.get_family(), self.font).into_font()
    }

    pub(crate) fn get_big_font(&self) -> FontDesc<'_> {
        (self.get_family(), self.font * 1.15).into_font()
    }

    /// Plot curves and linkages.
    ///
    /// 2D example:
    ///
    /// ```
    /// use four_bar::{plot::*, FourBar};
    /// let fb = FourBar::example();
    /// let mut buf = String::new();
    /// fb::Figure::new_ref(&fb)
    ///     .axis(false)
    ///     .add_line("First Curve", fb.curve(180), Style::Line, BLACK)
    ///     .plot(SVGBackend::with_string(&mut buf, (1600, 1600)))
    ///     .unwrap();
    /// ```
    ///
    /// 3D example:
    ///
    /// ```
    /// use four_bar::{plot::*, SFourBar};
    /// let fb = SFourBar::example();
    /// let mut buf = String::new();
    /// sfb::Figure::new_ref(&fb)
    ///     .axis(false)
    ///     .add_line("First Curve", fb.curve(180), Style::Line, BLACK)
    ///     .plot(SVGBackend::with_string(&mut buf, (1600, 1600)))
    ///     .unwrap();
    /// ```
    pub fn plot<B, R>(&self, root: R) -> PResult<(), B>
    where
        B: DrawingBackend,
        Canvas<B>: From<R>,
        Self: Plot,
    {
        Plot::plot(self, root)
    }

    /// Plot the 2D curve and linkages dynamically.
    ///
    /// This is the `curr`/`total` frame of the animation.
    pub fn plot_video<B, R, const D: usize>(
        &self,
        root: R,
        curr: usize,
        total: usize,
    ) -> PResult<(), B>
    where
        B: DrawingBackend,
        Canvas<B>: From<R>,
        M: crate::mech::CurveGen<D>,
        Self: Plot,
    {
        Plot::plot_by(self, &Canvas::from(root), Some(self.get_t(curr, total)))
    }
}

impl<'a, M: Clone, const D: usize> FigureBase<'a, '_, M, [f64; D]> {
    /// Add a line with unit vectors.
    pub fn add_pose<S, L1, L2, Color>(
        mut self,
        label: S,
        pose: (L1, L2, f64),
        style: Style,
        color: Color,
        is_frame: bool,
    ) -> Self
    where
        S: Into<Cow<'a, str>>,
        Cow<'a, [[f64; D]]>: From<L1> + From<L2>,
        Color: Into<ShapeStyle>,
    {
        self.push_pose(label, pose, style, color, is_frame);
        self
    }

    /// Add a line with unit vectors in-placed.
    pub fn push_pose<S, L1, L2, Color>(
        &mut self,
        label: S,
        (curve, uvec, length): (L1, L2, f64),
        style: Style,
        color: Color,
        is_frame: bool,
    ) where
        S: Into<Cow<'a, str>>,
        Cow<'a, [[f64; D]]>: From<L1> + From<L2>,
        Color: Into<ShapeStyle>,
    {
        let curve_p = Cow::from(curve);
        let uvec = Cow::from(uvec);
        let curve_q = zip(&*curve_p, &*uvec)
            .map(|(p, v)| std::array::from_fn(|i| p[i] + length * v[i]))
            .collect::<Vec<_>>();
        self.push_series(label, (curve_p, curve_q), style, color, is_frame);
    }

    /// Add a line with unit vectors and default settings.
    pub fn push_pose_default<S, L1, L2>(&mut self, label: S, pose: (L1, L2, f64), is_frame: bool)
    where
        S: Into<Cow<'a, str>>,
        Cow<'a, [[f64; D]]>: From<L1> + From<L2>,
    {
        self.push_pose(label, pose, Style::default(), RED, is_frame);
    }

    /// Add two lines as a motion.
    pub fn add_series<S, L1, L2, Color>(
        mut self,
        label: S,
        series: (L1, L2),
        style: Style,
        color: Color,
        is_frame: bool,
    ) -> Self
    where
        S: Into<Cow<'a, str>>,
        Cow<'a, [[f64; D]]>: From<L1> + From<L2>,
        Color: Into<ShapeStyle>,
    {
        self.push_series(label, series, style, color, is_frame);
        self
    }

    /// Add two lines as a motion in-placed.
    pub fn push_series<S, L1, L2, Color>(
        &mut self,
        label: S,
        (curve_p, curve_q): (L1, L2),
        style: Style,
        color: Color,
        is_frame: bool,
    ) where
        S: Into<Cow<'a, str>>,
        Cow<'a, [[f64; D]]>: From<L1> + From<L2>,
        Color: Into<ShapeStyle>,
    {
        let label = label.into();
        let line = LineType::Pose {
            curve_p: curve_p.into(),
            curve_q: curve_q.into(),
            is_frame,
        };
        self.push_line_data(LineData { label, line, style, color: color.into() });
    }

    /// Add two lines as a motion with default settings.
    pub fn push_series_default<S, L1, L2>(&mut self, label: S, series: (L1, L2), is_frame: bool)
    where
        S: Into<Cow<'a, str>>,
        Cow<'a, [[f64; D]]>: From<L1> + From<L2>,
    {
        self.push_series(label, series, Style::default(), RED, is_frame);
    }
}

impl<'a, M: Clone, C: Clone> std::ops::Deref for FigureBase<'a, '_, M, C> {
    type Target = Opt<'a>;
    fn deref(&self) -> &Self::Target {
        &self.opt
    }
}

impl<'a, M: Clone, C: Clone> std::ops::DerefMut for FigureBase<'a, '_, M, C> {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.opt
    }
}

/// 2D/3D plot option.
#[cfg_attr(
    feature = "serde",
    derive(serde::Deserialize, serde::Serialize),
    serde(default)
)]
#[derive(Clone, PartialEq)]
pub struct Opt<'a> {
    /// Stroke size
    pub stroke: u32,
    /// Font size
    pub font: f64,
    /// Font family
    pub font_family: Option<Cow<'a, str>>,
    /// Show grid
    pub grid: bool,
    /// Show axis
    pub axis: bool,
    /// Legend position
    pub legend: LegendPos,
}

impl Opt<'_> {
    /// Create a new instance.
    pub const fn new() -> Self {
        Self {
            stroke: 7,
            font: 90.,
            font_family: None,
            grid: false,
            axis: true,
            legend: LegendPos::UR,
        }
    }
}

impl Default for Opt<'_> {
    fn default() -> Self {
        Self::new()
    }
}