ggplot_rs/geom/
errorbar.rs

1use crate::aes::Aesthetic;
2use crate::coord::Coord;
3use crate::data::DataFrame;
4use crate::position::identity::PositionIdentity;
5use crate::position::Position;
6use crate::render::backend::{DrawBackend, LineStyle, Linetype};
7use crate::render::RenderError;
8use crate::scale::ScaleSet;
9use crate::stat::identity::StatIdentity;
10use crate::stat::Stat;
11use crate::theme::Theme;
12
13use super::{Geom, GeomParams};
14
15/// Error bar geometry — vertical bars with whisker caps.
16pub struct GeomErrorbar {
17    pub color: (u8, u8, u8),
18    pub width: f64,
19    pub cap_width: f64,
20    pub alpha: f64,
21}
22
23impl Default for GeomErrorbar {
24    fn default() -> Self {
25        GeomErrorbar {
26            color: (0, 0, 0),
27            width: 1.0,
28            cap_width: 0.03,
29            alpha: 1.0,
30        }
31    }
32}
33
34impl Geom for GeomErrorbar {
35    fn draw(
36        &self,
37        data: &DataFrame,
38        coord: &dyn Coord,
39        scales: &ScaleSet,
40        _theme: &Theme,
41        backend: &mut dyn DrawBackend,
42    ) -> Result<(), RenderError> {
43        let x_col = data
44            .column("x")
45            .ok_or(RenderError::MissingAesthetic("x".into()))?;
46        let ymin_col = data
47            .column("ymin")
48            .ok_or(RenderError::MissingAesthetic("ymin".into()))?;
49        let ymax_col = data
50            .column("ymax")
51            .ok_or(RenderError::MissingAesthetic("ymax".into()))?;
52
53        let plot_area = backend.plot_area();
54        let y_scale = scales.get(&Aesthetic::Y);
55
56        let style = LineStyle {
57            color: self.color,
58            alpha: self.alpha,
59            width: self.width,
60            linetype: Linetype::Solid,
61            ..Default::default()
62        };
63
64        let xm = super::support::XMapper::new(data, scales);
65        let color_col = data.column("color");
66        let dodge_n_col = data.column(crate::position::DODGE_N_COL);
67        for i in 0..data.nrows() {
68            let nx = xm.map(&x_col[i], i);
69            let ny_min = y_scale.map(|s| s.map(&ymin_col[i])).unwrap_or(0.0);
70            let ny_max = y_scale.map(|s| s.map(&ymax_col[i])).unwrap_or(0.0);
71            let color = color_col
72                .and_then(|cc| scales.map_color(&Aesthetic::Color, &cc[i]))
73                .unwrap_or(self.color);
74            let style = LineStyle {
75                color,
76                ..style.clone()
77            };
78
79            // One connected polyline per bar — cap, bar, cap — transformed
80            // point by point so it is correct under coord_flip too.
81            // B3-7 (allowed #8): a discrete `position_dodge` shrinks the
82            // cap by the dodge group count, so caps from adjacent groups
83            // don't visually overlap — same idea as the bar/point offset
84            // `XMapper` already applies.
85            let dodge_n = dodge_n_col
86                .and_then(|c| c.get(i))
87                .and_then(|v| v.as_f64())
88                .filter(|v| v.is_finite() && *v > 0.0)
89                .unwrap_or(1.0);
90            let c = self.cap_width / dodge_n;
91            let t = |p: (f64, f64)| coord.transform(p, &plot_area);
92            super::support::mark_interval(
93                backend,
94                scales,
95                data,
96                i,
97                &x_col[i],
98                &ymin_col[i],
99                &ymax_col[i],
100            );
101            backend.draw_line(
102                &[
103                    t((nx - c, ny_max)),
104                    t((nx + c, ny_max)),
105                    t((nx, ny_max)),
106                    t((nx, ny_min)),
107                    t((nx - c, ny_min)),
108                    t((nx + c, ny_min)),
109                ],
110                &style,
111            )?;
112        }
113        super::clear_mark(backend);
114
115        Ok(())
116    }
117
118    fn required_aes(&self) -> Vec<Aesthetic> {
119        vec![Aesthetic::X, Aesthetic::Ymin, Aesthetic::Ymax]
120    }
121
122    fn default_stat(&self) -> Box<dyn Stat> {
123        Box::new(StatIdentity)
124    }
125    fn default_position(&self) -> Box<dyn Position> {
126        Box::new(PositionIdentity)
127    }
128    fn default_params(&self) -> GeomParams {
129        GeomParams::default()
130    }
131    fn name(&self) -> &str {
132        "errorbar"
133    }
134
135    fn apply_element_geom(&mut self, el: &crate::theme::elements::ElementGeom) {
136        if let (true, Some(ink)) = (self.color == (0, 0, 0), el.ink) {
137            self.color = ink;
138        }
139    }
140
141    fn set_series_color(&mut self, color: (u8, u8, u8)) {
142        self.color = color;
143    }
144}
ggplot_rs/geom/errorbar.rs

ggplot_rs/geom/
errorbar.rs
