ggplot_rs/geom/
col.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, RectStyle};
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/// Tessellate a bar — angle span `[t0, t1]`, radius span `[r0, r1]` in
16/// normalized coords — into a radial-sector polygon of pixel points under a
17/// polar `coord`. Both arcs are sampled so the fill follows the circle.
18pub(crate) fn polar_sector(
19    coord: &dyn Coord,
20    area: &crate::render::Rect,
21    t0: f64,
22    t1: f64,
23    r0: f64,
24    r1: f64,
25) -> Vec<(f64, f64)> {
26    const N: usize = 48;
27    let mut pts = Vec::with_capacity(2 * (N + 1));
28    if coord.polar_theta_is_x() {
29        // angle = x: sweep x along the outer radius (r1), back along the inner (r0)
30        for k in 0..=N {
31            let t = t0 + (t1 - t0) * k as f64 / N as f64;
32            pts.push(coord.transform((t, r1), area));
33        }
34        for k in 0..=N {
35            let t = t1 + (t0 - t1) * k as f64 / N as f64;
36            pts.push(coord.transform((t, r0), area));
37        }
38    } else {
39        // angle = y (pie): sweep y along the outer radius (t1), back along t0
40        for k in 0..=N {
41            let r = r0 + (r1 - r0) * k as f64 / N as f64;
42            pts.push(coord.transform((t1, r), area));
43        }
44        for k in 0..=N {
45            let r = r1 + (r0 - r1) * k as f64 / N as f64;
46            pts.push(coord.transform((t0, r), area));
47        }
48    }
49    pts
50}
51
52/// Column geometry — like GeomBar but with pre-computed heights (uses StatIdentity).
53pub struct GeomCol {
54    pub fill: (u8, u8, u8),
55    pub color: (u8, u8, u8),
56    pub alpha: f64,
57    pub width: f64,
58}
59
60impl Default for GeomCol {
61    fn default() -> Self {
62        GeomCol {
63            fill: (97, 156, 255),
64            color: (50, 50, 50),
65            alpha: 1.0,
66            width: 0.9,
67        }
68    }
69}
70
71impl Geom for GeomCol {
72    fn draw(
73        &self,
74        data: &DataFrame,
75        coord: &dyn Coord,
76        scales: &ScaleSet,
77        _theme: &Theme,
78        backend: &mut dyn DrawBackend,
79    ) -> Result<(), RenderError> {
80        let x_col = data
81            .column("x")
82            .ok_or(RenderError::MissingAesthetic("x".into()))?;
83        let y_col = data
84            .column("y")
85            .ok_or(RenderError::MissingAesthetic("y".into()))?;
86        let fill_col = data.column("fill");
87
88        let plot_area = backend.plot_area();
89        let x_scale = scales.get(&Aesthetic::X);
90        let y_scale = scales.get(&Aesthetic::Y);
91        let x_is_discrete = x_scale.map(|s| s.is_discrete()).unwrap_or(false);
92
93        let ymin_col = data.column("ymin");
94        // A `label` mapping (and the value) becomes a hover tooltip on each bar.
95        let label_col = data.column("label");
96
97        // Bar width in normalized coords — computed once, not per row (breaks()
98        // allocates every level label, which made many-category charts O(n²)).
99        let half_width = if x_is_discrete {
100            let n_breaks = x_scale.map(|s| s.breaks().len()).unwrap_or(1);
101            self.width / (n_breaks.max(1) as f64 * 1.1) / 2.0
102        } else {
103            super::continuous_bar_half_width(
104                x_col.iter().filter_map(|v| x_scale.map(|s| s.map(v))),
105                self.width,
106                0.02,
107            )
108        };
109
110        for i in 0..data.nrows() {
111            let nx = x_scale.map(|s| s.map(&x_col[i])).unwrap_or(0.0);
112            let ny = y_scale.map(|s| s.map(&y_col[i])).unwrap_or(0.0);
113            // Honor a stacked/filled base (ymin) so stacked columns draw as
114            // distinct segments rather than all from zero.
115            let ny_base = ymin_col
116                .and_then(|c| c[i].as_f64())
117                .and_then(|v| y_scale.map(|s| s.map(&crate::data::Value::Float(v))))
118                .unwrap_or_else(|| {
119                    y_scale
120                        .map(|s| s.map(&crate::data::Value::Float(0.0)))
121                        .unwrap_or(0.0)
122                });
123
124            let (fr, fg, fb) = if let Some(fc) = fill_col {
125                scales
126                    .map_color(&Aesthetic::Fill, &fc[i])
127                    .unwrap_or(self.fill)
128            } else {
129                self.fill
130            };
131            let style = RectStyle {
132                fill: Some((fr, fg, fb)),
133                stroke: Some(self.color),
134                stroke_width: 0.5,
135                alpha: self.alpha,
136                clip: !coord.is_polar(),
137            };
138
139            let label = label_col.and_then(|c| match &c[i] {
140                crate::data::Value::Str(s) if !s.is_empty() => Some(s.clone()),
141                v => v
142                    .as_f64()
143                    .map(|f| format!("{}", (f * 1000.0).round() / 1000.0)),
144            });
145            // The tooltip reports the measured value — for stacked/filled bars
146            // the segment's own value, not the cumulative stack top.
147            let raw = super::measured_value(data, i);
148            let yval = raw
149                .as_deref()
150                .and_then(|r| r.parse::<f64>().ok())
151                .map(|f| format!("{}", (f * 1000.0).round() / 1000.0));
152            let tip = match (label, yval) {
153                (Some(l), Some(y)) => Some(format!("{l}: {y}")),
154                (Some(l), None) => Some(l),
155                (None, Some(y)) => Some(y),
156                (None, None) => None,
157            };
158            super::set_mark(
159                backend,
160                tip,
161                Some(super::tip_value(&x_col[i])),
162                super::series_key(data, i),
163                raw,
164            );
165
166            if coord.is_polar() {
167                // A bar becomes a radial sector: tessellate the outer arc
168                // (radius = value) and the inner arc (radius = base) so the
169                // filled polygon follows the circle instead of a warped quad.
170                let points = polar_sector(
171                    coord,
172                    &plot_area,
173                    nx - half_width,
174                    nx + half_width,
175                    ny_base,
176                    ny,
177                );
178                backend.draw_polygon(&points, &style)?;
179            } else {
180                let (left_px, top_px) = coord.transform((nx - half_width, ny), &plot_area);
181                let (right_px, bottom_px) = coord.transform((nx + half_width, ny_base), &plot_area);
182                backend.draw_rect(
183                    (left_px, top_px.min(bottom_px)),
184                    (right_px, top_px.max(bottom_px)),
185                    &style,
186                )?;
187            }
188        }
189        super::clear_mark(backend);
190
191        Ok(())
192    }
193
194    fn required_aes(&self) -> Vec<Aesthetic> {
195        vec![Aesthetic::X, Aesthetic::Y]
196    }
197
198    fn default_stat(&self) -> Box<dyn Stat> {
199        Box::new(StatIdentity)
200    }
201
202    fn default_position(&self) -> Box<dyn Position> {
203        Box::new(PositionIdentity)
204    }
205
206    fn default_params(&self) -> GeomParams {
207        GeomParams::default()
208    }
209
210    fn name(&self) -> &str {
211        "col"
212    }
213
214    fn include_zero_baseline(&self) -> bool {
215        true
216    }
217
218    fn set_series_color(&mut self, color: (u8, u8, u8)) {
219        self.fill = color;
220    }
221}
ggplot_rs/geom/col.rs

ggplot_rs/geom/
col.rs
