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        // A discrete-axis dodge stores per-row offsets (in category units) and
111        // the number of groups sharing the slot; bars shift and narrow by them.
112        let x_mapper = super::support::XMapper::new(data, scales);
113        let dodge_n = data.column(crate::position::DODGE_N_COL);
114
115        for i in 0..data.nrows() {
116            let nx = x_mapper.map(&x_col[i], i);
117            let half_width = match dodge_n.and_then(|c| c[i].as_f64()) {
118                Some(n) if n > 1.0 && x_is_discrete => half_width / n,
119                _ => half_width,
120            };
121            let ny = y_scale.map(|s| s.map(&y_col[i])).unwrap_or(0.0);
122            // Honor a stacked/filled base (ymin) so stacked columns draw as
123            // distinct segments rather than all from zero.
124            let ny_base = ymin_col
125                .and_then(|c| c[i].as_f64())
126                .and_then(|v| y_scale.map(|s| s.map(&crate::data::Value::Float(v))))
127                .unwrap_or_else(|| {
128                    y_scale
129                        .map(|s| s.map(&crate::data::Value::Float(0.0)))
130                        .unwrap_or(0.0)
131                });
132
133            let (fr, fg, fb) = if let Some(fc) = fill_col {
134                scales
135                    .map_color(&Aesthetic::Fill, &fc[i])
136                    .unwrap_or(self.fill)
137            } else {
138                self.fill
139            };
140            let style = RectStyle {
141                fill: Some((fr, fg, fb)),
142                stroke: Some(self.color),
143                stroke_width: 0.5,
144                alpha: self.alpha,
145                clip: !coord.is_polar(),
146            };
147
148            let label = label_col.and_then(|c| match &c[i] {
149                crate::data::Value::Str(s) if !s.is_empty() => Some(s.clone()),
150                v => v
151                    .as_f64()
152                    .map(|f| format!("{}", (f * 1000.0).round() / 1000.0)),
153            });
154            // The tooltip reports the measured value — for stacked/filled bars
155            // the segment's own value, not the cumulative stack top.
156            let raw = super::measured_value(data, i);
157            let yval = raw
158                .as_deref()
159                .and_then(|r| r.parse::<f64>().ok())
160                .map(|f| format!("{}", (f * 1000.0).round() / 1000.0));
161            let tip = match (label, yval) {
162                (Some(l), Some(y)) => Some(format!("{l}: {y}")),
163                (Some(l), None) => Some(l),
164                (None, Some(y)) => Some(y),
165                (None, None) => None,
166            };
167            super::set_mark(
168                backend,
169                tip,
170                Some(super::tip_value(&x_col[i])),
171                super::series_key(data, i),
172                raw,
173            );
174
175            if coord.is_polar() {
176                // A bar becomes a radial sector: tessellate the outer arc
177                // (radius = value) and the inner arc (radius = base) so the
178                // filled polygon follows the circle instead of a warped quad.
179                let points = polar_sector(
180                    coord,
181                    &plot_area,
182                    nx - half_width,
183                    nx + half_width,
184                    ny_base,
185                    ny,
186                );
187                backend.draw_polygon(&points, &style)?;
188            } else {
189                let (left_px, top_px) = coord.transform((nx - half_width, ny), &plot_area);
190                let (right_px, bottom_px) = coord.transform((nx + half_width, ny_base), &plot_area);
191                backend.draw_rect(
192                    (left_px, top_px.min(bottom_px)),
193                    (right_px, top_px.max(bottom_px)),
194                    &style,
195                )?;
196            }
197        }
198        super::clear_mark(backend);
199
200        Ok(())
201    }
202
203    fn required_aes(&self) -> Vec<Aesthetic> {
204        vec![Aesthetic::X, Aesthetic::Y]
205    }
206
207    fn default_stat(&self) -> Box<dyn Stat> {
208        Box::new(StatIdentity)
209    }
210
211    fn default_position(&self) -> Box<dyn Position> {
212        Box::new(PositionIdentity)
213    }
214
215    fn default_params(&self) -> GeomParams {
216        GeomParams::default()
217    }
218
219    fn name(&self) -> &str {
220        "col"
221    }
222
223    fn include_zero_baseline(&self) -> bool {
224        true
225    }
226
227    fn set_series_color(&mut self, color: (u8, u8, u8)) {
228        self.fill = color;
229    }
230}
ggplot_rs/geom/col.rs

ggplot_rs/geom/
col.rs
