ggplot_rs/geom/
count.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, PointShape, PointStyle};
7use crate::render::RenderError;
8use crate::scale::ScaleSet;
9use crate::stat::sum::StatSum;
10use crate::stat::Stat;
11use crate::theme::Theme;
12
13use super::{Geom, GeomParams};
14
15/// Count geometry — draws points sized by the number of overlapping observations.
16pub struct GeomCount {
17    pub color: (u8, u8, u8),
18    pub alpha: f64,
19    pub min_size: f64,
20    pub max_size: f64,
21}
22
23impl Default for GeomCount {
24    fn default() -> Self {
25        GeomCount {
26            color: (50, 50, 50),
27            alpha: 0.7,
28            min_size: 2.0,
29            max_size: 12.0,
30        }
31    }
32}
33
34impl Geom for GeomCount {
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 y_col = data
47            .column("y")
48            .ok_or(RenderError::MissingAesthetic("y".into()))?;
49        let n_col = data
50            .column("n")
51            .ok_or(RenderError::MissingAesthetic("n".into()))?;
52
53        let plot_area = backend.plot_area();
54        let x_scale = scales.get(&Aesthetic::X);
55        let y_scale = scales.get(&Aesthetic::Y);
56
57        // Compute n range for size scaling
58        let n_values: Vec<f64> = n_col.iter().filter_map(|v| v.as_f64()).collect();
59        let n_min = n_values.iter().cloned().fold(f64::INFINITY, f64::min);
60        let n_max = n_values.iter().cloned().fold(f64::NEG_INFINITY, f64::max);
61        let n_range = n_max - n_min;
62
63        for i in 0..data.nrows() {
64            let nx = x_scale.map(|s| s.map(&x_col[i])).unwrap_or(0.0);
65            let ny = y_scale.map(|s| s.map(&y_col[i])).unwrap_or(0.0);
66            let (px, py) = coord.transform((nx, ny), &plot_area);
67
68            let n = n_col[i].as_f64().unwrap_or(1.0);
69            let size = if n_range > 0.0 {
70                self.min_size + (n - n_min) / n_range * (self.max_size - self.min_size)
71            } else {
72                (self.min_size + self.max_size) / 2.0
73            };
74
75            let color = scales
76                .map_color(&Aesthetic::Color, &x_col[i])
77                .unwrap_or(self.color);
78
79            backend.draw_shape(
80                (px, py),
81                size,
82                &PointStyle {
83                    color,
84                    alpha: self.alpha,
85                    filled: true,
86                    shape: PointShape::Circle,
87                },
88            )?;
89        }
90
91        Ok(())
92    }
93
94    fn required_aes(&self) -> Vec<Aesthetic> {
95        vec![Aesthetic::X, Aesthetic::Y]
96    }
97
98    fn default_stat(&self) -> Box<dyn Stat> {
99        Box::new(StatSum)
100    }
101
102    fn default_position(&self) -> Box<dyn Position> {
103        Box::new(PositionIdentity)
104    }
105
106    fn default_params(&self) -> GeomParams {
107        GeomParams::default()
108    }
109
110    fn name(&self) -> &str {
111        "count"
112    }
113
114    fn set_series_color(&mut self, color: (u8, u8, u8)) {
115        self.color = color;
116    }
117}
ggplot_rs/geom/count.rs

ggplot_rs/geom/
count.rs
