ggplot_rs/geom/
segment.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/// Segment geometry — line segments from (x, y) to (xend, yend).
16pub struct GeomSegment {
17    pub color: (u8, u8, u8),
18    pub width: f64,
19    pub alpha: f64,
20}
21
22impl Default for GeomSegment {
23    fn default() -> Self {
24        GeomSegment {
25            color: (0, 0, 0),
26            width: 1.0,
27            alpha: 1.0,
28        }
29    }
30}
31
32impl Geom for GeomSegment {
33    fn draw(
34        &self,
35        data: &DataFrame,
36        coord: &dyn Coord,
37        scales: &ScaleSet,
38        _theme: &Theme,
39        backend: &mut dyn DrawBackend,
40    ) -> Result<(), RenderError> {
41        let x_col = data
42            .column("x")
43            .ok_or(RenderError::MissingAesthetic("x".into()))?;
44        let y_col = data
45            .column("y")
46            .ok_or(RenderError::MissingAesthetic("y".into()))?;
47        let xend_col = data
48            .column("xend")
49            .ok_or(RenderError::MissingAesthetic("xend".into()))?;
50        let yend_col = data
51            .column("yend")
52            .ok_or(RenderError::MissingAesthetic("yend".into()))?;
53        let color_col = data.column("color");
54
55        let plot_area = backend.plot_area();
56        let x_scale = scales.get(&Aesthetic::X);
57        let y_scale = scales.get(&Aesthetic::Y);
58
59        for i in 0..data.nrows() {
60            let nx1 = x_scale.map(|s| s.map(&x_col[i])).unwrap_or(0.0);
61            let ny1 = y_scale.map(|s| s.map(&y_col[i])).unwrap_or(0.0);
62            let nx2 = x_scale.map(|s| s.map(&xend_col[i])).unwrap_or(0.0);
63            let ny2 = y_scale.map(|s| s.map(&yend_col[i])).unwrap_or(0.0);
64
65            let (px1, py1) = coord.transform((nx1, ny1), &plot_area);
66            let (px2, py2) = coord.transform((nx2, ny2), &plot_area);
67
68            let line_color = color_col
69                .and_then(|cc| scales.map_color(&Aesthetic::Color, &cc[i]))
70                .unwrap_or(self.color);
71
72            backend.draw_line(
73                &[(px1, py1), (px2, py2)],
74                &LineStyle {
75                    color: line_color,
76                    alpha: self.alpha,
77                    width: self.width,
78                    linetype: Linetype::Solid,
79                },
80            )?;
81        }
82
83        Ok(())
84    }
85
86    fn required_aes(&self) -> Vec<Aesthetic> {
87        vec![Aesthetic::X, Aesthetic::Y, Aesthetic::Xend, Aesthetic::Yend]
88    }
89
90    fn default_stat(&self) -> Box<dyn Stat> {
91        Box::new(StatIdentity)
92    }
93    fn default_position(&self) -> Box<dyn Position> {
94        Box::new(PositionIdentity)
95    }
96    fn default_params(&self) -> GeomParams {
97        GeomParams::default()
98    }
99    fn name(&self) -> &str {
100        "segment"
101    }
102
103    fn set_series_color(&mut self, color: (u8, u8, u8)) {
104        self.color = color;
105    }
106}
ggplot_rs/geom/segment.rs

ggplot_rs/geom/
segment.rs
