ggplot_rs/geom/
waffle.rs

1//! Unit charts: `geom_waffle` (a square grid of units) and
2//! `geom_parliament` (seats on concentric half-circle arcs). Each unit is
3//! one item of its `fill` category. Layout by [`StatWaffle`].
4
5use crate::aes::Aesthetic;
6use crate::coord::Coord;
7use crate::data::{DataFrame, Value};
8use crate::position::identity::PositionIdentity;
9use crate::position::Position;
10use crate::render::backend::{DrawBackend, PointStyle, RectStyle};
11use crate::render::RenderError;
12use crate::scale::ScaleSet;
13use crate::stat::waffle::{StatWaffle, UnitLayout};
14use crate::stat::Stat;
15use crate::theme::Theme;
16
17use super::{Geom, GeomParams};
18
19/// Waffle / parliament chart. Map `fill` (category) and `weight` (units
20/// per row; 1 when unmapped).
21pub struct GeomWaffle {
22    pub layout: UnitLayout,
23    /// Gap between units as a fraction of the unit size.
24    pub gap: f64,
25    /// Corner radius of waffle squares as a fraction of their size.
26    pub roundness: f64,
27    /// Fill when `fill` is unmapped.
28    pub fill: (u8, u8, u8),
29    pub alpha: f64,
30}
31
32impl Default for GeomWaffle {
33    fn default() -> Self {
34        GeomWaffle {
35            layout: UnitLayout::Waffle { rows: 10 },
36            gap: 0.12,
37            roundness: 0.0,
38            fill: (97, 156, 255),
39            alpha: 1.0,
40        }
41    }
42}
43
44impl GeomWaffle {
45    /// A waffle `rows` units high.
46    pub fn waffle(rows: usize) -> Self {
47        GeomWaffle {
48            layout: UnitLayout::Waffle { rows },
49            ..Default::default()
50        }
51    }
52
53    /// A parliament (hemicycle); `rows = 0` picks the number of arcs.
54    pub fn parliament(rows: usize) -> Self {
55        GeomWaffle {
56            layout: UnitLayout::Parliament { rows, inner: 0.4 },
57            ..Default::default()
58        }
59    }
60}
61
62impl Geom for GeomWaffle {
63    fn draw(
64        &self,
65        data: &DataFrame,
66        coord: &dyn Coord,
67        scales: &ScaleSet,
68        _theme: &Theme,
69        backend: &mut dyn DrawBackend,
70    ) -> Result<(), RenderError> {
71        let col = |n: &str| {
72            data.column(n)
73                .ok_or_else(|| RenderError::MissingAesthetic(n.into()))
74        };
75        let (xc, yc, uc) = (col("x")?, col("y")?, col("unit")?);
76        let fill_col = data.column("fill");
77        let area = backend.plot_area();
78        let px = |x: f64, y: f64| {
79            let sx = scales.get(&Aesthetic::X).map(|s| s.map(&Value::Float(x)));
80            let sy = scales.get(&Aesthetic::Y).map(|s| s.map(&Value::Float(y)));
81            coord.transform((sx.unwrap_or(0.5), sy.unwrap_or(0.5)), &area)
82        };
83        // Pixel size of one unit radius: the smaller axis scale keeps squares
84        // square and seats round whatever the panel aspect.
85        let unit_px = |x: f64, y: f64, u: f64| {
86            let c = px(x, y);
87            let (a, b) = (px(x + u, y), px(x, y + u));
88            ((a.0 - c.0).hypot(a.1 - c.1)).min((b.0 - c.0).hypot(b.1 - c.1))
89        };
90        let square = matches!(self.layout, UnitLayout::Waffle { .. });
91        for i in 0..data.nrows() {
92            let (Some(x), Some(y), Some(u)) = (xc[i].as_f64(), yc[i].as_f64(), uc[i].as_f64())
93            else {
94                continue;
95            };
96            let c = px(x, y);
97            let r = unit_px(x, y, u) * (1.0 - self.gap);
98            let fill = fill_col
99                .and_then(|f| scales.map_color(&Aesthetic::Fill, &f[i]))
100                .unwrap_or(self.fill);
101            let series = super::series_key(data, i);
102            super::set_mark(backend, series.clone(), None, series, None);
103            super::set_row_extras(backend, data, i);
104            if square {
105                backend.draw_rect(
106                    (c.0 - r, c.1 - r),
107                    (c.0 + r, c.1 + r),
108                    &RectStyle {
109                        fill: Some(fill),
110                        stroke: None,
111                        stroke_width: 0.0,
112                        alpha: self.alpha,
113                        clip: true,
114                        corner_radius: 2.0 * r * self.roundness,
115                    },
116                )?;
117            } else {
118                backend.draw_circle(
119                    c,
120                    r,
121                    &PointStyle {
122                        color: fill,
123                        alpha: self.alpha,
124                        filled: true,
125                        ..Default::default()
126                    },
127                )?;
128            }
129        }
130        super::clear_mark(backend);
131        super::clear_row_extras(backend);
132        Ok(())
133    }
134
135    fn required_aes(&self) -> Vec<Aesthetic> {
136        Vec::new()
137    }
138
139    fn default_stat(&self) -> Box<dyn Stat> {
140        Box::new(StatWaffle {
141            layout: self.layout,
142        })
143    }
144
145    fn default_position(&self) -> Box<dyn Position> {
146        Box::new(PositionIdentity)
147    }
148
149    fn default_params(&self) -> GeomParams {
150        GeomParams::default()
151    }
152
153    fn name(&self) -> &str {
154        "waffle"
155    }
156
157    fn consumes_tooltips(&self) -> bool {
158        true
159    }
160
161    fn set_series_color(&mut self, color: (u8, u8, u8)) {
162        self.fill = color;
163    }
164}
ggplot_rs/geom/waffle.rs

ggplot_rs/geom/
waffle.rs
