ggplot_rs/position/
fill.rs

1use std::borrow::Cow;
2use std::collections::HashMap;
3
4use crate::data::{DataFrame, Value};
5
6use super::{Position, PositionParams};
7
8/// Normalized stacking to 100% — like PositionStack but scales to [0, 1].
9pub struct PositionFill;
10
11impl Position for PositionFill {
12    fn compute(&self, data: &mut DataFrame, _params: &PositionParams) {
13        let x_col = match data.column("x") {
14            Some(c) => c.to_vec(),
15            None => return,
16        };
17        let y_col = match data.column("y") {
18            Some(c) => c.to_vec(),
19            None => return,
20        };
21        super::preserve_raw_y(data, &y_col);
22
23        // First compute totals per x group
24        let mut x_totals: HashMap<Cow<'_, str>, f64> = HashMap::new();
25        for (x, y) in x_col.iter().zip(y_col.iter()) {
26            *x_totals.entry(x.key_str()).or_insert(0.0) += y.as_f64().unwrap_or(0.0);
27        }
28
29        // Then compute normalized stacked positions
30        let mut x_cumsum: HashMap<Cow<'_, str>, f64> = HashMap::new();
31        let mut new_y = Vec::with_capacity(y_col.len());
32        let mut ymin_vals = Vec::with_capacity(y_col.len());
33
34        for (x, y) in x_col.iter().zip(y_col.iter()) {
35            let x_key = x.key_str();
36            let y_val = y.as_f64().unwrap_or(0.0);
37
38            let total = x_totals.get(&x_key).copied().unwrap_or(1.0);
39            let total = if total.abs() < f64::EPSILON {
40                1.0
41            } else {
42                total
43            };
44
45            // ggplot2 puts the first group at the top, so fill downward from 1.
46            let consumed = x_cumsum.get(&x_key).copied().unwrap_or(0.0);
47
48            let norm_y = y_val / total;
49            new_y.push(Value::Float(1.0 - consumed));
50            ymin_vals.push(Value::Float(1.0 - consumed - norm_y));
51
52            *x_cumsum.entry(x_key).or_insert(0.0) += norm_y;
53        }
54
55        if let Some(col) = data.column_mut("y") {
56            *col = new_y;
57        }
58        if !data.has_column("ymin") {
59            data.add_column("ymin".to_string(), ymin_vals);
60        } else if let Some(col) = data.column_mut("ymin") {
61            *col = ymin_vals;
62        }
63    }
64
65    fn name(&self) -> &str {
66        "fill"
67    }
68}
ggplot_rs/position/fill.rs

ggplot_rs/position/
fill.rs
