ggplot_rs/position/
dodge.rs

1use crate::data::{DataFrame, Value};
2
3use super::{Position, PositionParams};
4
5/// Place groups side-by-side.
6pub struct PositionDodge;
7
8impl Position for PositionDodge {
9    fn compute(&self, data: &mut DataFrame, params: &PositionParams) {
10        let x_col = match data.column("x") {
11            Some(c) => c.to_vec(),
12            None => return,
13        };
14
15        // Determine groups from fill or color aesthetic
16        let group_col = data
17            .column("fill")
18            .or_else(|| data.column("color"))
19            .or_else(|| data.column("group"));
20
21        let group_keys: Vec<String> = match group_col {
22            Some(col) => col.iter().map(|v| v.to_group_key()).collect(),
23            None => return, // No grouping, nothing to dodge
24        };
25
26        // Find unique groups
27        let mut unique_groups: Vec<String> = Vec::new();
28        for g in &group_keys {
29            if !unique_groups.contains(g) {
30                unique_groups.push(g.clone());
31            }
32        }
33
34        let n_groups = unique_groups.len() as f64;
35        if n_groups <= 1.0 {
36            return;
37        }
38
39        let width = params.width;
40        let group_width = width / n_groups;
41
42        let mut new_x = x_col.clone();
43        for (i, (x, group)) in x_col.iter().zip(group_keys.iter()).enumerate() {
44            let group_idx = unique_groups.iter().position(|g| g == group).unwrap() as f64;
45            let offset = (group_idx - (n_groups - 1.0) / 2.0) * group_width;
46
47            if let Some(x_val) = x.as_f64() {
48                new_x[i] = Value::Float(x_val + offset);
49            }
50        }
51
52        if let Some(col) = data.column_mut("x") {
53            *col = new_x;
54        }
55    }
56
57    fn name(&self) -> &str {
58        "dodge"
59    }
60}
ggplot_rs/position/dodge.rs

ggplot_rs/position/
dodge.rs
