geom-violin
Violin layer: mirrored density silhouette of y per x bucket.
Defaults to stat = "ydensity", so the layer accepts raw observations and estimates each bucket’s density internally. The default position = "identity" keeps buckets at their categorical x slot; switch to "dodge" for side-by-side violins per fill level.
Usage
geom-violin(
mapping: none,
data: none,
width: 0.9,
bw: auto,
adjust: 1,
n: 512,
trim: true,
scale: "area",
colour: auto,
fill: auto,
stroke: 0.6pt,
alpha: auto,
stat: auto,
position: "identity",
key: auto,
inherit-aes: true,
)Parameters
| Parameter | Default | Description |
|---|---|---|
mapping |
none |
Layer-specific aesthetic mapping built with aes. Must map x and y. |
data |
none |
Layer-specific dataset, or a function applied to the plot data returning the layer frame. Falls back to the plot data when none. |
width |
0.9 |
Full violin width in x data units at violinwidth = 1. |
bw |
auto |
Kernel bandwidth. auto applies Silverman’s rule of thumb; pass a positive number to fix it. |
adjust |
1 |
Bandwidth multiplier: adjust: 0.5 halves the smoothing, adjust: 2 doubles it. |
n |
512 |
Number of evenly spaced grid points the density is evaluated at per bucket. |
trim |
true |
Whether to restrict each silhouette to its bucket’s y range instead of letting the tails decay. |
scale |
"area" |
Width normalisation across buckets: "area" (default), "count", or "width". See stat-ydensity. |
colour |
auto |
Fixed outline colour. auto resolves via the colour scale, falling back to the theme ink. |
fill |
auto |
Fixed body fill. auto resolves via the fill scale, falling back to the theme paper. |
stroke |
0.6pt |
Outline thickness (a Typst length) or stroke dictionary; none disables the outline. |
alpha |
auto |
Fill opacity in [0, 1]. |
stat |
auto |
Statistical transform. auto builds stat-ydensity from the parameters above; pass a stat name or stat object to override. |
position |
"identity" |
Position adjustment name. "identity" (default) or "dodge". |
key |
auto |
Legend glyph override built with a draw-key-* helper. auto picks the default for the geom. |
inherit-aes |
true |
Whether to merge the plot-level mapping into this layer’s mapping. |
Returns
Layer dictionary consumed by plot.
Examples
Violins of a skewed sample per group.
#let ys = (1, 2, 2, 3, 3, 3, 4, 4, 5, 7)
#let d = ()
#for (i, grp) in ("a", "b", "c").enumerate() {
for y in ys {
d.push((grp: grp, y: y + i))
}
}
#plot(
data: d,
mapping: aes(x: "grp", y: "y"),
layers: (geom-violin(),),
width: 10cm,
height: 6cm,
)
Map fill and dodge for side-by-side violins per level; keep the tails with trim: false.
#let ys = (1, 2, 2, 3, 3, 3, 4, 4, 5, 7)
#let d = ()
#for grp in ("a", "b") {
for lvl in ("u", "v") {
for y in ys {
d.push((grp: grp, lvl: lvl, y: y + (if lvl == "v" { 2 } else { 0 })))
}
}
}
#plot(
data: d,
mapping: aes(x: "grp", y: "y", fill: "lvl"),
layers: (geom-violin(trim: false, position: "dodge", alpha: 0.7),),
width: 10cm,
height: 6cm,
)
