scale-alpha-manual
Manual discrete alpha scale: supply a per-level array of opacities.
Use when each level should map to a chosen opacity in [0, 1] rather than the evenly-spaced range that the discrete inference would assign.
Usage
scale-alpha-manual(
values: (),
name: none,
limits: none,
labels: auto,
)Parameters
| Parameter | Default | Description |
|---|---|---|
values |
() |
Array of opacities in [0, 1], one per level (in limits order when set, otherwise in first-seen order). |
name |
none |
Legend title. Overrides any name set via labs when both are present. |
limits |
none |
Array of level names controlling order and inclusion, or none. |
labels |
auto |
Array of legend labels aligned with limits, or auto. |
Returns
Scale object consumed by plot.
Examples
Three groups assigned dim/medium/full opacity.
#let d = (
(x: 1, y: 1, g: "a"), (x: 2, y: 2, g: "a"),
(x: 1, y: 2, g: "b"), (x: 2, y: 3, g: "b"),
(x: 1, y: 3, g: "c"), (x: 2, y: 4, g: "c"),
)
#plot(
data: d,
mapping: aes(x: "x", y: "y", alpha: "g", group: "g"),
layers: (geom-point(size: 4pt, fill: rgb("#1f77b4")),),
scales: (scale-alpha-manual(values: (0.2, 0.55, 1)),),
width: 10cm,
height: 6cm,
)
