scale-alpha-identity
Alpha scale that uses each row’s value as the opacity directly.
Values are clamped to [0, 1] before being applied to the colour. No legend is drawn because the column carries the visual outcome verbatim.
Usage
scale-alpha-identity(
name: none,
)Parameters
| Parameter | Default | Description |
|---|---|---|
name |
none |
Legend title. Identity scales draw no legend. |
Returns
Scale object consumed by plot.
Examples
Per-row opacity carried straight through to the point fills.
#let d = (
(x: 1, y: 2, w: 0.2),
(x: 2, y: 3, w: 0.5),
(x: 3, y: 4, w: 0.8),
(x: 4, y: 5, w: 1.0),
)
#plot(
data: d,
mapping: aes(x: "x", y: "y", alpha: "w"),
layers: (geom-point(size: 6pt, fill: rgb("#1f77b4")),),
scales: (scale-alpha-identity(),),
width: 10cm,
height: 6cm,
)
