selection: Add a selection parameter (advanced)

In glyph: A Grammar of Interactive Graphics

Add a selection parameter (advanced)

Description

For complex interactions: define a named selection that can be referenced by marks and scales. This is how you build linked views, conditional encoding, and interactive legends.

Usage

selection(
  spec,
  name,
  type = "point",
  on = "click",
  fields = NULL,
  resolve = "global"
)

Arguments

spec	A glyph_spec
name	Selection name (referenced in conditional encodings)
type	"point", "interval", or "legend"
on	Event trigger: "click", "mouseover", "drag"
fields	Which data fields the selection projects onto
resolve	For composed views: "global", "union", "intersect"

Value

Modified glyph_spec

Examples

# Interactive legend: click legend entries to filter
glyph(mtcars, x = wt, y = mpg) |>
  mark_point(color = cyl) |>
  selection("legend_filter", type = "legend", fields = "cyl")

glyph documentation built on Oct. 21, 2026, 5:12 p.m.