Convert a scene to and from a plain list

as_scene_spec() turns a rendered-ready scene into a plain nested list of R vectors, and from_scene_spec() rebuilds the scene from it. Together they make a compiled scene a value you can store or send, rather than something that only exists inside the session that built it.

Usage

as_scene_spec(scene)

from_scene_spec(spec)

Arguments

scene

A vl_scene(), or anything with an as_vellum_scene() method.

spec

A list from as_scene_spec().

Value

as_scene_spec(): a nested list, with a version element. from_scene_spec(): a vellum_scene.

Details

This is one level below vellumplot's plot spec. A plot spec is portable and re-renderable at any size; a scene spec is the resolved artifact — the grobs, units and viewports as they will actually be drawn. They compose: keep the plot spec to re-render, keep the scene spec to reproduce exactly this scene.

The conversion is generic over the S7 property model rather than written per grob type, so a grob added to vellum later serializes with no change here.

See also

scene_write(), scene_diff(), scene_hash()

Examples

s <- vl_scene(3, 2) |>
  draw(circle_grob(r = 0.3, gp = vl_gpar(fill = "tomato", col = NA)))
spec <- as_scene_spec(s)
spec$version
#> [1] 1
identical(as_scene_spec(from_scene_spec(spec)), spec)
#> [1] TRUE