display() re-renders scene to fill the current graphics device and draws it
there. Interactively this is the RStudio / Positron Plots pane; inside a
knitr / Quarto chunk it becomes the chunk's figure (it draws to the chunk's
device). This is the seam any package built on vellum can call to show output
instead of writing a file: scene is coerced via as_vellum_scene(), so it
also accepts e.g. a grammar's plot spec.
Arguments
- scene
A
vl_scene()or anything with anas_vellum_scene()method.- ...
Unused.
Details
To fill the window (no letterbox margins, like ggplot2) the scene is re-rendered
at the device's size and pixel density, so its relative (npc/native/layout)
content reflows to the window and absolute (mm/in/pt) content keeps its
physical size. It draws through a grid grob that re-rasterizes on every draw, so
resizing the Plots pane re-renders the scene crisply at the new size (round
markers stay round) rather than stretching one bitmap. Use render() to write
the scene at its authored width/height. Auto-printing a scene at the console
(or calling plot() on it) displays it.
Inside a knitr / Quarto chunk the chunk's dpi option wins, so
knitr::opts_chunk$set(dpi = 200) yields a genuine 200-dpi figure even on
knitr's default dev = "png" device (which misreports its pixel density);
outside knitting the scene's authored vl_scene() dpi is honored unless the
live device reports a trustworthy higher density (e.g. a resized Plots pane).
Examples
if (FALSE) { # \dontrun{
vl_scene(4, 3) |>
draw(circle_grob(r = 0.3, gp = vl_gpar(fill = "tomato", col = NA))) |>
display()
} # }