Design Goals

Composition first

If a visual can be expressed by combining mark_* + project_* + scale_* + split_* in one pipeline, plotit does not add a mark for it. High-value combinations ship as recipes in the Gallery. A new mark is only added when the visual cannot be expressed in a reasonable pipeline (external layout algorithms, novel data encodings).

# Pie is a recipe: mark_bar + project_polar — not mark_arc
data.frame(cat = c("A", "B", "C"), n = c(40, 35, 25)) |>
  plotit(encode(x = 1, y = n, fill = cat)) |>
  mark_bar(position = "stack", width = 1) |>
  project_polar(theta = "y", inner_radius = 0.4)

Verb-prefix grammar

Every exported function starts with a verb that names its role: mark_* adds geometry, scale_* maps data to visuals, project_* changes coordinates, split_* facets, label_* sets text, compose_* assembles panels, layout_* bakes relational coordinates, style themes, export writes files. One verb, one meaning. All of them return a plotit object so the native pipe |> is the only composition operator users need.

Zero-dependency relational layouts

Sankey, chord, treemap, network, tree and dendrogram layouts are self-built, deterministic R engines. No external graph library is required — publication-reproducible by construction (ggbeeswarm is the single, documented exemption).

Defaults that publish

Canvas size, colour, dodge, and theme are chosen so a first plot is already report-ready. Users override deliberately (scale_*, style, label_*) instead of rebuilding chrome from scratch.

Explicitly out of scope

plotit targets static print/publication output. Interaction (tooltips, brushing, linking), 3D, animation, and automatic mark selection are out of scope. Statistical p-values are computed by the user and fed into mark_significance() as a table.

The pipeline is the narrative

ggplot2::mpg |>
  plotit(encode(x = displ, y = hwy, colour = class)) |>
  mark_point(size = 2, alpha = 0.7) |>
  scale_color(range = "friendly") |>
  label_title("Fuel economy by class")
#> Scale for colour is already present.
#> Adding another scale for colour, which will replace the existing scale.