ggplot2 Playground

Build a ggplot layer by layer with live R code output, so every aesthetic choice becomes visible

Purpose

Most readers learn ggplot2 by adapting existing plots, which means they miss the layered logic of the grammar of graphics. The ggplot2 Playground forces the layered mental model: pick a dataset, map a variable to each aesthetic, add geoms one at a time, tune scales, and watch the plot assemble. At every step, the R code that reproduces the current plot is shown in a copy-ready panel.

User inputs

• Dataset (built-in or user-uploaded CSV)
• Aesthetic mappings (x, y, colour, size, shape, alpha) by dropdown
• Geom toggles (point, line, bar, histogram, boxplot, smooth, density, text)
• Scale options: colour palette, axis transformations, limits
• Facet options: facet_wrap, facet_grid, free vs. fixed scales
• Theme options: complete theme, font size, legend position

Outputs

• The current plot, updating on every input change
• A syntax-highlighted R code panel showing the exact ggplot() call that produced it
• An export button producing PNG, SVG, or PDF at manuscript resolution

Didactic value

The app foregrounds the grammar: adding a geom extends the plot; adding a mapping connects data to geometry; adding a scale shapes how the mapping is rendered. By the third or fourth plot, the reader can predict what a given code change will produce, which is the goal of learning ggplot2.

Embedded in

• visualisation/grammar-of-graphics.md
• visualisation/aesthetics-and-geoms.md
• Every plot-type tutorial as a “try it yourself” coda

Source code

Local: apps/06-ggplot-playground/

Run with:

shiny::runApp("apps/06-ggplot-playground")