gg2d3

gg2d3 renders ggplot2 objects with D3 in the browser (via htmlwidgets). Under the hood, gg2d3 converts a ggplot into a small intermediate representation (IR) and draws it in SVG with D3.

Installation

Install the development version from GitHub:

# install.packages("devtools")
devtools::install_github("DavidZenz/gg2d3")

Quick start

library(ggplot2)
library(gg2d3)

p <- ggplot(mtcars, aes(wt, mpg, color = factor(cyl))) +
  geom_point() +
  ggtitle("mpg vs wt")

gg2d3(p)

v1.13 support and validation contract

The v1.13 release track adds regression confidence and bounded geometry polish without broadening gg2d3 into a full ggplot2 or GIS topology clone.

• Browser visual validation has a dedicated GitHub Actions workflow and a CI-equivalent local mode. It writes inspectable index.html, index.json, fixture HTML, screenshot, DOM-summary, and browser-log artifacts under test_output/browser-visual-smoke/ when enabled, while local runs may skip cleanly if optional browser tooling is unavailable.
• Pkgdown site evidence has a separate release role: source docs define the intended public support contract, generated docs/ proves local/pkgdown rendering, GitHub Pages output proves publication, and browser visual smoke artifacts prove representative browser behavior.
• Generated-site validation is available with rtk Rscript --vanilla tools/validate-pkgdown-site.R --mode quick; use release mode before shipping when source docs may have changed. Publication artifacts or gh-pages checkouts can be inspected with rtk Rscript --vanilla tools/inspect-pkgdown-publication.R --site-root <site-root>; see vignettes/d3-drawing-diagnostics.md for the gh workflow run, artifact download, and gh-pages fallback flow.
• Local sf/GDAL setup can be diagnosed with rtk Rscript --vanilla tools/diagnose-spatial-stack.R; see vignettes/d3-drawing-diagnostics.md for how to distinguish local environment repair from gg2d3 regressions when pkgdown reports classified_skip.
• Renderer wiring is guarded by inst/htmlwidgets/modules/geom-contracts.js and source tests for module load order, render/update selectors, interactivity selectors, and public payload sanitization. Selected IR helper-boundary tests cover theme extraction and geom parameter routing while full as_d3_ir() modularization remains future work.
• Geometry support is bounded: ordinary geom_label() renders SVG label boxes; ordinary geom_polygon() keeps grouped closed-path behavior and explicitly does not infer topology or holes; geom_rect() and geom_tile() filter non-finite transformed SVG bounds before emitting rect attributes.
• Deferred work remains explicit in diagnostics, including future pixel-diff thresholds, public hosted visual reports, full IR modularization, generated renderer documentation, repelled label placement, and broad GIS-style topology repair.

See vignettes/d3-drawing-diagnostics.md for validation commands, pkgdown artifact taxonomy, artifact paths, CI-mode behavior, architecture boundaries, geometry caveats, and future work IDs.

Features

Geoms

Category	Geoms
Basic	geom_point, geom_line, geom_path, geom_bar, geom_col, geom_rect, geom_tile, geom_text, geom_label, geom_polygon
Area/Ribbon	geom_area, geom_ribbon
Intervals	geom_segment, geom_errorbar, geom_linerange, geom_pointrange
Annotation	geom_hline, geom_vline, geom_abline, geom_rug
Statistical	geom_boxplot, geom_violin, geom_density, geom_smooth (loess, gam, lm), geom_dotplot

Ordinary geom_polygon() renders as grouped closed SVG paths with ggplot2 built row order preserved inside each group. The shipped contract covers core fill/stroke/alpha/linewidth/linetype styling, facets, zoom/update behavior, and the existing tooltip, hover, brush, handler, and linked-view hooks. Brush selection is path-bounds based and callback payloads use sanitized representative source rows.

geom_rect() and geom_tile() support distinguishes scale-limit censoring from coord_cartesian() panel clipping: scale limits can remove or censor bounds before gg2d3 sees them, while coordinate limits keep finite rect/tile bounds and clip in the SVG panel. Discrete tile geometry is closed for initial render and update paths. Log, sqrt, and reverse transformed rect/tile bounds use ggplot2 built values directly, and non-finite scaled SVG bounds are filtered before rect attributes are emitted.

Ordinary geom_label() renders bounded SVG label groups with a backing rect and text, including useful support for fill, stroke/colour, alpha, size, numeric padding, hjust, vjust, angle, and family. Ordinary geom_text() shares the small placement support for hjust, vjust, angle, and family.

gg2d3 also supports geom_sf() for polygon-family (POLYGON, MULTIPOLYGON), point-family (POINT, MULTIPOINT), and line-family (LINESTRING, MULTILINESTRING) geometries, plus geom_sf_text() and geom_sf_label() annotations at projected anchors aligned with those accepted sf families. Rows that are unsupported, empty, invalid, or missing are skipped with warnings while accepted rows render; known CRS inputs are normalized in R before serialization, and missing CRS coordinates are serialized as-is with a warning. Optional browser validation is R/testthat/chromote based and may skip cleanly; when available, it covers sf family interactivity, stacked overlays, faceted and empty panels, projected anchor placement, sanitized interactivity payloads, and zoom suppression.

These support claims are intentionally scoped. gg2d3 does not claim complete ggplot2 parity for polygon topology/hole repair beyond grouped closed paths, ordinary polygon subgroup / rule compound-path rendering, tile basemaps, slippy controls, JavaScript-side CRS reprojection, repelled label placement, rich text, or path-following annotation placement. See vignettes/d3-drawing-diagnostics.md for detailed geometry caveats.

Scales & Coordinates

• Continuous and categorical x/y scales with full parity
• Advanced scale configuration: breaks, minor_breaks, expand, and oob (squish/censor) logic
• Log, sqrt, and reverse scale transforms
• Date and datetime (POSIXct) scales with timezone parity
• coord_flip, coord_fixed, and coord_polar (pie, coxcomb, radar)

Layout & Guides

• Centralized layout engine for high-fidelity panel, axis, and header positioning
• Interactive Legends: Click to toggle, Double-click to solo, Hover to preview
• Legends for color, fill, size, shape, and alpha aesthetics
• Continuous colorbars with gradient rendering
• Support for hierarchical facet headers (nested variables)

Theming

• Deep theme inheritance (matches ggplot2 parent-child element tree)
• Full support for element_blank() and detailed element styling
• Text justifications (hjust, vjust), margins, and rotations
• Legend box backgrounds and borders

Interactivity

Composable pipe-based API:

gg2d3(p) |>
  d3_tooltip() |>
  d3_hover() |>
  d3_zoom() |>
  d3_brush() |>
  d3_transitions() |>
  d3_handlers(click = "console.log(d)")

• Tooltips — hover to see data values (with date/time and custom formatting)
• Hover highlighting — dim non-hovered groups with configurable styles
• Zoom & pan — scroll to zoom, drag to pan (smooth transitions)
• Brush selection — drag to select data regions (rectangular or axis-only)
• Animated Transitions — smooth, object-constant enter/update/exit animations
• Custom Handlers — execute custom JavaScript on mark interaction
• Shiny Sync — automatic synchronization of plot interactions with Shiny inputs
• Linked views — Crosstalk integration for cross-widget brushing

Troubleshooting

• Blank widget / only axes Ensure D3 is bundled correctly in the package (inst/htmlwidgets/lib/d3/d3.v7.min.js) and inst/htmlwidgets/gg2d3.yaml declares it.

• Console says “no marks drawn” Your layer may be missing a recognized geom or data columns. Start with a simple scatter and inspect the IR:

  ir <- gg2d3:::as_d3_ir(p)
  str(ir$layers[[1]], max.level = 1)

Development (for contributors)

Vendor D3 v7 locally:

dir.create("inst/htmlwidgets/lib/d3", recursive = TRUE, showWarnings = FALSE)
download.file(
  "https://d3js.org/d3.v7.min.js",
  destfile = "inst/htmlwidgets/lib/d3/d3.v7.min.js",
  mode = "wb"
)

Iterate:

devtools::document()
devtools::load_all()
devtools::test()

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Note: README.md is generated from README.Rmd. Use devtools::build_readme() to re-render.