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Contributing to cfbplotR

Source: CONTRIBUTING.md

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Thanks for your interest in improving cfbplotR, the SportsDataverse ggplot2 extension for college-football logos, wordmarks, and player headshots!

By participating you agree to abide by the Code of Conduct.

Ways to Contribute

  • Report a bug – open an issue using the Bug Report template.
  • Request a feature – open an issue using the Feature Request template.
  • Improve docs – typo fixes, clearer examples, and updated screenshots are always welcome.
  • Add or fix a geom/element/scale/gt helper – see the conventions below.
  • Update team data – logo and wordmark URLs go stale; PRs that refresh data-raw/ are valuable.

Getting Set Up

  1. Fork and clone the repository.

  2. Install development dependencies (pak recommended):

    # recommended:
install.packages("pak")
pak::local_install_dev_deps()

# or with devtools:
install.packages("devtools")
devtools::install_dev_deps()

  3. Load the package for interactive development:

    devtools::load_all()

Development Workflow

devtools::load_all()      # load the package
devtools::document()      # regenerate man/ + NAMESPACE after changing roxygen2
devtools::test()          # run the full test suite
devtools::check()         # full R CMD check -- run before opening a PR
devtools::build_readme()  # re-render README.md from README.Rmd
pkgdown::build_site()     # preview the pkgdown site locally

Coding Conventions

cfbplotR follows the conventions documented in CLAUDE.md. The essentials:

Architecture

cfbplotR is a thin domain layer on top of ggpath. ggpath owns image fetching, caching, colorizing, and rendering. cfbplotR:

  1. Resolves a CFB team name or ESPN player ID to an image URL/path (via logo_from_school(), wordmark_from_school(), headshot_from_id() in R/utils.R).
  2. Delegates rendering to ggpath (ggpath::GeomFromPath$draw_panel() for geoms; ggplot2::element_grob(ggpath::element_path(...)) for theme elements).

Never re-implement ggpath rendering inside cfbplotR.

ggpath S7 note

ggpath::element_path is an S7 object. The internal helper .cfb_element_to_path_grob() must construct it via ggpath::element_path(alpha=..., colour=..., hjust=..., vjust=..., size=...). Do NOT structure() a plain list and re-class it – S7 property access will break.

Naming

Family Pattern Example
Geoms geom_cfb_* geom_cfb_logos()
Theme elements element_cfb_* element_cfb_logo()
Color/fill scales scale_color_cfb, scale_fill_cfb
Position scales scale_x_cfb, scale_y_cfb
gt formatters gt_fmt_cfb_*, gt_cfb_* gt_fmt_cfb_logo()
Team utilities cfb_* cfb_team_tiers()
Name cleaners clean_* clean_school_names()

Internal resolvers

Use the three resolver helpers – do not inline URL construction:

  • logo_from_school(team) – team name -> logo URL (falls back to NCAA logo)
  • wordmark_from_school(team) – team name -> wordmark URL (falls back to NCAA wordmark)
  • headshot_from_id(player_id) – ESPN player ID -> ESPN CDN headshot URL

Re-exporting ggpath

Add new ggpath re-exports to R/reexports.R using the standard roxygen2 pattern:

#' @importFrom ggpath new_symbol
#' @export
ggpath::new_symbol

Team data

R/sysdata.rda is generated from data-raw/. After updating team data, re-source the relevant script and run devtools::document(). Never edit sysdata.rda by hand.

Messaging

Use cli::cli_warn() for user-facing warnings, cli::cli_abort() for errors, and cli::cli_inform() for informational messages. Do not use bare warning() or message().

Testing

Test types

  • Snapshot tests: visual geoms and theme elements use vdiffr::expect_doppelganger(). After intentional visual changes, run vdiffr::manage_cases() to review and accept new snapshots. Do not delete .svg files manually.
  • Data/resolver tests: cleaning helpers and resolver functions use plain expect_*.
  • Network tests: guard with skip_if_offline() and skip_on_cran().

Test pattern

test_that("geom_cfb_logos renders a known team", {
  skip_on_cran()
  skip_if_not_installed("vdiffr")

  p <- ggplot2::ggplot(
    data.frame(x = 1, y = 1, team = "Alabama"),
    ggplot2::aes(x = x, y = y, team = team)
  ) +
    geom_cfb_logos(width = 0.1)

  vdiffr::expect_doppelganger("geom-cfb-logos-alabama", p)
})

Column assertions (subset direction)

Use subset-direction assertions so that upstream data additions never break the suite:

expect_in(sort(required_cols), sort(colnames(df)))   # expected ⊆ actual

Never write expect_equal(sort(colnames(df)), sort(required_cols)) – that fails if the upstream data gains a new column.

Adding a test file

Name it tests/testthat/test-<function-slug>.R. Gate network tests as described above.

Documentation

  • Never hand-edit NAMESPACE or anything in man/ – regenerate with devtools::document().

  • Re-render README.md with devtools::build_readme() and commit README.Rmd + README.md together. Never hand-edit README.md.

  • Add new exported functions to the reference: section of _pkgdown.yml if they are not already covered by the existing starts_with() selectors.

  • For user-visible changes, update NEWS.md.

  • Regenerate doctoc TOCs after editing this file, CLAUDE.md, .github/copilot-instructions.md, or .github/pull_request_template.md:

    Rscript tools/run_doctoc.R --maxlevel 2 \
  CONTRIBUTING.md CLAUDE.md \
  .github/copilot-instructions.md .github/pull_request_template.md

Commit & PR Conventions

  • Use Conventional Commits: feat(geom):, fix(elements):, docs:, test:, refactor:, chore:, ci:. Mark breaking changes with type!: or a BREAKING CHANGE: footer.
  • Keep unrelated changes in separate commits.
  • Do not add AI tools (Claude, Copilot, etc.) as commit co-authors.
  • Open your PR against main, fill in the PR template, and confirm devtools::check() and devtools::test() pass before requesting review.

Thanks again for contributing!