feat: random_image_ext() — Lorem Picsum images for Shiny prototyping (closes #8)

[VincentGuyader]

Reworks @feddelegrand7's PR #8 into a mergeable state (the original branch is 5 years stale and had no tests).

What it does

random_image_ext(width = 400, height = 400, seed = NULL) returns an <img> htmltools tag whose src points at the Lorem Picsum API:

random_image_ext()                          # <img src="https://picsum.photos/400/400">
random_image_ext(width = 200, height = 300) # <img src="https://picsum.photos/200/300">
random_image_ext(seed = "caramba")          # <img src="https://picsum.photos/seed/caramba/400/400">

No network request is performed by the function itself — only the URL is built; the browser fetches the image. Drop it straight into a Shiny UI.

Changes vs PR #8

• Dropped the glue dependency — plain sprintf().
• Input validation: width / height must be single positive integers; seed must be a single non-missing scalar (coerced to character).
• seed is URL-encoded (utils::URLencode(reserved = TRUE)), so spaces / slashes don't break the URL.
• @examples no longer hit the network in a way that bothers R CMD check (the call only builds a tag).
• Full test suite: tests/testthat/test-image-ext.R (return type, dimensions in URL, seeded URL + encoding, validation of every argument). Written first (red), then the implementation.
• htmltools added to Imports (used by htmltools::img); the previously-unused utils import is now actually used (URLencode).

Test plan

• devtools::test(): 3170 PASS / 0 FAIL (the single pre-existing WARN is the geom_line(size=) deprecation on master, addressed by fix: 3 shinipsum issues — geom_line(size=) deprecation (#13), random_image args (#9), n_bars (#5) #15 / feat: random_ggplot('ts'), random_mock(), random_text(var=) — issues #4 #1 #3 #16, untouched here).
• R CMD check --no-manual: Status: OK (0 error / 0 warning / 0 note).
• New file R/random_image_ext.R at 100% coverage.

Note for the merge

Touches DESCRIPTION (adds htmltools to Imports) like #15 / #16 — trivial conflict if those land first. Independent of everything else otherwise.

Closes #8

[Copilot]

Pull request overview

Adds a new random_image_ext() helper to generate an htmltools <img> tag whose src points at the Lorem Picsum API, intended for quick Shiny UI prototyping.

Changes:

• Introduces random_image_ext(width, height, seed) with input validation and URL-encoding for seed.
• Adds test coverage for URL construction and argument validation.
• Wires the feature into the package exports/docs and adds htmltools to Imports.

Reviewed changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
R/random_image_ext.R	New implementation of random_image_ext() building a Picsum URL and returning an htmltools::img() tag.
tests/testthat/test-image-ext.R	New tests validating return type, URL formatting, seed encoding, and argument validation.
NAMESPACE	Exports random_image_ext() and imports htmltools::img, attempt::stop_if_not, utils::URLencode.
DESCRIPTION	Adds htmltools to Imports and updates RoxygenNote.
man/random_image_ext.Rd	Generated documentation for the new function.
NEWS.md	Changelog entry for random_image_ext().
man/shinipsum-package.Rd	Minor package documentation formatting adjustment.

Files not reviewed (2)

• man/random_image_ext.Rd: Language not supported
• man/shinipsum-package.Rd: Language not supported

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 7 changed files in this pull request and generated no new comments.

Files not reviewed (2)

• man/random_image_ext.Rd: Language not supported
• man/shinipsum-package.Rd: Language not supported

[VincentGuyader]

Thanks @copilot — all 3 points addressed in fa86cdd:

• valid_dim() could return NA / throw: the predicate is now total — is.numeric(.x) && length(.x) == 1L && is.finite(.x) && .x >= 1 && .x == round(.x). Inf / NaN / 1e400 / complex / logical all fail with the friendly `width` must be a single positive integer message instead of an NA predicate or a low-level error. Dimensions are now formatted with %.0f so there's no as.integer() overflow-to-NA either.
• seed predicate could throw on non-atomic input: added an is.atomic(.x) guard, so seed = list("a") (and friends) fail with the custom message.
• Tests: added explicit cases for width = Inf / NaN / 1e400 / 1+0i / TRUE and seed = list("a") / seed = TRUE.

R CMD check: Status OK (0/0/0). R/random_image_ext.R at 100% coverage.