Add labels to gallery thumbnail size controls

[whitewooood]

Summary

• add accessible labels to the gallery thumbnail size decrease button, range control, and increase button
• route those labels through gallery content config with default fallbacks
• add locale entries for supported locale files and a puppeteer regression test

Fixes #1488.

Validation

• npm run build
• CI=true npm test -- tests/test.js -t "labels gallery thumbnail size controls" --runInBand
• npx prettier --check tests/test.js src/content-handlers/iiif/modules/uv-shared-module/GalleryComponent.ts src/content-handlers/iiif/extensions/config/ContentLeftPanel.ts src/content-handlers/iiif/extensions/uv-openseadragon-extension/config/Config.ts src/content-handlers/iiif/extensions/uv-av-extension/config/config.json src/content-handlers/iiif/extensions/uv-openseadragon-extension/config/config.json src/locales/cy-GB.json src/locales/en-GB.json src/locales/fr-FR.json src/locales/pl-PL.json src/locales/sv-SE.json
• npx eslint tests/test.js src/content-handlers/iiif/modules/uv-shared-module/GalleryComponent.ts src/content-handlers/iiif/extensions/config/ContentLeftPanel.ts src/content-handlers/iiif/extensions/uv-openseadragon-extension/config/Config.ts
• npm run build-tsc
• npm run checkLocaleUsage
• npm run findMissingTranslations (reports pre-existing missing keys for adjust image labels; no new thumbnail-size keys missing)
• CI=true npm test -- --runInBand (first run had a transient thumbnail image load failure; the failing test passed when rerun directly, and the full suite passed on rerun: 4 passed, 1 skipped)

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
universalviewer	Ready	Preview, Comment	Jun 12, 2026 7:26am

[vercel]

@whitewooood is attempting to deploy a commit to the Universal Viewer Team on Vercel.

A member of the Team first needs to authorize it.

[demiankatz]

Thanks for your contribution, @whitewooood -- I took a quick look and have a question and suggestion below.

[demiankatz]

Is there a particular reason why you chose to shorten the string names when including them in content? I think it might be better to use decreaseThumbnailSize or decreaseThumbSize instead of just decreaseSize to reduce potential ambiguity if we add more strings in the future relating to different size-related functionality. (This is also true of increaseSize and especially size).

[demiankatz]

Where/how did you source your non-English translations? Do we need to have our translation team review them for accuracy?

[whitewooood]

Thanks for the review. I pushed an update using more specific content keys: decreaseThumbnailSize, thumbnailSize, and increaseThumbnailSize.

For the non-English strings, I added direct equivalents so the new labels resolve in the existing locale files. They have not gone through a separate translation-team review, so adjustments from the translation workflow would be welcome.