[Squeaks72]

Summary

The reader already knows a series' reading direction: rtl in web/app/reader/page.tsx is set from metadata.readingDirection === 'RIGHT_TO_LEFT', or from the downloaded record when offline. It uses that only to swap the two halves of a double spread. The paged track itself always runs left to right, so a right-to-left manga still has its next page on the right.

This makes paged mode follow that direction:

• New reader setting Reading direction (pagedDirection: series | ltr | rtl, default series), in the reader's settings sheet and in Profile → Settings → Reading, shown only in paged mode.
• series (default). A series whose readingDirection is RIGHT_TO_LEFT gets a right-to-left track: the next page is on the left, so you swipe right, tap the left edge or press ←, and a spread puts its first page on the right. Every other series reads exactly as it does today. That includes every series on the built-in library, because seriesDto in lib/ownedCatalog.ts answers WEBTOON for all of them. So on the default backend nothing changes for anyone until a series actually reports right-to-left. On a Komga backend, series that Komga marks right-to-left start paging right to left.
• ltr / rtl override it for every series, for readers who want one direction everywhere.
• On a right-to-left track the bottom bar mirrors (dir="rtl"): the page slider fills and drags from the right, the same way as the pages, and previous/next chapter swap sides with their chevrons swapped to keep pointing outwards. The 12/40 counter stays LTR.

How it works: the track gets dir="rtl", where scrollLeft runs from 0 into negative values. trackSign (−1/+1) turns a slide index into a scrollLeft for the initial landing, the resume and the page-grid jump. onScroll reads Math.abs(scrollLeft). Changing the direction mid-chapter puts you back on the page you were looking at. Tap zones already use a physical scrollBy, so tapping the left edge reveals what is on the left, which is the next page on an RTL track. On an RTL track the spread pair swap is skipped, because dir already lays the pair out right to left.

A fix that comes with it: the Arabic UI. Under Arabic, <html dir="rtl">, and the paged track inherited it, while the scroll maths assumed a positive scrollLeft. Scrolling produced negative values, Math.round(scrollLeft / width) clamped to slide 0, and the counter stayed on page 1. A resume or a page-grid jump (positive scrollLeft) clamped to the first page too. The track now always states its dir (ltr unless the setting says otherwise), so the paged track in Arabic runs left to right and tracks pages correctly, the same as in every other language. The bottom bar still takes the page's direction unless the track is right to left.

Interplay with the arrow-key PR (#92). That PR binds ←/→/↓/↑/Space/PageUp/PageDown in paged mode to scrollBy(±width). ←/→ are physical and stay correct on an RTL track (← reveals the next page). The direction-free keys (Space, PageDown, ↓ = next; PageUp, ↑ = previous) need trackSign on an RTL track. Whichever PR lands second should map them as page(trackSign) / page(-trackSign) and add trackSign to that effect's deps. Neither PR depends on the other.

docs/USAGE.md (section 5) describes the setting. New strings (Reading direction, Left to right, Right to left, Series default) are translated in all eight locales.

Type

• Fix
• Feature
• Docs
• Refactor / chore

(Plus the Arabic paged-track fix described above.)

Testing

Re-run after rebasing onto v0.45.0 (91b41aa): bff 1857 tests, 1844 pass, 9 fail, 4 skipped — the same 9 embedded-Postgres entrypoint failures main has in this environment (main: 1857 / 1844 / 9 / 4), nothing new; web 432/432; both typechecks OK. The detail below is from the first run, on v0.44.0.

• web/test/readerPrefsJunk.test.ts gains "paged mode follows the series unless overridden": the default is series, stored settings without the key migrate to it, an explicit ltr/rtl is kept, and an unknown stored value falls back to the default (migratePrefs now validates it the way it validates junkPages).

Run in node:24-alpine against a real postgres:16-alpine (TEST_DATABASE_URL set, so the SQL tests run), first on plain main (a8bc502) and then on this branch:

	main (baseline)	this branch
bff tsc --noEmit	OK	OK
bff tests	1834 tests: 1821 pass, 9 fail, 4 skipped	same: 1834, 1821 pass, 9 fail, 4 skipped
web tsc --noEmit	OK	OK
web tests	421 / 421	422 / 422 (+1 new)

The 9 bff failures are the same on both: the embedded-Postgres entrypoint tests (not ok 291–299), which cannot run in this sandbox. No new failures.

npm run test:i18n was not run: it is the puppeteer walk (test/e2e/i18n.mjs) that needs a running app and Chromium. The new keys were checked to exist in all eight locale files, and each file still parses as JSON. The RTL track was not exercised in a real browser for this PR. The track code itself has been in daily use with right to left as the default; this PR changes only where the direction comes from.

Checklist

• Focused scope (one topic)
• Matches the existing TypeScript style
• Docs updated if user-facing (docs/USAGE.md)
• No new default sources hardcoded to specific sites (the engine system reaches sites by URL)

🤖 Generated with Claude Code

[AngeloSha]

Thanks, this is a nice one, and it also fixes a bug on main: under the Arabic interface the paged track inherited right-to-left and the page counter got stuck on page 1.

Fixes on top:

• Resume and ?page= links opened a right-to-left series on page 1. A streamed series learns its direction in the same tick it becomes ready, so the new flip effect ran right after the resume scroll, still holding page 0.
• In paged mode the bottom bar follows the track in both directions now. On a left-to-right read under Arabic it was inheriting RTL and running the opposite way to its own pages.
• Text inside the track (the missing-page caption, the Up Next and failure cards) was taking the track's direction. It keeps the interface's now.
• A double-tap zoom in paged mode centred scrollLeft, which in paged mode is the page itself, so it jumped to the middle of the chapter.

I kept the spread swap when a right-to-left series is forced to read left to right, on purpose: a double-page spread is one drawing, and it only fits back together with its first page on the right. There's a comment saying so.

One thing I found while testing: Uchiyomi's own library reports every series as WEBTOON (ownedCatalog.ts:111), so at the time Series default only turned right to left on a Komga library. On the built-in library you pick it per series, per source (with #95) or as your default under Profile → Settings. Since v0.48.0 (#102) the library works it out by itself, from ComicInfo's Manga field, the source, then AniList, so it's right on the built-in library too.

Merged, and it shipped in v0.46.0.