[chortya]

Contribution pause

The maintainer lifted the pause and invited split PRs in #286.

• The change is scoped to one feature (two-page spreads for paginated comics). Stacked on feat: two-page EPUB spreads on unfolded foldables and landscape tablets (refs #286) #300 (EPUB spreads: shared policy, window tracker and setting). Only the commits after feat: two-page EPUB spreads on unfolded foldables and landscape tablets (refs #286) #300 belong to this PR; it will rebase cleanly once feat: two-page EPUB spreads on unfolded foldables and landscape tablets (refs #286) #300 is merged.
• Compatible with the provider-module refactor: reader-only, uses the existing comic decode loader and page cache.
• Tests and manual-validation status are documented.
• No credentials, cookies, API keys, private server URLs, or generated local data are included.

Summary

On an unfolded foldable or a landscape tablet, paginated CBZ/CBR/CB7 shows facing pages like a printed book. The same Two-page spread when unfolded switch as EPUB controls it.

Piece	What it does
comicSpreads() pairing	Cover alone (setting Show cover alone, default on), double-page (landscape) images alone with the following pairs re-aligned, optional one-page shift (Shift page pairs), right-to-left libraries put the earlier page on the right.
ComicSpreadReader	Compose pager that replaces the Readium image navigator while a spread is active. It reuses the continuous-comic decode loader and LRU cache, decoding pairs at half width (at most two prefetch decodes at a time). Pinch-zoom works on the spread, and long-pressing a half exports that page. Tap zones, volume buttons and the page list move by spread. The footer reads Pages N–M of T.
Resume/progress	The spread's first page is persisted as the resume locator; the last visible page is reported as progress. Folding reopens on the first page of the spread; unfolding reopens on the spread containing the saved page. Detected wide pages are remembered per book (ComicWidePageStore) so a reopened book shows the same facing pages.
Hinge	A separating vertical hinge is kept free of artwork (readerSpreadGutterPx, hinge converted from window to reader coordinates); otherwise the pages meet with no gap. A hinge change re-measures the gutter without a rebuild.
Layout direction	The spread reader lays out left-to-right regardless of the device locale, because page order, swipes and hit-testing already follow the book's reading direction. Long-press undoes zoom/pan and splits at the actual gutter.
Lifecycle	Spread changes rebuild the reader in place only while it is started. A debounced change arriving after onSaveInstanceState waits for the next start instead of running a fragment transaction (that crashed the fork build).

PDF stays single-page. New test dependency: androidx.window:window-testing 1.5.1, used to simulate fold postures.

Verification

• ./gradlew :app:testDebugUnitTest — 1005/1005 pass (new ComicSpreadPairingTest, ComicSpreadLayoutTest, gutter cases in ReaderSpreadPolicyTest, comic settings in LibraryReaderPreferencesTest). :app:lintDebug — 0 errors. :app:assembleDebug succeeds. No added trailing whitespace; line endings preserved.

• Connected, Pixel Fold API 36 emulator unfolded (2208×1840):

  • New ComicSpreadActivityInstrumentedTest 4/4 — spread on the unfolded window and resume after recreation, a remembered wide page keeps the same pairs on reopening, setting off keeps the Readium navigator, rotate-to-portrait fallback.
  • New ComicSpreadReaderInstrumentedTest 12/12 — pairing, navigation, tap zones applied to the spread on screen, hinge re-measure, long-press in RTL books, an RTL device locale not mirroring the spread (fails without the fix), half-width decodes, pinch-zoom locking swipes, re-pairing after a wide page is found, and a wide page found elsewhere keeping the current spread zoomed (fails without the fix).
  • New ComicSpreadPostureInstrumentedTest 2/2 (window-testing fold postures) — a posture change after state is saved does not crash and is applied on return.
  • ReadiumComicOpenInstrumentedTest 7/8 (single-page cases pinned to a phone-sized window). continuousRemotePageAllowsChunkedResponsesWithoutContentLength also fails on main on this emulator. centerTapOpensComicChromeInTwoPageSpread failed once and passed on rerun.
  • EpubSpreadActivityInstrumentedTest 5/5 (no EPUB regression).

• Device: comic spreads are used on a Galaxy Z Fold8 from the fork build. This branch itself was run only on the emulator. Real hinge hardware with a side inset is not covered.

• Peer review (Codex GPT-6-Astra), four rounds. Findings, all fixed:

  • wide-page classifications were lost on reopening;
  • an RTL device locale mirrored the spread a second time;
  • long-press ignored zoom/pan and an off-centre hinge;
  • hinge bounds were used in window rather than reader coordinates;
  • a wide page discovered mid-swipe jumped back to the previous spread (no automated test, timing-dependent);
  • re-pairing reset the zoom but not the pan.

  Each round found new edge cases. The last round's fixes have not had a further review pass.

🤖 Generated with Claude Code

[van-geaux]

Thanks @chortya, the comic spread implementation looks good, and the test coverage is thorough. As this PR is stacked on #300, please rebase it after #300 is merged, resolve the remaining documentation conflict, and rerun CI. Once that is done, it should be ready to merge.

[chortya]

Rebased onto current main (with #300 and #301). The architecture doc conflict is resolved: the comic spread notes sit under the spread section, followed by the OLED section. CI is green.

[van-geaux]

Thanks @chortya, the comic spread implementation and test coverage look thorough, especially the hinge handling and spread re-pairing cases.

When reviewing the code, I found one account-isolation issue in ComicWidePageStore (ReadiumComicReaderActivity.kt:1390-1405). The stored wide-page classifications are keyed only by readerKey, which is built from book.id|fileId (BookOrbitApp.kt:785-790). If the same book or file ID exists on another server or account, it can inherit the previous profile’s wide-page classifications and produce incorrect spread pairing.

Could you scope this store key to the active server profile/provider, similar to the other account-owned reader state, and add a cross-profile regression test?

[chortya]

Thanks, good catch. Rebased onto current main and fixed:

• Wide-page store per profile: ComicWidePageStore is now keyed by the active server profile as well as book.id|fileId, the same ServerProfileStore.activeId() boundary the per-book EPUB language uses. A profile belongs to one provider, so that covers the provider too. The reader captures the profile when it opens. Saving an empty set now removes the entry.
• Cross-profile regression tests: ComicSpreadPairingTest checks the per-profile keys. In ComicSpreadActivityInstrumentedTest, widePageStoreKeepsProfilesApart checks the store, and widePagesRememberedForAnotherProfileDoNotChangeThePairs opens the reader with page 2 remembered as wide only for another profile and checks it pairs as if nothing were remembered (resumes on page 4, not 5). The existing same-profile test proves the remembered pages are still used.
• i18n: the spread footer ("Pages 2–3 of 40") and its spoken label, the "Show cover alone" and "Shift page pairs" settings, the page-load error, Retry, and the TalkBack page descriptions now use string resources with zh-CN translations. The localization validator and the new hardcoded-string guard pass.
• Rotation tests and target SDK 36: with targetSdk = 36, Android ignores requestedOrientation on large screens, so the comic and the already-merged EPUB "rotated to portrait" tests timed out on an unfolded foldable. Both now rotate the device through UiAutomation.setRotation and unfreeze rotation afterwards.

Verified: JVM tests, lint, androidTest compile, and all 25 tests in ComicSpreadActivityInstrumentedTest, ComicSpreadReaderInstrumentedTest, ComicSpreadPostureInstrumentedTest and EpubSpreadActivityInstrumentedTest pass on a Pixel Fold API 36 emulator; CI is green.

[van-geaux]

Thanks @chortya, the comic spread implementation and test coverage look thorough. I found no functional blockers in the source review.

Before merge, please remove these generated Python bytecode files from the PR:

• tools/__pycache__/test_validate_android_localizations.cpython-313.pyc
• tools/__pycache__/validate_android_localizations.cpython-313.pyc

The JVM tests, Android test compilation, debug build, and CI check pass. The connected tests were not independently validated on my attached Samsung device because Espresso failed before reaching the test assertions with the existing InputManager.getInstance reflection error.

[chortya]

Rebased onto current main again. The conflict was with #390: the comic footer now takes both showBorder and the spread page range, and the spread reader shares that one footer, so the border option applies there too. JVM tests, lint, androidTest compile, the localization and hardcoded-string checks, and all 25 comic/EPUB spread connected tests (Pixel Fold API 36 emulator) pass; CI is green.

[van-geaux]

Thanks, @chortya. The implementation and tests look good. Since the generated bytecode files are still in the PR, would you prefer to remove them in a follow-up PR after this one merges, or update this PR before merge?

[chortya]

Thanks, and sorry about that. They were Python __pycache__ files from running the localization validator locally. I removed them in this PR (62bef02), so they won't reach main; the PR diff now has no generated files. CI is green.

[van-geaux]

@chortya, I found no blocking issues. This PR looks ready to merge. Thanks for the thorough work and tests!