Reordering pages (manual + auto)

Scans often arrive out of order — flipping a book, retaking a bad scan, batch-importing photos. Two ways to fix it.

Manual reorder

Tap the Move icon in the project header. Every page card becomes draggable. Drag to rearrange, then tap Save order at the bottom (or Cancel to bail).

The save is atomic — either every page moves to its new number or nothing does. No partial state to clean up.

Auto-order (layout-aware)

Tap the ArrowDownUp icon. The app calls Google Vision on each page image, finds text tokens in the top 12 % or bottom 12 % strip that look like short numeric page numbers, and proposes an ordering that puts:

1. Front matter (numberless pages in the first 15 % of scan order)
2. Body (sorted by the detected page number)
3. End matter (numberless pages in the last 15 %)
4. Unknown pages (numberless middle pages — figure plates, etc.)

An "Analyzing pages…" overlay shows while it runs (~1 min per 100 pages on the first run). Subsequent runs are instant because detected numbers are cached on each page row.

You get a confirm dialog with a summary ("Detected numbers on 236 of 409 pages. The remaining 173 will be placed based on scan position.") before anything moves.

Why the layout-aware version works better than text search

Page numbers print in the corner as short standalone tokens. Ordinary OCR text jumbles them among body prose where "42" could be a chapter reference. The layout-aware version only looks at the top/bottom marginal strip of the page image, so "42" alone in the corner is unambiguously the page number.