Unified Undo / Redo Timeline

Status: placeholder — content pending. Fill freely in English or 中文.

Scope

The single backend history timeline (stage 2 consolidation):

flowchart LR
    E1["paint"] --> T["ONE timeline<br/>history.rs"]
    E2["fill"] --> T
    E3["erase"] --> T
    E4["manual edits"] --> T
    T --> UN["undo"]
    T --> RD["redo"]
    T --> ST["history_state"]

Topics to cover: undo / redo / history_state covering paint, fill, eraser and manual region edits; the deleted former manual_region_undo / restore_face_colors commands (no parallel history paths); frontend useHistory wiring; how snapshots stay memory-bounded on 1.5M-face models.

Code pointers

• src-tauri/src/commands/history.rs · src-tauri/src/mesh/history.rs
• src/hooks/useHistory.ts

TODO

• Memory model per snapshot (what is stored, coalescing rules)
• Interaction with segmentation resets