MeldUI

Plugin: History

Undo / redo stack for annotation operations.

The History plugin tracks annotation mutations (create, update, delete) on a stack and powers undo / redo.

Enabling flag

features.undoRedo: true — auto-enabled when features.annotations is on.

What it does

  • Pushes a history entry for every annotation create / update / delete
  • Undo / Redo toolbar buttons
  • Ctrl/Cmd + Z / Ctrl/Cmd + Shift + Z keyboard shortcuts (when features.keyboardShortcuts is on)
  • Stack is per-document and cleared when source changes

Composable

useHistoryCapability() from @embedpdf/plugin-history/vue. DocumentViewer re-exposes undo, redo, canUndo, canRedo on its instance.

Events

None surfaced externally — toolbar state observes canUndo / canRedo reactively.

Dependencies

  • annotation (the source of historical operations)

Configuration

No featureConfig.

Scope

Phase 1 history covers annotation mutations only. Document-level operations (zoom changes, page navigation) are not undoable. Phase 2 may extend to redaction-apply and signature-place operations.

When you’d touch it directly

To clear the history (e.g. after loading saved annotations so the load isn’t undoable):

import { useHistoryCapability } from '@embedpdf/plugin-history/vue'

const hist = useHistoryCapability()
hist.provides.value?.clear()

See also

Introduction