Undo

Show the state before the step shown now, as the State panel's Undo does; the step stays in the history, to redo.

Usage

cellucid_history_undo(viewer)

Arguments

viewer

A viewer cellucid_view() or cellucid_serve() returned.

Value

A cellucid_action_request, at once and invisibly: the action is sent now, or when the viewer's channel opens. cellucid_action_result(request) returns its outcome: a list of head (The step shown now), moved (Whether the history moved: not when there was no step to move to (nothing to undo, or nothing to redo)).

Details

The viewer's action history.undo (History). It moves the viewer's history, as the person's Undo, Redo or a click on a step does: it makes no step of the history.

See also

cellucid_act() sends any action by its type, and cellucid_action_result() collects its answer.

Examples

if (interactive() && requireNamespace("SeuratObject", quietly = TRUE)) {
  data("pbmc_small", package = "SeuratObject")
  viewer <- cellucid_view(SeuratObject::UpdateSeuratObject(pbmc_small))
  request <- cellucid_history_undo(viewer)
  print(request)
  # cellucid_action_result(request) waits for its outcome.
  cellucid_stop(viewer)
}