Module undo 

Undo service, commands and other types.

The UNDO service can be used to operate the contextual undo stack, you can also use the service to implement undo/redo for any variable using UNDO.watch_var. The UNDO_CMD and REDO_CMD commands can be used with undo_scoped to control the focused undo scope. The history::UndoHistory! widget visualizes the undo or redo stack of the focused undo scope. The example below demonstrates all of this together to define two widgets that undo and redo and shows the history in a drop-down.

use zng::prelude::*;

fn undo_combo(op: zng::undo::UndoOp) -> UiNode {
    let cmd = op.cmd().undo_scoped();

    Toggle! {
        style_fn = toggle::ComboStyle!();

        widget::enabled = cmd.flat_map(|c| c.is_enabled());

        child = Button! {
            child = cmd.flat_map(|c| c.icon()).present_data(());
            child_spacing = 4;
            child_right = Text!(cmd.flat_map(|c| c.name()));
            tooltip = Tip!(Text!(cmd.flat_map(|c| c.name_with_shortcut())));
            on_click = hn!(|a| {
                a.propagation().stop();
                cmd.get().notify();
            });
        };

        checked_popup = wgt_fn!(|_| popup::Popup! {
            child = zng::undo::history::UndoHistory!(op);
        });
    }
}

Wrap! {
    spacing = 5;
    zng::focus::alt_focus_scope = true;
    children = ui_vec![undo_combo(zng::undo::UndoOp::Undo), undo_combo(zng::undo::UndoOp::Redo),];
}

Full API

See zng_ext_undo for the full undo API.

Modules

history

Undo history widget.

Structs

UNDO

Undo-redo service.

UndoActionMergeArgs

Arguments for UndoAction::merge.

UndoMix

m Undo scope widget mixin.

UndoStackInfo

Snapshot of the undo or redo stacks in an UNDO scope.

UndoTransaction

Represents captured undo actions in an UNDO.transaction operation.

UndoVarModifyTag

Identifies var modify requests by undo/redo action.

WidgetUndoScope

Represents a widget undo scope.

Enums

UndoFullOp

Represents a full undo/redo action.

UndoOp

Represents an undo/redo action.

Statics

CLEAR_HISTORY_CMD

Represents the clear history action.

REDO_CMD

Represents the redo action.

UNDO_CMD

Represents the undo action.

Traits

CommandUndoExt

Undo extension methods for commands.

RedoAction

Represents a single redo action.

UndoAction

Represents a single undo action.

UndoInfo

Metadata info about an action registered for undo action.

UndoSelect

Selects actions to undo or redo.

UndoSelector

Represents a type that can select actions for undo or redo once.

WidgetInfoUndoExt

Undo extension methods for widget info.

Functions

undo_enabled

P Enable or disable undo inside the widget.

undo_interval

P Sets the time interval that undo and redo cover each call for undo handlers in the widget and descendants.

undo_limit

P Sets the maximum length for undo/redo stacks in the widget and descendants.

undo_scope

P Sets if the widget is an undo scope.