/// <summary>
/// Record the last saved zoom level, so that we can return to it if no activity for 750 milliseconds
/// </summary>
public void DelayedSaveZoom750Miliseconds()
{
if (_timer750Miliseconds?.Running != true)
{
_viewportZoomCache = CreateUndoRedoStackItem();
}
(_timer750Miliseconds ?? (_timer750Miliseconds = new KeepAliveTimer(TimeSpan.FromMilliseconds(740), () =>
{
if (_undoStack.Any() && _viewportZoomCache.Equals(_undoStack.Peek()))
{
return;
}
_undoStack.Push(_viewportZoomCache);
_redoStack.Clear();
_undoZoomCommand?.RaiseCanExecuteChanged();
_redoZoomCommand?.RaiseCanExecuteChanged();
}))).Nudge();
}
/// <summary>
/// Record the previous zoom level, so that we can return to it.
/// </summary>
public void SaveZoom()
{
_viewportZoomCache = CreateUndoRedoStackItem();
if (_undoStack.Any() && _viewportZoomCache.Equals(_undoStack.Peek()))
{
return;
}
_undoStack.Push(_viewportZoomCache);
_redoStack.Clear();
_undoZoomCommand?.RaiseCanExecuteChanged();
_redoZoomCommand?.RaiseCanExecuteChanged();
}
/// <summary>
/// Jump back to the previous zoom level, saving current zoom to Redo Stack.
/// </summary>
private void UndoZoom()
{
_viewportZoomCache = CreateUndoRedoStackItem();
if (!_undoStack.Any() || !_viewportZoomCache.Equals(_undoStack.Peek()))
{
_redoStack.Push(_viewportZoomCache);
}
_viewportZoomCache = _undoStack.Pop();
this.AnimatedZoomTo(_viewportZoomCache.Zoom, _viewportZoomCache.Rect);
SetScrollViewerFocus();
_undoZoomCommand?.RaiseCanExecuteChanged();
_redoZoomCommand?.RaiseCanExecuteChanged();
}