/// <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();
}
/// <summary>
/// Record the last saved zoom level, so that we can return to it if no activity for 1550 milliseconds
/// </summary>
public void DelayedSaveZoom1500Miliseconds()
{
if (!_timer1500Miliseconds?.Running != true)
{
_viewportZoomCache = CreateUndoRedoStackItem();
}
(_timer1500Miliseconds ?? (_timer1500Miliseconds = new KeepAliveTimer(TimeSpan.FromMilliseconds(1500), () =>
{
if (_undoStack.Any() && _viewportZoomCache.Equals(_undoStack.Peek()))
{
return;
}
_undoStack.Push(_viewportZoomCache);
_redoStack.Clear();
_undoZoomCommand?.RaiseCanExecuteChanged();
_redoZoomCommand?.RaiseCanExecuteChanged();
}))).Nudge();
}
public bool Equals(UndoRedoStackItem obj)
{
return(Zoom.IsWithinOnePercent(obj.Zoom) && Rect.Equals(obj.Rect));
}
public bool Equals(UndoRedoStackItem obj)
{
return(Math.Abs(obj.Zoom - Zoom) < Zoom * .01 && Rect.Equals(obj.Rect));
}
