Hi T N,
For now, as Boby said in his previous post, you can implement your own custom tool which provides the desired functionality, because such a tool is not currently available in RadImageEditor.
However, it's logged in our backlog and here is the related item
in our feedback portal, so you can vote for it. I suggest you to subscribe to the item in order to track its progress.
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.