Add a manual clone tool so that the users can fix up before or after processing

Like the tool in other editors, you have two cursors which are fixed relative to each other. One cursor reads the pixels behind it, the other copies those pixels when the mouse button is pressed. You also need the ability to move the "from" cursor and to change the size of the brush.
The net result is you can replace unwanted areas with precisely the part of the image you want. Very useful when the inpainting just can't get it right.