I have some photos of framed paintings that were taken slightly off-centre in both horizontal and vertical directions. This results in a trapezoidal shape and I can't completly square it up using combinations of vertical, horizontal and rotation corrections. I beleive the reason is that LR assumes the edges incline equally about the mid-line of the photo, but that is not the case in my pictures, probably due to the closenes of the camera to the subject. See image.
In Corel Paintshop Pro there is a tool that allows me to click on the 4 corners of a trapezium and it transforms it to a perfect rectangle. Is there a way of achieving this in LR4? 