For those of us brought up on classic Disney animation - from the first, Snow White and the Seven Dwarfs, through The Jungle Book and Lady and the Tramp to, more recently, The Lion King and Beauty and the Beast - it’s sad to think that a whole generation of children have seen animated films only through CGI and Pixar. But now comes The Princess and the Frog, Disney’s first entirely 2D, hand-drawn animation since 2002, which, with its sumptuous drawings, soft colours and Jazz Age setting, could almost be seen as a retro exercise.