Rotate-able tiles

It would be helpful to be able to rotate the orientation of a type of floor tile before dropping it. For example, the other day I wanted to use the Farmland tile to hint and a line across the floor where a swinging blade trap had etched into the floor. However, I had to completely re-orient the room so that the blades would match the direction of the lines on the tile. I'm surprised this isn't already an option, considering the tile rotates on the preview when you select it.