Your sewing area is so great with all that light. What I see is your GAS FIREPLACE. The pilot light is on and warm. I think this is why your long rulers are warped. It doesn't take a lot of heat, but just steady heat. I'm so sorry, have you thought about turning your rulers over and hang them again in the same places to try to warp them back. Good luck, but I would move all of the rulers away from the fireplace.