iOS OpenGL Texture Map to distort images

I am looking for a quick simple app that takes an image, converts it to an OpenGL texture map which can be morphed or pulled to distort the image . An good example would be a PaintShop Pro Pinch filter. Essentially, the filter can pull the image inward. The effect should distributed evenly throughout the image without drastic warping. If the effect can be achieved another way that is fine instead of OpenGL texture / map. See the attached image. The effect should be transformable using a UISlider control. Should be able to touch a specific point on the image to attach the effect to.