If you’re doing 2D gaskets, a 3D scanner is definitely not what you want, because it does not have the sub-millimeter-scale resolution and accuracy required to put the holes in the right place.
It is not clear to me what an iPad brings to the table, but if it’s a camera then there are much much less expensive and more convenient ways to take pictures.
In point of fact, any camera will do what you want. Position the gasket on a flat surface, take a picture from directly overhead, scale the image to the proper size, and you’re done: