ImageMagick / Magick.NET knows nothing about 'shapes'. It can create images of the frames but knows nothing about individual points. This information is probably hidden in the metadata. I might be able to help you find it if you share a link to your image. But you will have to figure out how to interpret it yourself.
You could also add a clip mask to your layer, but I am not sure if ImageMagick reads clip mask for individual layers.
You could also add a clip mask to your layer, but I am not sure if ImageMagick reads clip mask for individual layers.