Canvas size: Is it the size of the front face or does it include the wrapped edges?

[gleamweather]

I'm trying to make a wrapped canvas product, but I can't quite get the dimensions right.  When it says 36" x 12", what is it measuring?

1. Is the front face 36" x 12", so you have to add some extra margin around the image for the wrapper?
2. Is the whole printed canvas 36" x 12", so the actual front is smaller than that?

[BKMuir]

When you are in the design mode, you will see a green line around the print area - this is what will show on front of canvas (the dimensions you choose). If you want the image to wrap around the edges, just size the image to fill the entire design area (outside of the green lines).